Analysis of welding techniques for spheroidal graphite cast iron

¹ University of Johannesburg, Engineering Metallurgy, Johannesburg, South Africa
² Advanced Materials Division, Mintek South Africa

^* Corresponding author: ed.maya.dm@gmail.com

Abstract

Although Spheroidal Graphite Cast Iron (SGCI) has good machinability, high strength, and ductility, its high carbon content makes welding difficult because it forms martensite and carbides in the heat-affected areas. This study examines welding techniques used in SGCI, with an emphasis on process variables, filler metal selection, and the impact of thermal cycles. It has been demonstrated that nickel-based electrodes with Inconel 625 fillers are efficient in lowering carbide precipitation and encouraging graphite production, which enhances ductility and lowers the danger of cracking. Better mechanical strength and toughness are achieved by further reducing hardness gradients, residual stresses, and brittle microstructures with preheating and post-weld heat treatments. A comparative study of Tungsten Inert Gas (TIG) and Shielded Metal Arc Welding (SMAW) reveals that the most dependable method for creating strong, machinable joints in SGCI components is to combine nickel-based fillers with ideal thermal treatments.