42CrMo钢在氯离子溶液中的腐蚀行为研究

发布时间：2018-09-01 08:51

【摘要】：目的通过研究42CrMo钻具用钢在常温下不同Cl~-浓度溶液中的腐蚀行为,为其腐蚀速率的预测奠定一定基础。方法采用浸泡实验、电化学测试技术研究42CrMo在不同浓度NaCl溶液中的平均腐蚀速率和电化学特性,并结合SEM扫描电镜对浸泡58 h后的挂片试样进行分析。结果浸泡实验分析表明,当Cl~-达到60 g/L时,42CrMo钢的腐蚀速率达到最大值,为0.124 g/(m~2·h);当Cl~-浓度继续增大时,腐蚀速率随Cl~-浓度的增加而逐渐减小。开路电位Eocp分析表明,随着Cl~-浓度的增加,Eocp总体呈现下降趋势,显示出较大的腐蚀倾向性。极化曲线分析表明,阴极极化曲线的斜率明显比阳极大,并且自腐蚀电流密度在60 g/L Cl~-溶液中达到最大值,为5.952 35μA/cm~2。腐蚀形貌研究表明,42CrMo浸泡58 h后,表面的腐蚀产物分布并不均匀,均发生了局部点蚀现象。结论随着Cl~-浓度的不断增大,42CrMo钢的平均腐蚀速率呈现先增大后减小的趋势,且在Cl~-为60 g/L时,平均腐蚀速率最大。42CrMo钢在静态常温下高Cl~-浓度溶液中以局部点蚀为主,其电化学腐蚀过程主要受阴极去氧极化的控制。
[Abstract]:Objective to study the corrosion behavior of 42CrMo drilling tool steel in solution of different Cl~- concentration at room temperature, and to lay a foundation for predicting its corrosion rate. Methods the average corrosion rate and electrochemical characteristics of 42CrMo in different concentrations of NaCl solution were studied by immersion test and electrochemical test. The specimens after 58 h immersion were analyzed by SEM scanning electron microscope (SEM). Results the immersion test showed that the corrosion rate of 42CrMo steel reached the maximum when Cl~- reached 60 g / L, which was 0.124 g / (m ~ (-2) h);). When the concentration of Cl~- continued to increase, the corrosion rate gradually decreased with the increase of Cl~- concentration. The open-circuit potential (Eocp) analysis showed that with the increase of Cl~- concentration, Eocp showed a downward trend and showed a large corrosion tendency. Polarization curve analysis shows that the slope of the cathodic polarization curve is obviously larger than that of the anode, and the self-etching current density reaches the maximum value in 60 g / L Cl~- solution, which is 5.952 渭 A / cm ~ (2). The corrosion morphology study showed that the corrosion products were distributed inhomogeneously after immersion for 58 h, and the local pitting corrosion occurred on the surface of C42CrMo. Conclusion with the increasing of Cl~- concentration, the average corrosion rate of 42CrMo steel increases first and then decreases. When Cl~- is 60 g / L, the maximum corrosion rate of steel is local pitting corrosion in the solution with high Cl~- concentration at static room temperature. The electrochemical corrosion process is mainly controlled by cathodic deoxidation polarization.
【作者单位】：重庆科技学院冶金与材料工程学院;
【基金】：重庆科技学院校内科研基金资助项目(CK2015Z18);重庆科技学院研究生科技创新项目(YKJCX1620202) 重庆高校优秀成果转化项目(KJZH17136)~~
【分类号】：TG178

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