铸铁喷焊组织及力学性能研究

Study on the Surfacing Microstructure and Mechanical Property of Surfacing Cast Iron

为了解决铸铁焊补中焊缝处存在白口、淬硬组织以及裂纹等问题,采用氧乙炔火焰喷枪喷焊自熔性合金粉末F101和Ni60焊接球墨铸铁和用铸铁焊条Z308电弧冷焊球墨铸铁,并对试样进行抗拉强度、硬度测试和金相组织观察。结果表明:用铸铁焊条电弧冷焊后焊缝有白口、淬硬组织及裂纹;用Ni60合金粉末喷焊后熔合区硬度出现突变,硬度高达701HV,与母材硬度值差别很大,用F101合金粉末喷焊后热影响区及焊缝处硬度值与母材差别不大;金相组织观察表明焊缝与母材除了机械结合外,还有冶金结合。喷焊的焊缝无裂纹,且结合强度高于铸铁焊条的焊缝。

In order to avoid chill and quenched structure, spheroidal graphite iron was welded using oxyacetylene torch with self-fluxing alloy powder F101 and Ni60 and it was welded using arc cold welding method with cast iron electrode Z308. The strength of extension, hardness and metallurgical structure of samples were inspected. The results indicate that chill, quenched structure and crack were appeared in the welding seam of arc cold welding. The hardness of fusion area of surfacing using Ni60 alloy powder mutated up to 701HV, and it is harder much more than that of base metal. The hardness of heat-affected zone and welding seam of surfacing using F101 alloy powder is almost the same as that of base metal. And metallurgical structures indicate that there exists metallurgical bonding besides mechanical bond, and there isn＇t any crack in the welding seam of surfacing and the bond strength of it higher than that of arc welding with cast iron electrode.