November/December AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 1 8 2 8 formation variables and martensite content leading to a change in residu- al stress. Analysis of residual stress and martensite content at different tem- peratures shows that martensite con- tent decreases at a temperature of 150 ° C, which is higher than the de- formation-induced martensite phase transformation temperature (Fig. 8). At 150 ° C, the deformation-induced mar- tensite phase transformation behavior disappeared, and the martensite con- tent decreased by 48.4% compared with room temperature. No phase transformation behavior led to a de- crease in the residual stress value. As shown in Fig. 8, the residual stress val- ue after stamping at 150 ° C decreased by 40.6%. ~AM&P Acknowledgment: We thank Henan Shenzhou Heavy Head Co. Ltd. for supporting this experimental work, Mr. Li of Changchun Automotive Ma- terials Research Institute for his advice on residual stress measurement, and other team members for help with ex- periments and discussions. For more information: Shi-Hong Zhang, Institute of Metal Research, Chinese Academy of Sciences, Shen- yang 110016, China, +86 24.8397.8266, shzhang@imr.ac.cn . References 1. X.T. Deng, et al., Residual Stress Analysis of Hot Stamping for Spherical Head, Forging & Stamping Technol., 24, p 14-18, 2016. 2. A. Laamouri, H. Sidhom, and C. Braham, Evaluation of Residual Stress Relaxation and its Effect on Fatigue Strength of AISI 316L Stainless Steel Ground Surfaces: Experimental and Numerical Approaches, Intl. J. of Fatigue, 48, p 109-121, 2013. 3. P.J. Withers, et al., Recent Advances in Residual Stress Measurement, Intl. J. of Pressure Vessels and Piping, 85, p 118-127, 2008. 4. Z. Ding, B. Li, and S.Y. Liang, Phase Transformation and Residual Stress of Maraging C250 Steel During Grinding, Matls. Letters, 154, p 37-39, 2015. 5. J. Shen, et al., Research Status of Residual Stress Physical Method Measurement Techniques, Matls. Rev., 26, p 120-125, 2012. 6. M. Salio, T. Berruti, and G.D. Poli, Prediction of Residual Stress Distri- bution After Turning in Turbine Disks, Intl. J. Mech. Sci., 48, p 976-984, 2006. 7. K. Moussaoui, et al., Studying the Measurement by X-Ray Diffraction of Residual Stresses in Ti6Al4V Titanium Alloy, Matls. Sci. & Engrg. A, 667, p 340-348, 2016. 8. G. Cios, et al., The Investigation of Strain-Induced Martensite Reverse Transformation in AISI 304 Austenitic Stainless Steel, Metal. and Matls. Trans. A, 48, p 4999-5008, 2017. 9. R. J. Gaboriaud, F. Paumier, and B. Lacroix, Disorder-Order Phase Transformation in a Fluorite-Related Oxide Thin Film: In-Situ X-Ray Diffrac- tion and Modelling of the Residual Stress Effects, Thin Solid Films, 601, p 84-88, 2016. 10. J. Toribio, et al., Residual Stress Redistribution Induced by Fatigue in Cold-Drawn Prestressing Steel Wires, Construction and Buckling Matls., 114, p 317-322, 2016. Fig. 7 — Comparison between residual stress andmartensite content at locations on outer wall of dome-shaped specimen. Fig. 8 — Comparison between residual stress andmartensite content on outer wall of dome- shaped specimen formed at room temperature (25°C) and 150°C.