Research on metal wear-resistant materials (1)
Metal wear-resistant materials include both plastic materials and brittle hard materials. At present, the following types are widely used.
(1) Austenitic wear-resistant manganese steel Austenitic manganese steel is known for its high toughness and easy work hardening. The austenitic manganese steel produced and applied at home and abroad is still mainly Mnl3 series, and its chemical composition is: = 1.0% ~ 1.4%, = 11% ~ 14%. After 1000 ~ 1050% water toughening treatment, a single austenitic manganese steel can be obtained. body tissue. So far, it has been used in abrasive wear conditions with large impact loads (such as the rolling wall and crushing wall of the cone crusher, the lining plate of the gyratory crusher, the particle plate of the large and medium-sized particle crusher, the hammer head of the large hammer crusher, and the large and medium-sized wet crusher. Austenitic manganese steel is still mainly used under the mine ball mill liner. Some countries such as Japan prefer Mnl3Cr2 wear-resistant steel with higher yield strength and wear resistance. In the 1950s and 1960s in my country, high manganese steel was almost used as a universal wear-resistant material, but in production practice, it was found that high manganese steel was wear-resistant only under the conditions of large impact, high stress, and hard abrasives, and its Low yield strength, easy to deform.
The technical progress of austenitic manganese steel is mainly manifested in the strict control of Si and P content that affects performance during the production process, especially the limitation of P content; in addition, in order to reduce the slag inclusion, columnar grain and coarse grain Trace elements such as V, NI) and RE are often added to high manganese steel. Mnl7 (Mnl8) and Mn25, which are known as ultra-high manganese steels, are beneficial to solve the problem that carbides are easy to appear inside the manganese steel after liquid toughening treatment of thick and large sections, and the toughness is reduced, and it is also beneficial to solve the problem of manganese steel parts that may be brittle when used in low temperature conditions. broken problem. However, the wear resistance and cost performance of ultra-high manganese steel under the condition of large impact load and abrasive wear, the selection of Mn, C and Mn/C related to /6 lack, especially the key issues such as low life under low stress wear, are still to be solved. It needs in-depth research and practical verification of wide application under different working conditions.
(2) Chromium-based white cast iron The development of foreign wear-resistant white cast iron is divided into three stages: ordinary white cast iron, nickel-hard cast iron and high-chromium white cast iron. Chromium-based white cast iron is still the mainstream of wear-resistant cast iron at home and abroad . Crl5, Cr20, Cr26 series of high-chromium wear-resistant cast irons have been mass-produced and applied in the United States, Japan and my country. On the basis of high-chromium cast iron, my country has studied medium-chromium-silicon wear-resistant cast iron and low-chromium wear-resistant cast iron suitable for as-cast applications, and has been mass-produced and industrially applied.
The structure of high chromium cast iron after solidification is (Fe, Cr) C carbide and phase. When the matrix is all martensite, the wear resistance of this alloy is the best. If there is residual austenite in the matrix, it usually requires Carry out heat treatment; low chromium alloy white cast iron has better carbide stability than ordinary white El cast iron. In the study of chromium-based white cast iron, it is often considered that the harder the cast iron, the more wear-resistant it is. In fact, the blind pursuit of hardness may not necessarily achieve the desired effect, but will greatly increase the cost and cause waste. Tests have shown that the high chromium cast iron is close to 90%. When corner erosion wears, its wear resistance is not as good as 20 steel.
