大壁厚X80钢焊接HAZ沿壁厚方向的低温韧性  

Low temperature toughness of heavy-wall X80 steel welded HAZ along wall thickness direction

作　　者：付超[1] 刘阳[1,2] 王勇 李学达[1] 曲畅[3] Fu Chao;Liu Yang;Wang Yong;Li Xueda;Qu Chang(China University of Petroleum,Qingdao 266580,Shandong,China;Pingdu Technician Institute,Qingdao 266700,Shandong,China;Harbin Welding Institute Limited Company,Harbin 150028,China)

机构地区：[1]中国石油大学(华东),山东青岛266580 [2]平度市技师学院,山东青岛266700 [3]中国机械总院集团哈尔滨焊接研究所有限公司,哈尔滨150028

出　　处：《焊接》2023年第6期9-17,共9页Welding & Joining

基　　金：国家自然科学基金项目(51801233);山东省自然科学基金项目(ZR2017BEE065);东营市科学发展基金(DJ2020015)。

摘　　要：为研究大壁厚X80钢焊接热影响区(HAZ)沿壁厚方向的低温韧性,研究临界再热粗晶区(ICCGHAZ)的局部脆化对焊接接头韧性的影响,选用中俄东线站场用低温钢管(ϕ1422 mm×22 mm)焊接接头,利用-80~20℃系列温度冲击试验分别评价距外表面2 mm,4 mm,6 mm,8 mm处的冲击吸收能量,评价V形缺口前端包含ICCGHAZ时的韧性。结果表明,大壁厚X80钢焊接HAZ沿壁厚方向韧脆转变规律一致,在-60℃以上均具备良好的低温韧性,但应注意CGHAZ的粗晶脆化引起的偶发脆化现象;ICCGHAZ全温度范围内都是焊接接头的局部脆化区(LBZ),其影响整体焊接接头韧性的程度与温度相关,临界温度为-45℃。在-45℃以上时,不会导致整体脆化;-45℃及以下时,随着温度的降低会显著降低整体韧性,增大脆化概率。建议服役温度低于-45℃的大壁厚耐低温管线技术条件增加1组V形缺口经过ICCGHAZ的夏比冲击试验。To clarify low temperature toughness of heavy-wall X80 steel welded heat-affected zone(HAZ)along wall thickness direction and influence of local brittleness of intercritically reheated coarse-grained heat-affected zone(ICCGHAZ)on welded joints,welded joints of cryogenic steel tubes(ϕ1422 mm×22 mm)in the eastern China-Russia station was selected to evaluate impact absorbed energy at 2 mm,4 mm,6 mm,and 8 mm from the outer surface by−80~20℃series of temperature impact tests and toughness when the front end of V-notch contained ICCGHAZ.The results showed that brittle-ductile transition rule of heavy-wall X80 steel welded HAZ along wall thickness direction was consistent,with well low-temperature toughness above−60℃.However,attention should be paid to occasional embrittlement caused by coarse grain embrittlement of CGHAZ.ICCGHAZ was local brittle zone(LBZ)of welded joints throughout the temperature range,the degree of its influence on toughness of the whole welded joints was related to temperature,and the critical temperature was−45℃.At−45℃and below,the overall toughness would be significantly reduced with the decrease of temperature,and probability of brittleness was increased.Under technical conditions for heavy-wall cryogenic pipelines with service temperature below−45℃,it was recommended to increase one set of Charpy impact test,in which V-notch went through ICCGHAZ.

关 键 词：大壁厚X80钢 粗晶区 临界再热粗晶区 局部脆化 

分 类 号：TG406[金属学及工艺—焊接]