Plasma ARC welding of NiTi and 304 steel

Abstract

Heterogenous welds of Nitinol and austenitic stainless steel 304 were done by micro plasma welding. Both materials have wide utilization in medicine, especially NiTi is very promisive material, but with rather difficult weldability. The quality of welds was estimated by means of metallography, hardness measurement, and tensile strength test. It was found out that homogenous welding of NiTi as well as heterogenous NiTi+304 welds very much decreases mechanical properties. In homogenous weld, strength, hardness drops to 260 HV (BM 350 HV) because of grain growth. Heterogenous welds have high hardness, up to 800 HV caused by precipitation of brittle intermetalics. PAW was found not to be suitable for nitinol welding. Copyright © (2012) by Danube Adria Association for Automation and Manufacturing (DAAAM).