A Brief Study on Defect Reduction of Cast Fe-Ni-Cr Alloy (UNS N08120) for Petrochemical Industry

Abstract

In the current advancing world, operability and ease in processability of a material define its selection criteria for the intended applications. Hence, the industrial applications requiring high temperature sustenance, strength and corrosion resistance desperately demand the materials which employ simple processing in an economical way. Contemplating last few decades, it has been discovered that industries like petrochemical, power generation, nuclear energy, etc. greatly relied on nickel-based alloys till Fe-Ni-Cr based alloys were not introduced. The usable components are obtained either in cast or wrought form as per requirements. Fully killed alloy, developed under controlled conditions with some precautions during the casting process can lead to sound casting. The current study adopts a novel preliminary approach to control the quality of cast UNS N08120 material and minimize the possibility of defect generation. The possible reasons behind cast defects and how they transform into intrinsic defects have also been discussed. Calcium-based fluxes are introduced to molten metal as a degassing agent for the elimination of lighter impurities and entrapped gases. By the addition of quicklime (CaO) as a flux material during the sand casting process, an attempt has been made to reduce the presence of gases and impurities by more than 80%.