【作者】 方百友；

【Author】 Fang Baiyou;Baosteel-Nippon Steel Automotive Steel Sheets Co., Ltd.;

【机构】 宝钢日铁汽车板有限公司技术质量管理部；

【摘要】 本文运用金相显微镜、白光干涉显微镜、X射线衍射、腐蚀电化学测试以及湿热试验等多种方法,就DP590双相组织与表面形貌和残余应力对其腐蚀行为的影响进行了研究。研究结果发现马氏体含量最高的试样没有表现出最快的腐蚀速度,这表明DP590钢的腐蚀行为并不仅仅受到马氏体含量的影响。事实上,粗糙的表面以及残余拉应力均会降低钢的耐蚀性能,而压应力能够有效的减缓腐蚀的萌生过程。因此具有较高含量的马氏体,却同时具有较为光滑的表面并受到残余压应力影响的试样表现出与马氏体含量较低的试样相似的耐蚀性能。也就是说,DP590钢的腐蚀速度并不仅仅依赖于某个单一因素,而是受到这些因素的综合作用。更多还原

【Abstract】 In most literatures, the corrosion rate of DP steels mainly depended on the volume fraction of martensite, in which the increased amount of martensite significantly lifted the corrosion rate. The effects of surface topography and residual stress on the corrosion rate of DP590, however, are seldom taken into consideration. In this paper, the effects of these two factors are discussed combining with that of the dual phase microstructure. The surface features of DP590 steel samples were characterized with optical interferometric microscopy and X-ray diffraction, respectively. And corrosion properties were evaluated using potentiodynamic polarization and damp heat tests. It was found that the sample with a highest volume fraction of martensite did not show the highest corrosion rate, vice versa. It was indicated that the volume fraction of martensite was not the only determinant factor in this case. In fact, rougher surface and tensile residual stress bear adverse effects on the corrosion resistance of the steels, while compressive residual stress is considered to effectively retard corrosion initiation. Therefore, the sample with a higher martensite proportion, a relatively smooth surface and a compressive residual stress may possess a similar corrosion behavior to the one with a lower martensite proportion. The experiment results in this study verified that he corrosion rate of DP590 was not determined by only one factor, but the comprehensive effect of these factors.更多还原