The characterization of HG10MNN and an evaluation of suitability for use in naval applications

• HG10MNN alloy showed good strength, hardness and ductility compared to NAB.
• In air, four point bending fatigue tests suggest an endurance limit between 8 and 10 ksi.
• As compared to NAB, HG10MNN has excellent casting and corrosion behavior.

An initial mechanical evaluation and standard material characterization were conducted for the stainless steel alloy HG10MNN in order to evaluate its use in naval and marine applications. HG10MNN is a newly developed stainless steel designed for improved resistance to mechanical and thermal fatigue. This material could eventually replace the Nickel–Aluminum–Bronze (NAB) currently used in many naval propulsion systems, however, additional testing is required to validate the alloy's performance characteristics. Although stainless steels are commonly used in marine applications, there is insufficient HG10MNN documentation to permit its use in naval ship design. This investigation also involved an evaluation of castability and machinability to determine whether the material could be formed into the complex shapes required in a modern naval construction. Initial results showed that the alloy exhibits a fully austenitic microstructure in the as-cast condition, while maintaining acceptable mechanical properties and superior castability as compared to NAB.