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| Electrochemical Behavior of Cold Rolled 304 Stainless Steel in Dilute Sulfuric Acid Solution |
| Received:June 04, 2021 Revised:July 17, 2021 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/issn.1672-9242.2021.08.014 |
| KeyWord:cold rolled 304 stainless steel corrosion electrochemistry |
| Author | Institution |
| LAI Wei-ya |
State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
| QIN Guo-min |
Daqing Petrochemical Company, CNPC, Daqing , China |
| DU Xiao-ying |
Changqing Petrochemical Company, CNPC, Xianyang , China |
| FU An-qing |
State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
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| Abstract: |
| The purpose of this paper is to test the electrochemical behavior of cold rolled 304 stainless steel samples with different thickness in 0.5 mol/L H2SO4 solution, and study the corrosion rate changing with dislocation density, martensite content and residual compressive stress. The original thickness of the plate was 5 mm, and the thickness of the cold-rolled sample was 4.5 mm, 4.0 mm, 3 mm, 2.5 mm, 2.0 mm and 1.0 mm, respectively. Х ray diffraction method is used to measure residual austenite content in the different thicknesses of sample, and seeking difference worth to martensite volume fraction. Х ray stress meter is used to measure the thicknesses of different sample surface residual compressive stress. IM6ex electrochemical workstation is used to test polarization curve, impedance spectrum and electrochemical noise of samples with different thicknesses. The electrochemical noise is made up of unrelated three-electrode electrolytic cell system. Corrosion electrochemical behavior of cold rolled plastic specimens with different thicknesses is systematically studied by electrochemical test.With the decrease of the cold rolling thickness, the martensite content and residual compressive stress increases. The maximum martensite content and residual compressive stress of the cold rolling sample are approximately 45% and 600 MPa respectively. According to electrochemical test, as the thickness of cold rolling decreases, the corrosion rate first increases and then decreases, with the peak corrosion rate of 7.7 ×10‒4 A/cm2 and the minimum value of 3.2×10‒4 A/cm2. After testing and analyzing the electrochemical noise time-domain curve and frequency-domain curve of the non-plastic specimens with a thickness of 4.0 mm, 3.0 mm and 1.0 mm, the corrosion rate variation trend is consistent with the polarization curve and impedance spectrum test results. With the decrease of cold rolling thickness, dislocation density and martensite content increase, the corrosion of cold rolling specimen is accelerated. When the cold rolling thickness is very thin, the higher residual compressive stress and crystal orientation weaken the influence of dislocation density and martensite content on corrosion, thus reducing the corrosion rate. |
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