According to the industry’s need to an appropriate bonding process for components made of AISI 321 austenitic stainless steel, which is used in power-plant parts such as turbines, transient liquid phase (TLP) bonding of AISI 321 steel using MBF-20 interlayer
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According to the industry’s need to an appropriate bonding process for components made of AISI 321 austenitic stainless steel, which is used in power-plant parts such as turbines, transient liquid phase (TLP) bonding of AISI 321 steel using MBF-20 interlayer was studied in this research. TLP bonding was performed in a vacuum furnace at 1050, 1100, 1150 and 1200oC for 30-120 minutes. The microstructural studies were conducted on the joints using an optical microscope and an scanning electron microscope (SEM). Phase analysis of the joints was also performed a SEM/EDS and XRD system. To investigate the distribution of elements across the joints, line scan analysis was used. The shear strength test and the micro hardness measurement test were conducted on the joints, in order to study the joints’ mechanical properties. The minimum time of complete isothermal solidification at 1050, 1100 and 1150oC was obtained as 75, 45 and 30 minutes, respectively. At the incomplete isothermal solidification condition, Fe-B, Cr-B, Ni-Si and Ni-B phases were observed at the joint centerline and diffusion affected zone (DAZ). With increasing bonding temperature and time, more homogenous joint, lower hardness at the different zones of the joints and higher shear strength were obtained. But for the joints made at 1200oC, higher than the critical bonding temperature, the joint shear strength was reduced. For the joints made at 1150oC for 60 minutes and also at 1050oC for 120 minutes, the maximum shear strength was obtained as 95 and 94 percent of that of the base metal, respectively.
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