P91导汽管焊后热处理对母材组织与性能影响  

Effect of P91 PWHT on Performance and Microstructure of Parent Material

作　　者：赵永峰[1] 蔡红生[1] 耿进锋[1] 马东方[1] 牛玉静[1] 

机构地区：[1]河南省电力公司电力科学研究院,河南郑州450052

出　　处：《热加工工艺》2014年第7期54-56,60,共4页Hot Working Technology

摘　　要：由于对P91焊缝的焊后回火热处理控制不当,导致过回火。过回火致使焊缝附近P91母材硬度降低到约145 HB,与正常管段硬度约205 HB相比降低了60 HB。采用光学显微镜对低硬度区和硬度合格区组织进行观察,结果显示低硬度区组织异常、组织劣化,硬度合格区组织正常。对低硬度区和硬度合格区常温、高温拉伸强度以及夏比冲击功进行了测试,并用扫描电镜对拉伸和冲击断口进行了分析。结果表明,低硬度区与硬度正常管段相比,拉伸强度、夏比冲击功降低,力学性能劣化,断口形貌不佳。分析认为过回火导致了P91组织异常,材料力学性能降低,影响了其长期安全使用,应予以更换或重新热处理。Because of improper controlling of post weld heat treatment （PWHT） of P91 weld, the over-tempering of welding appears. Over-tempering can lead to the hardness decrease to about 145HB, which was lower than 60HB compared with normal pipe. By using optical microscope, the microstmcture of unqualified hardness area and normal hardness area were observed. The results show that the microstmcture of unqualified hardness area is abnormal while normal area is qualified. The hardness of abnormal area and hardness of normal area of P91 steel at room temperature, high-temperature tensile strength and Charpy impact energy were measured. By scanning electron microscopy （SEM）, the tensile and impact fTacture surface was analyzed. Compared with normal pipe, the tensile strength and Charpy impact energy of hardness of unqualified pipe greatly reduce. The mechanical properties deteriorate, and fiacture morphology is poor. The analysis considers that over-tempering leads to P91 microstructure abnormalities, the decrease of mechanical properties, the decrease of continued safe use, and then the material should be replaced or be heat-treated again.

关 键 词：P91钢 过回火 组织 力学性能 

分 类 号：TG441.8[金属学及工艺—焊接]