Production application of austenitic base high chrome cast iron grinding balls (1)
Abstract: The production process and main points of high austenitic chromium cast iron grinding ball are introduced. Because of its as-cast austenite structure, it has a high impact toughness. Besides, under impact friction, the microstructure will change to Martensite Matrix, resulting in hardening, which makes the material have high impact wear resistance and high toughness. Production should show that this grinding ball has different wear resistance and economy.
Keywords: high chrome cast iron grinding balls, austenitic, work hardening, wear resistance
As one of the most anti-wear metal materials, high chromium cast iron has been widely used in recent years, especially in the production and application of cast iron grinding and ball.
Because the strength and toughness of common high chromium cast iron grinding ball are not high, the fracture and spalling are serious in use. It has been proved that the wear resistance of high chromium cast iron depends not only on the hardness determined by the type and quantity of carbide but also on the impact toughness, working hardening ability of the material determined by the Metal Matrix structure.
The austenitic matrix high chrome cast iron grinding ball is derived from the above principles by adding austenitizing alloy elements and reducing the carbon content to reduce, reduce the total microstructure, the amount of crystalline carbide, at the same time, using metal mold casting method, after rapid cooling, as-cast austenite and austenite are formed, and the impact toughness of the material is improved. Under the condition of impact wear, martensite transformation is induced by friction and impact, and the comprehensive properties of strength, toughness, high wear resistance, and wear resistance are achieved.
AUSTENITIC, base strength and toughness high chromium cast iron grinding ball material grade are ZQC2.4CR15MN2; the main elements are carbon (C), chromium (CR), manganese (MN).
C on the hardness of the material, the greatest impact, hardness, and C’s content increase and increase. When the C’s content is high, the amount of microstructure and medium carbide increases, the primary carbide is coarse, and the hardness further increases, but the fracture degree of the Matrix increases, the toughness and strength of the material decrease, and the medium crack and spalling phenomenon increase. Therefore, 2.0%-2.7% of c content is suitable.
CR is the main alloy element in high chromium cast iron, which is used to form FECR 7C3 carbides with high microhardness in one part and to enhance the strength of the Matrix by dissolving in the Matrix. In this way, the hard carbide is embedded in the tough Matrix and the body structure so that the high chromium cast iron has both hard and tough properties. The content of CR was 13% ~ 17% , w (CR)/W (C) was 5.6 ~ 7.
MN has the function of stabilizing austenite and carbide; for example, adding MN: 1.5% ~ 3.0% in high chromium cast ball, the as-cast sub-stable austenite structure can be obtained by using metal mold casting process, which can improve the structure of as-cast sub-stable austenite, the toughness of the high chromium cast iron material is obtained, and the material has the conditions of working hardening and using in the impact wear environment.