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为了获得一种良好强韧性匹配的390MPa级船板钢,通过NbV-N复合微合金化及不同热处理工艺(正火+回火、淬火+回火),对实验室钢板的室温拉伸、-40℃冲击性能及钢的微观组织、析出相等进行了分析研究。结果表明,钒、铌的添加能细化晶粒,且氮质量分数的增加使得这种细晶效果更为显著,从而使得钢的强韧性,特别是冲击韧性明显提升。相比轧态,正火+回火、淬火+回火热处理后钢的力学性能均有明显提高,特别是低温韧性有明显改善,这得益于回火过程中大量微合金碳氮化物的弥散析出及钢的有效晶粒尺寸的显著细化。
In order to obtain a good strength and toughness matching 390MPa class ship steel, through the NbV-N composite micro-alloying and different heat treatment process (normalizing + tempering, quenching + tempering), the laboratory steel plate at room temperature, 40 ℃ impact properties and the microstructure of steel, precipitation equal analysis and research. The results show that the addition of vanadium and niobium can refine the grains, and the increase of nitrogen content makes the grain refinement effect more remarkable, so that the toughness of steel, especially the impact toughness is obviously improved. Compared with nip, normalizing and tempering, the mechanical properties of steel after quenching and tempering heat treatment are obviously improved, especially the low temperature toughness has significantly improved, thanks to the dispersion of a large number of micro-alloy carbonitride during tempering Precipitation and significant refinement of the steel’s effective grain size.