X70管线钢焊接接头断裂韧度试验  

Experiment on the Fracture Toughness of Weld Joint of X70 Pipeline Steel

作　　者：蔡晓静[1] 林卓英[1] 孟祥琦[1] 姜晶晶[1] 刘飞[1] 冯淼林[1] 

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海200240

出　　处：《实验室研究与探索》2013年第8期33-36,84,共5页Research and Exploration In Laboratory

摘　　要：采用裂纹尖端张开位移(CTOD)测试技术和金相显微组织分析,设计2种三点弯曲试样,测试了X70管线钢埋弧焊焊接接头低温-10℃的断裂韧性,比较接头焊缝、热影响不同区域金属断裂韧性,分析组织结构对力学性能的影响。结果显示,焊缝中心金属性能均匀,裂纹尖端张开位移平均值为0.346 mm,断裂韧性小于热影响区稳定裂纹扩展的CTOD值。热影响区组织不均匀,包括稳定裂纹扩展和中途失稳断裂,出现不同特征的CTOD值。热影响细晶区组织为细小的多边形铁素体和珠光体,在-10℃环境下仍有良好的低温韧性。热影响粗晶区组织主要是板条状贝氏体和粒状贝氏体,而且晶粒尺寸粗大,该区域在-10℃时容易失稳断裂,呈现低温脆性。The crack tip opening displacement （CTOD） testing technology and microstructure analysis were contributed to investigate the fracture toughness of weld joint under submerged arc welding（SAW） of X70 pipeline steel, which was under the condition of the temperature of - 10 ℃ , using two kind of three-point bending specimens to compare the fracture toughness of weld metal and heat affected zone （ HAZ）. The results indicate that value of CTOD in the uniform weld center metal is less than that of heat affected zone with an average value of 0. 346 mm. There are various types of fracture toughness within the area of HAZ with the performances of stable crack growth and fracture instability. In the refined-grain area of HAZ, the toughness is excellent at low temperature due to the fine grain size of polygon ferrite and pearlite. However, the weak toughness and brittle fracture are found because the lath bainite and granular bainite are in the coarse-grain zone of HAZ.

关 键 词：焊接接头 断裂韧度 热影响区 热影响粗晶区 微观组织 

分 类 号：TG142.1[一般工业技术—材料科学与工程]