正火处理对高强钢临界变形粗晶组织的影响

Effect of normalizing treatment on critical deformed coarse grains of high-strength steel

18CrNi4A钢小圆材主要是以锻锤成材,而小圆锻材表面层易出现临界变形粗晶缺陷,严重影响其综合力学性能,采用OM、SEM分析研究了正火处理对18CrNi4A高强钢临界变形粗晶组织的影响。结果表明:860℃正火处理对高强18CrNi4A圆钢临界变形粗晶具有显著的细化作用,消除了晶界遗传的影响,使得圆钢的表面层粗晶形貌得到细化,圆钢心部和边部微观组织整体均得到改善,正火处理后圆钢的平均晶粒尺寸为27μm。

The 18CrNi4A small round bar is mainly made of forging hammer,while the surface layer of small round forging bar is prone to critical deformation coarse grain defects,which seriously affects its comprehensive mechanical properties.Effect of normalizing treatment on the critical deformation coarse grains of high strength steel 18CrNi4A was studied by using OM and SEM.The results show that the normalizing treatment at 860℃has a significant refinement effect on the critical deformation coarse grains of high-strength steel 18CrNi4A round steel,eliminating the influence of grain boundary heredity,and refining the coarse-grained surface of the round bar.The core and edge microstructures are all improved.The average grain size of the round steel after normalizing treatment is 27μm.