Effect of shot peening on the surface properties, corrosion and wear performance of 17-4PH steel produced by DMLS additive manufacturing

• Published in: Archives of Civil and Mechanical Engineering Vol. 21; no. 4; p. 157
• Main Authors: Walczak, Mariusz, Szala, Mirosław
• Format: Journal Article
• Language: English
• Published: London Springer London 24.09.2021; Springer Nature B.V
• Subjects: Additive manufacturing; Alloys; Ceramics; Civil Engineering; Corrosion effects; Corrosion resistance; Corrosion resistant steels; Corrosive wear; Crystal defects; Engineering; Fatigue wear; Grain size; Granular materials; Hardness; Laser sintering; Manufacturers; Manufacturing; Martensite; Martensitic stainless steels; Mechanical Engineering; Mechanical properties; Medical device industry; Medical equipment; Microstructure; Morphology; Nickel chromium steels; Original Article; Precipitation hardening steels; Raw materials; Retained austenite; Scanning electron microscopy; Shot peening; Stainless steel; Steel products; Structural Materials; Surface defects; Surface properties; Surface roughness; Tribology; Wear resistance; Germany; Corrosion; Surface engineering; Wear; 17-4PH steel; Shot peening; Additive manufacturing; Tribology
• ISSN: 2083-3318; 1644-9665; 2083-3318
• DOI: 10.1007/s43452-021-00306-3

Components produced by additive manufacturing (AM) via direct metal laser sintering (DMLS) have typical as-fabricated surface defects. As a result, surface properties of AM products should be modified to increase their strength, anti-wear behaviour, and at the same time to ensure their high corrosion resistance. Surface modification via shot peening is considered suitable for additive manufacturing of medical devices made of 17-4PH stainless steel. The objective of this study was to determine the effect of shot peening pressures (0.3 MPa and 0.6 MPa) and three types of blasting media (CrNi steel shot, nutshell granules and ceramic beads) on the tribological characteristics and corrosion resistance of specimens of DMLS 17-4PH stainless steel. Results demonstrated that shot peening caused steel microstructure refinement and—except for the nutshell shot-peened specimens—induced both martensite (α) formation and retained austenite (γ) reduction. 17-4PH specimens peened with steel and ceramic shots showed the highest increase in surface hardening by approx. ~ 119% (from 247 to 542 HV), which significantly improved their wear resistance. The highest mechanical properties (hardness and wear resistance) and corrosion resistance were obtained for the surfaces modified using the following media: ceramic beads > CrNi steel shot > nutshell granules. Adhesive and fatigue wear were two predominant mechanisms of tribological deterioration. Results demonstrated that the application of shot peening using ceramic beads led to grain size refinement from 22.0 to 14.6 nm and surface roughness reduction, which in turn resulted in higher corrosion resistance of the material. DMLS 17-4PH specimens modified by shot peening using ceramic beads and a pressure of 0.6 MPa exhibited the optimum surface morphology, hardness and microstructure, and thus improved wear and corrosion performance.