模拟汽车动态大气环境对热轧钢板的腐蚀行为影响

Effect of Simulated Dynamic Atmospheric Environment on Corrosion Behavior of Hot Rolled Steel Plate

研究了热轧钢板(SPHC)在汽车动态行驶中及温湿度环境仓下的腐蚀速率,并采用扫描电镜(SEM)、X-射线衍射仪(XRD)分析了SPHC钢经历5天、7天、20天试验后的腐蚀面的微观形貌和物相。结果显示,在模拟汽车动态大气环境下,相对湿度交变运行下的SPHC钢的腐蚀速率要高于相对湿度单一运行,而两者的腐蚀速率均随试验时间呈现出相似的非线性变化趋势。在试验的第1到5天,腐蚀速率迅速增加,锈层表面生成Fe_(2)O_(3),这是腐蚀过程的初期加速阶段;当试验进行到第7天时,腐蚀速率开始下降,此时锈层比较密实,腐蚀面生成Fe_(2)O_(3)和具有保护性的α-FeOOH,增强了SPHC钢的抗腐蚀性能;然而,当试验持续至第20天时,腐蚀速率再次上升到一个较高水平,锈层开始剥落,表面生成Fe_(2)O_(3)、微量的α-FeOOH和Fe_(3)O_(4)等腐蚀产物。

The corrosion rate of hot rolled steel plate(SPHC)was studied in dynamic driving and temperature and humidity environment.The morphology and phase of the corroded surface of SPHC steel after 5 days,7 days and 20 days were analyzed by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The results show that the corrosion rate of SPHC steel under the simulated dynamic atmospheric environment is higher than that under the single operation,and the corrosion rate of both of them presents a similar nonlinear change trend with the test time.In the first five days of the test,the corrosion rate increased rapidly,and Fe_(2)O_(3) was formed on the surface of the rust layer,which was the initial acceleration stage of the corrosion process.On the 7th day of the test,the corrosion rate began to decrease,and the rust layer was relatively dense,and Fe_(2)O_(3),and a-FeooH were formed on the corroded surface,which enhanced the corrosion resistance of SPHC steel.However,when the test continued to the 20th day,the corrosion rate again rose to a higher level,the rust layer began to peel off,and the surface generated Fe_(2)O_(3),trace amounts of a-FeOOH and Fe_(3)O_(4) corrosion products.