采用电化学测试和腐蚀形貌观察，研究了极化对X70钢在不同含量NaCl溶液中腐蚀行为的影响。结果表明：在1.5% NaCl溶液中，与未极化试样相比，极化试样的自腐蚀电流密度更大，腐蚀速率更高；极化作用下腐蚀内层生成的低价铁氧化物参与了阴极反应，加快了阴极还原过程，从而加速了试样的腐蚀。在不同含量NaCl溶液中，极化作用初期出现了3.5%的临界腐蚀浓度；极化作用后期，NaCl含量越大，腐蚀倾向及腐蚀速率反而越小。

The effect of polarization on the corrosion behavior of X70 steel in the solution containing different concentrations of NaCl was studied by electrochemical tests and corrosion morphology observation. The results showed that the self-corrosion current density and corrosion rate of the ploarized sample were higher than those of the unpolarized sample in 1.5% NaCl solution. Ferrous oxides formed in the corrosion layer under the action of polarization were involved in the cathodic reaction, which accelerated the cathodic reduction process and the corrosion of the sample. In NaCl solution of various concentrations, during the initial stage of polarization, the critical corrosion concentration was 3.5%. In the later stage of polarization, the greater the concentration of NaCl, the less the corrosion tendency and the corrosion rate.