某机组高压外缸开裂原因分析

采用残余应力测试、力学性能测试、断口分析和金相检验等方法分析了某机组ZG15Cr1Mo1V-B2钢高压外缸在泵水时开裂的原因。结果表明:开裂始于高压外缸内表面的补焊区,该区为缩松缺陷密集区,材料塑性指标不符合技术条件要求,导致缺陷处的承载能力下降,应力集中加剧;另高压外缸补焊区的残余应力较大,硬度与基体之间的差异也较大;可见,汽缸在补焊过程中未能将铸造缺陷彻底清除干净,焊接质量不高和焊后去应力处理不充分是造成该高压外缸在泵水时开裂的主要原因。

Reason Analysis on Cracking of a Unit High Pressure Outer Casing

The cracking reasons of a ZG15Cr1Mo1V-B2 steel high preesure outer cylinder which cracked when pumping were analyzed by means of residual stress test,mechanical properties test,fracture analysis and metallographic examination.The results show that the cracking started from the repairing welding area where loose defects concentrated and the ductility of the material didn't meet with the requirement.So the bearing capacity of the defect area decreased and the stress concentration was aggravated.At the same ti...