蒸汽输送用X80钢级UOE焊管的高温蠕变行为研究及断口分析  

High Temperature Creep Behavior and Fracture Analysis of X80 UOE Welded Pipe for Steam Distribution

作　　者：李龙 章传国 孙磊磊 郑磊[1] 胡平 LI Long;ZHANG Chuanguo;SUN Leilei;ZHENG Lei;HU Ping(Tube and Pipe Department,Baosteel Research Institute,Baoshan Iron and Steel Co.,Ltd.,Shanghai 201900,China)

机构地区：[1]宝钢中央研究院钢管技术中心,上海201900

出　　处：《焊管》2021年第7期1-8,共8页Welded Pipe and Tube

摘　　要：为了确保X80钢级蒸汽输送用UOE焊管服役安全性,在450℃下对其管体和焊缝进行不同应力条件的蠕变试验。结果表明,管体预期蠕变持久寿命长于焊缝,但均满足使用要求;管体和焊缝蠕变断口存在显著差异,管体试样出现明显颈缩现象,断口呈韧窝状,焊缝试样无明显颈缩,断口为沿晶型和韧窝型的混合断口;焊缝试样HAZ粗晶区晶粒粗大,且晶界上存在较多夹杂,在蠕变试验过程中,空洞易在晶界处萌生并长大,形成裂纹源并发生沿晶断裂,从而降低其蠕变性能;焊缝蠕变在较低应力条件下,断口出现部分解理形貌,抗蠕变性能进一步恶化。In order to ensure the service safety of X80 UOE welded pipe for steam transportation,creep tests were carried out on the pipe body and weld under different stress conditions at 450℃.The results show that the expected creep rupture life of the pipe is longer than that of the weld,but both meet the service requirements.The results show that there is a significant difference in the creep fracture between the pipe and the weld.The pipe body sample has obvious necking phenomenon,and the creep fracture is dimple type.The weld sample has no obvious necking,and the creep fracture is a mixed fracture of intergranular and dimple type.The grain size in HAZ coarse grain zone of the weld samples is coarse and there are many inclusions on the grain boundary.During the creep test,voids are easy to form and grow at the grain boundary,forming crack sources and intergranular fracture,thus reducing its creep properties.Under the condition of low stress,the creep fracture of the weld appears partial cleavage morphology,and the creep resistance is further deteriorated.

关 键 词：UOE焊管 高温性能 蠕变 断口形貌 

分 类 号：TG111.8[金属学及工艺—物理冶金]