Evaluation of the effect of shot peening over the fatigue strength of AISI 304 stainless steel

• Grant number: 17/14126-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2017
• End date: September 30, 2018
• Field of knowledge: Engineering - Mechanical Engineering - Manufacturing Processes
• Principal Investigator: Armando Ítalo Sette Antonialli
• Grantee: Rulian Pedro Morais
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Shot peening is an abrasive machining process that promotes local strain hardening on the surface of mechanical parts, which induces compressive residual stresses that may significantly improve their lifetime. Several authors report 19 to 67 % increase in the fatigue limit of ferrous alloys subjected to shot peening, numbers that raise the urge for new studies that might link surface integrity and mechanical behavior under cyclic loads. In this work, the effect of shot peening over the fatigue strength of AISI 304 austenitic stainless steel will be evaluated through rotating Cantilever bending fully reversed fatigue tests, that is, with zero mean stress and minus one stress ratio, using the staircase method (up-and-down). The specimens will be tested at two different conditions: as machined by turning, and after finishing by shot peening, Additionally, optical microscope metallography and plastic characterization by tensile test will be held, besides X-ray diffractometer residual stress measurements on every specimen before and after fatigue tests. Results will be compared using three statistical approaches found in the literature, that may highlight the effect of shot peening over the fatigue strength of AISI 304 stainless steel. (AU)