共查询到19条相似文献,搜索用时 187 毫秒
1.
带钢在层流冷却过程中距表面较近的区域温度存在反复升降的现象,造成厚度方向上组织和性能的差异。结合酒钢CSP热轧带钢生产数据,建立一维热轧带钢有限元模型,计算层流冷却过程中带钢的温度场。提出了冷却过程中带钢冲击穿透深度的概念,并初步探究其影响因素。厚度为3和4mm的带钢计算得出的卷取温度比实测温度分别高3和8℃,相对误差分别为0.44%和1.16%,验证了模型和假设的合理性。结果表明,冷却过程中冲击穿透深度受带钢的导热系数、平流区的对流换热系数、带钢表面温度和喷嘴分布的影响;带钢上表面喷嘴分布较少,冲击穿透深度随对流换热系数的增大而增加,下表面喷嘴分布密集起主导作用,增加对流换热系数,冲击穿透深度几乎不受影响。 相似文献
2.
3.
针对卷取温度为500℃的12 mm厚X70管线钢热轧带钢,利用MARC有限元软件建立层流冷却过程中的热-力-相变耦合的数学模型,计算两种下上冷却水比时层流冷却过程中温度场、应力、应变、相变体积分数和翘曲度随时间的变化.结果表明:1.25水比的冷却过程中,厚度方向上各面的冷却速度不一致,导致水冷前期带钢上下表面应变不同,带钢会产生向上的翘曲,冷却过程中边部最大的翘曲量达到21.84 mm;水冷后期带钢板形会逐渐恢复平直,但由于水冷过程中发生塑性变形,终冷时厚度方向上贝氏体含量的差异,卷取时带钢边部依然有-9 mm的翘曲量.上下表面的不均匀冷却是引起翘曲的根本原因.在保证X70管线钢性能条件下,采用1.58的下上水比工艺,卷取时边部翘曲量仅为-0.58 mm,合适的下上水比能大幅度减小层流冷却过程中带钢的横向翘曲. 相似文献
4.
5.
6.
热轧带钢层流冷却系统的设计 总被引:3,自引:0,他引:3
本钢1700mm热轧带钢层流冷却系统采用的是带钢管层流冷却和高压喷嘴冷却相结合的方式。介绍了此系统的设计过程及总用水量和上喷、下喷和侧喷水量的计算。 相似文献
7.
8.
9.
10.
热轧带钢层流冷却温度控制模型的应用分析 总被引:1,自引:0,他引:1
工业大学金属材料与加工重点实验室, 安徽 马鞍山 243002) 摘要:在带钢热轧后的冷却过程中,热轧带钢卷取温度的数学模型是至关重要的。介绍了某热轧带钢厂的卷取温度控制数学模型,针对传统的热轧带钢层流冷却卷曲温度控制中数学模型的固有缺陷,分别采用了差分方程和有限元数值模拟的方法,建立带钢厚度方向上的温度场。对测得的数据进行了分析,结果表明:在考虑带钢与介质的热交换的同时再考虑带钢内部的热传导大大提高模型的预报精度,为定量地描述计算值与实测值之间的偏差提供了依据。 相似文献
11.
LIUZheng-dong IVSamarasekera 《钢铁研究学报(英文版)》2004,11(3):15-23
The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip. The heat of a hot steel strip is mainly extracted by cooling water during runout. In order to study the heat transfer by water jet impingement boiling during runout, a pilot facility was constructed at the University of British Columbia. On this pilotfacility, the water jet impingement tests were carried out under various cooling conditions to investigate the effect of processing parameters, such as cooling water temperature, water jet impingement velocity, initial strip temperature, water flow rate, water nozzle diameter and array of water nozzles, on the heat transfer of heated strip. The results obtained contribute to the optimization of cooling water during runout. 相似文献
12.
To gain insight into the effects of various parameters controlling the thermal behaviour of a quenched steel strip during the process of accelerated cooling by an array of planar water jets, a parametric study has been performed using a previously developed and validated mathematical model. The behaviour of the strip was characterized by its coiling temperature, top and bottom surface temperature variations and heat extraction in the jet impingement region, top surface heat extraction in the film boiling region, and top and bottom surface thermal penetration depths. Parametric variations included cooling system design conditions, such as the top and bottom nozzle widths, and operating conditions such as the top nozzle discharge velocity, the cooling water temperature, and the ratio of volumetric water flow rates applied at the top and bottom surfaces. The effects of steel strip parameters such as strip thickness and strip velocity were also considered. 相似文献
13.
14.
Hot strip rolling process includes four main stages, which are reheating process, roughing and finishing process, laminar‐cooling process, and coiling process respectively. Temperature is the most sensitive parameter and has direct effect on the microstructural evolution and further the mechanical properties, and the accurate control of temperature guarantees the quality of products and homogeneity of properties along the strip length. However, for the conventional hot strip rolling process, thermal history along the strip length is very complex, the related temperature variation concerns air cooling, water cooling, heat transmission by roll contact, heat generation by deformation and friction. Based on the actual hot strip mill, the thermal models are established in this paper to simulate the temperature distribution along the whole strip length from the reheating furnace exit to the down coiler. Different interface heat transmission coefficients are selected for the scale breaking and spray water‐cooling process, and a self‐learning algorithm is thus employed to improve the calculation accuracy. This model is characterized as simple and fast, and convenient for on‐line/off‐line prediction of temperature. Finally the simulated results are verified by the on‐line temperature detection at typical points such as roughing exit (RT2), finishing exit (FT7) and coiling position (CT). 相似文献
15.
16.
17.
热连轧层流冷却系统的控制模型及控制策略 总被引:6,自引:1,他引:6
主要介绍了热轧带钢层冷系统中的控制模型及控制策略,包括液位控制、目标卷取温度的前馈控制和带有Smith预估器反馈控制等。其中通过液位控制可以得到稳定的液位,这对保持集管流量的稳定和上位机预设定的精度都是非常重要的。卷取温度的前馈控制和反馈控制对卷取温度控制精度的提高是必不可少的手段。这些控制模型和控制策略已经在工厂中得到应用,并且取得了很好的控制效果,说明这些控制模型和控制策略可以广泛应用于热连轧厂的冷却系统中。 相似文献
18.
以面向对象的视角审视热轧带钢轧后冷却过程涉及的轧件、辊道、集管、冷却介质与仪表5要素,对轧件在辊道的传热过程、冷却水量和温度的控制过程进行分析、分解并抽象成类。利用面向对象的方法对卷取温度控制(coiling trmperature control,简称CTC)模型的体系结构进行设计,结合模型的触发逻辑进行对象设计,利用C++语言开发面向对象的卷取温度模型。基于有限差分计算方法的模型设定时间满足在线快速计算的要求,模型具有良好的可移植性和可扩展性。现场应用表明,冷却控制系统运行稳定,模型设定准确,卷取温度控制效果良好。 相似文献