薄壁低碳钢管钎焊应力腐蚀开裂分析

Analysis of stress-corrosion-crack( SCC) of low-carbon thin-walled steel pipes when being brazed

在以钢代铜的背景下,针对薄壁低碳钢管在加工及使用过程中出现泄漏、断裂等个案,运用金相技术、断口扫描分析手段,同时排除其他如材质等可能因素,经分析讨论,推断出应力腐蚀是导致钢管开裂的主要原因之一。通过对应力腐蚀三因子———温度、应力、腐蚀介质影响进行详细分析,提出采取适当的加热工艺、控制钢管残余应力水平等措施,可降低低碳钢管钎焊应力腐蚀开裂的风险。

With the background of＂replacing copper by steel＂,based on some incidents like leakages and ruptures,which occurred in the process when low-carbon and thin-walled steel pipes were processed and in use,the authors,together with their team mates used metallographic techniques and fracture scanning means to get a conclusion that the stress-corrosion-crack（SCC） was one of the main reasons that led to cracks of steel pipes and other factors like material quality,etc.were excluded after analysis and discussion.With detailed analysis of the three stress corrosion factors—temperature,stress,corrosive media,an appropriate heating process was advanced to control the residual stress in steel pipes,which could really lower the risk of stress-corrosion-crack of low-carbon steel pipes when they were brazed.