Joining of SS304-SS316 through novel microwave hybrid heating technique without filler material

Abstract

Microwaves are type of electromagnetic radiations with a wide range of wavelength varying from 1 m to 1 mm and frequency between 300 MHz and 300 GHz for different wavelengths. Rapid heat transfer takes place through microwaves and these waves can easily penetrate throughout the material leading to localized volumetric heating. Joining of materials through microwaves seen a rapid increase in current years over conventional methods because of its high diffusion rate, lower power consumption, lower defects and improved mechanical and physical properties; at the same time; this technology is non hazardous to the environment. In this work, microwave joining technique has been used to join stainless steel of different grades (SS304 and SS316). Experiments were carried out in 900 W and 2.45 GHz microwave oven. Specimens of cross-section 6 × 5 mm2 were selected for butt joining purpose, completed by each half of SS304 and SS316. No filler powder was used during this joining process. Direct joining of stainless steel specimen SS304 and SS316 was done with the help of microwave hybrid heating technique. Charcoal powder was used as susceptor to accelerate the initial heating process. Optimum process time for joining of SS304-SS316 has been found by trial method, using constant gap of 10 s between successive trials. The joints have been characterized mechanically through micro-hardness test. Physical characterization of joint was also performed through scanning electron microscopy and energy dispersive spectroscopy method. Results show that proposed method is able to develop joints with good mechanical and physical properties.