LPB as a Crack Initiation Resistant Surface Treatment Process for Case Hardened Steels

The goal of the proposed SBIR work is to develop Low plasticity burnishing (LPB) as a manufacturing process to increase the high cycle fatigue (HCF) strength of case carburized steels by creating a crack initiation resistant surface structure with superior surface roughness. Bell Helicopter (TPOC: Ryan Ehinger, Project Area Lead for Drive System Research) will be the OEM partner in this proposed program. LPB offers the benefits of controlled depth and magnitude of compression, a smooth often mirror-like surface finish, and very low cold work (hence stable compression). Costs for implementing the LPB process are comparable to conventional shot peening and other peening processes, leading to a highly favorable cost-benefit ratio. The depth of compression can be precisely controlled at every location on the component by initial selection of the tool and closed loop process monitoring and control. LPB tool pressure control provides a process that exceeds six sigma. With a total solution approach, the LPB application and the combined benefits of automated design and analytical tools developed at Lambda will lead to a TRL and MRL of 7 at the end of Phase II of this program.