连铸板坯连续矫直过程充分利用钢高温特性的研究

在连续矫直过程中,铸坯温度高,蠕变及应力松弛现象十分明显,坯壳处于高温、低应变和低应变速率的状态。在Gleeble-3500型热/力模拟试验机上模拟连铸坯连续矫直的工艺条件,对普碳钢的高温蠕变、应力松弛等进行了定性实验,实验结果表明,该条件下钢的蠕变及应力松弛速度很快。以某钢厂板坯连续弯曲、矫直改造为例,计算了连续矫直过程中坯壳固液相界面处的矫直应变。现场实际应用效果表明,通过采用矫直区由两段光滑连接的曲线段组成的设计方案,对连续矫直区合理布置,从而充分利用钢的高温蠕变及应力松弛现象,对降低矫直应变速率,提高连铸坯质量有很重要的意义。

Study about using the elevated temperature characteristics of steel during continuous straightening

In the process of the continuous straightening during continuous casting,temperature of steel slab is very high,elevated temperature creep and stress relaxation are remarkable,and the characteristic of deformation is low strain and low strain rate.Experiments of elevated temperature creep and stress relaxation were carried on Gleeble-3500 thermal-force simulation machine and the results indicate that both the creep speed and the stress relaxation speed are very fast in the conditions of continuous straightening.Based on a practical continuous bending/straightening modification to a straight-arc caster used in a steel making plant,the straightening strain at the solid-liquid interface was calculated.The effects show that the design of bending/straightening zone composed by two curves which connected smoothly can make full use of the characteristics of creep and stress relaxation;it can greatly reduce the strain rate and has great importance to improve the quality of the slab.