压下量和终轧温度对硅-锰系含铌热轧双相钢组织与性能的影响

Effects of Reduction and Finishing Temperature on Microstructure and Mechanical Properties of Nb Bearing Si-Mn Hot-Rolled Dual-phase Steel

以30 mm厚硅-锰系含铌热轧双相钢为研究对象,在实验室进行了5道次热轧试验,研究了压下量(93.3%,85.0%和81.7%)和终轧温度(790,750和720℃)对其显微组织和力学性能的影响。结果表明:增大压下量,可以获得均匀细小的铁素体-马氏体组织,在强化基体的同时对塑性影响较小;降低终轧温度,可以获得较高的强度,但易出现混晶组织,对塑性影响较大;在本试验条件下压下量在85.0%左右,终轧温度为790℃时,可以使试验钢的抗拉强度达700 MPa以上,屈强比为0.65,伸长率达23%以上。

The effects of reduction（93.3%,85.0%and 81.7%） and finishing temperature（790,750℃and 720℃） on microstructure and mechanical properties of 30 mm thickness Nb bearing Si-Mn hot-rolled dual-phase steel were studied at laboratory by 5 passes hot-rolled test.The results show that the uniform and small ferritemartensite microstructure could be obtained through increasing the reduction with little influence on plasticity while strengthening the matrix.The high strength could be obtained through reducting the finishing temperature with considerable influence on plasticity,but the mischcrystal would appear.Under the present testing condition and when the reduction was around 85.0%and the finishing temperature was 790℃,the tensile strength could be ahove 700 MPa,yield ratio was 0.65 and the elongation was above 23%.