基于薄板固有特性的连续热镀锌带钢表面质量在线控制

On-line Control of Strip Surface Quality for a Continuous Hot-Dip Galvanizing Line Based on Inherent Property of Thin Plate

对源于气刀附近带钢振动的连续热镀锌带钢表面质量在线控制理论和方法进行研究。建立连续热镀锌镀后冷却段的带钢振动模型,基于哈密顿原理得到振动模型固有特性的解析解,对振动模型的合理性进行数值仿真验证,结合现场测试结果和表面质量实时监测技术,提出连续热镀锌带钢表面质量在线控制的基本思想和解决方案。研究表明,带钢线张力和速度分别对带钢固有频率和激励频率产生显著影响,可以作为表面质量在线控制的主要参数。计算带钢固有频率时可以忽略轴向速度的影响。数值仿真结果确认振动模型中用简支代替接触辊支撑和稳定辊支撑的正确性。带钢固有特性求解的解析形式能够满足在线控制的需要。建议加强稳定辊和接触辊的支撑刚度来抑制气刀附近带钢振动。

Theory and method of on-line control for surface quality during continuous hot-dip galvanizing process due to vibration of steel strip near the air knife box are investigated.A model of strip vibration for cooling section is established.Analytic solutions of the model for natural property are obtained by using the Hamilton＇s principle.Numerical simulations are employed to verify rationality of the model.Basic ideas and solutions for on-line control of surface quality in continuous hot-dip galvanizing are presented,based on field testing results and technique of real-time surface detection.The research shows that tension and velocity of the strip have noticeable effect on natural frequencies and excitation frequencies respectively.They may be regarded as key parameters for on-line control of surface quality.Axial velocity of the strip is negligible in calculations of natural frequencies.Numerical simulations confirm the validity of substituting simple support for contact rolls and stabilizing rolls in the vibration model.Analytic solutions of natural property make it possible to realize on-line control of surface quality.A vibration suppression scheme by improving support stiffness of contact rolls and stabilizing rolls is proposed.