极薄钢板高效气淬技术开发与应用

Development and application of high efficiency air-jet quenching technology for ultra-thin steel sheets

气体射流冷却均匀、流动性好是极薄钢板高平直度淬火的理想冷却方式.通过对不同条件下的钢板气淬过程进行模拟,探究雷诺数Re、无量纲高度H/D和移动速度v对钢板温降的影响规律,得到最优工艺参数;经过试验验证与工业测试,获得组织性能合格、板形良好的2 mm厚NM400钢板.结果表明:在动态气冷条件下,钢板冷却速度与射流雷诺数成正比,与无量纲高度成反比,与移动速度成正比;试验条件下最优气淬工艺为Re=15 185、H/D=46、v=0.05 m/s.经工业测试可得,2 mm厚NM400钢板气淬后的组织为马氏体,其抗拉强度1 204 MPa、伸长率10.0%、布氏硬度>372,钢板整板淬火不平度≤3 mm/m.

The air jet has cooling uniformity and good fluidity, which is an ideal cooling method for the quenching of ultra-thin steel sheets with high flatness. By simulating the steel sheet quenching process under different conditions, the influence law of Reynolds number Re, dimensionless height H/D and moving speed v on the steel sheet quenching process was obtained, and finally, the optimal process parameters were found out. After experimental verification and industrial testing, the 2 mm NM400 steel sheet with qualified micro-structure, mechanical properties and good sheet shape was obtained. The results show that under dynamic air-jet cooling conditions, the steel plate cooling rate is proportional to the jet Reynolds number, inversely proportional to the dimensionless height, and proportional to the moving speed. The optimal air-jet quenching process under the experimental conditions is Re=15 185, H/D=46, v=0.05 m/s. Under industrial testing, the micro structure of the 2 mm NM400 steel sheet after air-jet quenching is martensite, the tensile strength is 1 204 MPa, the elongation is 10.0%, the Brinell hardness is more than 372 HB, and the quenching unevenness of the steel sheet is less than 3 mm/m.