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高强度23MnNiMoCr54链环钢是煤矿设备主要部件,在进行生产测试过程中发生断裂。对该链条钢裂纹部位进行了金相检测、化学元素成分检测、扫描电镜和断口检验和俄歇电子能谱仪分析。结果表明,链条钢的化学元素组成、气体含量、低倍组织和夹杂物含量符合相关技术标准要求;其金相组织为回火屈氏体,实际晶粒度为4级,断口为典型的脆性断口,断裂方式为沿晶脆性断裂。由于链环在生产过程中热处理不当,淬火加热温度过高,产生过热组织,造成链环晶粒粗大,在随后的回火过程中由于加热温度或者加热时间不当,导致晶界处杂质元素偏析,从而形成回火脆性。在晶粒粗大的情况下同时出现回火脆性,导致了链环钢在试验检查时发生沿晶脆性断裂。
High-strength 23MnNiMoCr54 chain ring steel is the main component of coal mining equipment, in the production test occurred during the fracture. The steel cracks on the chain were metallographic examination, chemical composition testing, scanning electron microscopy and fracture analysis and Auger electron spectroscopy analysis. The results show that the chemical composition, gas content, low magnification and inclusion content of chain steel meet the requirements of relevant technical standards. The microstructure of the chain steel is tempered troostite, the actual grain size is grade 4, the fracture is typical brittleness Fracture, fracture along the crystal brittle fracture. Due to improper heat treatment in the production process of the chain link, the quenching heating temperature is too high, resulting in overheated structure, resulting in the coarser grain of the chain link. In the subsequent tempering process, due to heating temperature or improper heating time, impurity elements are segregated in the grain boundary, Thus forming temper brittleness. In the case of coarser grain temper brittleness at the same time, leading to chain ring steel in the test when the crystal brittle fracture occurred.