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Advances in Materials Science and Engineering
Volume 2018 (2018), Article ID 2892361, 6 pages
https://doi.org/10.1155/2018/2892361
Research Article

Forming Mechanism of High-Speed Cold Roll Beating of Spline Tooth

1School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China
2Shanxi Key Laboratory of Metallic Forming Theory and Technology, Taiyuan 030024, China
3School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China

Correspondence should be addressed to Zhi-Qi Liu; moc.qq@983830372

Received 29 January 2018; Accepted 20 March 2018; Published 15 April 2018

Academic Editor: Guru P. Dinda

Copyright © 2018 Ting Niu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The spline tooth of ASTM 1045 was fabricated by high-speed cold roll-beating (HSCRB) process at room temperature. Microhardness of the spline tooth was examined by a nanoindenter. The grains and misorientation angle distributions were measured by electron backscatter diffraction (EBSD). The results showed that the microhardness was improved up to 1280 m deep from the surface of the spine tooth. The microhardness and the grain sizes gradually decreased in the direction away from the surface. On the surface, the fraction of ultrafine grains increased up to about 90%, and the average grain diameter (which was ∼0.56 µm) decreased by 71.4%. The model of grain evolution during HSCRB process is proposed in this work. New grains appear first on the boundaries of the elongated grains within numerous subgrains. The elongated grains are refined as a result of subgrain rotation. By analyzing the HSCRB technical principle, we concluded that the process parameters affect the refinement degree of studied steel by determining beating pass, beating pass interval time, and strain rate.