为了研究连续油管对接焊时焊接热影响区的显微组织特征,选取连续管管材及焊接接头,通过显微硬度变化确定焊接热影响区(heat affected zone,HAZ)位置,观察热影响区显微组织,利用金相显微镜、XRD、EBSD及TEM对HAZ区域进行表征。试验结果表明,连续油管管材显微组织主要以粒状贝氏体为主,其中还存在少量针状铁素体及等轴晶铁素体组织,EBSD试验结果得出管材平均晶粒尺寸为4.9μm,利用TEM观察到大量位错及第二相。并对焊接热影响区中粗晶区、细晶区及不完全重结晶区进行了表征,得到了一系列具有对比性的结果。
In order to research the microstructure of coiled-tubing pipe and welding heat affected zone(HAZ), coiled-tubing and welded joint were selected, the position of HAZ was determined by the change of microhardness, the microstructure of HAZ was observed, and the HAZ region was characterized by metallographic microscope and transmission electron microscope. The results showed that the microstructure of coiled-tubing was mainly granular bainite and slightly acicular ferrite and equiaxed ferrite. The EBSD results showed that the average grain size was 4.9 μm, and a large number of dislocations and second phases were observed by transmission electron microscope. The coarse-grained, fine-grained and incomplete recrystallization regions in the HAZ were characterized, and a series of comparative results were obtained.
Welded Pipe and Tube