中频感应加热弯制91级弯头开裂分析

摘要

通过金相检验、断口检验及模拟热循环等方法对中频加热弯制的91级弯头开裂原因进行了分析。结果表明开裂是因为加热温度过高，加之中频加热的趋肤效应，使钢管近表面发生过热乃至过烧，晶界结合力严重弱化，弯制形变应力作用下开裂。并详细地描述了中频加热弯管超温的失效特征，从金属角度讨论了中频加热弯管的相关注意事项。%By metallographic examination,surface observation and simulated heat cycle tests the failure reason of grade 91 elbow cracked during induction heat bending has been analyzed.The results revealed that the elbow outside surface overheated or even overburnt led the grain boundary seriously weakened, and then fractured under the bending stress due to heating temperature too high and skin effect of induc-tion heating.The over temperature failure characteristic of hot bending by induction heating were de-scribed,and the matters need attention were discussed in induction heating bending from point view of metal.