利用等离子堆焊技术在PH17-4马氏体沉淀硬化不锈钢表面堆焊Stellite12钴基合金熔覆层,并在堆焊后对其进行热处理.采用光学显微镜(OM)、扫描电镜(SEM)、电子探针(EPMA)、维氏显微硬度计等测试手段,研究了固溶及固溶后时效处理对堆焊层、母材热影响区组织结构及显微硬度的影响.结果表明:焊缝金属与母材间界面熔合良好,堆焊层组织均匀,在母材中靠近熔合线处出现了宽度为2 mm左右的热影响区;焊后进行1 050℃的固溶处理,母材热影响区消失,组织均匀化,堆焊层组织细化,同时显微硬度提高;固溶后分别进行480℃,540℃及620℃的时效处理,母材中有硬质相析出,显微硬度增加,且随着时效温度升高显微硬度降低.%Precipitation hardening martensite stainless steel PH17 -4 was deposited with Co-based alloy stellite12 by the plasma -transferred arc welding, and then heat treatment was carried out. The microstructure and microhardness of the coating and heat affected zone (HAZ) were analyzed, and tested by optical microscope, scanning electron scanning microscope, EPMA and hardness tester. The results show that the interface between weld metal and base metal is favorable, and the microstructure of the coating is uniform. The width of HAZ is about 2 mm. HAZ disappears and the microstructure of coating is refined after solution treatment at 1 050 ℃, and the microhardness of the coating increases. Aging treatment at 480℃ , 540 ℃and 620 ℃ after solution results in high microhardness due to the formation of precipitation, but the microhardness decreases with the increase of aging temperature.
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