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针对SAW和GMAW在阀体材料上堆焊12Cr密封面进行了焊接工艺评定试验。利用光学显微镜分析了焊接接头热影响区(粗晶区)金属的显微组织;并进行了拉伸、弯曲、冲击试验和焊缝及热影响区的显微硬度测试。结果表明,2.25Cr-1Mo阀体材料具有较强的冷裂倾向,焊前需250℃以上的温度预热;GMAW焊试样得到的焊接接头性能略优于SAW焊试样,两种工艺方法得到的接头性能均满足密封面要求。
Welding process qualification tests were performed on the 12Cr sealing surface of the valve body material for SAW and GMAW. The microstructure of the metal in the HAZ (coarse grain region) of the welded joint was analyzed by optical microscope. The tensile, flexural and impact tests and the microhardness test of the weld and HAZ were carried out. The results show that the 2.25Cr-1Mo body material has a strong tendency of cold cracking and preheating needs to be carried out at a temperature above 250 ℃ before welding; the performance of welded joints obtained by GMAW welding specimens is slightly better than that of SAW welded specimens. The resulting joint performance meets the sealing surface requirements.