Abstract: Multi-arc ion plating technique is adopted to deposite five different thickness TiN coatings on W6Mo5Cr4V2 high speed steel. A curvature method and a finite element method are used to study the TiN coatings residual stresses. Results show that TiN coatings thickness affects greatly on residual stresses, especially on intrinsic stresses. When the coatings thickness changes from 3 μm to 11 μm, the total residual stresses of TiN coatings change from −3.12 GPa to −2.29 GPa, the intrinsic stresses from −1.17 GPa to −0.37 GPa, the thermal stresses from −1.96 GPa to −1.92 GPa. The proportion of thermal stresses in the total residual stresses is about 62%～68%. The TiN residual stresses increase nonlinearly with the increasing coatings thickness, when the ratio of TiN coatings thickness to substrate thickness ξ is 0.017, the total residual stresses reach to the maximum value −3.12 GPa, then decrease with the increasing ξ value. These changes are ascribed to the intrinsic stresses, which are greatly affected by the defects in the TiN coatings, such as the micro-holes, supercooled liquid drops and micro-cracks in the interface between the coatings and the substrate, increase with the increasing TiN coatings thickness, which causes the intrinsic stresses in TiN coatings to release effectively.

Key words: Curvature method, Finite element method, High speed steel, Residual stress, TiN coatings