Joining of duplex stainless steel through selective microwave hybrid heating technique without using filler material

In this paper, the feasibility of joining duplex stainless steel (SS2205) through a novel microwave joining technique has been investigated. Specimens of cross-section 3.5 mm x 5 mm were selected for butt joining purpose, completed by each half of SS2205 and SS2205. Experiments were carried out in a microwave applicator at 2.45 GHz frequency and 900 W. Duplex stainless steel specimens have been successfully joined through selective microwave hybrid heating technique at 300 s of exposure time. The vertical cavity-type feeder was used to feed charcoal in order to concentrate the heating effect around the joining region. Charcoal powder was used as a susceptor to initiate as well as accelerate the heating process. Optimum process time for joining of SS2205-SS2205 has been found by the trial method, using a constant gap of 30 s between successive trials. The joints have been characterized mechanically through the micro-hardness test. Hardness tests validate a proportional increase in hardness from heat affected zone to the joining region for all manufactured joints. (C) 2020 Elsevier Ltd. All rights reserved.