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测定了高频淬火后经不同温度回火的 1Cr12Ni2W 1Mo1V钢试样在不同腐蚀环境以及有外加应力作用下的点蚀电位。结果表明 ,1Cr12Ni2W 1Mo1V钢的点蚀萌生不仅与材料的热处理工艺、微观组织以及腐蚀环境有关 ,而且与外加应力有很大的关系。点蚀电位Eb 随氯离子浓度CCl- 增大而降低 ,且Eb 与logCCl- 呈直线关系。对于高频淬火 +低温回火试样 ,在一定氯离子浓度 (4 .373mol/LCl-)下 ,pH值对点蚀电位影响不大 ;而对调质试样 ,pH值对Eb 影响较大。高频淬火后试样的点蚀电位随外加应力变化可分为三个区 :在应力小于 5 0MPa时 ,点蚀电位随应力增加而急剧下降 ;在5 0～ 40 0MPa范围 ,点蚀电位随应力增加而缓慢减小 ;当应力大于 40 0MPa时 ,点蚀电位基本趋于稳定。在此基础上提出了 1Cr12Ni2W 1Mo1V钢在外加应力作用下的钝化膜破裂机理
The pitting potentials of 1Cr12Ni2W 1Mo1V steel samples tempered at different temperatures after quenching at different temperatures were measured under different corrosive environments and with applied stress. The results show that the pitting initiation of 1Cr12Ni2W 1Mo1V steel is not only related to the material heat treatment process, microstructure and corrosion environment, but also has a great relationship with the applied stress. The pitting potential Eb decreases with increasing chloride concentration CCl-, and Eb has a linear relationship with logCCl-. For high-frequency quenching and low-temperature tempering samples, pH value had little effect on pitting potential at a certain concentration of chloride ion (4.373mol / LCl-), while for tempered samples, pH value had a greater effect on Eb. The pitting potential of the sample after high frequency quenching can be divided into three zones according to the change of applied stress: when the stress is less than 500MPa, the pitting potential sharply decreases with the increase of the stress; in the range of 50 ~ 40MPa, the pitting potential The stress increases slowly and decreases slowly. When the stress is more than 40 0MPa, the pitting potential tends to be stable. On this basis, the rupture mechanism of passivation film of 1Cr12Ni2W 1Mo1V steel under the applied stress