600MPa级热轧双相钢组织及扩孔性能的研究

Study on Microstructure and Hole-expanding Property of 600 MPa Grade Hot-rolled Dual Phase Steel

研究了600MPa级热轧双相钢的CCT曲线,据此选择低温卷取工艺并进行了试制。结果表明:结合低温卷、取工艺,通过Nb、Ti微合金化可生产出具有良好的强塑性的热轧双相钢。采用低温卷取工艺生产的热轧双相钢的马氏体岛尺寸比较细小,且弥散均匀分布,马氏体岛内部亚结构为板条状,且含有高位错密度,既起到了强化作用,又保证了材料一定的韧性。试验钢具有良好的综合力学性能和扩孔性能。

The CCT-curve of 600 MPa grade hot-rolled dual phase steel was studied. Based on this, the low temperature coiling process was selected and trial-produced. The results show that combined with low temperature coiling process, the hot rolled duplex steel with good strength-plasticity can be produced by Nb and Ti microalloying. The martensite island size of hot rolled duplex steel produced by low temperature coiling process is relatively small, and the distribution is uniform. The substructure of martensite island is lath and it contains high dislocation density. It not only has strengthening effect, but also ensures the toughness of the material. The test steel has good comprehensive mechanical properties and hole-exparding property.