Metallurgical Failure Investigation of a Surface Hardened Drive Shaft Made of Tempered Low-Alloy Steel 25CrMo4 (1.7218)

Abstract A drive shaft of a multifunctional mechanical processing machine for large components broke down during processing. The OEM shaft was worn-out after years of operation and was recently replaced. The replaced drive shaft was delivered to the materials laboratory of the Berlin gas turbine plant in order to identify the cause of the damage. It was found that the component failed due to high cycle fatigue failure, HCF, on the tooth roots after a short period of operation. The teeth of the damaged shaft were inappropriately induction surface hardened.