特厚钢板差温轧制变形渗透机理和模型研究

A key issue of ultra-heavy plate rolling is to ensure the deformation permeate into the core, which has already obtained the results by continuum medium mechanics, the conclusion is that the critical condition for the deformation zone shape parameter is greater than 0.518. But the first few passes can't meet this condition during ultra-heavy plate rolling which leads to the product internal quality defects. This application provides an academic idea of temperature-differential rolling, that is to obtain temperature gradient in the direction of the thickness of the rolled piece by using nearly stand ultra-fast cooling technology, high deformation resistance zone at low temperature is generated nearly rolling work piece surface, the surface deformation is limited, It cannot satisfy the 0.518 critical condition, but still can cause deformation of rolled piece permeate into the core so as to eliminate the core flaw. Therefore study is need to start as following: 1）Build temperature-differential rolling movement velocity field and the flow function equation, reveal temperature-differential rolling deformation law, Solve the critical value of deformation of penetration with a specific temperature gradient; 2）Study the relationship between stress and strain with temperature-differential rolling, determine rolling parameters calculation method on temperature-differential rolling conditions, build related process control models; 3）Study work piece core organization characteristics of temperature-differential rolling by the experiment, Find out influence law for internal pressing defects by the effect of deformation of penetration degree, set up organization forecast model with temperature-differential rolling. The research results presented above have a realistic significance for application of the nearly stand ultra-fast cooling technology as well as improving core quality of ultra-heavy plate.

轧制特厚钢板的一个关键问题是确保变形渗透到心部，连续体介质力学对此已有论解，指出其临界条件为变形区形状参数大于0.518。但是轧制特厚板的前几个道次不能满足此条件，造成产品内部质量缺陷。本申请提出特厚板差温轧制的学术思想，即利用近机架超快冷获得轧件厚度方向温度梯度，使近轧件表面产生低温高变形抗力区，限制其表面变形，使其在不能满足0.518临界条件时，仍能促使变形深入到轧件的心部，以便消除心部缺陷。为此需要研究：1）建立差温轧制运动许可速度场及流函数方程，揭示差温轧制变形规律，求解特定温度梯度下的变形渗透临界值；2）研究差温轧制应力应变关系，确定差温轧制条件下轧制参数计算方法，建立相关过程控制模型；3）实验研究特厚板差温轧制工件心部组织特点，找出变形深透程度对内部缺陷压合的影响规律，建立差温轧制组织预测模型。上述研究成果对近机架超快冷技术的应用及改善特厚板件心部质量具有现实意义。

特厚钢板广泛应用于大型汽轮发电机组、海洋石油平台、军舰和坦克装甲板、核电站、大型模具钢等特殊用途部件，这些部件对钢板的心部性能要求较高，但如何生产出心部性能较好的产品是一个比较棘手的问题。轧制特厚钢板的一个关键问题是确保变形渗透到心部，连续体介质力学对此已有论解，指出其临界条件为变形区形状参数大于0.518。但是轧制特厚板的前几个道次不能满足此条件，造成产品内部质量缺陷。本课题提出了特厚板差温轧制的策略，即利用近机架超快冷获得轧件厚度方向温度梯度，使近轧件表面产生低温高变形抗力区，限制其表面变形，使其在不能满足0.518临界条件时，仍能促使变形深入到轧件的心部，以便消除心部缺陷。通过特厚钢板差温轧制变形渗透机理和模型研究：1）建立了差温轧制运动许可速度场及流函数方程，揭示了差温轧制变形规律，求解了特定温度梯度下的变形渗透临界值；2）研究了差温轧制应力应变关系，确定了差温轧制条件下轧制参数计算方法，建立了相关过程控制模型；3）实验研究了特厚板差温轧制工件心部组织特点，找出了变形深透程度对内部缺陷压合的影响规律，建立了差温轧制组织预测模型。上述研究成果对近机架超快冷技术的应用及改善特厚板件心部质量具有现实意义。