700 MPa级高强钢层流冷却过程的多场耦合数值模拟

Multi-field Coupling Numerical Simulation of Laminar Cooling Process of 700 MPa Grade High Strength Steel

结合首钢京唐2250热轧产线,采用有限元方法研究了700 MPa级高强钢在层流冷却过程中温度场、应力场以及相场的演变规律。结果表明:模型计算的钢板宽度方向温度分布与实际测量值基本吻合,水冷过程中表面冷速大于心部,水冷后带钢表面出现“返温”现象;带钢在冷却过程中的相变潜热对卷取温度的贡献约为40℃;层冷结束后,带钢上表面板宽中部和边部分别存在160和203 MPa的拉应力,并且边部下翘产生浪形,这是带钢宽度方向冷却不均所致。通过设置50、100以及150 mm的边部遮蔽宽度,分析其对带钢边部温度和残余应力的影响,得出当遮蔽宽度为100 mm时,带钢边部温度、残余应力及板形改善明显。

Combined with the 2250 hot rolling production line of Shougang Jingtang,the evolution law of temperature field,stress field and phase field of 700 MPa grade high strength steel in laminar cooling process was studied by the finite element method.The results showed that the calculated temperature along the strip width was basically consistent with the measured values,the cooling rate at the surface was greater than that in the core during water cooling,and the“return temperature”phenomenon appeared on the strip surface after water cooling.The latent heat of phase transformation in the strip steel during cooling contributed about 40℃to the coiling temperature.After laminar cooling,there were tensile stresses of 160 and 203 MPa in the middle and edge along the width direction of upper surface of the strip steel,respectively,and the edge warped downward to produce a shape wave,which was caused by the uneven cooling in the width direction of the strip steel.By setting the edge masking width of 50,100 and 150 mm,the influence of edge masking width on the edge temperature and residual stress of the strip steel was analyzed,it was concluded that when the edge masking width was 100 mm,the edge temperature,residual stress and shape of the strip steel were significantly improved.