Q235钢在含硫污水中的腐蚀行为研究

Corrosion Behavior of Q235 Steel in Sulfur-Contaminated Wastewater

为了评价含硫污水的腐蚀性,采用失重法、腐蚀形貌分析、XRD物相结构分析等手段,研究了Q235钢在60℃石化含硫污水介质中不同暴露方式(大气区、全浸区)及不同浸泡时间的腐蚀行为;采用电化学测试技术研究了含硫污水介质中温度对Q235钢电化学腐蚀行为的影响。结果表明:Q235钢在污水介质中腐蚀严重,在大气区的腐蚀性比全浸区的大,大气区最大腐蚀速率达258.0μm/a,全浸区最大腐蚀速率为94.6μm/a,并且随着时间的延长,Q235钢在大气区和全浸区的腐蚀速率均有所降低,表明Q235钢表面的腐蚀产物膜对其腐蚀起到了一定的抑制作用;Q235钢在全浸区的腐蚀产物主要是FeS,在大气区的腐蚀产物主要是FeOOH、FeS、Fe_2O_3和Fe_3O_4;随着含硫污水介质温度的升高,腐蚀电流密度明显增加,低频阻抗值明显降低,污水介质的腐蚀性增强,加快了Q235钢的腐蚀。

The corrosion behavior of Q235 steel in different exposure modes （atmospheric zone, immersion zone） and different immersion dura- tions in petrochemical sulfide-containing wastewater at 60 ℃ was studied by weight loss method, corrosion morphology analysis and＇XRD phase structure analysis. Electrochemical test technique was used to study the effect of temperature on the electrochemical corrosion behavior of Q235 steel in sulfur- contaminated sewage medium. Results showed that the corrosion of Q235 steel in sewage medium was serious, and the corrosion degree in atmospheric zone was larger than that in full immersion zone. The maximum corrosion rate in atmospheric zone and full immersion zone were 258.0 μm/a and 94.6 μm/a respectively. With the increase of time, the corrosion rates of Q235 steel in atmospheric zone and im- mersion zone all decreased, indicating that the corrosion products of Q235 steel surface had some protective effect on the Q235 steel from corro- sion. The corrosion products of Q235 steel in the full immersion zone were mainly FeS, while those in the atmosphere were mainly FeOOH, FeS, Fe2 03 and Fe3 04. With the increase of the temperature of the sulfur-containing sewage medium, the corrosion current density was im- proved obviously, and the low-frequency impedance decreased obviously, which inferred that the corrosion capacity of wastewater medium was enhanced and the corrosion rate of Q235 steel in the sewage medium was accelerated.