Abstract
This study investigates the influence of geometric parameters on residual compressive stress (RCS) in hollow cylindrical parts subjected to induction surface hardening, a crucial factor for improving fatigue strength in components under cyclic loading. Through analytical modeling and numerical simulations, the authors develop expressions that quantitatively decompose and evaluate various factors contributing to residual stress distributions in internally and externally hardened hollow cylinders. Using Ck45 steel with consistent wall thickness (30 mm) but varying internal diameters (25-100 mm), the research demonstrates that while volumetric strain consistently produces high RCS of approximately -600 MPa regardless of geometry, the deviatoric strain components exhibit significant differences between internal and external hardening processes. Notably, small internal radii combined with internal hardening generate substantial tensile stresses due to tangential deviatoric strain distribution, potentially counteracting the beneficial compressive stresses from martensitic transformation. Conversely, external hardening, particularly with small external radii, produces additional compressive stresses that enhance the overall RCS beyond what would be expected from martensitic dilatation alone—providing valuable insights for optimizing induction hardening processes in various geometrical configurations.
