Metallurgical Case Studies of Induction Hardening

Using a series of case studies, the relationship of how induction heat treating process parameters affect the metallurgy of production parts is examined. Examples include case studies of quench deflection in automotive wheel bearings; alignment issues in small diametral pitch gears, cracking in large diameter rolled rings, and heat migration issues in axle shafts. Parameters discussed include the importance of starting microstructure, impact of frequency selection, how heat migration can affect case microstructure, and control of overheating. Issues relating to quenching will also be discussed. This presentation makes extensive use of photomicrographs as a means to interpret processing problems and offers solutions to correct induction heat treating issues.