含铜贝氏体钢的组织及耐蚀性研究

Microstructure and Corrosion Resistance of Bainitic Steel Containing Copper

通过金相显微镜、透射电镜以及极化曲线技术研究了回火温度和ε-Cu的析出和对一种含铜贝氏体钢耐蚀性的影响。试验结果表明,对于含铜量较低的试样(0.03%、0.50%),Cu含量对耐蚀性的影响不大,缺陷多少及内应力大小是决定试样耐蚀性的主要因素,他们是腐蚀孔的优先形成处。对于含铜量较高的试样(1.0%、1.5%、2.0%),淬火后存在基体中的大量固溶铜可提高试样的耐蚀性。试样在400℃回火后的耐蚀性最好,当回火温度太高时,ε-Cu颗粒粗化导致腐蚀电流增加,耐蚀性下降。

The effects of tempering temperatures and ε-Cu precipitation on the corrosion resistance of a copper-containing bainitic steel were analyzed by optical microscopy, transmission electron microscopy(TEM) and polarization cure test. The results show that, in the samples with low Cu content(0.03%, 0.5%), Cu has very little effects on the corrosion resistance of ULCB steels. The defects and stress deformation is a major factor in determining the corrosion resistance of the sample,where the pitting corrosion is preferential site. Regarding the samples with high Cu content(1.0%, 1.5%, 2.0%), the presence of a large number of solid solution copper in the matrix after quenching can improve the corrosion resistance of the sample. The samples tempered at 400 ℃ have the best corrosion resistance. But when tempering is carried at higher temperature, the coarsening of ε-Cu particles results in the obvious increase of corrosion current and decrease of corrosion resistance.