研究了新型低合金钢Q415NH在模拟南海大气环境下的腐蚀行为及耐蚀机理,为新型耐候钢的研制与开发提供思路,为合金元素Ni对金属耐蚀性的影响提供依据。实验通过0.1% NaHSO₃和1% NaCl混合溶液中的周浸腐蚀实验模拟南海大气环境,并检测不同腐蚀周期后的腐蚀速率、腐蚀形貌及腐蚀产物。研究表明,Q415NH在模拟南海大气环境下的耐蚀性优异,其耐蚀机理主要表现为:合金元素的添加改变了低合金钢的微观组织,形成大量细小弥散的贝氏体,影响金属的耐蚀性;由于合金元素的影响,Q415NH具有更高的腐蚀电位与锈层电阻,促进金属阳极氧化,提高金属耐蚀性;Q415NH的锈层更致密、细小、连续,并且具有阳离子选择性,从而阻挡腐蚀性阴离子的侵入,提高锈层的保护性和金属的耐蚀性。

The corrosion behavior of a new low alloy steel Q415NH is investigated by its exposure to alternate conditions of 12min immersion in a mixed NaCl and NaHSO₃ solution and 48min drying at 45℃ to provide a basis for developing new weathering steels and studying the effects of alloy elements on the corrosion resistance under high Cl^- atmospheric conditions. The results suggest that the corrosion resistance of Q415NH is much better than Q420, and the anticorrosion mechanism can be summarized into the following three aspects: (1) Due to the addition of 3%Ni, Q415NH have a microstructure of large number of fine bainites dispersed on ferrite; (2) The addition of Ni can increase the potential of the steel and the resistance of rusts to improve the anodic passivation; (3) The rusts of Q415NH are much more protective by the formation of a compact and fine structure with the anodic ion-selection.