Failure analysis of a martensitic stainless steel steam turbine blade

Abstract

This work investigated the possible causes of premature failure of a steam turbine blade made from X20CrMo13 stainless steel. During their operation in power generation plants, the blades may suffer service failures that occur naturally or accelerated due to metallurgical or mechanical causes. In this work, one investigated the possible causes of the failure of a martensitic stainless steel turbine blade operating in a 25 MW turbine in a quenched and tempered cogeneration plant that fractured during operation. The results showed a martensitic structure with a delta ferrite content above 5%. Beach marks and fatigue striations were observed, arising from fatigue crack propagation. The tensile test showed an area reduction of 15%, probably due to carbide precipitation.