Low-alloy bainite ductile iron abrading-ball

Abstract

A low alloy bainite ductile iron grinding ball is provided. The chemical compositions of the grinding ball (weight percentage) are as follows: 3.5 to 3.8 percent of C, 2.8 to 3.8 percent of Si, 0.1 to 0.5 percent of Mn, 0.15 to 0.35 percent of Cr, 0.35 to 0.5 percent of Mo, less than or equal to 0.03 percent of S, less than or equal to 0.1 percent of P, 0.03 to 0.08 percent of Mg, 0.5 to 1.5 percent of Cu, 0.01 to 0.03 percent of Bi and 0.02 to 0.07 percent of Re, and the rest is Fe. The ball is made through the following heat treatment steps: (1) heating the grinding ball to be at 880-960 DEG C; (2) quenching in mechanical oil; (3) taking the ball out when the surface temperature is 150-230 DEG C; (4) implementing the sands burying and the insulation tempering rapidly with temperature for 6-8h or taking the ball out for the air cooling after the sands burying and the insulation tempering for 1-3h. The obtained grinding ball has the advantages of reasonable organization structure, high surface strength, high hardness, good wear resistance, high inner toughness and perfect comprehensive property and is especially applied to crushing materials.

Description

technical field [0001] The invention relates to metal materials, especially ductile iron, more specifically low-alloy bainite ductile iron grinding balls. Background technique [0002] Low-alloy bainitic ductile iron has high strength, hardness and toughness, and has good casting performance. It is known as one of the major achievements in cast iron metallurgy in the past 40 years. At present, the heat treatment methods for obtaining bainitic ductile iron mainly include traditional salt bath isothermal cooling and water medium controlled cooling method isothermal quenching (CN200510044091.X) Wei Deqiang "Development and Production of Bainite Ductile Iron Grinding Ball Material" (Journal of Xiangtan University of Science and Technology 2005.Vo27 No1.: 94-97) discloses the production of low alloy (M o , M n 、C u 、C r ) The method of ductile iron grinding ball material, using 900 ~ 950 ℃ hot open case rapid cooling (oil quenching) to M s point slightly lower, avoiding the ...

AI Technical Summary

Problems solved by technology

The isothermal furnace cannot effectively control the holding temperature, which affects the structure and material properties of ductile iron. The residual austenite in the structure increases, and even pearlite transformation occurs. Therefore, when the size of the part is large, the depth of the hardened layer cannot reach Requirements, so that the internal strength, hardness and toughness of the material will be significantly reduced