Optimization of Stellite Defect in Manufacturing of Engine Valves: A Review

Abstract

Intake and exhaust valves are the important components of an engine valves which are used to control flow and replacement of fuel gases inside the cylinder. This work mainly deals with defect known as stellite defect in different sizes of engine valves; and methodology adopted to prevent valve from stellite defect. Valve base material is low alloy steel (AISI 4140) and upper surface of engine valve is generally hard faced with cobalt material to prevent valve from wear and thermal damages. Stellite defect is generated in the form of crack on to the welded cobalt hard faced surface. Hard facing is done with shielded metal arc welding procedure using stellite 6 (Cobalt-based alloy) as electrode at preheating temperature up to 40°C. By increasing preheating temperature current chances of crack propagation would be decreased