The Effects of Welding Temperature and Time on the Bond Strength in Diffusion Welding of Austenitic Stainless Steel ۳۰۴ to Inconel ۶۰۰

Dissimilar diffusion welding (DW) of superalloy Inconel ۶۰۰ to austenitic stainless steel ۳۰۴ was investigated in argon atmosphere with purity of ۹۹.۹۹۹% at four different temperatures ۹۵۰, ۱۰۰۰, ۱۰۵۰ and ۱۱۰۰◦C for three different bonding times ۱۵, ۳۰ and ۶۰ minutes under ۱۰ MPa uniaxial pressure. Microstructure of the interface and fractography was evaluated by optical and scanning electron microscopy, X-ray diffractometry and energy dispersive spectroscopy. Mechanical property of the weld was assessed with shear test. The results declared that intermetallic compounds such as FeNi, FeCr or Ni۲.۹Cr۰.۷Fe۰.۳۸ are formed across the bond by increasing time and temperature. Type and amount of the formed intermetallic compounds are dependent upon important variables of DW such as temperature and time. Mode of fracture was ductile at ۱۰۵۰ ◦C and brittle at ۱۱۰۰ ◦C due to formation of brittle phases in the latter. Shear strength of the joint is strongly dependent upon depth of diffusion, width of diffusion zone (DZ) and also phases and compounds. The best shear strength, ۱۵۲ MPa, was achieved at ۱۰۵۰ ◦C and ۶۰ min. An equation was estimated by general design of experiment (DOE) for predicting shear strength of the joints.

کلیدواژه ها:

Diffusion welding ، Inconel ۶۰۰ ، Austenitic stainless steel ۳۰۴ ، Shear strength ، Microstructural studies ، Design of experiment