The China steel structure components production of steel and steel castings varieties, specifications, performance

Quality of imported steel products should meet the requirements of the standards of design and contract provisions. Variety of welding materials, specifications, and performance should be consistent with the current national standards and design requirements. Steel connection connected with high strength large hexagon head bolts Vice torsional shear type high strength bolts connecting Vice steel grid with a high-strength bolts, common bolts, rivets, self-tapping screws, pop rivets, Nailing, riveting bolt (mechanical type and the formula dosage forms), foot riveting bolt fastening standard parts and nuts, washers and other standard accessories, varieties, specifications, performance should be consistent with the current national standards and design requirements. High strength large hexagon head bolts connection deputy China steel structure and torsional shear type high strength bolts connecting the factory should be, respectively, with the box with torque coefficient and fastening axial force (pre-tension) inspection reports.

The welders must, pass an examination and obtain a certificate of competency. The permittee the welder must in passing the examination of the project and its scope of accreditation welding. Design requirements for full penetration of the two weld ultrasonic inspection for internal defects inspection, ultrasonic inspection can not make judgments on the defects, should be used ray detection the internal defect classification and testing methods should be consistent with the current national standard "ultrasonic testing of steel weld by hand methods and classification of testing results Act "GB1135" steel melt welded butt joints radiographic inspection and classification of "GB3323 requirement.

Steel columns, steel girder webs material should pay attention to the cross-sectional dimensions of change, allowance should be left at both ends the beam weld using automatic submerged arc welding, welding sequence according to the welding process requirements of the order. Hole, all connecting plate, gusset plate must be paired drilling hole on accuracy should meet the specification requirements. The anticorrosion coating: shot blasting reach ST2 level. The surface of the component should not China steel structure mistaken coated friction connection (especially face), drain coating, the coating should not be peeling back to rust. The coating should be uniform, no obvious creasing flow fall, such as pinholes and bubbles. Steel structure components factory inspection and No. No. generally marked the axis of the column number, overweight super long the components sometimes also marked the position of the center of gravity of the weight and lifting. The difference of the light steel and heavy steel truss steel structure construction process

China steel structure the altitude assembly method according to the structure type and construction conditions

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Application and development of the grid steel structure report

The grid structure of the spatial structure of the most widely used type, medium and small span are applicable. steel structure called the grid structure that is flat grid. Surface grid that reticulated shells. The three types of single, double and multi-layer network structure. The most commonly used is a double, rarely used monolayer, when the span is large (e.g. 100 meters) can be used three grids. The grid structure has unique advantages over other spatial structure, the first in our applications, so far applications are most widely used up to the fast pace, large scale, the sheer number, called the world grid large country. The grid structure development began in the 1960s, first built in Shanghai a leaf node grid, followed by a 1965 study successfully welded hollow spherical joints grid. Welded hollow spherical joints is simple, has many advantages, grid structure soon in our country to promote them bolted spherical joints grid over time. Both node has its own advantages, neck and neck have been widely adopted.

Grid provisions in China's "network structure design and construction rules in the form of 13, depending on the span, flat shape and purpose and the use of different forms of grid. Square or rectangular plane is the most commonly used is a positive square pyramid, is put to find time PYRAMIDIC and the diagonal square pyramid grid, sometimes two of orthogonal and two the orthogonal diagonal mesh frame; circular or hexagonal plane, commonly used three-way triangular pyramid and taking the time to triangular pyramid grid. The other two diagonal Bias, checkerboard, star PYRAMIDIC, honeycomb grid is not commonly used on the plane for the long and narrow one-way mansard more economical and reasonable.

In addition to the double-grid three grid more applications in large span. Three grid stiffness segment uniform internal force, and reduce the internal force peak, short rod and mesh the advantages of small capital airport hangar, Changsha Huanghua Airport hangar and Guixi Power Plant dry coal shed three-tier grid. The double grid winding instead of the concrete slab, and the combination node instead of winding node is a combination of network structure, and many buildings have been built in our country.

First is the design of the grid in Wangjiagongcheng grid is calculated according to the span size, grid type and Engineering require precise calculation method (the space trusses displacement method) or the simplified calculation method (such as differential method, sandwich plate method imaginary moment method) to calculate the internal forces and displacements simplified calculation method has also published some form for the look-up table to calculate. Later, the rapid development due to a computer, the Computer technical strength and growth, basically accurate method without approximation. Computer not only theoretical analysis but also to optimize and construction plans drawn. Computer software applications has become popular in the various units of the country. Zhejiang University, Tongji University, Tianjin University, Shanghai Jiaotong University, the best software today also unveiled.

With good design after grid construction is very important. The grid construction combined with China's specific situation many earth approach, as well Tuyangjiehe way, bolt ball node grid use more high-altitude bulk method (full house steel structure node grid of solder balls to use more artificial winch pull lever lifting the overall law, small and medium-sized span of 2 to 4 uprooted rod can be used, a larger span of 13 uprooted lever can be used, the Shanghai Hongkou Stadium 17 uprooted rod, while up to 27 uprooted Terra-Cotta Warrior Museum II Museum rod are using artificial twist, these indigenous methods both effort and smooth, low-cost construction, in line with China's national conditions. Other lifting methods of summed up over the years more mature 7 has adopted specification: altitude bulk method - small fight unit or rod assembled directly at high altitude; slitting or block installation method - grid divided into the strip unit or block unit integrally connected at high altitude; sliding method - a single slip gradually accumulated slip and carriage law; overall lifting method - single or uprooted rod lifting, can also be used a one or more cranes lifting; the overall upgrade method - lifting equipment installed in a structure to enhance grid, while improving the grid can also be conducting column slipform construction, the structure can be used as the operating platform; overall jacking Law; overall fold l law - the like the internationally famous climb up to the dome Act (Pantadome).

Grid ability to promote the use of mainly rely on what node in the grid structure engineering grid node is the most critical component. Of the most common node is welded hollow spherical joints and bolted spherical joints, other board node specification has been satisfied with, but not actual engineering using; intersecting node in the grid is not very suitable, suitable for triangle space truss. China has built the grid of the various forms of thousands of seats, many worth mentioning the typical Wangjiagongcheng, industrial plants, aircraft hangars, terminal, railway stations and other types of representative works include: the FAW the Volkswagen PQ35 project final assembly workshop Yunnan Yuxi Cigarette Factory, the capital airport bit steel structure, Capital Airport Terminal T3A, Shenyang Expo Center are more successful grid structure engineering, and to some extent, promote technological progress of China's grid structure engineering .

Fireproof coatings use of countermeasures

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Rise steel engineering cranes installed

Rise steel major mechanical installation of tower cranes. The selection should be based on the structure of planar geometry and dimensions, components, weight, etc.. Tower crane choose the general case, as far as possible outside with cranes, easy disassembly. Elected tower crane attached to the outer, Taki optional in the basement or another Taki; elected with climbing tower, tower cranes generally located at the elevator shaft. The position and performance of the choice of the position and performance of the tower crane tower crane should be able to meet the following requirements:
1) To make the length of the arm has enough surface coverage (buildings);
2) have sufficient crane capacity, to meet the requirements of the different location component lifting weight;
3) tower crane wire rope capacity to meet the requirements of the lifting height and lifting capacity; the steel engineering  speed have the grades to meet installation requires;

4) multi-machine operation, should be considered: When the tower crane is horizontal arm, the arm must have enough height difference, not collision should be adequate safety distance between each tower crane capable of safe operation to ensure the interoperability of the arm with the tower collision; crane jacking jacking, anchoring, or climb the tower crane, anchor or climb should consider the following questions: 1 attached to the outside of tower crane hook height shall meet the requirements of the height difference between the mounting height and tower crane, and in accordance with the tower crane tower body to allow the free height to determine the anchoring number of times. The anchor point of the tower crane should be conducive to the strengthening of steel structures, and the first to form the framework of the overall structure conducive to the curtain wall installation site. Anchorage points should be calculated. Within the climbing tower crane tower crane climb the position should meet the the tower free height and steel structure of each section of the column unit installation height requirement. Should be calculated to determine the inner climbing tower crane base with steel beam - column connection method. Climbing tower crane location within the steel structure, should climb before welding is completed, to form a whole.
Li, dismantle the tower crane Notes

1) selection of tower crane legislation to consider the construction site, the demolition of the condition of the tower crane.
2) legislation tower.steel engineering  attached tower crane in deep foundation pit slope established tower, Taki can choose according to the specific circumstances of stationary or walking base, but to consider the foundation pit slope stability, to consider the value of the maximum wheel pressure and appropriate safety measures . Within the climbing tower stand tower can be used inside buildings and steel on the platform.
3) The demolition of the tower. Externally attached tower crane, the main consideration should be given to the impact of the construction of high-rise buildings housing the demolition of the tower. Within the climbing tower demolition to rely on the the roof crane disintegration, so to be considered buried shall not be greater than the carrying capacity of the steel structure of the roof hanging maximum the wheel pressure value and track.
4) Where the legislation, dismantle the tower crane caused the pit, the additional load of the steel structure, shall require the prior structure checking.

The Comparison of the Series of the light steel structure workshop

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light steel structure CAD software functions and applications of the STS

Construction steel has the advantage of also becoming more prominent. The improvement of the quality of steel, the type of the rich, the perfection of the design theory for the development of the steel structure to lay the foundation, steel, up especially light light steel structure in China's rapid development. CAD technology development and to promote the success to complete the steel structure of the computer analysis by means of computer-aided design software to optimize the design and drawing work, on the one hand, can provide accurate calculations and drawing tools to the engineering design and improve design efficiency, safer design economic,
The other hand, will also play a significant role in promoting the further development of the steel structure. PKPM Series software is the most widely set of integrated CAD software, won the National Science and Technology Progress Award, is the only independent platform for the computer-aided design system, has now become a including architectural design, structural design, equipment design, integrated CAD system, including the multi-storey and high-rise, industrial plants and civil construction, superstructure and all kinds of basic structural design, and are to the development of integrated and intelligent direction. In this case, the China Academy of Building Research PKPMCAD engineering department from May 1995 to organize forces to study the STS steel structure CAD software to develop their own copyright, independent development of the software development to PKPMCAD Engineering Department of CFG Chinese graphics support system as a platform, to PKPM Series software PMCAD PK based. The functional requirements of the STS: the integration of CAD software, features include input from the steel building model, the cross-section optimization, structural analysis, component strength and stability checking, node design, draw until the construction details; software is applicable to multi- , high-level framework, plane frame, continuous beam, light steel portal frame, bent frame, frame - bent,
Steel truss and other structural forms; software requires simple operation, high degree of automation, user-friendly, easy to learn and use; construction drawings detailing standard drawings shall prevail, and provides convenient editing tools; software module PKPM series can interface with other modules; first STS become mainstream domestic steel CAD software, and then expand the foreign version of the specification, the international software market. 2STS software technical conditions as a professional steel structure engineering design software, must comply with the existing national norms, rules and standards. The STS software development based primarily on: the cold-formed steel design specification of the design of steel structures (GBJ17-88) (GBJ18-87) "Tall Buildings steel structure technical regulations" (JGJ99-98) "door frame light house steel structure technical regulations (CECS102: 98) light steel structure design point of order "(DBJ08-68-97) In addition, STS software follow the commonly used steel structures design manual, the provisions of the standard map. The About 3STS software function 31 model input STS model inputs can be used three-dimensional and two-dimensional methods.
The use of interactive three-dimensional modeling, guiding the user layer by layer the layout layers plane and floors, and then enter storey establish a description of the overall structure of the building data, three-dimensional modeling program has strong load statistics and conduction calculation function, in addition to the calculated weight, also done automatically calculated from the floor to the light steel structure beam, secondary beam to the main beam, main beam to the load-bearing columns, walls, and then spread from the upper structure based plus part of the applied load, can be easily established throughout the building load data. Section type of three-dimensional modeling of China and the world standard section steel composite section, welded H-beam (including a wedge-shaped cross-section), custom cross-section of the tube, box-shaped, Z-shaped, grooved steel pipe, concrete, steel reinforced cross-section in the form of concrete section, applicable to the needs of the various structural forms. Two-dimensional modeling data that can be generated by the three-dimensional modeling of the data plane frame, continuous beam data file automatically generated can also employing machine interaction to generate convenient to establish the model of the plane frame structure. Two-dimensional human-computer interaction modeling framework, portal frame, bent frame bent, continuous beams, trusses, brackets, continuous beam, a variety of structural forms of model can create various types of plane frame gantry frame, frames, trusses, curved axis also provides fast input wizard to quickly enter, you can enter a variety of roles in the form dead load, live load, wind load (can automatic layout), crane load (including pumping pillar crane load) parameters calculated and seismic.
Section type in addition to the type of cross-section of the three-dimensional modeling, two-dimensional modeling to provide the type of cold-formed steel composite section, solid web composite section, lattice composite section, composite beams, arbitrary cross-section. 32 the section optimization-section optimization is to meet the specification requirements, looking for the smallest amount of steel section size. STS software can light steel portal frame and steel truss section optimization. Gabled frames are often used in the variable cross-section member, so the constraint variables are optimized big endian, the height of the small end, the upper and lower flange width, thickness, web thickness, seven factors, STS software can be in the range of variation of the automatic or manual definition inner and quickly find the smallest cross-sectional dimension of the amount of steel. The truss optimization can be carried out lever member packet, divided into a group of the lever member has the same cross section after optimization. The optimization procedure is faster and better applicability. The 33 structure analysis and member checking STS three-dimensional, two-dimensional modeling data can interface three-dimensional analysis procedures and plane frame analysis program for structural analysis and member checking.

light steel structure Engineering and the Built Environment

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New technology -steel structure warehouse following the concrete technology

The new technology of concrete in the steel structure of the building in the traditional, most concrete technology. In the building now, concrete technology has been rare. More and more steel structure warehouse  in the construction of a wide range of application. It is understood that in summing up the past major construction process in the experiences and lessons of the technical issues,

Steel structure engineering of new materials, manufacturing process, the installation program, application technology research is currently under construction, face new challenges and new challenges, learn new construction techniques and construction methods. Steel structure housing construction technology compared with other concrete technology, design technology is not important, relatively speaking, material, theory in the design of the research phase is well engaged in the construction aspect is concerned with the concrete as well as other aspects of construction difficulty and problems encountered in a little more

Many areas to re-examine the new understanding, especially since the recent situation of many of the new steel structure warehouse in the country generally build up a lot of new construction. Toward highly integrated building technology, many industries need a lot of technical, need to combine, under the present conditions, and energy conservation, the environment, the combination of this seminar is from more structural technology, construction and installation, welding, etc. discuss, which is the most basic and fundamental essence, throughout construction science, construction environment far not to these areas, the steel structure is also combined with the built environment. The environment created, this is a big premise can not be changed.

Superfinishing surface quality influencing factors and control measures

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To detectsteel structure steelwork content and method

steel structure engineering major test content: scantlings and flatness detection; component surface defect detection; detection of the connection (welded, bolted); steel corrosion detection; the fire coating thickness detection. If the steel factory certification, or have doubts about its quality, should increase the mechanical properties of the steel test necessary to detect its chemical composition. Keywords: detection Steel Engineering steel structure used in the member is generally from steel mills mass production, and the need for compliance certification, and therefore, the strength and the chemical composition of the material is a good guarantee. Engineering detected focus quality problems generated in the installation, splicing process.
A major test content, steel works: scantlings and flatness detection; component surface defect detection; detection of the connection (welded, bolted); steel corrosion detection; the fire coating thickness detection. If the steel factory certification, or have doubts about its quality, should increase the mechanical properties of the steel test necessary to detect its chemical composition.
Second, the steel structure of the application of the test specification range of knowledge
Third, each size of the detection of the component size and flatness in the three parts of the member measured, taking the average of the three as a representative value of that size. The steel member the size of the deviation should be calculated on the basis of a predetermined size of the design drawings the the size deviation; deviation allowable value should be consistent with its product standards requirements. The beam vertical steel structureplane deformation and plane lateral deformation and the deformation of the truss members, so you want to detect both directions flatness. Deformation of the column tilt and deflection of the pillar. First visual check, anomalies or doubt on the beam, truss member fulcrum tensioning a wire or thin wire, and then measuring the vertical deviation of the points; theodolite column tilt available or lead vertical measurement. The column flexural member fulcrum tighten a wire or thin wire measuring four components detection of surface defects - Magnetic Particle Testing 1, the basic principles of magnetic particle inspection applied magnetic field on the magnetization of the workpiece (only ferromagnetic material), If there is defect, the magnetization of the workpiece after its various parts of the basic magnetic properties, while the presence of defects such as cracks, pores, or a nonmetallic substance slag, since they will be on the workpiece caused by the air gap or non-magnetic gap, so that the reluctance of the defective portion is greatly increased, the normal propagation of the magnetic lines of force in the workpiece has been the barrier, in accordance with the principles of the magnetic continuity, then the lines of magnetic force of the magnetizing field to be forced to change the path of escaping the workpiece, and the leakage magnetic field is formed in the surface of the workpiece . 2, the leakage magnetic field strength depends mainly on the degree of influence of the magnetic field strength and defects for the vertical section of the magnetizing field. The use of magnetic leakage magnetic field given show or measured, to analyze the presence or absence of defects judge its position and size. The ferromagnetic material powder is sprinkled on the workpiece, is adsorbed on a position of the leakage magnetic field of the magnetic powder, thereby forming the shape of the display defect of the magnetic marks, the detected defects can be more intuitive. This method is the application of the first and most widely destructive testing methods. Magnetic Particle general industrial pure iron or iron oxide production, is usually made of iron oxide (Fe3O4) powder of fine particles as magnetic particle. Magnetic particle fluorescent magnetic particle can be divided into two categories of non-fluorescent magnetic particle, fluorescent magnetic particle in ordinary magnetic powder particles coated with a layer of fluorescent material, so that it can emit fluorescence under UV irradiation, the main role is to enhance the contrast easy observation.
Magnetic particle testing is divided into two kinds of dry and wet: dry - the magnetic powder directly sown in the workpiece surface. For ease of powder particles to roll to the leakage magnetic field, the magnetic powder particles used in the dry assay usually larger, so the detection sensitivity is low. However, when wet with water or oil contact, the test piece, such as a higher temperature, then only the wet method is not allowed in the workpiece. Wet - magnetic particle suspended in a carrier liquid (water or kerosene, etc.) formed among the magnetic suspension is sprayed to the surface of the workpiece, when the magnetic powder by means of the good characteristics of liquid flow, and can be relatively easily to weak The leakage magnetic field while moving the wet good fluidity and can be employed than the dry method is more fine magnetic powder, so that the magnetic powder and slight leak magnetic field easier by the adsorbent, and thus a steel structure detection sensitivity of the method of the wet Bigan. 3, applied to the general magnetic particle inspection program (pretreatment - magnetization - magnetic particle - Observation records) · pretreatment component surface grease, paint and rust removed, so as not to affect the magnetic particle attached to the defect. · Magnetized choice of appropriate magnetization method and the magnetization current, power, the magnetization is performed on the member.
Vibration Stress Relief equipment on the benefits of casting, welding and other components：http://structureworkshop.blogspot.com/2012/12/vibration-stress-relief-equipment-on.html

Steel structure design to solve structural problems of common problems to solve other problems.

One, if there is a gutter, tied not to cling to the top part, or may lead to installation of the water pipe.In addition the gutter downspouts and tied and the column brace position must consider well, otherwise either tied or meet, meet braces between columns.

In two, steel structure warehouse strength bolt position must be reasonable, steel structure engineering should consider twisting device and a torque wrench construction space, not at the time of installation, because the space is too small, twisting device and a torque wrench can not in place, resulting in high strength bolts plum head to break or to tighten high strength bolts.Once met some design and the position of the sleeve will not give.Three, the party's "load data" must understand its true meaning, because the party often do not understand these things too specialized.We should accomplish transposition thinking, preliminary work done, follow-up is well developed.In four, high strength bolt connecting plate if possible, steel structure housing as a symmetrical upper and lower bolt layout method.Once in contact above 4 to below 6, shop workers take part installed do not care to be reversed, at the site of sorry to.Five, wind-resistant column and steel beam connection as a spring board connection, because the middle cross beam after the installation of deflection is bigger, Liang Ruo of bolts and wind-resistant column connection, will cause the roof.

Six, do not one-sidedly in purlin brace hole on account of "tension side pressure side," and other factors, hit the top and bottom margins ranged from the hole, because the installation is easily reversed, but the results of adverse.

In seven, a horizontal support a flower basket bolt location arrangement must be reasonable, do not stray too far from a girder, should consider convenient installation.Otherwise, workers in the installation must be bent to tighten the screw bolt or ladder up, or after the purlins mounted climb purlin tightening screw bolt which is not safe.In addition to consider brace layout position, not in the layout of horizontal strut and bracket.

Eight, windows and doors of angle plates can lump together in construction, because you could not guarantee that plate in the pressure plate crest or trough.

Nine, do bar window apron plate stiffener toward the window direction, so the bar window to the floor, do not go past.In the bar the purlins mounted window to use countersunk head screws.

In ten, the anchor bolts are steel structure warehousegenerally buried civil unit, manufacturer of steel structures of a map, they can sometimes turn bolt location turned 90 degrees, and reexamination, it was too late; and size deviation give you an offset of 50~100mm is not strange.So in the former construction must be reminded, preferably clarification on the basis of language (self protection).In eleven, large project, deepen the figure number must take into account the production, delivery, installation convenience.

Twelve, roof purlin layout and steel detailing should check seriously, often found roof purlin layout and steel detailing the purlin number disagreement.

In thirteen, the node board without stiffening ribs, some designers are not designed for, leading to subsequent welding, node plate deformation.

Fourteen, beam column do tie connecting plate, no holes extended in some places appropriate, because the tie-bar connecting plate on too long, resulting in too small space, tied too long to fit inside.Some secondary beam structures often have this case.In fifteen, light steel structure if maintenance brick wall, must advance with the construction unit and construction unit butt good, because it relates to the construction of steel structure and the problem of two respects, because civil brick probably do not straight, but the color steel plate flashing and could not do suddenly large and small, the result is the color steel and brick wall crack suddenly large and small, color steel plate and the brick wall water treatment is very difficult to do well, make construction unit of a prepared mind.

In sixteen, the upper bar window and door frame too close, no room for Hupon.

In seventeen, the window frame adjacent purlin distances without brace layout, bar end head and the window frame conflict.
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The Superfinishing metal shaping tool

There are no high-strength steel. There is no high-strength tool if people encounter the word "steel", just as the term "high intensity" encounter. On the market, especially in the automotive industry, the increasingly strong demand for high-strength steels, and the need for better performance and economy. However, the wear in the process has been more serious. Processing of conventional high-strength steels tool life how long?Although these tools typically have surface expensive coating, but its life is not long enough. Until the new tool steel in order to ensure that the tool has a more economical, longer service life. For example, after the after heat treatment "integrated coating" on the tool can continue to be used for processing. Proposed new requirements necessary tool manufacturing and vehicle production process in order to continue to reduce the weight of the car. Metal processing requires the use of new high-strength materials and innovative tool, inSuperfinishing to achieve a controlled, inexpensive production process. For example, if people compare the proportion of high-strength steel used in the old and new generations Volvo S40 sedan, can clearly understand this. 
The previous generation S40 sedan using a total of 36.4% of the high-strength steel, the rest are conventional steel. Despite the use of high-strength steel in the new generation of cars in S4O proportion decreased to 31.3%, but the use of the proportion of ultra-high-strength and ultra-high-strength steel rice has reached 22.8%. That is, the proportion of the high strength steel sheet used in the new generation of S40 sedan in total has reached 54.1%. But it needs to be pointed out that so far do not have a uniform definition of high-strength steel and ultra-high strength steel. The most common definition of the base by Volvo Cars, and SSAB United Fat City standards, according to the strength of the standard high-strength steel should be 340 ~ 60OMPa, the strength of the ultra-high-strength steel rice should be 600 to 800 MPa ultra-high strength steel strength should be at least 800MPa. Processing of these plate means facing many new challenges. In order to processing the new high-strength steels. Would first need a higher pressure is applied on the press, and the corresponding change in the design of the tool. While increasing the feed rate of the tool, in order to reduce the number of stations, to improve the economy. Furthermore, we need to reduce the "danger" of lubricant use, or simply stop using the lubricant. The funds invested in the metal forming tools are usually more than the the tool belongs machine investment. Into the Optional regular chanting of tools and materials in the molding of high-strength steel can reduce costs. When people seriously consider forming tools, the need for a substantial increase friction, cutting force and forming force.
This will in the molding process of the conventional steel village produce very high pressure. Statistics about the tool can be found with the use of steel, the most over the past decade Superfinishingused 1.2379 steel; higher quality using powder metallurgy, is the most commonly used 1.3344PM. But whether these two materials can be more economical processing of high-strength steel? The answer is complex, you need to consider the relationship between the processing batch and part geometry, high-strength steels for tool manufacturing new requirements, that is, the need for an easy to shape innovative material coating can extend the service life of the tool, only through continuous Debug tool to be able to get a better match between the tool, lubricant and workpiece material new system. Although this system can be used for many occasions, but not as widely they solutions. Even inside the Volkswagen Golf to install the latest engine it is impossible to win the F1 Formula One motor racing, this car is always the Volkswagen Golf, will never become racing, despite the Volkswagen Golf is undoubtedly excellent models in which the host level. When it comes to ultra-high-strength steel and ultra-high strength steel molding, if it comes to the tool manufacturing F1 race. Another is necessary is that the coating at any time only as to improve the means of optimization of the tool performance, and the production of the coating process requires a relatively large investment in additional. Of course, but also provide a tool does not require coating material on the market. Without coating material such as Swedish tool manufacturer Uddeholm Corporation (www.uddeholm.com) production Vaneron 40 tool can exponentially improve the overall economy of the process, because the removal of the old coating, grinding, polishing , create a new layer of Xu process incur additional charges. Knife manufacturer to respond to new requirements to provide what possibilities it? Standards for the processing of high-strength steel steel 1.2379 (D2) has two of the main reasons for the failure: cold surfacing (BUE, attached to the wear and tear) and cutting edge crack (fatigue damage). However, there are different solutions.Must develop an appropriate processing methods for different situations, such as part complexity, processing batch tool size, and other decisive factors will affect the tool. At this point, should provide the support of the other aspects. Now, by means such as PVD, CVD, or coating technology in the TD can be controlled cold surfacing generated, because the friction between the tool in the case of coating the surface and the workpiece material can be reduced. The disadvantage of this technique is that an arbitrary geometry can not be processed. In addition - as already mentioned coating needs to "maintenance", which will have a greater cost, therefore a need to develop an undesirable coating of steel. Avoid splashing phenomenon. Stamping boast song characteristic parameter of the work is often used as the reaction force of the standard to measure the tool steel to resist the splash phenomenon. This figure four tool steel, for example: orange the Caldie, dark blue for the Vanadis 4 Extre, gray Vancron 40, light blue conventional tool steel 1.379. 

China steel structure steel structure construction technology

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steel shed construction technology research bridge bearing replacement

steel shed the lifting speed is generated by the inconsistent between the beam bodies internal stress interaction complex.According to past experience, every piece of lifting beam between the maximum lifting height control in average height of 1 mm or less, can guarantee the beams and continuous slab-deck structure safety.Due to the traditional lifting process is improved, so the lifting equipment is adjusted accordingly, Jack should be placed at the beam end horseshoe, the past design without much consideration after the lifting bearing replacement spacing, at the site of the field reconnaissance and found the beam end, horseshoe and coping at the top of the pitch in the 7.8 general to 8.8 cm, so Jack thickness should not only meet the space requirements, but also meet the requirement of lifting stroke (replacing support),



To this end, we contacted the professional Jack manufacturers, specializing in the production of the special-shaped jack.The same pier 10 jacks use 1 sets of pump control, thus 10 jacks synchronization.The present bridge single every hole consists of 5 pieces of T beam.Each beam weight includes the whole layer of bridge deck pavement and bumpers, weight.One of the dead weight of the beam aggregate 43 tons, edge beam weight aggregate 46 tons.Folding each bearing under self-weight load for middle beam 211 kn, edge beam of 225 kn.Using 150 tons of Jack, each beam bottom arrangement 1, relative to the load beam is about 7 times the safety coefficient, edge beam is about 6.5 times the safety coefficient, the bearing capacity is enough.The actual beam construction measurement of pump pressure of about 40 mpa.The construction steps of traditional work generally consider the erection bracket system form working platform, support system, adopted for lifting hydraulic system, operator and all quality by the tie beam, slab or foundation directly bear.Considering the engineering schedule and site conditions, the traditional process for improvement of the beam end, arranged for workers to operate the work platform - light hanging basket, basket field processing, at the same time, hanging basket mounted on both sides of the handrail, and ensure construction safety.The cap top surface and bottom surface of the beam body put Jack position steel shed, to ensure both surfaces are parallel; according to Jack the layout principle of its respective position; the oil pump machine is arranged in a good field of view position; according to a direction identification, easy to control principle,
 jack




Oil pipe and oil valve connected in order.Installation pipe should pay special attention to inspection of tubing joints found dirt should be cleaned, to avoid lifting plug oil pump or oil.Jack is installed before the need for a trial run and debugging, to provide certain top lift its rate of roughly the same, error control in 1 mm.Check before installation jack and sealing, to ensure Jack good seal, oil and oil quantity to meet the requirements of varieties.After the examination, manual installation and adjustment in the jack, Jack pretravel, ensure the jack and the cushion block between close.General insurance block by steel plate, planar size should not be less than the total height of the 2/3, to ensure that the case role pad not instability.All the preparations are available after (such as inspection pad, Jack installation, bearing the basis of legislation, all construction equipment and materials etc.), Jack to simultaneously actuate, try to top, according to lifting stroke is lifting control.After unloading shall carefully check the system respective control system and epigenetic phenomena, check the key: all the oil has no leakage, Jack has no abnormal phenomenon, power supply lines and apparent wear.After unloading at the same time also should check the jack plate has no deformation, when necessary, can adjust the thickness of the sheet to meet the jacking requirement; check Jack position under the structure has no difference from the lift before the event, such as the existence of, should be carefully to find out why before the formal lifting, no case unknown continued jacking.Try top end, the professionals under the unified command of all Jack slowly force whole jacking beam,



When the top lifting synchronism rises, each top with displacement between hierarchical control, the piers and abutments to radio contact, began in 3 millimeter level, each level in place after the uniform stop, padded steel stool and steel, check the top case, ensure good working condition before proceeding to the next stage lift, so repeatedly.Lifting height above the support design height of 20 mm.In order to ensure that each piece of beam uniformity synchronous rise gradually to the upper top beam, classification, various height of 3 mm, from the top to the construction requirements of height, pad groove plate bench, and in the steel shed jacking process of complete measurement, recording work, ensure that the girder, bridge bearing replacement repair consistent.As a result of new old bearing height ranging from as far as possible, take on the same pier uniform replacement of all support measures, to ensure the same pier all support the same height.Demolition of old support, cleaning up old support around the debris; the beam bottom steel plate rust rust and antirust processing; epoxy material pad bearing pad stone and beam bottom surface is not parallel to part (both in horizontal plane shall prevail); according to the accurate position of the installation of the new support lofting.Construction process control measures of bearing replacement need top up the entire span bridge, enhance the capacity, enhance the speed, displacement control is strict, glue River Bridge at the most need dozens of Jack synchronous operation, at the same time insurance block change, replacing the bearing, displacement measurement, the oil valve control needs more skilled workers in a relatively short period of time in a tacit understanding with homework.Thus on the whole process control is particularly important.Top beam before operation must be prepared for all the equipment and materials.The oil pump, oil pipe and each jack to do maintenance and debugging.The site must have enough wearing parts and spare materials.The new support, epoxy self-leveling material and its preparing tools must be at the scene ready, and staff for.Top beam work must do all workers training, for every worker must confirm their responsibilities and proficiency.Personnel must be thoroughly familiar with the top command process in all aspects, as well as matters needing attention and emergency countermeasures.Before operation should first check personnel, equipment and materials to and normal use.The implementation of jacking focus when control of pump and valve division division personnel, strictly in accordance with predetermined step steel shed command operations, in each stage were carefully check the hydraulic condition, vertical displacement of beam body.Rubber bridge bearing replacement of the whole process of construction smoothly, the construction speed is faster, without any accidents.In the process of bridge bearing replacement, without interruption, jacking process and jacking construction monitoring shows that after the completion of the bridge deck pavement, bridge structure includes did not show any abnormalities.Therefore, glue river bridge bearing replacement of successful experience, to the same type of simply supported bridge bearing replacement construction is had draw lessons from action.

Jingtabuilding :http://www.jingtabuilding.com/ 

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Liquid metal processing management help enterprises

The quality of metalworking fluids can better power processing, how to pass effective chemicals management to extend the use of metalworking fluids cycle, so as to achieve the purpose of reducing enterprise cost,
Has attracted more and more attention from enterprises.Selection of suitable liquid metal processing metal processing liquid emulsion for moderate to heavy duty cutting and grinding, semi-synthetic cutting fluid suitable for most mild to moderate load all types Superfinishingof cutting and grinding, synthetic cutting fluid is only applicable to light cutting load and mild to moderate grinding.
1 from the processing methods for the analysis of higher cutting speed roughing (such as turning, milling and drilling) requirements of cutting fluid has good cooling performance, this should be using semi synthetic cutting fluid and a low concentration of emulsion.In some precision high strength processing (e.g., broaching, tapping, deep hole drilling and processing gear), need cutting fluid has good lubricating property, can choose high extreme pressure emulsion.
2 from the use of tool analysis (1) tool steel tool: This tool heat temperature at 200 ～ 300 ℃, bad thermal stability, high temperature will lose hardness, thus requiring the cooling properties of the cutting fluid, with a low concentration emulsion as appropriate.(2) high speed steel tool: high speed rough cutting, large amount of cutting heat is generated, in order to avoid the workpiece burn and affect the quality of the product, should be used in cooling of synthetic or semi-synthetic cutting fluid; the use of high-speed steel cutting tools in machining, low speed, in order to reduce the friction between the tool and the workpiece, suppressing cutting aneurysm formation, generally take a high concentration of emulsion.(3) cemented carbide cutting tools: such tool melting point and hardness is higher, in general can be used in the processing of emulsion.If heavy cutting, the cutting temperature is high, easy fast wearing of the cutting tool, should be used at this time flow sufficient cooling and lubricating liquid, with 3% ～ 5% emulsion is appropriate (using spray cooling, is better.).(4) ceramic cutting tooSuperfinishingls, diamond and cubic boron nitride cutting tools: these tools higher hardness and wear resistance, cutting generally do not use cutting fluid, sometimes also can use the synthetic cutting fluid.Liquid metal processing costs accounted for about 7% ～ 17% total manufacturing cost, reasonable selection of cost-effective liquid metal processing can be the first step for the enterprise to reduce manufacturing cost.Cutting fluid maintenance and liquid control through good maintenance to extend the life of the processing liquid to reduce cost.In a liquid dispensing before confirming the machine and water clean, and then in the water tank by adding a certain amount of water, and according to the requirements of cutting fluid concentration slowly adding and stirring, until the appearance of uniform.Note: must in the clean water tank blending; must add oil into the water but not vice versa; diluent to adjust the concentration of.In actual use the following parameters will change to control: 1 appearance: appearance changes mainly by external contamination, grey or black primarily involving bacteria and metal particles caused by the saponification, iron processing in common; Brown is and saponification iron; in the liquid surface with creamy material suggests working liquid stability.2 concentrations: control more stringent than better, because of the high concentration of 1% ～ 2% set out under the condition of low running cost.PH: 3 new liquid usually in 9.2 ～ 9.5 between, in the processing of fast will drop to 9 ~ 9.2, every detection helps to extend the working fluid life, because the pH drop is a marker of bacterial infection.PH below 8.7 should adopt add antiseptic measures.4 miscellaneous oil: mainly comes from the machine tool hydraulic and lubricating system, will promote the growth of bacteria, affect the tool life andSuperfinishing the working fluid, should be controlled within 2%, available oil skimmer and centrifugal method to remove.5 of the total hardness of water: depends on the total content of calcium and magnesium ions, too high will affect the working fluid stability and foam level, thus leading to fatty acid soap consumption, we can add water softening or reverse osmosis membrane method to reduce the hardness hardness control, usually at 5 ° dH to 30 ° dH.6: high chlorine content can lead to rust and damaged the working fluid stability, should be controlled within 150PPM, can be added to soften water and concentrated liquid solutions.7: high conductivity can lead to rust and damaged stability of working liquor, affecting tool life.Should be controlled within 5000 μ S/cm, can take part replacement and add softened water solution.Therefore, the metal working fluid life depends mainly on the outside pollution and biological control, practice has proved, good maintenance can make the liquid metal processing prolonging 1 times, produce benefit remarkable.
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Framework structure which classes? Housing construction structure which several types?

Classified according to the structure of housing construction steel structure is the main component of the load-bearing steel material construction, including cable structures.Steel, reinforced concrete structure is the main component of the load-bearing steel, reinforced concrete construction. The reinforced concrete structure is the main component of the load-bearing is constructed of reinforced concrete. Including shell structure template situ structure and the use of sliding mode, up board construction of the reinforced concrete structure of the building. The hybrid structure is the main components of the load-bearing reinforced concrete and brick and wood construction. Such as a beam of the house is made of reinforced concrete, brick wall is load-bearing walls or beams are constructed of wood, the column is constructed of reinforced concrete. Brick and wood is the main component of the load-bearing brick, wood construction. Such as a housing frame wooden room, brick walls, wooden construction. Other structure who does not belong to the above structure houses shall such. Such as bamboo structure, brick arch structure, cave. The main difference is the superstructure, the frame structure, a shear wall, the vertical stiffness of the frame structure is not strong, senior or super high-rise building frame structure especially! To solve this problem it is to use shear walls you can go frame structure, frame structure, residential refers to the load-bearing beams and columns of reinforced concrete poured pounded with precast aerated concrete, expanded perlite, pumice, vermiculite, Tao bad light sheet wall splitting assembled whileResidential. Suitable for large-scale industrial construction, high efficiency, good quality of the project. The frame structure constituted by the beams and columns, smaller member section bearing capacity and stiffness of the frame structure are lower, it's the mechanical characteristics of similar vertical cantilever shear beam, the higher the floor, the horizontal displacement of the slower, high-level framework in aspect both directions under great horizontal force, In this case, cast floor also as a beam working together, the role of the prefabricated floor is not considered, the frame structure of the wall is filled wall, from envelope and separated the role of the characteristics of the framework structure is provided for the construction of the flexible use of space, but poor seismic performance. 1. Frame - shear wall structure, the called frame structure, it is the combination of the two systems of the frame structure and shear wall structure, drawing on their respective strengths, both for building layout provides a greater use of space, but also has good lateral force resisting performance. Wall structure in the shear wall can be set individually, can take advantage of the wall of the elevator shaft, stairwell, tube wells.Therefore, this structure has been widely used in various types of housing construction. 2.The deformation of the superstructure, scissors curved. As we all know, the deformation of the frame structure is relatively small deformation shear, upper layer, the lower layer relative deformation. Shear wall structure deformation for bending, large relative deformation in the upper layer, the lower layer is relatively small deformation. Wall structure, due to the deformation compatibility of the two structures work together to form a curved shear deformation, thereby reducing the pending cut the layer relative displacement ratio and vertex displacement ratio, the lateral stiffness of the structure has been improved. 3. Horizontal load shear walls to withstand. From the characteristics of the force, due to the lateral stiffness of shear wall in the wall structure is much larger than the lateral stiffness of the frame, the horizontal loads, under normal circumstances, about 80% more than in shear wall commitments. Therefore, the frame structure under lateral loads assigned story shears, than the kind of evenly distributed along the height closer to the moment of layers beamed beneficial to reduce the beam-column specifications, to facilitate construction. 

The perfect performance of the of quality cutting fluids in metal processing

A small drop of cutting fluid, related to the processing of the results. Both high-speed processing efficiency, accurate processing effects, or environmental process, the quality of the cutting fluid can bring a good performance. Metal cutting fluid market in recent years, with the metal processing industry is changing and the rapid progress of the metal processing technology, as well as the end user of the continuous improvement of the product quality requirements, along with the rapid expansion of the customers of the metal processing industry, metal cutting fluid The performance also been put forward new demands, mainly including the following aspects: the processing industry continues to expand the scope of metal cutting fluid market is mainly concentrated in the automobile manufacturing, aerospace manufacturing, medical equipment and medical equipment manufacturing. In recent years, the steel industry, home appliance manufacturing and mining equipment manufacturing industries have sprung up everywhere, more detailed requirements for metal cutting fluid, harsh and specialization. Processing materials and processing technology diversified now, endless kinds of new materials, innovative processing technology. The diversification of the materials, means that the material processing difficulty varies, the need to adapt to the difficulty of the range is increased, and nonferrous metals and alloys are increasingly being used to enhance the protective properties of the material surface, also called metal cutting fluids. Meanwhile, the processing technology is no longer a single, more and more combinations, disposable shaping craft growing tendency to put forward higher requirements, and adaptability of metalworking fluids. The increasingly high machining accuracy, surface quality requirements for the accuracy and surface finish of the workpiece, with more and more demanding requirements, the service life of the tool, the rejection rate of the products of the metal cutting fluid new challenges. Reduce overall operating and maintenance costs in the metal processing industry, customers for the cost of the metal cutting fluid control are becoming increasingly strict. Customer requires metal cutting fluid performance, stability, reduce downtime, workpiece rework, to extend the use of oil and tool life, thereby reducing their overall operating costs. Green, environmental protection, energy saving ideas intensifying as China's economic development, resource issues become increasingly prominent, and constantly enhance people's awareness of environmental protection, green concept is gaining in popularity. More and more customers require metal cutting fluid manufacturers to provide products to meet health and environmental requirements. Selected according to the characteristics of a number of different processing materials, different processes, different processing conditions ...... all of which affect the choice of cutting fluid. How to select the most suitable cutting fluid processing is a problem that must be given attention in the metal processing. Cutting fluid can generally be divided into water-based cutting fluids and oil-based cutting fluids. Oil-based cutting fluid is relatively higher prices, the overall performance is superior. For expensive machine or the workpiece surface quality requirements, generally used in oil-based cutting fluid. While the main processing requirements of efficiency and cost, you can choose to use a water-based cutting fluids. Secondly, the characteristics of the machine itself, also affect the choice of cutting fluid. Typically, the machine tool manufacturers in the design of the machine, taking into account the use of cutting fluids, so they recommend some brands of cutting fluid for their own equipment, such as some of the open machine oil cutting fluid can not be used to prevent large number of cutting oil evaporation and dissipation. In addition, a different tool and the workpiece material, because of their respective heat resistance, hardness, cutting different index, for the selection of the cutting fluid also of the same. Different processing methods, such as turning, milling, drilling, broaching, grinding, cutting fluid requirements. Solution times the performance of Flowserve Flowserve Corporation has long been a number of high-tech products to China, for example ECOCUTMIKROPLUS20 PLANTOCUTSERIES, ECOCOOLS71B ECOCOOL2506S, ECOCOOLSYN7045, ECOCUT7520LE-S, etc.. Dry machining emerging, due to its inherent heat generated in the process is difficult to be taken away, and the chip is more difficult to discharge, a greater impact on the life of the tool and other shortcomings, MQL will become metalworking trend. MQL Flowserve China will launch a special ECOCUTMIKROPLUS20 this product, the product with the equipment, minimal dosage. To achieve the same processing results and processing the number of cases, compared to the traditionally used oily cutting oil, the amount of the product is only 4 to 8%, the processing efficiency is high, can significantly reduce the processing time after processing tool, workpiece, chips are kept dry, the chip does not need treatment can be recycled, greatly reducing the cost of waste disposal, and the product has excellent extreme pressure be applied to almost any harsh processing, such as the crankshaft deep hole drilling (5 ~~ 7mm in diameter, depth of 80 to 107mm), another example reaming of the cylinder head, its excellent lubricating properties to ensure the machining accuracy of the workpiece, while reducing tool wear and extend tool life, has a number of well-known enterprises in the automotive industry With the success case. Flowserve particularly developed a series of maintenance-free products, such as ECOCOOL600NBFC, ECOCOOL700NBFC, ECOCOOL3015GSWNC, ECOCOOL2030S and so on. In most cases, metalworking fluids recycling, product stability and routine maintenance of the quality of its processing performance, strong the Flowserve biological stability, and therefore can do no rust sterile, thus long service life of the product, without late additives, and no downtime maintenance, to improve production efficiency, reduce maintenance costs, and help reduce production costs. The previously described ECOCUTMIKROPLUS20 is one of the outstanding representatives. In environmental protection, Flowserve more positive action everywhere rushed to take practical actions to reflect the importance of environmental protection. Back in 1976 developed the first patented low-pollution lubricants; 1979, Fox has begun a total ban on use of nitrite and ammonium nitrite products

Public financial construction of super lightweight foam concrete characteristics

1, saving energy source environmental protection foam concrete raw materials for cement, unlike polystyrene plastic extrusion plate, such as energy as raw material, and can use large amount of industrial waste residue.Cement production, although there are energy, but compared to the polystyrene foam and other organic insulation material production has been reduced a lot.In addition, foam concrete using inorganic materials as the main body, production without harmful substances produced, the production site without peculiar smell.In the application process will not produce decomposition, green environmental protection.The raw material of foaming agent for neutral, benzene, formaldehyde and other harmful substances, avoiding environmental pollution and fire hazard.From the perspective of green architecture, also should be the best choice for building insulation.2, lightweight foam concrete density, density grade is 300-1800kg/m3, commonly used in the foam concrete density rating of 300-1200kg/m3, in recent years, density of 160kg/m3 ultra light foam concrete in construction engineering was applied.As the foam concrete density, in both inside and outside the building, floor, wall, column dimensions in building structures such as the materials, the general can make the structure weight is reduced by about 25%, some up to structure weight 30%-40%.The foam concrete wall and roof materials in reducing the self weight of buildings at the same time, to increase the floor height, realize the construction of high-rise, thereby saving building area.At the same time, it can reduce the pressure on the ground buildings, reducing the building foundation, beam, column structure, can save building materials and engineering cost, greatly reduce the engineering amount, shorten time limit for a project, have remarkable economic benefits.3, good insulation properties as the foam concrete containing large closed small pores, so it has good thermal performance, namely, good insulation performance, which is not possessed by common concrete.Usually dry bulk density is 400 ～ 700kg/m3 foam concrete its thermal conductivity is usually 0.09 ～ 0.17W/ (m · K),

insulation for clay brick for 7 times, 10 times that of ordinary concrete.Practice has proved, in the northern regions of China 20cm thick foam concrete wall, the insulation effect and 49cm clay brick wall quite.Under the same heating condition, foam concrete building indoor temperature than the traditional clay brick houses can be increased by 5 ℃.In hot regions, and can greatly reduce the summer air conditioning starting frequency, to reduce electricity consumption, can effectively reduce the cost of living.Foamed concrete is our country at present all kinds of wall materials, without adding other insulating material or air layer, can achieve energy saving 65% preferred the new energy-saving wall materials.Table 1-1 foam concrete and several commonly used building material heat conductivity comparison.4, good fireproof performance of foam concrete cement as main material, inorganic material, in order to fully burning material.Fire resistance limit greater than 2h, can reach a standard.So it has good fire resistance,

 in buildings, can improve the fireproof performance.Another advantage is, we have R & D cast-in-place concrete foam insulation wall of steel structure, can be completely coated in the foam concrete, the steel structure protection, even fire, steel structure deformation is not easy to collapse, this also to a certain extent, solve the problems of steel structure fire protection, can play a double the role of fire.5, seismic performance foundation load is small, the seismic force is more powerful.Foundation load and wall materials wall materials directly related to density, density is small, the foundation of the building load is smaller, because, wall material weight to account for building 70% weight.

Steel production and installation of anti-corrosion fire prevention knowledge

Structure of the production process flow


(1) the mechanical index: steel structure indexes including the yield point, tensile strength, elongation, impact toughness.These indicators should be consistent with the "code for design of steel structure" requirement, but the low temperature impact toughness of structure may be in only in low temperature environment to test work.The mechanical indexes determination shall be in accordance with the "steel mechanical and technical performance test sampling rules" (GB2975-82)


(2): steel steel composition and processability, toughness, durability and other relevant.Which is the main content of carbon, alloy element content and sulfur, phosphorus and other trace elements content restrictions shall meet the specification requirements (GB222-84).


(3): process performance process performance include solderability and processing properties.Weldability and carbon content and carbon equivalent (low alloy steel), available solderability test identification.Processing performance through cold bending test to determine.According to (GB232-88) as the standard.


(4): deviation of the geometric size of steel (steel, steel, round steel, steel) dimensions and theoretical size deviation must be within the allowable range.Allowable deviation value may refer to national standard GB709-88, GB706-88, GB787-88, GB978-88, GB707-88, GB816-87 etc..


(5) steel shape blemish: steel surface shall be bubble, crack, crack, wrinkle, scar, mixed and pressed into the iron oxide.These defects must be removed, after the removal of the dent depth shall not be greater than the thickness of steel negative deviation.In addition, when the steel surface rust, pitting or scratches and other defects, its depth shall not be greater than the thickness of the steel negative deviation of 1/2 value.


(6) mechanical cutting: the use of mechanical force (shear, sawing, cutting, grinding) corresponding mechanical cutting plate machine, sawing machine, grinding wheel machine, is suitable for thickness of 12 ~ 16mm plate or profile of the linear cutting.


(7) cutting: the use of oxygen - acetylene, propane, liquefied petroleum gas flame heating to melt the metal, which uses compressed air to blow away erosion of metal liquid, so that the metal cut off, suitable for curve cutting and cutting.)


(8) plasma cutting: using plasma arc cutting flow, applied to stainless steel and other materials with high melting point cutting.


(9) hot forming processing: refers to the steel is heated to a certain temperature after further processing.This method is suitable for forming, bending and correction in room temperature can not do the workpiece.Thermal processing end temperature shall not be lower than 700 ℃.Heating temperature 200 ～ 300 ℃ steel have a blue brittleness, prohibited the hammering and bending.Carbon content beyond the low carbon steel's steel not general thermal processing.


(10): cold forming processing is performed at room temperature.Due to external force exceeds the yield strength of the material and the material to produce the required permanent deformation, or due to external force exceeds the ultimate strength of the material and portions of the materials according to the requirements and materials from the.Cold processing of all the materials hard and brittle tendency, which can make the steel through heat treatment in normal state or gouging out more serious edge portion of hardening.The ambient temperature is lower than -16 ℃ not cold working steel.Is lower than -12 ℃, and shall not process of low alloy steel.


(11) bending processing: according to the design requirements, the use of processing equipment and tooling plate or steel bent into a certain shape of the process.Cold bending for sheet, small steel; hot bending for thick plate and complex components, steel, hot bending temperature at 950 ～ 1100 ℃.


(12) coil processing: under the action of external force so that the flat plate of the outer fiber elongation, the inner layer of fiber shortening and deformation method.Coil coiling machine is completed by.According to the materials of different temperature, is divided into cold rolled and hot rolled.Coil for welding tube column, pipeline, air bag.


(13): the steel structure components of the hem edge bending at a certain angle or certain shape process called folding.Hems are generally used for thin plate.Edge folding machine used, with appropriate mould.


(14) molded: molded in pressure equipment using molds to make the steel molding method.Specific practice of blanking and forming, cutting, bending, roll round, drawing, rolling and other.


(15): shovel shovel edge edge is through to the shovel head hammer action and eradication of metal edge spare part and forming groove.Shovel edge there are manual and pneumatic parts, pneumatic tool with.Shovel edge precision is low, generally used for less demanding, a small groove processing.(


16) planing edge: edge planing workpiece is pressed, along the edge planer processing for reciprocating motion, planed groove.Edge planing planing straight edge or edges.(17): milling milling and planing edge similar, just the edge planer tool box tool and cutter of disk milling cutter for milling cutter in which replaced, along the edge of a straight line and also to make the rotary motion, the processing efficiency is high.


(18) carbon arc air gouging: carbon as electrode, and the planing metal arc heating a metal to a molten state, and then use compressed air to blow off of melted metal.High efficiency.


(19) the ground sampling method: in the assembly platform placed according to 1:1 component samples, then according to the position of the parts in the samples, were assembled into components.

Embodied in the steel production process

1, Steel plant units with no installation process, install components without order. If a hall, a building area of ​​6,000 square meters, a total of 4 layers. The members have all been installed to the ceiling, but the main steel columns are still not fixed welding small steel columns of the edge of the auxiliary have all welding finished. In another example, the steel columns installed as soon as possible the steel columns at the bottom of the pad pad flat weld it, then dense with fine stone. But some site color plate has begun to install the column foot has not closed.
Mishandling installation of the steel columns, like a candle, a root single plug up the day they can not form a solid framework unit, windy way, resulting in the collapse. Such security incidents occur several times, and should definitely be avoided.
3 anchor bolts uneven, the column feet plane without the prior measurement, embedded dislodged a column deviation, should be measured buried.
4 field welds generally not in place. Rigid connection pad welding gap is too small, not penetration results pad hand to pull it off; liner plate specifications do not meet the requirements, or even replaced with steel; the bad weld forming, rugged, and varies in width spatter, weld flash is not clear, bite the meat more stomata; the arc head arc tail without lead arc quenching board dishing and so on.
Steel company to install high-strength bolts, some more: Luya, even lower than the nut; bolts not tightened SHEAR Plum head not wring, the large hexagon no early wring final screw marked ; install the friction surface of the protective paper is not torn; high-strength bolts for temporary fixing, not lacquer sealed 48 hours after installation; without making torque and axial force re-examination, the tightening torque is calculated according to the specified; the friction coefficient trial is not in place, Some do, some do only one group. Rod bolts are not tightened, Rod is not straight, waist round hole is not big washers, caused by the nut base metal contact surface is too small, easily perforated.
 6 drawings reviewing carefully, resulting in the installation of quality defects. Such as design drawings did not indicate that drilling in the crane beam wing board, the construction unit has not argued, results welded mounting rails, causing the crane beam deflection. Violation of the mandatory provisions relating to crane beam does not allow flexible provisions.
7 the envelope color plate patchwork of tight close adverse side the nostrils "not plugging the impact against leakage of rainwater and beautiful. This article comes from the steel structure engineering network

Arc spraying anticorrosion technique in steel structure application

In today's society, as a systems engineering, is directly related to the safe operation and the service life of the steel structure of the anticorrosion engineering under engineering using method, design method and construction method and other aspects of attention.Practice has proved: strengthening steel structure fabrication and maintenance of anti-corrosion construction management and supervision for engineering use, side, the construction side and supervision side, it is quite important; in the steel structure design and production process, must have the professional anti-corrosion engineering and technical staff and experts involved or guidance.In recent years, arc spraying long-acting compound anticorrosion technology is gradually in steel production in the promotion and application of.

One, overview

Because the steel structure has good mechanical properties, bearing capacity of strong, easy manufacture, easy use in industrial production, construction and installation cycle is short, good sealing performance advantages, in the development of national economy, has been widely used in large span structures (bridges, for example, stadium house), light steel structure (large and medium-sized workshops), top building (New York World Trade Center and the Shanghai trade building etc.), shell (pressure vessel and pipeline).However, the steel structure in the service period, and it is the environment medium between prone to chemical, electrochemical and physical action, cause material modification and steel structure failure, it is often referred to as the corrosion of steel structures.

It has been recognized, the human use of steel structure is rarely due to the simple mechanical factors (such as tension, pressure, impact, fatigue, fracture and wear) or other physical factors (such as heat energy, light energy etc.) cause damage, most of the metal structure is destroyed and the surrounding environment factors.Therefore, the corrosion and corrosion protection of steel structures has become today's materials science, industrial and engineering fields can not be ignored important task, by the government and application in steel structures related to the attention of industries.

In two, long-term anti-corrosion steel structure engineering application necessity

So far, the steel structure corrosion problems are to world economy to bring huge loss.According to the developed country of a few industry statistics, each year as a result of steel structure corrosion caused economic loss accounted for about 2% of GDP in 4%.The United States in 1975 because of the economy loss caused by corrosion of approximately US $70000000000, accounting for about 4.2% of GDP in 1982, $126000000000; 1969 UK corrosion loss of 1365000000 pounds, accounted for 3.5% of GDP in 1976 in Japan; corrosion loss of $9200000000, accounting for 1.8% of GDP; according to our statistics in 1995, corrosion losses as high as 150000000000 yuan, accounting for about 4% of the gross national product.At present, around the world each year due to steel structure corrosion caused by the economic losses of hundreds of billions of dollars have been.

Moreover, the steel structure caused by corrosion accident endangering the safe operation of the structure.Corrosion cause of catastrophic accidents it is often seen., extremely serious consequences, especially for welding steel structure and under great stress of steel structure, because under the action of stress, corrosion will be greatly accelerated, namely so-called stress corrosion problems in steel structural damage, is very common.For example, the bridge structure or high roof truss structure because of the serious corrosion problems, must be reconstructed, otherwise, will cause serious consequences, of course, economic investment is quite large, now, the domestic construction of a large steel structure bridge, will cost to a few billion yuan.Japan 1970 to underground pipeline due to corrosion fracture, caused by gas explosion, 75 people were killed.In 1979 our country city of liquefied petroleum gas tank explosion casualties due to corrosion, dozens of people, the direct economic losses of 6300000 yuan.And, due to accidents caused by the shutdown, shutdown of indirect economic losses caused by, may exceed the direct economic loss of the number of times.

Because of this, the anticorrosive techniques of steel structures, especially long-term preservation new technologies using becomes and important.If a steel structure in 15 ～ 50 years of free maintenance, user can save a great amount of maintenance funds, and greatly improve the safety of steel structure and service life.

So far, from the steel structure project using method, design method and construction method and other aspects are still on the steel structure of the long-term preservation of the importance of the lack of sufficient attention, in the sense that still stays in the traditional anti-corrosion technology, the maintenance of later period may not follow.And, even if is the traditional anti-corrosion coating, because in the process of construction anti-corrosion construction technology is not good, often resulting in premature corrosion or damage of steel structure.For example, in 1965 March, the United States a gas pipeline for stress corrosion cracking on fire, causing the death of 17 people.Another example of a swimming pool early during the construction paint engineering construction technology of anticorrosion of steel structure, causing local premature corrosion, as shown in Figure 1, plus early roof system design of anticorrosion technology limitations of the times, makes the use of Party must be spent millions on the replacement or maintenance.

In addition, some projects also exist a larger problem, namely the implementation of the project before the special anti-corrosion engineering experts on steel structure anticorrosion technology assessment; engineering transfer, not to appoint a professional anti-corrosion construction engineer or specialist for the entire steel structure anticorrosion of strict quality testing; anticorrosive construction after the late sleep without any anxiety, periodic inspection and maintenance have no or reduced; regardless of the actual situation of anti-corrosion engineering costs, and construction units are combined with each other, thereby producing unqualified "bean curd dregs".

Various aspects of the problem, concentrated in the together time, the entire steel structure life is certainly doubtful, to date, there have been several accidents of steel structure, its direct consequences are disastrous, direct proof of the above analysis.

The steel structure anticorrosion project known as project of a system, it is because it relates to the steel structure engineering, engineering design, use, construction method and construction supervision and other aspects of the comprehensive factors.Only the aspects of reasonable combination and much attention, steel structure safety and the service life can be a reliable guarantee.