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The Corrosion Behavior of Automobile Steel in theSnow Water with Snow Melting Salt

Ning Shugang, Shi Yanhua, Liang Ping， Lin Li

Abstract （423）

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The immersion and electrochemical methods has been used to study the corrosion behavior of automotive steel Q255 in different content of snow melting salt (NaCl) solution. Immersion test show that, the snow melting salt solution is more corrosive than the natural snow solution. The corrosion rate of Q255 steel in the natural water water is smaller than that of the snow melting salt solution, with the corrosion rate of 0.021 07 mm/a after the immersion of 168 h.The corrosion rate increased with the increase of NaCl concentration of the snow solution. The corrosion rate of Q255 steel could reach 0.039 71 mm/a in 3%NaCl solution, the value of which was almost double to the natural snow solution. Electrochemical experiments show that, the presence of chloride ions accelerated the dissolution and mass transfer process of F e 2+ corrosion products, subsequently reduced the adhesion of the corrosion product. Accordingly, the corrosion products would not be able to protect the steel surface, thus the corrosion rate accelerated.

2015, 35 (1): 58-61,66. DOI: 10.3696/j.issn.1672-6952.2015.01.015

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Corrosion Behavior of Q345 Steel in Soil Contaminated by Lead

CHEN Siyao, LI Tao, LI Quanli, SHI Yanhua, LIANG Ping

Abstract （427）

PDF （4075KB）（280）

The lab simulation test of corrosion behavior of Q345 steel in soil contaminated by lead was investigated as time proceeds. The corrosion morphology, corrosion products, chargetransfer resistance and electric current density of Q345 steel were studied by SEM, XRD and electrochemical measurement technology. The experimental results showed that local corrosion and corrosion pits occur at the initial stage, and then with the increase of immersion time, the corrosion forms turn to general corrosion and pitting corrosion. At the initial stage, it could form homogeneous corrosion product film in the sample surface, which had protection effect for matrix, but with the immersion time increases, the corrosion film thicken and fall off. The electrochemical measurement technology research showed that the chargetransfer resistance increased with the time, but decreased suddenly three weeks later and the protective capability of film got weak.

2013, 33 (4): 70-73.

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Corrosion Behavior of Q235 and Q345 Steel in Simulated Seawater

SHI Yanhua, LIANG Ping, WANG Yuan, WU Zhanwen

Abstract （770）

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The effect of soaking temperature and stirring rate on the corrosion behavior of Q235 and Q345 steel in simulated seawater environment (3.5%NaCl) was investigated by using soaking experiment. The surface morphology and chemical composition of corrosion products were analyzed by means of SEM and EDS. The results show that the corrosion rate of Q235 and Q345 steel has little difference and increase with increasing temperature in static seawater environment, reaching approximately 0.28 mm/a at 40 ℃. The stirring rate has a significant effect on the corrosion behavior of Q235 and Q345 steel and the corrosion rate accelerates with increasing stirring rate. When stirring rate is 300 r/min, the corrosion rate reaches 1 mm/a that is about 3.5 times as big as temperature effect. Uniform corrosion was observed on Q235 steel in simulated seawater. But the local corrosion morphology is found on Q345 steel and the main corrosion product is iron oxides. The application of Q345 material should be cautious compared with Q235 material in the same seawater environment.

2013, 33 (1): 5-8.