Effect of High Velocity Oxygen Fuel (HVOF) Coating on the Tensile and High Cycle Fatigue Properties of AISI 1045 Steel

Effect of high velocity oxygen fuel (HVOF) coating on the tensile and high cycle fatigue properties of S45C steel was investigated. Three kinds of thermal spray coating material layers (WC-12Co, WC-10Co-4Cr and Cr₃C₂-25NiCr, wt.%) were fabricated by using HVOF thermal spray process on the pre-machined tensile and fatigue specimens of S45C steel. Cr plating layer as a reference coating material was also prepared on the tensile and fatigue specimens and compared. Thicknesses of HVOF coating layers were found to be WC-12Co : 90.7㎛, WC-10Co-4Cr : 131.4㎛, and Cr₃C₂-25NiCr : 74.0㎛. Tensile test results showed that HVOF coated specimens have higher values of yield strengths and elongations than those of Cr plated specimens. In the high cycle fatigue results, fatigue limits of 365 MPa (WC-12Co), 340 MPa (WC-10Co-4Cr), 395 MPa (Cr₃C₂-25NiCr), and 330 MPa (Cr-plating) were obtained. HVOF coated samples showed better fatigue properties than that of Cr plated samples. After tensile and fatigue tests, fractographies of HVOF thermal sprayed specimens were observed. Based on the above results, the deformation and fracture mechanisms of thermal sprayed S45C steel were identified. [Supported from the ‘Industrial Strategic Technology Development Program’ found by Ministry of Trade, Industry and Energy, Korea]