A3钢在含Fe^（3＋）的盐酸溶液中的脆断机理

FRACTURE MECHANISM OF MILD STEEL IN HYDROCHLORIC ACID CONTAINING Fe￣(3+)

应用原子氢渗透速率测量传感器测定了在５％ＨＣｌ溶液中添加不同含量的Ｆｅ（３＋）时体系渗氢水平（渗氢电流）的变化；采用慢应变速率拉伸（ＳＳＲＴ）试验研究了Ａ３钢在５％ＨＣｌ＋Ｆｅ（３＋）溶液中于阴、阳极极化电位下的脆断敏感性及其断裂机制．结果表明，随着溶液中Ｆｅ（３＋）含量的增加，渗氢水平逐渐下降；Ａ３钢在溶液中的脆性系数（Ｆ％）随Ｆｅ（３＋）含量变化曲线上出现一个极小值；在含０．０１％Ｆｅ（３＋）的盐酸溶液中，阴极极化使Ｆ％增大，阳极极化则使Ｆ％减小；而在含０．３％Ｆｅ（３＋）的盐酸溶液中，极化的作用相反．结合断口的ＳＥＭ照片分析，认为５％ＨＣｌ溶液中Ｆｅ（３＋）含量的增加，使得Ａ３钢在该溶液中的断裂由氢致开裂机制向阳极溶解机制转变．

A new kind of electrochemical sensor was used for measuring the permeation rate of atomic hydrogen(H permeation current) through the sensor in 5% HCl solution containing Fe(3+) at different concentrations.The susceptibility and mechanism of brittle fracture of A3 mild steel were studied by slow strain rate tensiletechnique (SSRT), scanning electron microscope (SEM) and cathodic/anodic polarization measurements.The embrittlement susceptibility of the steel in the solution was expressed as the index of embrittlement(F%).The results showed that the fracture mechanism of the steel in 5% HCl aqueous solution containingFe(3+)would be changed from hydrogen induced cracking (HIC) to anodic dissolution in nature with theimcrease of the concentration of Fe(3+) in the solution.