摘要
某公司负责施工的天然气管线,地基下沉,打压时发现,多处环形焊缝开裂。对其法兰、焊肉、焊材进行化学成分分析,焊缝金属及母材进行金相检验等,找出了焊缝开裂的原因。结果分析表明:该环形焊缝开裂的主要原因是焊条的药皮中硫含量超标,引起焊缝金属中硫元素过高,硫与铁形成低熔点共晶物,在焊缝熔池凝固过程中形成热裂纹,在打压过程中失稳扩展开裂。
The cracking of many circumferential weld is found as ground subsidence during the pressure test in the natural gas pipelines been responsible for a company. Reason of welds cracking is found out after chemical composition analysis for its flange,weld deposit and welding consumable,and metallographic examination for weld metal and base metal. The test results show that the main reason of circumferential weld cracking is exceeding of sulfur content in welding agent of electrode to cause excessive sulfur elements in the weld metal. Low melting point eutectic formed by sulfur and iron elements,which lead to hot crack formed during solidification in molten pool of weld. and the cracking of instability propagation formed during pressure test.
出处
《热处理技术与装备》
2018年第1期62-64,共3页
Heat Treatment Technology and Equipment
关键词
热裂纹
环形焊缝
失稳扩展
hot crack
circumferential welds
instability propagation
