低温环境用X80直缝埋弧焊管焊缝韧性波动分析  

Analysis of weld toughness fluctuation of X80 LSAW pipe for low temperature environment

作　　者：黄晓辉 牛爱军[1,2] 王博玉 韦奉[1,2] 张君 刘斌 Huang Xiaohui;Niu Aijun;Wang Boyu;Wei Feng;Zhang Jun;Liu Bin(Chinese National Engineering Research Center for Petroleum and Natural Gas Tubular Goods Co.,Ltd.,Xi’an 710018,China;Baoji Petroleum Steel Pipe Co.,Ltd.,Baoji 721008,China)

机构地区：[1]中油国家石油天然气管材工程技术研究中心有限公司,西安710018 [2]宝鸡石油钢管有限责任公司,宝鸡721008

出　　处：《低温工程》2023年第2期90-96,共7页Cryogenics

基　　金：中国石油天然气股份有限公司重大科技项目“超临界二氧化碳长距离管道关键技术研究”(2021ZZ01-02)。

摘　　要：针对分别采用Ni-Nb-Cr和Ni-Nb-Mo两种合金设计的X80钢级管线用钢,采用同种轧制工艺和埋弧焊接制成ϕ1219×23.7 mm直缝埋弧焊管,发现-30℃低温环境下Ni-Nb-Cr合金板材焊接后焊缝韧性波动大,而Ni-Nb-Mo合金板材焊接后焊缝韧性稳定且较高。开展了金相(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)等试验研究,结果表明:板材成分设计差异导致焊接后过渡到焊缝中Cr和Mo含量不同,Ni-Nb-Cr板材焊接后的焊缝出现4.3%粗大先共析铁素体组织,焊缝低温韧性不稳定,而Ni-Nb-Mo板材焊接后焊缝中针状铁素体相互细密交错、较为均匀,含Mo焊缝低温韧性稳定。含Mo板材焊缝中M-A组元面积占焊缝面积的5.4%,粗大M-A组元和大块状M-A组元分别只占面积的1.0%和9.5%,相比含Cr板材焊接后焊缝中M-A组元面积分数以及粗大M-A和大块状M-A面积分数都较低。所以Mo元素加入能引起焊缝产生更多细小均匀的类圆形或球型M-A组元,弥散分布在焊缝中,确保焊缝低温韧性较高且稳定。The same rolling process and submerged arc welding were adopted to produceϕ1219×23.7 mm longitudinal submerged arc welded X80 steel grade pipeline,which was designed with Ni-Nb-Cr and Ni-Nb-Mo alloys respectively.After welding of Ni-Nb-Cr alloy plate,it was found that the weld toughness fluctuation phenomenon existed at-30℃,while the weld toughness was stable at-30℃after welding of Ni-Nb-Mo alloy plate.OM,SEM,TEM,XRD,and other experiments were proposed to study the weld toughness.The results show that the difference in the design of plate composition leads to the different content of Cr and Mo in the welding seam.The Cr-containing weld seam has 4.3%coarse pro-eutectoid ferrite structure,so the low-temperature toughness of the weld is unstable.The Mo-containing weld seam has an acicular ferrite structure,which intertwined with each other and more uniform,so the low-temperature toughness of the weld is stable.The area fraction of M-A group in the Mo-containing weld seam accounts for 5.4%,and the area fraction of the coarse M-A group and massive M-A group only accounts for 1.0%and 9.5%,respectively.Compared with the area fraction of M-A group in the Cr-containing weld seam,the area fraction of M-A group,the area fraction of the coarse M-A group and massive M-A group are all lower.Therefore,the addition of Mo elements can cause the weld to produce a more fine and uniform M-A group,and the M-A group appears to be round-like or spherical in shape,which is diffusely distributed in the weld,ensuring a higher and stable low-temperature toughness of the weld.

关 键 词：X80 低温 焊缝韧性 显微组织 M-A组元 

分 类 号：TB663[一般工业技术—制冷工程]