新型低合金钢Q415NH腐蚀行为研究

Corrosion Behavior of a New Low Alloy Steel Q415NH

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 NaC1 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. Due to the addition of 3%Ni, Q415NH have a microstructure of large number of fine bainites dispersed on ferrite. The addition of Ni can increase the potential of the steel and the resistance of rusts to improve the anodic passivation. The rusts of Q415NH are much more protective by the formation of a compact and fine structure with the anodic ion-selection.