Nb含量对高磷耐候钢力学性能的影响

Effects of Nb Content on Mechanical Properties of the High Phosphorus-bearing Weathering Steel

通过显做组织分析、拉伸试验和冲击试验，研究了Nb含量（0～0．090％）对经两相区轧制后的高磷耐候钢的组织形貌、强度和冲击韧性的影响。结果表明：随着Nb含量的增加，高磷耐候钢显微组织的条带状分布减弱，均匀性变好，埔服强度和抗拉强度均尤增大后趋于稳定，纵向冲击功先升高后降低，横向冲击功则先降低后升高。含0．042％Nb的高磷耐候钢，其显微组织的条带状分布明显减弱，平均晶粒尺寸最小，屈服强度和抗拉强度最大，纵向冲击功最大，而横向冲击功最小。当高磷耐候钢的Nb含量达到0．090％时，其显微组织中已无明显的条带状分布，与含0．042％Nb的高磷耐候钢相比，强度相当，冲击韧性的各向异性得到明显改善。

Investigation was made of the effects of Nb content on microstructure, strength and impact toughness of the high phosphorus bearing weathering steel by microstructure analysis, tensile test and impact test. The results show that with the increase of Nb content, the microstructure of the high phosphorus-bearing weathering steel becomes more uniform with weaker band like distribution, yield strength and tensile strength are improved at first and tend to be stable, and longitudinal impact energy in creases at first and then decreases, while transverse impact energy is the opposite. The high phosphorus bearing weathering steel with 0. 042 % Nb has the microstructure of obviously weakened band-like distribu tion,with the smallest average grain size,the maximum yield strength, tensile strength and longitudinal impact energy,and the minimum transverse impact energy. The high phosphorus-bearing weathering steel containing 0. 090% Nb,with no obvious band-like distributed microstructure, has the same strength, the narrowed anisotropy of impact toughness,compared with the one containing 0. 042% Nb.