Q235和Q345钢在模拟海水中的腐蚀行为

以Q235和Q345钢为研究对象,通过浸泡实验,对比研究了两种材质在模拟海水(质量分数3.5%NaCl)中浸泡温度和搅拌速度对腐蚀行为的影响规律,采用扫描电镜和能谱检测研究腐蚀后试样表面微观形貌及腐蚀产物成分。研究得出以下结论:静态海水中Q235和Q345钢腐蚀速度相差不大,且腐蚀速度随温度升高而增大,40℃时腐蚀速度约0.28mm/a;搅拌速度对腐蚀行为的影响是显著的,随搅拌速度增大腐蚀加速,300r/min时,腐蚀速度可达1mm/a,约是温度影响的3.5倍。腐蚀微观形貌观察发现Q235钢在模拟海水介质中表面发生了均匀腐蚀,而Q345钢表面出现了明显的点蚀形貌,腐蚀产物以铁的氧化物为主。在相同条件下的海水介质中,Q345钢的应用应谨慎。

Corrosion Behavior of Q235 and Q345 Steel in Simulated Seawater

The effect of soaking temperature and stirring rate on the corrosion behavior of Q235 and Q345 steel in simulated seawater environment （3. 5% NaC1） 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/rain, 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.