Surface grain boundary engineering of shot-peened type 304 stainless steel
- 386 Downloads
The effect of thermal annealing on shot-peened Type 304 stainless steel has been examined using electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The objective was to evaluate the potential for surface property control by grain boundary engineering. The near surface microstructure of shot-peened material showed a gradual change of the grain boundary character distribution with depth. Twin (Σ3) and higher order twin grain boundaries (Σ9, Σ27) identified closer to the shot-peened surface had significant deviations from their optimum misorientation. The subsequent application of annealing treatments caused depth-dependent changes of the near surface microstructure, with variations in grain size, low Σ CSL grain boundary populations and their deviation from optimum misorientation. Microstructure developments were dependent on the applied heat treatment, with the near surface microstructures showing similarities to microstructures obtained through bulk thermo-mechanical processing. Shot peening, followed by annealing, may therefore be used to control the near surface microstructure of components.
KeywordsAustenitic Stainless Steel Shot Peening Coincidence Site Lattice Coincidence Site Lattice Boundary Grain Boundary Engineering
The authors are grateful for the support of Rolls-Royce (Marine) Ltd. The authors are grateful to Metal Improvement Company for conducting the peening of the 304 stainless steel. The authors are also grateful for the technical assistance from Judith Shackleton with the X-ray diffraction measurements and Lai Mei Li with the plastic strain measurements.
- 7.Watanabe T (1984) Res Mech 11:47Google Scholar
- 8.Palumbo G (1997) Patent 5,702,543—Thermomechanical Processing of Metallic Materials. United StatesGoogle Scholar
- 9.Palumbo G (1998) Patent 5,817,193—Metals Having Improved Resistance to Intergranular Stress Corrosion Cracking. United StatesGoogle Scholar
- 18.Engelberg DL, Humphreys FJ, Marrow TJ (2007) J Microsc In PressGoogle Scholar
- 22.Jivkov AP, Stevens NPC, Marrow TJ (2007) J Pressure Vessel Technol T ASME In PressGoogle Scholar
- 31.Limoges DL, Palumbo G, Lin PK (2002) Patent 6,344,097 B1—Surface Treatment of Austenitic Ni-Fe-Cr-Based Alloys for Improved Resistance to Intergranular Corrosion and Cracking. United StatesGoogle Scholar
- 32.Lindsay JH (2004) Plat Surf Finish 91(7):1Google Scholar
- 33.Humphreys FJ (2001) Vmap—orientation mapping and quantitative metallography by EBSD. Manchester Materials Science Centre, The University of Manchester, ManchesterGoogle Scholar
- 36.Renzhi W, Xaingbin L, Yuanfa Y (1985) In: Niku-Lari A (ed) Advances in surface treatments: technology, applications, effects, vol 2. Pergamon Press, pp 161–170 (ISBN 0080325351)Google Scholar
- 41.Randle V, Jones R, Marrow J, Engelberg D (2008) Effect of Strain Path and Annealing on Development of Resistance to Intergranular Degradation in Austenitic Stainless Steel. ICOTOM 15. Pittsburgh: TMSGoogle Scholar