Table of Contents Author Guidelines Submit a Manuscript
Scanning
Volume 2017 (2017), Article ID 1928198, 8 pages
https://doi.org/10.1155/2017/1928198
Research Article

Corrosion Properties of 34CrMo4 Steel Modified by Shot Peening

1School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
2The Center of Material Analysis and Testing, Chongqing University of Science and Technology, Chongqing 401331, China

Correspondence should be addressed to Kejian Li; moc.liamg@nnaijekil and Dengming Chen; moc.621@26gnimdc

Received 28 July 2017; Revised 30 September 2017; Accepted 23 October 2017; Published 21 December 2017

Academic Editor: Guosong Wu

Copyright © 2017 Qiang Zheng 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

A nanocrystalline layer was prepared on the surface of 34CrMo4 steel by time controlling shot peening (SP, i.e., 1, 5, 10, and 20 minutes). Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis, and transmission electron microscope (TEM) were applied to analyze the surface, cross-sections, and grain size of the specimens before and after SP. The electrochemical corrosion behavior was used to simulate a liquid under the oil and gas wells environment. It was characterized by the potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The analysis results show that the surfaces of the SP samples were very rough and had numerous cracks. A passive film on SP surface was formed by nanocrystalline grains. However, the passive film formed in the initial stage was not dense or uniform, and cracks occurred in the passive film during peening, resulting in a decrease in corrosion resistance.