Microstructure and Properties of TIG Surfacing Co-Based Alloy on UMCo50 Process Burner

The surfacing layer of cobalt-based alloy is prepared using the tungsten inert gas welding (TIG) process and employing the UMCo50, ST1 and ST6 filler materials. The metallographic testing, hardness, wear and corrosion testing of different surfacing layers have been carried out. Each area of the surfacing layer is characterized using the optical and scanning electron microscope (SEM). Cellular and a few columnar dendrites have been observed near the fusion line of the UMCo50 surfacing layer, and cellular structure is observed in the central region. Dendrites and cellular crystals have been observed in the ST1 and ST6 surfacing layers. The average hardness of UMCo50, ST1 and ST6 surfacing layers are 320 HV, 672.3 HV and 497.5 HV, respectively. The wear loss of the ST1, ST6 and UMCo50 surfacing layer is 2.71 mg, 4.35 mg, and 14.57 mg, respectively. The corrosion weight loss of the ST1, ST6 and UMCo50 surfacing layers are 0.0388 g, 0.0477 g and 0.0833 g, respectively.