螺柱断裂分析及机制探讨

通过断口宏微观形貌观察、能谱分析、金相组织检查、硬度及拉伸性能测试、带状组织评级等手段，对螺柱断裂原因进行分析。结果表明:螺柱的断裂性质为氢脆断裂；起裂部位为螺柱中心位置，此处硬度远高于其他部位；能谱分析和金相组织检查发现裂纹起始处存在严重的碳偏析和合金元素偏析，这是造成螺柱在心部发生氢脆断裂的根本原因。

Fracture Cause and Mechanism Analysis of Double-screw Bolt

The fracture cause of a double-screw blot was studied by means of fracture observation, energy spectrum analysis, microstructure examination, hardness and tensile properties testing, and zonal structure rating. The results show that the fracture mode of the bolt is hydrogen embrittlement fracture, and the crack source is at the center of the bolt, where the hardness is much higher than that of other zones. Energy spectrum analysis and microstructure examination show that there is serious segregation of carbon and alloy elements at the source zone, which is the main cause for hydrogen embrittlement cracking at the center of the bolt.