Research Status of metal wear-resistant materials (一)
Metal wear-resistant materials have both plastic materials and brittle materials. At present, there are the following kinds of widely used materials.
(1) Austenitic wear-resistant manganese steel Austenitic manganese steel is known for its high toughness and easy hardening. At present, the austenitic manganese steel is still mainly composed of Mnl3 series, and its chemical composition is: = 1.0% ~ 1.4%, = 11% ~ 14%. After 1000 ~ 1050% water toughened treatment, single austenitic structure can be obtained. So far, austenitic manganese steel is still mainly used under large impact load abrasive wear conditions (such as rolled mortar wall and broken wall of cone crusher, circular crusher lining plate, large and medium-sized crusher lining plate, large hammer crusher hammer head, and large and medium-sized wet mine ball mill lining plate). Japan and other countries prefer Mnl3Cr2 wear-resistant steel with higher yield strength and wear resistance. In the 1950s to 1960s, high manganese steel was almost used as a universal wear-resistant material. However, in production practice, it was found that high manganese steel was wear-resistant only under the condition of large impact, high stress and hard abrasive, and its yield strength was low and easy to deformation.
In recent years, the technical progress of austenitic manganese steel is mainly manifested in strict control of the content of Si and P which affect the performance in the production process, especially the restriction of the content of P; In addition, in order to reduce the slag inclusion, columnar crystal and grain coarseness phenomenon, V, NI, RE and other trace elements are often added to high manganese steel. Mnl7(Mnl8) and Mn25, known as ultra-high manganese steel, are conducive to solving the problem that carbides are easy to appear in the internal of thick and large section manganese steel after liquid toughness treatment and to solving the problem that manganese steel may be brittle when used at low temperature. However, the wear resistance and cost performance of ultra-high manganese steel under abrasive wear conditions under large impact load, the selection of Mn, C and Mn/C associated with / 6 lack, especially the low life under low stress wear and other key issues still need to be studied deeply, and the practice verification of wide application under different working conditions.
(2) The development of wear-resistant white cast iron abroad is divided into three stages: ordinary white cast iron, nickel hard cast iron and high chromium white cast iron. The chromium 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 iron have been mass-produced and applied in the United States, Japan and our country. The wear-resisting cast iron of medium chromium silicon and low chromium wear-resisting cast iron suitable for as-cast application are studied in high chromium cast iron in our country, which has been mass-produced and industrial applications.
The microstructure of high chromium cast iron after solidification is (Fe, Cr)C type 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, heat treatment is usually required. Compared with ordinary white El cast iron, low chromium alloy white cast iron has better stability of carbide. In the study of chromium white cast iron, it is often considered that the harder the more wear resistant. In fact, the blind pursuit of hardness can not necessarily achieve the ideal effect, but will make the cost greatly increased, resulting in waste. Tests have shown that high chromium cast iron in close to 90. When angular erosion wear, its wear resistance is worse than 20 steel.
