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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
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在分析了钢坯出炉后热过程特点的基础上 ,建立了线材控冷轧制热过程数学模型 ,提出了“前馈+反馈”的温度控制方式。实际运行结果表明 :该控制方式能够合理地控制水箱水流量 ,从而确保线材水箱出口处的温度满足工艺要求 ,大大提高线材成品的质量。 相似文献
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与一般水系统变频改造项目相比,高压变频器在不锈钢中厚板淬火机冷却水系统的应用技术要求更高、与退火炉结合更为紧密、控制过程更为复杂。通过改造,有效解决了淬火机冷却水系统长期大流量、高能耗的弊端。 相似文献
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《钢铁冶炼》2013,40(7):552-560
AbstractA software to simulate the solidification, heat transfer and water flowrate distribution in slab continuous casting was developed by establishing a mathematical model for the heat transfer and solidification in medium thickness slab casting. This model was validated by pin shooting and surface temperature measurement experiments. A reasonable target surface control temperature was found by testing the high temperature mechanical properties of Nb bearing ship plate steel, and then the water flowrate of each loop of the secondary cooling zone was determined by the software. The influence of uneven secondary cooling in the slab width direction on the quality of the slab was also investigated, which provided data for the optimisation of the secondary cooling of the slab caster. On the basis of the above research, an optimisation scheme for a secondary cooling system was proposed. Experimental results showed that the quality of the slab was significantly improved after optimisation. The centreline macrosegregation was reduced, and the ratio of equiaxed grains was increased by 3·18%. In addition, the transverse cracking of the slab was almost eliminated. 相似文献
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为了提高钢筋力学性能的均匀性,建立了以钢筋冷却后自回火温度为主要控制参数的数学模型。研制了由过程控制、检测仪表、数据处理及生产管理、水量调节和冷却器装置所组成的自动控制冷却系统。通过试生产,证明该系统能够提高控制冷却钢筋的质量,同时改善了生产工艺、设备、管理方面的技术水平,经济效益显著。 相似文献
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天钢集团高速线材厂于1991年引进美国摩根90年代的高速线材轧机,它的热处理过程主要包括水冷和风冷。文章介绍了水冷控制的关键部分:水箱冷却系统。 相似文献
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通过调节MULPIC模型的流量值和上、下集管的水比,并对头尾遮挡的长度和流量进行调整,保证了X70管线钢的良好板型;通过调整冷却速度和终冷温度,保证了钢板的性能。 相似文献
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A mathematical model to predict steel bar thermal behaviour during continuous quenching after the finishing mill has been developed. The model includes process variables, such as finishing rolling speed, finishing temperature, rod size and chemical composition, water flowrate and mechanical design of the cooling device. It was found that empirical correlations for the heat-transfer coefficient belonging to water spray systems are suitable to simulate fast cooling employing submerged water-cooling tubes. Martensite depth is strongly influenced by the bar diameter and water velocity inside the submerged tube. Mist spray systems are not as effective as submerged tubes for cooling steel bars, although, the initial cooling rates are higher. The % volume of martensite is a direct function of the self-tempering temperature, and independent of the fast cooling device. 相似文献
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连续铸钢过程中结晶器的传热研究 总被引:1,自引:0,他引:1
为了研究结晶器内壁温度的分布,设计了模拟结晶器工作过程的实验装置,并进行了实验。实验结果表明,结晶器内壁温度趋近于冷却水温度。基于实验,推导了结晶器边界等效导热系数。该系数用于解决金属和冷却水之间的传热,即反映结晶器的传热能力。用等效导热系数处理结晶器的边界传热,对包括结晶器在内的连铸凝固进程温度场进行数值模拟既简单又方便,并且计算结果与实验结果符合。还讨论了拉坯速度和冷却水流量对结晶器温度场的影响。 相似文献
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《钢铁冶炼》2013,40(8):598-604
AbstractThe aim of the paper is to design the new wide plate mill. The work on the new cooling technology was supported by extensive laboratory testing while a simulator with full scale testing of cooling units was used. The principal objective of the investigation was to establish the design specification of equipment for accelerated cooling, particularly with respect to the product dimensions and steel grades. The possibilities of accelerated cooling are limited by technical parameters of cooling equipment such as thickness of water layer, flowrate, spray height, position of cooled surface to the nozzles and water or plate speed. These parameters were studied for different product temperatures and water impingement densities from 50 to 110 l s?1 m?2. The heat transfer coefficient was determined and compared for each case. There were three recognised significant cooling regions: water layer region, impinging jet region without water layer and impinging region with water layer, which must be taken into account. The application of the new cooling technology showed better flatness product and productivity higher than previous accelerated cooling system, even shorter cooling length. The rejection ratio by flatness problem of new mill was nearly half of the previous one. 相似文献
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采用Deform模拟计算加热炉铸坯温度分布,并通过‘黑匣子’试验验证,当加热时间为70 min时,铸坯心部与表面温差约66℃,80 min时降到15℃.模拟计算轧制和水冷过程心部和表面温度曲线,并通过测温仪验证,得出准确的摩擦热、塑性变形热以及水冷换热系数模型.采用Fluent模拟计算风机的风场,使用手持测风仪验证,再建立盘条搭接点温度模型,计算出风冷线上强迫对流换热、自然换热和辐射换热系数以及相变潜热,使用热成像仪测温验证.模拟与试验结果十分吻合. 相似文献
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为了优化82B钢的成分和热轧冷却工艺,以提高82B盘条的强度,测定了80钢和82B钢的等温转变温度对相变时间、珠光体片层间距的影响以及Cr元素对82B相变温度的影响,分析了Cr合金化和相变控制对82B盘条的微观组织和抗拉强度的影响。对于82B,当温度在595~615℃相变速度最快,其转变时间为10~15s,在590~625℃可得到理想的0.10~0.20μm的珠光体片层间距;通过添加0.18%~0.24%Cr和控制热轧冷却速度,可以控制82B钢的相变温度区间和相变速度,得到均匀细片状的珠光体组织;将Φ12.5mm 82B盘条的主要成分调整为0.78%~0.84%C、0.15%~0.35%Si、0.78%~0.88%Mn和0.18%~0.24%Cr;在热轧控冷过程中,弱化水冷,强化风冷,控制82B盘条的吐丝温度为840~880℃,目标值860℃,增大82B盘条在风冷线上的冷速,提高了盘条的强度。 相似文献
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斯太尔摩线是基于钢在冷却时组织的转变规律而设计出的一种控制冷却工艺,是控制线材组织性能的关键工序,在线材生产中有着广泛的应用.宝钢高线主要生产钢帘线、钢绞线等高附加值产品,用户反映产品强度波动较大.通过对工艺流程进行一一排查,发现强度波动的主要原因是由于斯太尔摩线冷却工艺无法适应化学成分波动,尤其是环境温度波动造成的.为了解决这一质量难题,根据C曲线原理,通过整体设计、增加硬件、编制软件、建立模型、实现通信和设备安装等一系列研究工作,成功开发出斯太尔摩线冷却监控系统,实现了线材轧后冷却的动态闭环控制.现场应用结果表明系统有效改善了化学成分和环境温度波动对强度的不良影响,显著提高了线材强度的稳定性,取得了预期的效果. 相似文献