变形对微合金钢组织性能的影响

INFLUENCE OF DEFORMATION ON MICROSTRUCTURE AND PROPERTIES OF MICRO ALLOYED STEEL

利用金相显微镜观察了微合金钢在奥氏体区高温变形后等温不同时间再水淬的显微组织,并用电阻仪和显微硬度计测量了相应的电阻率和显微硬度。结果表明,变形使得晶粒细化,促进碳氮化物析出,从而提高硬度。保温初期NbCN析出物导致电阻的小幅上升,同时基体中溶质原子含量急剧减少,电阻明显下降,致使初期电阻率整体下降,之后随着碳氮化物持续长大,与基体的关系从共格到半共格直至完全非共格,产生很大畸变,电阻率呈上升趋势。

The microstructure, electrical resistivity and hardness of the micro alloyed steel after deformation at high temperature and then holding for different times was studied by optical microscope, resistance instrument and micro hardness tester. The results showed that the deformation led to grain refinement and promotion of carbonitride precipitation. The NbCN precipitates resulting in the resistance increased lightly, while the matrix solute atom content decreased sharply which caused the initial first resistivity decreased totally. Then carbonitride continued to grow, the relationship with the matrix from the coherent to the semi-coherent until completely non-coherent developed, generating a large distortion so that a sharp rising appeared in the resistivity.