430铁素体不锈钢冷轧带钢连续退火过程的研究

发布时间：2018-06-04 05:07

  本文选题：430铁素体不锈钢冷轧带钢 + 卧式连续退火炉　； 参考：《北京科技大学》2015年博士论文

【摘要】：针对430铁素体不锈钢冷轧带钢在卧式炉内的连续退火过程,通过实验和数值研究,建立了其在退火过程中的温度、组织和力学性能预测模型。在本研究中利用高温表面气雾冷却实验结果,并结合火焰炉内对流换热和辐射换热的计算方法,建立了带钢在炉内的温度预测模型；采取等温退火实验建立了430铁素体冷轧带钢的再结晶动力学和再结晶完成后的晶粒长大动力学模型；通过模拟退火实验的方法,研究了连续退火过程中带钢组织和性能演变规律,并建立了430铁素体冷轧带钢在连续退火过程中的屈服强度和延伸率计算模型。在上述研究成果的基础上,基于Sheil叠加原理,将温度、组织和性能预测模型耦合,实现了实际退火过程的模拟和新退火工艺的制定。综观本文的研究工作,主要包括以下重要研究成果： (1)基于一维导热反问题的研究方法,搭建了高温表面气雾冷却实验平台。针对目前广泛使用的某型号扇形气雾喷嘴,研究了其在高温不锈钢表面的沸腾换热规律,在水流量V≤0.83×10-5m3/s的范围内建立了沸腾换热热流密度计算关联式。该研究成果一方面可以用于退火过程中带钢温度的预测；另一个方面可研究不同操控条件下气雾喷嘴在高温表面的冷却能力和冷却均匀性,为提升带钢气雾冷却的开始冷却温度提供重要指导； (2)针对卧式连续退火炉,建立了炉内带钢的一维非稳态导热模型,不同炉段的的换热过程以边界条件的形式进行考虑。在加热段内,利用辐射网络图法处理了带钢与炉气和炉墙之间的换热,根据经验公式计算炉气与带钢之间的对流换热问题。利用Holger Martin公式计算狭缝式喷气冷却情况下带钢表面对流换热系数。利用喷雾冷却实验得到的关列式计算喷雾冷却区带钢表面热流。经过实验验证,模拟预测得到的炉内带钢温度误差基本在±10%以内； (3)通过等温退火实验研究不同冷轧应变量条件下430铁素体不锈钢冷轧带钢的再结晶过程,并建立了Avrami再结晶动力学模型。利用等温退火实验,结合截线法得到了完全软化后材料内部的晶粒长大规律,并分析了晶粒长大过程中的织构演变规律。利用该模型可对连续退火过程中冷轧带钢的晶粒尺度和软化率/硬度进行预测； (4)利用CCT-AV-Ⅱ模拟退火试验机,研究了连续退火过程中带钢的组织和力学性能演变规律。利用所得到的实验结果,基于Hall-Peth公式,首次建立了430铁素体冷轧带钢退火过程中的屈服强度和延伸率计算模型； (5)利用本文所建立的430铁素体冷轧带钢在卧式炉连续退火炉内的温度、组织和力学性能预测耦合模型。对实际退火过程进行模拟预测,以评价实际退火过程中存在的问题,并提出解决方案。针对特定的卧式连续退火炉,制定出了适用于不同规格430铁素体冷轧带钢的退火工艺和操控参数。
[Abstract]:In view of the continuous annealing process of 430 ferrite stainless steel cold rolled strip steel in horizontal furnace, the prediction model of temperature, microstructure and mechanical properties of 430 ferrite stainless steel cold rolled strip steel during annealing process was established by experiment and numerical study. In this study, the temperature prediction model of strip steel in furnace is established by using the experimental results of high temperature surface aerosol cooling and the calculation method of convection heat transfer and radiation heat transfer in flame furnace. The kinetics of recrystallization and grain growth after recrystallization of 430 ferrite cold-rolled strip steel was established by isothermal annealing experiment. The evolution of microstructure and properties of 430 ferrite cold-rolled strip during continuous annealing was studied. The model of yield strength and elongation of 430 ferrite cold-rolled strip during continuous annealing was established. Based on the above research results and based on the Sheil superposition principle, the temperature, microstructure and properties prediction models are coupled to realize the simulation of the actual annealing process and the formulation of the new annealing process. The research work of this paper mainly includes the following important research results: 1) based on the research method of one-dimensional inverse problem of heat conduction, an experimental platform of high temperature surface aerosol cooling is built. The boiling heat transfer on the surface of high temperature stainless steel has been studied for a type of fan-shaped spray nozzle which is widely used at present. The correlation formula for calculation of boiling heat flux is established in the range of water flow rate V 鈮，

本文编号：1976075