Development of wear resistant steel industry
In recent decades, the development and application of high strength wear-resistant steel has developed rapidly. This kind of steel is developed on the basis of low alloy high strength weldable steel with good wear resistance and service life up to several times that of traditional structural steel plate. This kind of wear-resistant steel plate is suitable for various working conditions, so it is very popular with users. Some steel companies in Japan, Germany, Sweden and other countries all produce this kind of wear-resistant steel.
The development of this kind of steel started late in China. After the introduction of construction machinery manufacturing technology in recent 30 years, it broke the low-grade state of traditional wear-resistant materials and began to develop towards economy and high performance. However, compared with the imported wear-resistant steel sheet, the impact toughness of the domestic wear-resistant steel sheet is generally lower, while the imported wear-resistant steel sheet keeps good plastic toughness while the hardness level increases.
At present, domestic development has been made in the field of high strength wear-resistant steel. A number of iron and steel enterprises have developed a considerable number of wear-resistant steel varieties, and gradually serialized. However, the general and serialized standards have not yet been formed in China, and the high strength and wear-resistant steel system is not perfect.
For a long time, the wear resistance of China's basic parts is obviously lower than that of advanced products abroad. In recent years, great progress has been made in the field of wear-resistant steel in China. Many medium and heavy plate mills have been able to supply wear-resistant steel plates with hardness below HB400, and some manufacturers can produce wear-resistant steel plates with hardness below HB500. At present, more than HB400 grade wear-resistant steel is still mainly dependent on imports. Compared with foreign products, the hardness grade and performance of wear-resistant steel products in China are still quite different.
Low carbon, Mn, Si and Cr-Mo-V-B combinations are generally used in the composition design of high strength and wear-resistant steel in China. Most of them are delivered in quenching or quenching + tempering state. The steel plate is generally quenched to obtain lath martensite and a small amount of retained austenite. Some products were delivered in hot rolling, controlled rolling (or tempering) state, and the microstructure of bainite ferrite (BF) and retained austenite (AR) was obtained.
In order to meet the requirements of large-scale coal scraper conveyor and light-weight construction machinery, low-alloy high-strength wear-resistant steel sheets will be developed in the future in two directions: thick plate and thin plate. In the field of thick plate, the mastery of material uniformity and weldability technology will be the key to win the market, while in the field of thin plate less than 16mm, technology will also be the key to win.