Microstructure Characteristics of 30CrMnSiNi2A Steel After Ultrasound-Aided Deep Rolling
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JMEPEG (2013) 22:1642–1648 DOI: 10.1007/s11665-012-0459-x
Microstructure Characteristics of 30CrMnSiNi2A Steel After Ultrasound-Aided Deep Rolling Junfeng Xie, Youli Zhu, Yuanlin Huang, Chang Bai, and Xionglin Ye (Submitted June 21, 2012; in revised form November 6, 2012; published online December 28, 2012) Effects of ultrasound-aided deep rolling (UADR) process on the microstructure of 30CrMnSiNi2A steel were studied using nanohardness tester, x-ray diffraction (XRD), scanning electron microscope (SEM), electron backscattered diffraction (EBSD), and transmission electron microscope (TEM). Results show that surface nanocrystallization, grain refinement, strain-induced martensite transformation, shear bands, intense shear texture {110} Æ111æ, and rolling texture {112} Æ131æ in the surface and subsurface were produced by the severe plastic deformation in the UADR process. Although deep compressive residual stress, work hardening, and grain refinement were generated in the treated surface and subsurface, the full width at half maximum (FWHM) value of the XRD peak in this zone decreased ‘‘abnormally’’, which means that the FWHM value may not characterize correctly the degree of work hardening and grain refinement in this situation.
Keywords
FWHM, nanostructure, shear band, texture, UADR
1. Introduction 30CrMnSiNi2A steel is widely used in Chinese aviation industry as a kind of low-alloyed steel with ultra-high strength and favorable fatigue performance. However, the material has some disadvantages such as sensitivities to stress concentration, hydrogen embrittlement, and corrosion fatigue. Researches and applications have been carried out since the late 1970s in order to study and improve the fatigue performance of 30CrMnSiNi2A steel via shot peening and other surface treatments (Ref 1, 2). However, it is worth noting that shot peening has limitations on the enhancement of fatigue resistance of 30CrMnSiNi2A steel, especially in low cycle fatigue realm, due to the shallower compressive residual stress layer (typically within 0.3 mm) and deteriorated surface roughness produced by the shot peening process. Recently, developed alternative mechanical surface enhancement procedures, such as low plasticity burnishing (LPB), cold deep rolling (CDR), ultrasonic peening (UP), and ultrasonic-aided deep rolling (UADR) (Ref 3-6) extended researches and applications in combat against fatigue failures of parts in demanding applications, with regard to deeper layer of compressive residual stress, improved surface roughness and refinement of surface microstructure. Wang et al. (Ref 7) investigated the surface nanocrystallization in an ultrasonic surface rolling processing (USRP) and found that nanograined surface layers of 100 lm thick and accompanying plastic flow of 150 lm deep were produced in the treated subsurface of 40Cr steel. Altenberger et al. (Ref 4) Junfeng Xie, Youli Zhu, Yuanlin Huang, and Xionglin Ye, Faculty of Remanufacture Engineering, Academy of Armored Force Engineering, Beijing, China; and Chang Bai, China North Vehi
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