Failure analysis of impeller made of FV520B martensitic precipitated hardening stainless steel

•The failure mechanism of this failure impeller was Sulfide Stress Cracking (SSC).•We applied both experiment and FE methods for analysis.•The direct cause was high strength and high applied stress.

This paper presents the failure analysis of a centrifugal compressor impeller. The impeller made of FV520B martensitic precipitated hardening stainless steel, fractured after service for 4 months in moist H2S condition. Efforts were made to analyze the failure impeller in both experiment and FE methods. Sulfide Stress Cracking (SSC) was the primary failure mechanism for this investigated impeller. The martensite structure, the H2S medium, and the applied stress consisted of the SSC system. This paper exhibits the details of investigation and suggests remedial measures to improve performance of this type impeller under H2S corrosive environment.