Nb-V微合金化含Cu高强度耐候钢的开发和耐蚀性

通过合适的成分设计和控轧控冷工艺开发出一种综合力学性能优异的Nb-V微合金化含Cu高强度耐候钢（/%:≤0.12C,≤0.40Si,≤1.40Mn,≤0.020P,≤0.010S,0.40～0.45Cr,0.25～0.35Cu, ≥0.020Al,0.02～0.03Nb,0.02～0.03V）,并对其耐蚀性能进行了研究。该高强耐候钢组织由铁素体、珠光体和贝氏体组成,抗拉强度高达697 MPa,屈强比为0.73,断后伸长率为24.6%, -40℃纵向冲击功为70.6 J。盐雾及周期浸润试验结果表明,该钢耐蚀性能显著优于Q345B,其锈层主要由Fe₃O₄、α-FeO（OH）和γ-FeO（OH）构成,且随着时间增加,Fe₃O₄相对含量增加,α-FeO（OH）变化较小,γ-FeO（OH）减少。

Development and Corrosion Resistance of Nb-V Microalloyed Cu-Bearing High Strength Weathering Steel

A Nb-V Microalloyed Cu-Bearing high strength weathering steel (/% : ≤ 0.12C, ≤ 0. 40Si, ≤ l. 40Mn, ≤ 0.020P, ≤ 0. 010S, 0.40 ~0.45Cr, 0.25 ~0.35Cu, ≥ 0.020Al, 0.02 ~0.03Nb, 0.02 ~0.03V) with excellent comprehensive performance was developed by means of proper composition design and thermo mechanical control process ( TMCP), and its corrosion resistance was studied. The microstructure of the high strength weathering steel was composed of ferrite, pearlite and bainite, whose tensile strength reached 697 MPa, yield ratio was 0. 73, elongation was 24. 6% , and -40 ℃  longitudinal impact energy was 70. 6 J. The results of salt spray test and periodical immersed corrosion test indicted that the corrosion resistance of test steel was obviously better than Q345B, and the test steels rust layer after salt spray test by XRD analysis was mainly composed of Fe₃O₄, α-FeO( OH) and -γ-FeO( OH) , and the relative content of Fe₃O₄ increased with time, α-FeO(OH) changed slightly, γ-FeO(OH) decreased.