Effects of Si in Cast Iron on Welds Structure of Spheroidal Graphite Cast Iron and Stainless Steel

Abstract

  In this study, spheroidal graphite cast iron (FCD) with different Si content and stainless steel (SUS) were welded by the metal active gas (MAG) welding method using different types of Fe-Ni-Cr welding wires of different Ni and Cr equivalence. After welding, microstructure, Vickers hardness, quantitative and line analysis of alloying elements near the welding zone of each specimen were investigated. The results proved that a ledeburite layer is formed in the bonding interface between FCD and weld metals. Consequently Vickers hardness of the bonded zone was 800 to 900 HV. The widths of the ledeburite layer and heat affected zone (HAZ) was found to decrease with increasing Ni equivalent in welding wires and Si content in the FCD base metal respectively. Chromium carbide was found to precipitate in the grain boundary of weld metals using welding wire containing Cr