| LIU Xuan,SHAO Xiao-feng,GAO Jin,LI Yong-hong,HU Tian-qi,LIANG Shuai,SONG Jia-liang,XIAO Kui.Comparative Study on the Corrosion Behavior of 304 Stainless Steel and 5083-aluminum Alloy in Simulated Urban Underground Environment[J],51(11):287-294, 317 |
| Comparative Study on the Corrosion Behavior of 304 Stainless Steel and 5083-aluminum Alloy in Simulated Urban Underground Environment |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.11.027 |
| KeyWord:304 stainless steel 5083-aluminum alloy underground environment pitting corrosion corrosion behavior environmental spectrum |
| Author | Institution |
| LIU Xuan |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijing , China |
| SHAO Xiao-feng |
Zhuzhou CRRC Times Electric Co., Ltd., Hunan Zhuzhou , China |
| GAO Jin |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijing , China |
| LI Yong-hong |
Zhuzhou CRRC Times Electric Co., Ltd., Hunan Zhuzhou , China |
| HU Tian-qi |
Zhuzhou CRRC Times Electric Co., Ltd., Hunan Zhuzhou , China |
| LIANG Shuai |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijing , China |
| SONG Jia-liang |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijing , China |
| XIAO Kui |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijing , China |
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| Abstract: |
| According to the characteristics of Wuhan's underground environment, the author investigated the dynamic changes of the natural environment involved in Wuhan's underground, and calculated the annual operating time of facilities based on the operating conditions. At the same time, referring to the conversion coefficients of different metal materials, the environmental strength, duration and sequence were clarified, so as to design an indoor test spectrum that simulated the environmental corrosion equivalent of Wuhan. In this paper, the corrosion behavior of 304 stainless steel and 5083 aluminum alloy under simulated environmental spectrum was compared. One acceleration cycle was used to simulate the corrosion amount of 1 year in the actual service environment. In the corrosion cycle spectrum simulated for 1 year, the drying/humid heat test cycle was 3 times, the salt spray/humid cycle test was 3 times for stainless steel, and the salt spray/humid cycle test was 5 times for aluminum alloy. After completing the salt spray/humid cycle, the cleaning part was entered. Both 304 stainless steel and 5083 aluminum alloy were tested for 5 acceleration cycles to simulate the corrosion equivalent of 5 years in the actual environment. The surface morphology, composition of corrosion products and corrosion dynamics of 304 stainless steel and 5083 aluminum alloy were analyzed by scanning electron microscopy (SEM) and laser confocal microscopy. Results show that after 5 cycles, both stainless steel and aluminum alloy had local pitting corrosion to varying degrees. The passivation film on the surface of 5083 aluminum alloy was destroyed and the product accumulated, while the corrosion of 304 stainless steel was slight and had better resistance to pitting, which may be due to the formation of a passivation film on the surface. The main components of films were oxides containing Fe and Cr, and the passivation film could be the main source of the corrosion resistance of stainless steel. In line with the fitting results of the maximum pitting depth, the pitting depth of stainless steel and the corrosion time conforms to the exponential function relationship D1=7.637+1.212e0.517t, and the pits were small and deep, and the depth was increasing continuously. Aluminum alloy conforms to the power function relationship D2=11.75t0.699, so 5083-aluminum alloy mainly formed wide and shallow corrosion pits with a width-to-depth ratio increasing gradually. The corrosion dendrity decreases gradually, and tends to a lower state infinitely. For aluminum alloy, active ions in service environment will lead to the dissolution of passivation film, inducing surface pitting. However, the dissociation diffusion of Cl‒ was affected after the drying/humid heat cycle test, and the ion transfer of the cathode reaction was limited, resulting in a decrease in the rate of the cathode reaction. At the same time, the corrosion products on aluminum alloy surface also hindered the further development of pitting pits. The experiment of simulating the environmental conditions of the underground space in Wuhan shows that with the extension of service time, the pitting corrosion depth of 304 stainless steel in the simulated urban underground space environment develops faster than 5083 aluminum alloy. The pitting depth of 304 stainless steel is affected by the underground operating environment, and will increase year by year; However, the local corrosion of 5083 aluminum alloy will slow down due to the hindering effect of surface passivation film and corrosion products. |
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