590MPa级热轧V-N高强车轮钢组织性能控制

对一种低成本V-N微合金化钢进行了控轧控冷实验，探讨了相变机理与析出行为，并系统地研究了其综合力学性能.结果表明，显微组织为多边形铁素体、粒状贝氏体及少量的针状铁素体，纳米尺度V(C，N)析出质点弥散地分布于铁素体或贝氏体铁素体基体内部.抗拉强度615MPa实验钢具有优良的断后延伸率，冷弯性能合格，扩孔率达到95%，满足轮辐用钢的加工要求，低温冲击性能良好.细晶强化、位错强化、析出强化、相变强化为主要强化机制.

Microstructural Control and Mechanical Properties of 590 MPa Grade Hot-Rolled V-N High Strength Steel

The controlled rolling and controlled cooling test was conducted on low cost V N microalloyed steel. The transformation mechanisms and precipitation behavior were discussed， and the comprehensive mechanical properties were systematically studied. The results indicated that the microstructure composes of polygonal ferrite， granular bainite and small amount of acicular ferrite. The nano scaled V(C， N) precipitates distribute dispersedly in the matrix of ferrite or bainite ferrite. The experimental steel with tensile strength 615MPa possesses excellent elongation after fracture. The cold bending property is qualified. The hold expansion ratio is 95%， which meet the demand of the automotive wheel disc. The low temperature impact toughness is outstanding. The fine grain strengthening， dislocation strengthening， precipitation hardening and transformation strengthening are the main strengthening mechanisms.