低合金高强钢连退平整伸长率不足问题研究

Study on insufficient elongation of low alloy high strength steel during continuous annealing and tempering

平整过程中稳定的板带伸长率控制是确保成品质量的前提。针对某厂生产低合金高强带钢偶发带钢伸长率达不到目标伸长率,且通过增大轧制力和张力至设备极限亦无法解决的问题,建立了轧件-辊系一体化有限元仿真模型。仿真分析结果发现,随着带钢强度升高、厚度变厚、张力减小、弯辊力增大、界面摩擦因数增大都会使低合金高强带钢伸长率减小。基于有限元仿真计算结果并结合实际生产,确定了平整机轧制能力不足以及平整机辊系凸度设置不合理是是导致低合金高强带钢伸长率不足的主要原因。为此,设计了支撑辊辊形、优化了轧辊服役制度以及轧制规程,使低合金高强带钢伸长率不足钢卷比例由2.11%降至0.62%。

Stable elongation control of the strip in the tempering process is the prerequisite to ensure the quality of the finished product.During the production of low alloy high strength steel strip,the elongation of strip can not be reached the target elongation occasionally,and it cannot be solved by increasing rolling force and tension even to the limit capability of temper mill.To solve this problem,the finite element simulation model of rolled part and roll integration system was established.The simulation analysis results show that with the strength and thickness increasing of the strip,tension decreasing,bending roll force increasing and friction coefficient of interface increasing,the elongation of low alloy high strength steel decreased.Based on the results of finite element simulation and actual production situation,the main reasons of insufficient elongation of low alloy high strength steel strip are insufficient rolling capacity of the temper mill and unreasonable convexity setting of the roll system.Aiming at the above problems,the shape of back-up roll was designed,the roll lifecycle system and rolling regulations were comprehensively optimized,which effectively reduces the proportion of low alloy high strength steel coils with insufficient elongation from 2.11%to 0.62%.