热输入对CT90连续管对接接头热影响区组织及性能的影响

The Effect of Heat Input on Microstructure and Properties of Heat Affected Zone of CT90 Coiled Tubing Welded Joint

为了保证连续油管对接焊后焊接接头的使用性能,研究了不同热输入对CT90连续油管对接接头热影响区组织及性能的影响,采用TIG焊工艺分析了3层对接焊过程中焊缝热影响区的组织和性能的变化。结果显示,粗晶区、完全重结晶区组织以贝氏体为主,不完全重结晶区、回火区组织为块状铁素体、少量珠光体和渗碳体,随着热输入的增加,焊缝的晶粒尺寸变大,热影响区中软化区的宽度及幅度增大,软化区逐渐远离焊缝中心。

In order to ensure the performance of butt welding joint, the different heat input of microstructure and properties of heat affected zone of butt welding joint of CT90 coiled tubing were researched, and the changes of microstructure and properties of heat affected zone in 3 layers butt welding were analyzed by TIG welding.The results showed that the main structure of coarse grain zone and complete recrystallization zone was bainite, the structure of incomplete recrystallization zone and tempered zone were massive ferrite, minor pearlite and cementite. With the addition of heat input, grain size of weld became larger, the width and extent of softening zone in heat affected zone were increased, and the softening zone was away from the weld centre.