特厚板坯连铸蠕变过程热力耦合数值模拟  

Thermodynamic coupling numerical simulation on the creep process ofextra-thick slab continuous casting

作　　者：林威 何博[1] 王文学[1] 候凯凯 陈乐彤 LIN Wei;HE Bo;WANG Wenxue;HOU Kaikai;CHEN Letong(China National Heavy Machinery Research Institute Co.,Ltd.,Xi’an 710018,China)

机构地区：[1]中国重型机械研究院股份公司,陕西西安710018

出　　处：《重型机械》2024年第3期54-60,共7页Heavy Machinery

摘　　要：基于钢Q345的高温蠕变参数,建立了适用于Q345的蠕变表达式。将计算温度与实际温度结合,通过有限差分法计算了适用于Q345连铸过程二冷区的对流换热系数。将改良后的对流换热系数作为边界条件,计算出了铸坯在连铸过程中各位置的温度、变化趋势与坯壳厚度。计算结果表明,除铸坯角部外,铸坯各位置均处于一定的温度区间,且呈下降趋势,坯壳厚度缓慢增至21 mm。通过采用热力耦合数值模拟方法,在不同拉坯速度下,计算出了距离外弧表面0~30 mm处节点的蠕变应变、等效应力和总的等效塑性应变。通过计算结果表明,特厚板铸坯在连铸过程中发生应力松弛现象,铸坯只在刚进入圆弧段时发生塑性应变,大大降低了铸坯发生表面裂纹的风险,从而使特厚连铸板坯在超低应变速率下高效、稳定生产。Based on the creep parameters of steel Q345 at high temperature,a suitable creep expression for Q345 is established.By combining the calculated temperature with the actual temperature,the convection heat transfer coefficient in the secondary cooling zone of Q345 continuous casting was calculated by the finite difference method.Taking the improved convective heat transfer coefficient as the boundary condition,the temperature,variation trend and shell thickness of the billet at various positions during the continuous casting process were calculated.The results show that,except for the corner of the billet,all the positions of the billet are in a certain temperature range and show a downward trend,and the thickness of the billet shell slowly increases to 21 mm.By the thermodynamic coupling numerical simulation method The creep strain,the equivalent stress and the total equivalent plastic strain at the joints 0~30 mm away from the outer arc surface were calculated under different drawing speeds.The calculation results show that stress relaxation occurs during the continuous casting process,and plastic strain only occurs when the slab first enters the arc segment,which greatly reduces the risk of surface cracks,thus enabling efficient and stable production of extra-thick continuous casting slab at ultra-low strain rates.

关 键 词：特厚板坯 数值模拟 热力耦合 蠕变 

分 类 号：TF777.1[冶金工程—钢铁冶金]