棒材二辊矫直过程中的辊缝工艺参数

针对棒材实际矫直过程中辊缝不易确定的问题,采用大型非线性有限元软件建立棒材二辊矫直过程的三维弹塑性有限元模型,基于该模型研究了不同辊缝下矫直力、成品棒材残余应力、最大挠度和塑性变形深度的变化规律,综合分析提出合理的辊缝取值范围,并在实际生产中得到应用,减少了实际生产中辊缝调节所需时间.     

含稀土轧辊用高速钢淬回火过程微观组织转变

利用金相(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)及能损谱(EELS)等手段,研究了含稀土轧辊用高速钢在1100℃淬火和550℃两次回火热处理过程的微观组织变化特征,重点探讨了碳化物行为。结果表明,淬火加热过程中热稳定性较高的MC和M6C型一次共晶碳化物难以溶解,亚稳态的M2C型一次共晶碳化物则发生分解反应得到MC和M6C两种碳化物,分解形成的M6C较MC量多且尺寸较大,小颗粒MC包含在M6C之中;淬火基体组织由马氏体和残留奥氏体组成,淬火马氏体既有板条马氏体也有孪晶型马氏体。经两次回火后,残留奥氏体得以有效消除,大量细小富V的MC型二次碳化物弥散析出产生二次硬化现象。     

铜带热轧机无芯上卷取机的改造

文章从多方面介绍了铜带热轧机无芯上卷取机的技术改造,包括上卷取机的机械结构及其速度控制、三辊预弯装置辊缝预设定、6RA70直流调速器参数设定以及2台S7-300间的数据通讯等。通过技术改造,提高了生产效率,减少了天然气、水、电等能源介质的单耗。同时文章也总结了技术改造中存在的不足。     

连铸轻压下过程中辊缝偏差分析和控制

某中厚板坯连铸机在投入动态轻压下系统过程中,发现辊缝漂移、辊缝偏差等现象,经组织现场测试和机械受力分析计算,确定辊缝漂移来源于冷热态变化,辊缝偏差来源于浇钢过程中机架上下框架受力变化引起连接关键部件的弹性变形量变化,并采取针对性措施。     

六辊冷轧机辊系弹性变形快速算法

为了快速计算六辊冷轧机辊系的弹性变形,提出了一种新的辊系弹性变形算法。该算法直接采用数值法计算轧辊挠曲,避免了复杂的公式推导,简化了计算过程;在辊系协调变形的迭代计算过程中,内层迭代首次引入辊间中心点处压扁和辊间压扁区倾斜两个迭代调节量,建立了与辊间接触合力和接触区的总力矩的联系,外层迭代通过不断修正辊间相对压扁量增量循环迭代辊间接触力与轧辊挠曲,实现了整个辊系变形的快速协调。通过与国外计算结果比较和算例的验证,证明其有好的计算精度、收敛性和快速性,能离线指导新轧机工艺方案设计,具备板形在线设定计算应用的可能。     

八钢中厚板粗轧机除鳞与轧辊冷却改造

介绍对中厚板粗轧机除鳞水系统、工作辊冷却水系统、支承辊冷却水系统进行了技术改造,生产的连续化和自动化水平取得进步和提高。     

平整机辊系变形的有限元分析

通过对辊系变形的模拟,分析了轧制条件下对工作辊弯曲变形、支撑辊弯曲变形及接触应力的影响,借助大型有限元分析软件ANSYS的手段,对辊系进行了弹性力学结构分析,得出了在轧制过程中辊系的变形情况及载荷分布等详细直观的分析结果。     

热轧带钢局部高点产生机理及控制研究

针对迁钢2250mm生产线热轧卷出现局部高点的问题,分析了轧辊辊间接触压力、轧制计划编排、工作辊热凸度等因素对产生带钢局部高点的影响规律,提出了优化末机架工作辊辊型、合理编排轧制计划、严格冷却水喷嘴管理制度、控制轧辊热凸度、调整精轧轧制工艺等措施,改善了轧辊的不均匀磨损程度,使带钢局部高点控制在10μm以下。     

Interaction between amino acid degradation,sensory attributes and lipid peroxidation in wheat rolls

The influence of lipid peroxidation and heating duration on the amino acid pattern of wheat rolls was assessed in a model baking test. Therefore, three different types of dough were prepared including dough without any fat and two doughs with fat. To estimate the impact of lipid peroxidation products on the amino acid pattern, the two doughs containing fat were both made with rapeseed oil, one with fresh oil, the other with oxidised rapeseed oil. All kinds of dough were baked for three different duration times (18, 24 and 30 min). The lipid peroxidation status of both rapeseed oils was measured with the peroxide value and the p‐anisidine value of the unbaked fat. The amino acid content was analysed by HPLC after acid and alkaline hydrolysis. Besides determining water content and protein content, a sensory analysis was performed. Whereas the amino acid content in the dough without fat was only affected by the baking time, the doughs with rapeseed oil additionally showed a significant increase in amino acid degradation caused by lipid peroxidation products. Especially in the dough prepared with oxidised rapeseed oil, the amino acid content was partly decreased in raw dough without any heating influence. Confirming the influence of lipid peroxidation products in dough prepared with oxidised rapeseed oil, sensory analysis also showed the significantly worst overall score.     

Properties of Algin/Calcium and Salt/Phosphate Structured Beef Rolls with Added Gums

Ten polysaccharide gums at two levels (0.5 and 1.0%) were individually incorporated into algin/calcium (AC) and salt/phosphate (SP) structured beef rolls (<6% fat) prepared with 15 and 30% added water. Cook yield, pH, bind and textural properties were evaluated. Each gum had specific effects on properties of beef rolls. For example, kappa-carrageenan improved (P<0.001) cook yields and maintained or improved bind and texture of raw and cooked samples of both meat binding systems. Cook yields of AC products were improved with gellan gum, while yields of SP products were improved with iotacarrageenan. Other gums (xanthan, guar, pectin, carboxymethyl cellulose) improved water holding (cook yields) but had detrimental effects on product texture.