管线钢环焊接头热影响区热模拟实验及组织性能分析方法  

Thermal simulation test and microstructure characterization method of heat affected zone of pipeline steel girth weld

作　　者：张鹤松 崔绍华 刘诗琳 王浩 李园 ZHANG Hesong;CUI Shaohua;LIU Shilin;WANG Hao;LI Yuan(Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;China Oil&.Gas Piping Network,Beijing 100013,China;Construction Project Management Branch of China Oil&.Gas Piping Network,Langfang 065000,China)

机构地区：[1]钢铁研究总院有限公司,北京100081 [2]国家石油天然气管网集团有限公司,北京100013 [3]国家石油天然气管网集团有限公司建设项目管理分公司,河北廊坊065000

出　　处：《冶金分析》2024年第8期59-66,共8页Metallurgical Analysis

摘　　要：目前,高钢级大口径石油天然气长输管道普遍采用全自动环焊工艺,其环焊接头热影响区组织性能复杂,建立环焊接头热影响区组织和性能特征的系统性分析方法具有重要意义。本研究针对高级别管线钢的相变特征对焊缝热模拟试验的工艺路线进行了优化设计,利用Gleeble 3500热模拟试验机进行了焊缝热模拟试验,获得了不同热输入和峰值温度条件下的热模拟试样;采用扫描电子显微镜(SEM)和电子背散射衍射(EBSD)对显微组织及其亚结构的特征进行了分析,建立了显微组织与夏比冲击韧性之间的关系。结果表明,与环焊接头热影响区低温韧性密切相关的显微组织特征要素包括有效晶粒尺寸、大角度晶界比例以及马氏体/奥氏体(M/A)组元的形貌及尺寸分布特征;当有效晶粒尺寸较小、大角度晶界比例较高且具有颗粒状的小尺寸M/A组元时,具有较高的低温韧性;当出现大尺寸的M/A岛链状结构时,低温韧性较低。The automatic girth welding process is widely used in high grade oil and gas long distance pipe-lines with large diameter.The microstructure and property of the heat affected zone of the girth weld are complicated.It is important to establish a systematic analysis method for the microstructure and property of the heat affected zone of the girth weld.In this study,the process route of weld thermal simulation test was optimized according to the phase change characteristics of high-grade pipeline steel.Gleeble 3500 ther-mal simulation test machine was used to conduct the weld thermal simulation test,and the thermal simula-tion samples were obtained under different heat input and peak temperature conditions.The microstructure and its substructure were analyzed by scanning electron microscope(SEM)and electron backscattered dif-fraction(EBSD),and the relationship between microstructure and Charpy impact toughness was estab-lished.The results showed that the microstructure characteristics closely related to the low temperature toughness of the heat affected zone of the girth weld included effective grain size,high angle grain bounda-ry ratio,and the morphology and size distribution of martensite/austenite(M/A)components.When the effective grain size was small,the proportion of high angle grain boundary was large,and the small size M/A component was granular,it had high low temperature toughness.When the large size M/A island chain structure appeared,the low temperature toughness was low.

关 键 词：管线钢 环焊接头热影响区 焊接热模拟 显微组织 冲击韧性 

分 类 号：TG115.21[金属学及工艺—物理冶金] TG142.1[金属学及工艺—金属学]