裂纹及气孔对多丝埋弧焊焊缝冲击韧性的影响  

Influence of crack and porosity on impact toughness of multi-wire SAW weld

作　　者：刘斌[1,2] 刘云 牛辉 韦奉[1,2] 李霄 Liu Bin;Liu Yun;Niu Hui;Wei Feng;Li Xiao(Steel Pipe Research Institute,Baoji Petroleum Steel Pipe Co.,Ltd.,Baoji 721008,Shaanxi,China;National Engineering Technology Research Center for Petroleum and Natural Gas Tubular Goods,Baoji 721008,Shaanxi,China;Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]宝鸡石油钢管有限责任公司钢管研究院,陕西宝鸡721008 [2]国家石油天然气管材工程技术研究中心,陕西宝鸡721008 [3]西安石油大学,西安710065

出　　处：《焊接》2021年第11期42-47,63,64,共8页Welding & Joining

基　　金：国家重点研发计划项目(2017YFB0304902)。

摘　　要：文中针对X80钢级管线钢的内四丝+外五丝多丝埋弧焊焊缝,研究了焊缝中气孔及裂纹缺陷对冲击韧性的影响。受裂纹制备技术限制,冲击韧性试样采用了1/4试样,通过与全尺寸试样对比发现,在-10℃下1/4试样与全尺寸试样的冲击吸收能量比例系数为0.17。裂纹与气孔的作用研究结果表明直径为0.5 mm, 1.0 mm的气孔的存在降低冲击韧性,无止裂作用。对于与裂纹扩展路径垂直的预制裂纹,只要其位置在摆锤冲击处1 mm范围外,则可以通过塑性变形提高裂纹扩展阻力,使裂纹扩展路径弯曲,增大冲击吸收能量。横向预制裂纹的作用相当于大直径气孔,其下裂纹面可发生大量塑性变形,具有一定的止裂作用,提高试样的冲击吸收能量。X80管线钢焊缝中缺陷的存在改变了试样的冲击吸收能量,但微观断口分析结果表明断裂性质并未改变,其微观形貌仍然为韧窝型,与无缺陷试样一致。Influence of porosity and crack defects on impact toughness of X80 steel pipeline steel weld by multi-wire submerged arc welding with inner four wires and outer five wires was studied. Due to the limitation of crack preparation technology,1/4 specimen was used as impact toughness specimen. By comparing with full-scale specimen,it was found that the proportional coefficient of impact absorbing energy between 1/4 specimen and full-scale specimen was 0.17 at-10 ℃ . The results of study on the interaction between crack and porosity showed that porosities with diameters of 0.5 mm and 1 mm reduced the impact toughness without crack arresting effect. For the pre-made cracks perpendicular to the crack propagation path,as long as its position was in the zone 1 mm far from the impact location,the plastic deformation could improve crack propagation resistance,curve the crack propagation path and increase impact absorbing energy. The effect of transverse pre-made crack was equivalent to that of large-diameter air hole. A large amount of plastic deformation could occur on the lower crack surface,which had a certain crack arresting effect and improved impact absorbing energy of samples. The impact absorbing energy of X80 pipeline steel weld was changed by the existence of defects in the weld,while the microscopic fracture analysis results showed that fracture behavior was not changed,and microtopography was still dimple type,which was consistent with the defect-free samples.

关 键 词：X80管线钢 焊缝 气孔 裂纹 冲击韧性 

分 类 号：TG401[金属学及工艺—焊接]