Zheng Qiang, Li Kejian, Yin Xueguo, Li Bingbing, Li Chunhong, Ma Yilong, Sun Jianchun, Chen Dengming
School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China.
The Center of Material Analysis and Testing, Chongqing University of Science and Technology, Chongqing 401331, China.
Scanning. 2017 Dec 21;2017:1928198. doi: 10.1155/2017/1928198. eCollection 2017.
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.
通过控制喷丸时间（即1、5、10和20分钟）在34CrMo4钢表面制备了纳米晶层。采用场发射扫描电子显微镜（FESEM）、X射线衍射（XRD）分析和透射电子显微镜（TEM）对喷丸前后试样的表面、横截面和晶粒尺寸进行了分析。利用电化学腐蚀行为模拟油气井环境下的液体。通过动电位极化试验和电化学阻抗谱（EIS）对其进行表征。分析结果表明，喷丸处理后的试样表面非常粗糙，有许多裂纹。喷丸表面形成了由纳米晶粒组成的钝化膜。然而，初始阶段形成的钝化膜不致密、不均匀，喷丸过程中钝化膜出现裂纹，导致耐蚀性下降。
