论文部分内容阅读
采用化学成分分析、裂纹宏观分析、硬度测试及金相检验等方法,对空心圆柱模具内孔壁的纵向裂纹进行了检验和分析。结果表明:该空心圆柱模具内孔壁的纵向裂纹属于淬火裂纹,其主要原因是淬火冷却时模具各部分冷却速度不一致,尤其是模具轴向中部处的内孔冷却速度比外壁慢,导致在内孔壁形成以组织应力为主的切向拉应力,当内孔壁受到的切向拉应力大于钢的断裂强度而产生纵向裂纹。
The longitudinal cracks in the inner wall of the hollow cylindrical mold were tested and analyzed by chemical composition analysis, macro crack analysis, hardness test and metallographic examination. The results show that the longitudinal crack in the inner wall of the hollow cylindrical mold belongs to the quenching crack. The main reason is that the cooling rate of each part of the mold during quenching and cooling is not consistent. In particular, the inner hole in the axial middle of the mold cools more slowly than the outer wall, Tissue stress-oriented tangential tensile stress is formed in the pore walls. When the tangential tensile stress on the inner pore wall is greater than the fracture strength of the steel, longitudinal cracks are generated.