9Ni钢焊接接头裂纹尖端张开位移试验研究  

Experimental study on crack tip opening displacement of 9Ni steel welded joint

作　　者：路彦龙 王晓军[1,2] 俞伟元[1,2] 孙建新 LU Yanlong;WANG Xiaojun;YU Weiyuan

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050 [2]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《焊接技术》2022年第6期30-33,I0007,I0008,共6页Welding Technology

摘　　要：通过CTOD试验测试了液化天然气(LNG)储罐用9Ni钢埋弧焊(SAW焊)和TIP-TIG焊(简称TT焊)焊接接头的断裂韧性,分析了接头组织对断裂性能的影响。结果表明:SAW焊和TT焊接头CTOD值均能够满足相关工程标准要求,焊接接头达到失稳破坏时,TT焊接头需要更大的力,接头强度更高;SAW焊焊缝金属以长条状的胞状树枝晶为主,其间胞状晶,TT焊焊缝金属为细小均匀分布的胞状晶构成,细小均匀分布的胞状晶能够增加裂纹扩展抗力,利于提高焊缝金属韧性;TT焊应用于LNG储罐立焊缝,不仅可以去除打磨清根环节,还具有与SAW焊相当的焊接效率和焊接质量,自动化程度高,因此,具有很高的发展潜力。The fracture toughness of 9Ni steel rage tanks was tested by CTOD method,and the effect of microstructure on fracture properties of the welded joint was also analyzed by SAW and TIP-TIG welding( TT welding) processes for liquefied natural gas( LNG) storage. The results showed that the CTOD values of SAW and TT welded joints met the requirements of relevant engineering standards. When the welded joint reached instability failure,the TT welded joint needed more forces and bear higher strength. The microstructure of joint welded by SAW was mainly elongated cellular dendrites and some scattered cellular crystals. But that of TT welding process was fine and evenly distributed cellular crystals that might increase the crack propagation resistance and improve the toughness of weld metal. When TT welding process was applied to LNG storage tank vertical weld,it not only could remove the slag grinding and root cleaning,but also got the same automation efficiency and quality as SAW. Therefore, TT welding process would have a high development potential.

关 键 词：9NI钢 焊缝组织 裂纹尖端张开位移(CTOD) 

分 类 号：TG47[金属学及工艺—焊接]