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.