热输入对QT900对接焊CGHAZ韧性的影响  

Influence of heat input on toughness in coarse grain zone of QT900 coiled tubing butt welding

作　　者：侯春锋 石凯[1] 李霄[1] 梁维[1] 

机构地区：[1]西安石油大学材料科学与工程学院,西安710065

出　　处：《焊接学报》2017年第5期120-124,共5页Transactions of The China Welding Institution

摘　　要：文中采用热模拟技术、显微分析技术和断口分析等手段,研究了焊接热输入对QT900连续油管对接焊焊接热影响区粗晶区冲击韧性的影响规律及其脆化机理.结果表明,5 kJ/cm的焊接热输入下热影响区粗晶区可获得板条束细小的针状贝氏体,有利于吸收冲击能量,冲击韧性优良;随着焊接热输入从5 kJ/cm增大到10 kJ/cm,热影响区粗晶区晶粒尺寸增大,贝氏体铁素体板条变宽,并且沿着原始奥氏体晶界析出了网状的仿晶型铁素体,导致热影响区粗晶区韧性的恶化.In this paper,thermal simulation technology,microscope analysis and fracture surface topography analysis techniques are used to study the influence of heat input on the impact toughness and embrittlement mechanism of coarse grain zone in butt weld of QT900 coiled tubing. The result shows that fine needle lathe bainite can be obtained under 5 kJ/cm heat input,it improves impact energy and provides good impact toughness to coarse grain zone; with the heat input increaseed from 5kJ/cm to 10 kJ/cm,grain size increases in coarse grain zone,bainitic ferrite laths become widen,and the grain boundary allotriomorphs will nucleate and grow along the original austenite grain boundaries, which decrease toughness in coarse grain zone.

关 键 词：连续油管 焊接热输入 焊接粗晶区 冲击韧性 

分 类 号：TG406[金属学及工艺—焊接]