厚规格高强船板蛇形/差温协同轧制非均匀变形机理研究

Confine to the maximum thickness of the cast ingot, it’s difficult to satisfy the requirement of the required rolling ratio during rolling production. So the deformation in the inner region is insufficient, and the microstructure and properties between the surface and inner is non-uniform. The insufficient deformation in the inner region becomes the key technology bottleneck to improve the quality of the high-strength heavy ship plates. The early research found that the snake/gradient temperature collaborative rolling method can further improve the deformation in the inner region and the deformation permeability. So it is necessary to study the non-uniform deformation mechanism according to the characteristics of the snake/gradient temperature collaborative rolling. The variable friction condition will be setup by theory of the contact mechanics and tribology and the experiment, and the thermodynamic coupling models of the mechanical parameters which contain variable friction and deformation resistance gradient will be setup on this basis. And then the influencing law of mechanical parameters can be obtained. The element in the deformation zone will be taken out to be analyzed by the continuum mechanics and strain gradient theory and then the models of the strain along the thickness and the bending curvature after rolling which contain variable friction, deformation resistance gradient, residual stress and initial curvature can be setup by the slab method. The snake/gradient temperature collaborative rolling process and process parameters will be optimized and the models of the roll speed ratio and roll offset will also be built on this basis. The numerical method and experimental method will be conducted in order to obtain the non-uniform deformation mechanism of snake/gradient temperature collaborative rolling. The non-uniform deformation mechanism of the snake/gradient temperature collaborative rolling will be revealed. The theoretical system of the snake/gradient temperature collaborative rolling of the high-strength heavy ship plates will be setup and fill the gaps of deformation mechanism research of the snake/gradient temperature collaborative rolling.

厚规格高强船板轧制生产受连铸坯最大厚度限制，压缩比难以达到工艺要求从而导致心部变形不充分、表面和心部组织性能不均匀，成为提高厚钢板质量的关键技术瓶颈。前期研究发现蛇形/差温协同轧制可进一步提高厚钢板轧制变形渗透性，基于此，根据蛇形/差温协同轧制特点深入研究其非均匀变形机理。本项目采用接触力学和摩擦学等理论并结合实验建立蛇形/差温协同轧制变摩擦接触模型并耦合变形抗力梯度建立热力耦合力能参数模型，获得力能参数的影响机理；在此基础上，根据连续介质力学和应变梯度理论分析变形区基体，耦合变摩擦、变形抗力梯度、残余应力和初始曲率建立厚度方向应变模型和弯曲曲率模型；继而进行轧制工艺及工艺参数优化，建立异速比、工作辊错位量等工艺参数设定模型。同时对比展开模拟和实验研究，揭示蛇形/差温协同轧制非均匀变形机理，建立厚规格高强船板蛇形/差温协同轧制理论体系，填补蛇形/差温协同轧制非均匀变形机理研究方面的空白。

厚规格金属板材轧制生产受连铸坯最大厚度限制，压缩比难以达到工艺要求从而导致心部变形不充分、表面和心部组织性能不均匀，成为提高厚钢板质量的关键技术瓶颈。本项目以探索厚规格高强船板变形行为，解析多维度变形程度，提高厚钢板质量为目标，重点解决厚规格金属板材蛇形/差温协同轧制过程中的非均匀变形的科学问题。采用理论建模、数值模拟和实验等手段重点研究了①蛇形/差温协同轧制变形区变摩擦特性及力能参数建模，②蛇形/差温协同轧制非均匀变形机理及厚度方向应变与弯曲曲率建模和③蛇形/差温协同轧制工艺优化及最优化工艺参数设定。.本项目的研究获得以下重要结果和关键数据：① 研究了不同变形状态下变形区的摩擦力分布规律及其模型，在此基础上结合差温轧制分层特性，获得了蛇形/差温协同轧制变形区分层、分区方法，并结合修正的屈服准则，采用主应力法，建立了同径异速和同速异径蛇形/差温协同轧制力能参数模型，与实验和模拟结果相比，模型精度达7%；② 采用有限元模拟了蛇形/差温协同轧制过程，获得了热力耦合效应下应力应变和弯曲曲率数据，心部应变提高15%以上，板形得到很好的控制，证实了蛇形/差温协同轧制在提高心部变形及板形控制方面的积极作用，对比分析获得了变形渗透性影响机理；③ 根据变形区分区、分层方法，采用主应力法建立了蛇形轧制轧后弯曲曲率模型，耦合轧制过程热应力，建立了蛇形/差温协同轧制轧后弯曲曲率模型，模型精度达12%；④ 采用能量法建立了同步轧制、异步轧制和蛇形/差温协同轧制轧后应变计算模型，模型精度达13.44%，汇总以上研究结果获得了蛇形/差温协同轧制最优化工艺参数设定方法；⑤ 项目研究期间，共发表学术论文14篇，其中SCI收录8篇；申请发明专利11项，其中5项已授权；申请软件著作权4项；获得1项省部级二等奖奖励。本项目获得了一种提高厚度心部变形程度的有效方法，解决了厚板蛇形/差温协同轧制非均匀变形机理的科学问题，丰富了板带材轧制工艺和理论。