60Si2MnA弹簧圆钢拉伸脆断原因分析

Analysis on the Cause of Tensile Brittle Failure of 60Si2MnA Spring Round Bar

针对60Si2MnA弹簧圆钢在拉伸检验时出现拉伸脆断的问题,利用金相显微镜、扫描电镜等观察分析手段,对热处理后的拉伸试样断口形貌进行检查分析;对热轧状态试样进行了化学成分、低倍组织、显微组织和奥氏体晶粒度的检测分析;对热处理拉伸样进行了夹杂物、组织和氧氮氢含量的检测分析。检验结果表明,热轧圆钢心部存在的氢致裂纹以及较高的氮含量是造成弹簧圆钢拉伸脆断的原因。

To the problem of tensile brittle failure of 60Si2MnA spring round bar in the tensile check, the fracture morphology of tensile sam- ple after heat treatment were inspected and analyzed by means of metallographic microscope and scanning electron microscope （SEM） and In-spections were carried out on the chemical composition, maerostructure, microstructure, austenitie grain size of hot rolled state sample and In-spections also were carried out on the non-metallic inclusion, microstructure and Of N/H contents of tensile sample after heat treatment. The test results showed the micro-crack induced by the H in the core of the hot rolled round bar and N content which was comparatively higher in the spring round bar were the reasons caused the tensile brittle failure of 60Si2MnA spring round bar in the tensile check.