磨煤机加载拉杆失效分析

摘要

Fractured loading pull-rod of a roll type coal pulverizer was detected by means of chemical composition analysis,hardness test,OM and SEM.The results show that the fracture of the loading pull-rod is a bending fatigue failure,which arises essentially from the deep machining after quenching and tempering responsible for decrease in the surface strength,and from the sharp and deep turning incisions responsible for local severe stress concentration and,thereby,considerable decrease in the bearing capability of the pull-rod.%采用化学成分分析、硬度测试、光学显微镜、扫描电镜等手段对断裂的辊式磨煤机加载拉杆进行了检测。结果表明，加载拉杆的断裂为弯曲疲劳断裂。拉杆经调质处理后进行大深度的机加工降低了表面材料的强度，表面尖而深的车加工沟痕引起局部的强烈应力集中，使拉杆的承载能力大大下降，是造成拉杆疲劳断裂的主要原因。