X65钢高频焊管焊接区的显微组织和低温韧性

为查明X65钢高频焊管焊接区冲击功异常的原因,通过光学显微镜和X射线衍射对母材、焊缝及焊接热影响区进行微观研究.结果表明,显微组织对金属低温韧性有显著影响.当块状铁素体组织较多时,焊接区晶粒尺寸大,硬度小,冲击功低;当多边形铁素体组织较多时,焊接区晶粒尺寸小,硬度大,冲击功高.通过合理的热处理工艺,可在焊接区获得粒状铁素体组织,提高冲击功,改善焊缝和焊接热影响区低温韧性.

Micro-structure and low temperature toughness in welding zone of X65 high-frequency welding pipe

To investigate the reason of the great difference in impact toughness of welding zone of X65 high frequency welding pipe,the microstructures of specimens taken from parent metal,heat-affected zone and welding seam were analyzed through X-ray diffraction and optical microscope.Results show that the microstructures of specimens have a significant impact on the low-temperature toughness. When the massive ferrites are more,in the weld zone appear large grains,small hardness and low impact energy.Otherwise,when ...