Investigations on material characterization of joints produced using microwave hybrid heating

Abstract This paper describes the fabrication of butt joints of specimens of stainless steel SS304-SS316 through microwave hybrid heating technique. The filler material used here is powder form of SS316. Interface gap in between the surfaces to be joined is kept between 0.5 mm to 1 mm. This gap is then filled with filler metal powder. Microwave hybrid heating technique is used for the processing of materials of frequency 2.45 GHz and power supply of 900 Watt. Activated charcoal powder is used as susceptor which absorbs the microwave energy and ignition takes place after which high energy is produced over the joining area which is absorbed by the joining region. Due to burning of charcoal powder, temperature at the joining region reach above the melting point of powder due to which melting as well as joining of interface powder with parent metals takes place. Specimen exposure time is selected through many trials and it is found that best joint is obtained at 360 s. Joints characterization has been carried out to check the surface morphology of processed joints with the help of scanning electron microscopy and energy dispersive x-ray spectroscopy. Mechanical characterization is done with the help of cross-sectional hardness tests.