高温回火对GCr15SiMn轴承钢组织和力学性能的影响

Effect of high temperature tempering on microstructure and mechanical properties of GCr15SiMn bearing steel

研究了500℃以上高温回火对GCr15SiMn轴承钢组织形貌和力学性能的影响。结果表明,随回火温度的升高,试验钢的强度和硬度下降,塑性和韧性上升;在高温回火过程中,淬火马氏体的形态逐渐消失,碳化物聚集长大,强度和硬度下降,塑性升高。这是由于碳化物的长大对位错的钉扎作用减弱,而大颗粒的碳化物可以阻碍裂纹的扩展,使断裂的解理面减小,韧性得到改善。碳化物是影响力学性能的重要因素。

Effect of high temperature tempering on microstmcture and mechanical properties of GCr15SiMn bearing steel was investigated. It is shown that the strength and hardness of the steel decrease with the increase of tempering temperature while the ductility and toughness increase ; During the tempering process, the as-quenched martensite gradually disappears and the carbides aggregate and grow up. When the carbides grow up, the dislocation pinning effect is weakened, so the strength and hardness decrease and the ductility increases. Certainly, the crack expansion is impeded due to the large carbide particles and the fracture cleavage plane is decreased, so the toughness is improved. It is concluded that the carbides significantly affect the mechanical properties.