Research Initiation: Thermomechanical Treatment of Moving Metal Strips in Rolling Processes

提出了一种实验和数值相结合的方法来研究运动金属带材在轧制过程中的热机械处理(TMT)。为了提高产品质量，降低生产成本，采用了控制冷却的TMT技术。然而，关于冷却过程的热传递行为的信息很少。因此，研究带钢轧制过程中的热行为是本研究的出发点。重点研究了在运动条带上射流沸腾的局部对流换热系数的测量。将对三种冷却系统进行调查和比较：喷雾冷却、层流喷射和水幕。具有快速响应时间的表面热电偶和薄膜热流计将被用来测量瞬时表面温度和热流密度。有限差分法将使用欧拉和拉格朗日方法来分析数据和预测轧制条件下的带钢温度。研究了带材、带材温度、运动速度以及射流速度和射流结构对局部换热系数的影响。控制冷却技术是近年来发展起来的一种对热轧带钢轧辊进行在线热机械处理(TMT)的技术。其结果是在轧制条件下连续生产高质量的产品。然而，目前冷却系统的设计主要是基于试错的方法，因为对传热行为还没有很好的了解。需要更好地了解拟议研究中所描述的带钢冷却过程的热和机械行为。

A combined experimental and numerical research program is proposed to study the thermo-mechanical treatment (TMT) of moving metal strips in rolling processes. TMT using controlled cooling has been adopted to improve product quality and to reduce production cost. However, very little information is available on the heat transfer behavior of the cooling process. Therefore, this research is initiated to study the thermal behavior of strip rolling. Particular emphasis is placed on the measurement of the local convective heat transfer coefficients for jet boiling on moving strips. Three cooling systems will be investigated and compared: spray cooling, laminar jets, and water curtains. Surface thermocouples and thin film heat flux gages with fast response times (on the order of microseconds) will be used to measure the instantaneous surface temperatures and heat fluxes. Finite difference methods will be developed using Eulerian and Lagrangian approaches to analyze data and to predict strip temperatures in rolling conditions. The effect of strip material, strip temperature, and moving speed as well as the jet velocity and jet configuration on the local heat transfer coefficients will be investigated. Controlled cooling technology has recently been developed to perform on-line thermo-mechanical treatment (TMT) of the strips on the run out tables of hot-strip-mills. The result is a continuous process for producing high quality products in the as- rolled conditions. At present, however, the cooling system design is primarily based on a trial-and-error approach because the heat transfer behavior is not well understood. A better understanding of thermal and mechanical behavior of the strip cooling processes as described in the proposed research is needed.