Construction steel structure processing and coating

Construction steel structure processing and coating coating technologyConstruction steel structure processing and paint coating, sometimes encountered varieties to coating material can not sure, will cause the product touch paint coating process management; And because of construction steel structure without proper bottom paint variety, make the overall protective effect of the composite coating were affected.
1 construction steel structure assembly line homework

Steel structure processing enterprise assembly line in addition to processing ability difference, affect the service life of the coating have shot blasting surface treatment quality and the time interval of bottom paint coating.

Shipbuilding industry with inorganic zinc primer workshop as steel shot blasting derusting treatment after maintenance coating, then through cutting, forming, welding into profiles. Due to the maintenance of bottom paint coating is suitable for forming and welding coating operations, can meet the technological requirements of before, finalize the design product.

Construction steel structure processing more varieties of coating material change factors in the operation, processing, such as the follow-up process progress slow, due to the steel surface after treatment in the presence of oxygen in the air easy to rusty, placed under the environmental conditions of the relative humidity of 85% or less is only allowed 4 h, or less often in the bottom coating construction can't keep up with the rusty with the passing of time, have to make a second cleaning.

Formation of corrosion pits in shot blasting treatment manual surface processing to meet the St3 level, and the power tool cleaning work is big and the cost is high, because this kind of surface treatment does not affect the coating quality, often has greatly reduce the service life of construction steel structure.

2 construction steel structure coating material

2.1 paint variety adaptability of steel cleaning standards

Epoxy, epoxy zinc-rich) coating surface treatment to demand higher cleanliness, manual cleaning shall not be lower than St3 level. St2 level is only suitable for oily paint, alkyd paint coating.

2.2 construction steel components are reserved bolt junction surface coating requirements

Bolt junction surface is slip resistant requirement, and organic coating surface is smooth, does not have the function of slip resistance. Construction Steel Workshop  http://www.jingtabuilding.com/steel-structure-workshop.html product quality acceptance standard connection friction surface must be shot or grit blasting, coating of organic coating must be removed by mistake. After the coating process in the forming, blasting derusting, after processing to prevent the reserved surface coating and surface treatment of steel by mistake after coating, etc., should pay attention to in implementing.

3 construction steel members precoating end of inorganic zinc rich paint is feasible

3.1 maintenance of bottom paint coating of mature experience

Shipyards steel plate shot blasting derusting operation line is equipped with maintenance bottom paint spraying and drying process, paint coating and derusting short time interval,

Note: for fit; Delta is a bit not suitable for; X is not suitable for.

Steel surfaces is in active state, timely paint coating adhesion and antirust performance are very good, 20 microns thick workshop shop primer can adapt to the requirement of 6 months above slipway cycle rust, process design and technology is mature and reliable.

Construction steel structure manufacturing enterprise scale and capital investment and the shipyard difference is big, because of construction steel structure production front processes lack (compared with the shipyard), must increase the order quantity after. If considering a bit more investment funds, have the ability to shot blasting derusting, weld can reduce the secondary cleaning; Has a variety of bottom coating conditions to choose matching scheme.

3.2 management of construction steel structure coating technology

Steel processing and coating production line due to the equipment model is different, blanking, punching, welding and surface treatment cleaning sequence has the difference.

3.2.1 the steel surface treatment - forming - paint coating

Companies such as light steel surface treatment equipment simple, immediately is cutting, punching, welding, coating of coating and shot blasting derusting interval time long, or even exceed the maximum allowable time interval, only complete sliding friction resistance of the surface treatment requirement, the consequences are mostly in the bottom coating corrosion coating under the condition of base level, this is coating early rusty.

3.2.2 forming to rust removal, paint coating

Such companies have steel profiles of cutting, welding, surface treatment equipment, paint coating and shot blasting derusting short time interval, coating protective effect is relatively better.

According to the management requirements of the coating technology, coating of coating and surface treatment interval time more short more good, the steel surface after shot peening to minimize air exposed. After surface treatment with precoating increased maintenance base coating. And precoat bottom coating workshop is suitable for coated welding maintenance base coating. For class a craft, after coating, the coating surface retain qualified as long as the coefficient of friction, can completely molding components to meet the demand of the coating process. For class b process, increase the precoating after rust removal, may help reduce exposure to coating quality. The bottom coating maintenance coating, cost is not much, but because of the durability of good reflect the economic benefit is obvious.

3.3 the durability of the coating

3.3.1 factors affecting the durability of coating

Rust and corrosion protective coating technology ([day] sato? Jing) the steel surface derusting quality affect coating durability levels as close to 50%, as shown in table 2.

3.3.2 rainfall distribution on 10-12 cleanness of surface treatment and coating durability

The rust and corrosion protective coating technology ([day] sato? Jing) with the experimental data shows that the bottom of the cleanliness of all kinds of surface treatment coating durability, as shown in figure 2.

Cleanness of surface treatment of oily coating with red lead derusting paint coating is affected, especially for synthetic resin coating of a class, grade Sa3 differ with the durability of Sa2 level 4 times.

4 construction steel component bottom coating of inorganic zinc rich coating workshop maintenance applicability

4.1 inorganic zinc rich bottom coating maintenance of mechanical processing adaptability

4.4.1 coated cutting and welding performance

Welding performance is coating product maintenance at the end of the testing project. Workshop floor paint coating thin, low toxicity, resistance to high temperature of 450 ℃. Once the coating damage under high temperature, still do not break the protection of zinc on iron metal materials, and spread the area is small, the secondary cleaning, small amount of work will not affect the welding strength, and is suitable for coated cutting. But inorganic zinc rich paint after curing film, unlike general organic coating paint remover removal on easily.

4.1.2 coating of varieties of form a complete set

Inorganic zinc rich paint, epoxy, polyurethane varieties and good compatibility, and vinyl and rubber varieties by epoxy micaceous iron oxide layer coating as a transition. Alkyd surface coating class is a traditional varieties, although not directly in the zinc rich coating surface coating, but suitable for epoxy micaceous iron oxide coating transition layer of the coating.

4.2 with alkyd coating epoxy micaceous iron oxide intermediate coating

Inorganic zinc rich coatings have anti slip function, suitable for bolted friction surface coating, and assigned to the junction surface rust, and the quality of the coating in the long time stability. Inorganic zinc rich class bottom coating, though there are kinds of form a complete set of coating, but don't type suitable for alkyd coating, surface coating is oily coatings under the action of ultraviolet oxidation generating aldehyde compounds, alkyd resin free acidic materials such as phthalic anhydride, react with zinc metal to produce zinc salt, pushing oil resin coating layer. Habit with alkyd resins for surface coatings, again with epoxy micaceous iron oxide intermediate coating makes the transition, both are cut off from the activity of zinc metal, and for coating provides an ideal rough coating surface.

5 conclusion

5.1 steel by surface treatment, must be covered in a short time priming paint, and to ensure that the thickness of the bottom coating, prevent rusty.

5.2 inorganic zinc-rich coating maintenance good rust resistance, and have anti slip function, suitable for coating of construction steel components. Welding and molding process after the inorganic zinc rich paint coating, only in the weld part need to secondary cleaning, and then directly coating epoxy micaceous iron oxide intermediate coating or other coating antirust paint.

5.3 steel anti-corrosion coating paint varieties appropriate chooses inorganic zinc rich paint, friction surface by covering layer coating and surface coating, before construction craft is advanced. Though the process of coating cost increase, but can ensure the quality of steel structure rust protection, the existing coating process to improve the coating service life is 2 ~ 4 times.
China steel structure association four three times in the enlarged meeting
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