Cast components in super duplex alloys - intercomparison between bench moulding and 3D printing

Abstract

This research work is focused on the application of sand moulds made with 3D printing technology to manufacture super duplex stainless steel castings. It is well known that the corrosion resistance of the casting surface of stainless- steel castings deteriorates due to carburisation by the decomposition gas of the resin. In this research, it has been evaluated whether the carburised depth can be reduced by the control of different process variables - wall thickness of the sand mould, application of different organic binder systems and coating. In addition, the effect of carburisation has been evaluated in conventional bench moulding and 3D printed moulds. Carburisation depth is reduced as the sand mould becomes thinner and this effect is also greatly reduced applying a coating to the sand mould. It has become clear that the carburisation problems can be completely eliminated by the combination of these two actions. After these trials a cast impeller is produced in 5A super duplex stainless steel using 3D printing technology with satisfactory results. © 2018 Institute of Cast Metals Engineers. All rights reserved.