Engineering manufacturing of weather-resistant steel plates

The use of steel panels on building exteriors has a long history. In order to improve the corrosion resistance of steel plates, various coating treatments are usually carried out on the outer surface of steel plates, such as paint, enamel, galvanizing, etc. Since the 1960s, our country has developed a large amount of weathering steel. From 1965 to 1979, various low-alloy steels containing copper, phosphorus, rare earths, and titanium were exposed to different environments such as dry sandstorms, industrial atmosphere, humid cities, and rural areas for 15 years. Obtained first-hand data on weathering steel.

In 1984, my country formulated the "Atmospheric Corrosion Steel Standards" GB4171-84 and GB4172-84. Among them, there are three grades of high weather-resistant steel: 09CuCrNi-A, 09CuCrNi-B, and 09CuP. Weather-resistant steel for welded structures includes 16CuCr, 1MCuCr, and 15MnCuCr. , 15MnCuCr-Qt four grades.

The average corrosion depth of high-quality weathering steel in coastal environments after 16 years is about 0.1-0.2 mm, and the average corrosion depth in industrial areas and rural areas is about 0.02-0.04 mm. Tests of WISCO's weathering steel show that even in coastal cities, the average corrosion depth of weathering steel is about 0.02mm/year.

Principle of rusting

In the early stages of corrosion, the rust layer on the surface of weathering steel is denser than the rust layer on the surface of carbon steel, with relatively fewer cracks and voids. Then, delamination occurs in the carbon steel and weathering steel parts, with no difference in corrosion products. The main difference is the role of the alloying elements in the rust layer. The precipitation of copper and chromium alloy elements in the rust layer of weather-resistant steel can resist the intrusion of moisture and harmful ions in the atmosphere and prevent further corrosion of the base material. Thus achieving the effect of atmospheric corrosion resistance!

The formulation of wear-resistant steel standards began in August 2007. First, based on market demand and market research, and on the basis of collecting domestic and foreign data, the technical route for low-alloy high-strength wear-resistant steel was determined. From the perspective of science, practicality, cost and resource saving, low-alloy high-strength wear-resistant steel is an inevitable development trend. Developed JAR360F-JAR500F export wear-resistant steel, BIS52J/53J, BIS21J, domestic market JG-JG, B24S, etc. The main data collected include: advanced enterprise standards of Japan, Germany, Sweden, the United States and other countries, focusing on the technical conditions of wear-resistant steel in Germany, Sweden, Japan, combined with China's technical conditions, etc. On this basis, we will promote the maturity of domestic wear-resistant steel production enterprises as soon as possible. At present, there are no published national standards at home and abroad, so the formulation of this standard is of great significance.

Traditional wear-resistant steel generally refers to high manganese steel with impact hardening under impact load. Its main purpose is to have strong hardening ability after being subjected to impact stress during use. However, when the impact load is small, the hardness and wear resistance cannot be improved due to insufficient work hardening.

The main contribution of formulating this standard is to break through the traditional concept of high manganese steel, develop wear-resistant, impact-resistant low-alloy high-strength metal materials suitable for various working conditions in the machinery industry, and standardize industrial production. Promote the improvement of domestic product quality, provide resource-saving materials for the machinery industry, and reduce the number of machinery and equipment. Weight and corresponding costs.