低残余应力热轧带钢层流冷却工艺的数值模拟

通过建立厚度为3.0 mm的Q345热轧带钢在层流冷却过程中的温度与相变耦合计算有限元模型,计算了热轧带钢冷却后在宽度方向上温度、组织转变、内应力的分布,分析了采用2种冷却工艺下带钢宽度方向上的温度、相变和内应力的差别.结果表明:带钢经过中凸型水流分布的层流冷却后,沿带钢宽度方向温度趋于一致,从而使得相变后得到的铁素体及珠光体沿宽度方向上均匀分布.与常规均匀流量分布层流冷却相比,中凸水流量分布层流冷却后,带钢边部压应力减少80 MPa;带钢在宽度方向上的应变差变小,从原来的7.69×10-6减少到3.71×10-6,降低幅度为51.7%,有利于获得更好的板形。

Numerical Simulation of Laminar Cooling Process for Hot Rolled Strip With Low Residual Stress

The temperature and transformation coupling calculation model of FEM was established for hot rolled strip of Q345 steel in 3 mm thickness at run out table during laminar cooling.Then the temperature,phase transition and residual stress distribution in width of hot rolled strip during laminar cooling was calculated.The difference of temperature,transformation and residual stress in width of strip by two kinds of laminar cooling process was analyzed.The results show that the temperature and phase volume fraction in width of strip tended to be uniform after laminar cooling with crown profile water flow.The residual compressive stress in the edge of strip was reduced by 80 MPa and the maximum strain difference of the strip in width direction after cooling decreased from 7.69×10-6 in conventional even profile water flow laminar cooling process to 3.71×10-6.It was favorable for the hot rolled strip having better flatness.