某酸性气田集输管线16Mn钢三通管件服役1 a(年)后出现裂纹,通过宏观分析、化学成分分析,硬度测试、金相检验、腐蚀产物分析以及扫描电镜断口分析等方法,对三通管件的开裂原因进行了分析.结果表明:三通管件开裂为硫化物应力腐蚀开裂,材料硬度偏高和存在上贝氏体组织是造成管件发生硫化物应力腐蚀开裂的主要原因.建议严格控制三通管件原材料复验以及产品质量检验,同时定期对气田在役三通管件等关键部位进行无损检测,包括探伤、硬度检测等,预防类似事件的再次发生.

Cracks were found on a 16Mn steel tee in one sour gas field after a year of service,and the cracking reasons were analyzed by means of macroscopic observation,chemical compositions analysis,hardness test,metallographic examination,SEM observation and corrosion products analysis.The results show that the cracking of the tee was sulfide stress corrosion cracking,and the higher hardness and existence of upper bainite structure were main reasons for the cracking.It was recommended that the retesting for raw materials and production quality had to be strictly controlled,and non destructive testing should be performed periodically to the key positions in order to prevent similar incidents from happening again,including flaw detection,hardness testing,etc.