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采用钨极氩弧焊在X45CrSi9-3钢基体表面堆焊钴基合金。堆焊后,将堆焊试样分别放入500、550、650、700、750及780℃的热处理炉中对其进行热处理。对不同温度热处理后堆焊层的硬度进行了测试,采用光学显微镜观察了母材及不同温度热处理后堆焊层的金相组织。研究结果表明:在氩弧焊热源作用下,X45CrSi9-3钢表面发生微熔。钴基合金进入熔池后并未与基体发生剧烈的熔池搅拌。堆焊后,堆焊层界面平齐,无气孔及裂纹等缺陷,实现了冶金结合。钴基合金堆焊层的组织为共晶碳化物相(Cr,Fe)7C3和基体相γ(Co)。(Cr,Fe)7C3呈共晶形貌,并将γ(Co)夹于其间。随着焊后热处理温度的提高,堆焊层洛氏硬度值增加;热处理温度达到750℃时,其硬度值最高,进一步提高热处理温度,硬度值略有下降。
Using TIG welding on the X45CrSi9-3 steel substrate surface welding cobalt-based alloy. After welding, the welding samples were placed in 500, 550, 650, 700, 750 and 780 ℃ heat treatment furnace for heat treatment. The hardness of the surfacing layer after heat treatment at different temperatures was tested. The microstructure of the surfacing layer and the base metal after heat treatment at different temperatures were observed by optical microscope. The results show that micro-melting occurs on the surface of X45CrSi9-3 steel under the effect of argon arc welding heat source. Cobalt-based alloy into the pool did not violent pool with the substrate stirred. After surfacing, surfacing layer interface flush, no holes and cracks and other defects, to achieve a combination of metallurgy. The structure of the Co-based alloy overlay is eutectic carbide phase (Cr, Fe) 7C3 and matrix phase γ (Co). (Cr, Fe) 7C3 has a eutectic morphology with γ (Co) sandwiched in between. With the increase of the post-weld heat treatment temperature, the Rockwell hardness of the surfacing layer increases. When the heat treatment temperature reaches 750 ℃, the hardness value is the highest, further increasing the heat treatment temperature, the hardness value decreases slightly.