压下率对不锈钢/碳钢复合板界面剪切强度的影响

使用ANSYS有限元分析软件对不锈钢/碳钢复合板的轧制过程进行了探究,结合试验分析内容,对压下率对不锈钢/碳钢复合板界面剪切强度的影响进行了分析。分析结果显示:本试验条件下,压下率大于40%的情况时,不锈钢/碳钢复合板界面剪切强度符合国标要求;压下率大于40%后,界面剪切强度随压下率的增大增加不明显。     

冷轧不锈钢丝网增强铝基复合板性能分析

以冷轧复合法制备不锈钢丝网增强铝基复合板,采用金相显微镜观察复合界面微观形貌随压下率变化的演变规律,利用拉伸试验机获得复合板力学性能。结果表明:随着压下率增大,复合界面由最初的钢丝网与铝板间机械咬合转变为钢丝网交叉点与铝板间的局部点焊合,随后为钢丝网交叉点与铝板间的面焊合及非交叉点处钢丝与铝板间的局部点焊合;当压下率达到52.8%时,钢丝网与铝板间形成全面焊合及铝板与铝板间的结合。复合板力学性能测试结果显示:0°钢丝网增强复合板抗拉强度、比抗拉强度在一定范围内随着冷轧压下率、钢丝网目数的增大而提高,随铝板初始厚度增大呈下降趋势,当铝板初始厚度大于2 mm后,钢丝网增强效果较小。不同摆放角度钢丝网增强复合板较无钢丝网增强铝-铝复合板抗拉强度有所提高,0°钢丝网增强复合板提高22.5%,45°钢丝网增强复合板提高34.2%,但伸长率都有所下降,其中45°钢丝网增强复合板伸长率下降较少。     

压下率对不锈钢复合板组织及结合强度的影响

在不同压下率轧制工艺条件下,通过观察复合界面显微组织、界面特征、剪切试验和断口形貌,对比分析压下率对热轧不锈钢复合板复合界面组织及结合强度的影响。结果表明:不锈钢复合板界面结合良好,近界面碳钢侧内有宽约80μm的铁素体带,随着总轧制压下率的增加,碳钢侧铁素体组织晶粒逐渐细小、均匀化,晶界的面积也越来越大,可有效地提高不锈钢复合板的强度。但较大的压下率使碳钢侧晶体发生不同程度的晶内滑移,产生加工硬化现象,且随压下率的增加,晶内滑移更加明显,在铁素体中出现滑移带。通过系列剪切试验发现,复合板结合强度随总压下率的增加呈增加趋势,增加的趋势逐渐减缓,其断裂方式为脆性断裂+韧性断裂,最大剪切强度可达459.6MPa,远高于标准中规定的210MPa。     

2205双相不锈钢复合板爆炸-轧制工艺研制

就 2 2 0 5双相不锈钢复合板的生产工艺过程进行了研制、观察 ,重点介绍了厚复层 2 2 0 5双相不锈钢复合板爆炸焊接 ,轧制温度控制与相比例的关系及对板形的控制 ,并对试验结果进行了讨论 ,从而找出爆炸—轧制双相不锈钢复合板生产的可行性工艺路线。     

冷轧压下率和退火工艺对St37-2G结构用冷轧钢板组织和力学性能的影响

研究了冷轧压下率和退火工艺对St37-2G结构用冷轧钢板显微组织和力学性能的影响,并优化了生产工艺。结果表明:试验钢板经不同压下率冷轧并经670℃×5h退火后的显微组织均由铁素体、少量渗碳体和微量珠光体组成,仍保留着渗碳体沿轧向呈纤维状分布的特征;随着冷轧压下率的增大,试验钢板的硬度先增大后减小,在冷轧压下率60%时达到最大值;随退火升温速率的增大,试验钢板的屈服强度、抗拉强度以及塑性应变比明显下降,伸长率和加工硬化指数变化不大;最优的冷轧和退火工艺为冷轧压下率40%～50%,退火温度670℃,升温速率20℃·h-1。     

轧制压下率对碳钢/不锈钢复合板界面结合性能的影响

采用非真空轧制非对称组坯方式在不同总压下率(28％～70％)下制备Q235碳钢/304不锈钢复合板,研究了复合板界面处的组织、夹杂物形貌、硬度和剪切强度,探讨了界面夹杂物与脱碳层对界面结合强度的竞争性影响.结果表明:随着轧制总压下率的增加,复合板界面夹杂物由集中分布的块状变为均匀分布的颗粒状;当轧制总压下率由28％增大到47％时,影响复合板界面结合强度的主要因素是界面夹杂物,增加轧制压下率有利于提高界面结合强度;当轧制总压下率由47％增大到70％时,不锈钢侧晶粒尺寸急剧减小,碳钢侧脱碳层厚度增加,界面结合强度降低,脱碳层成为影响结合强度的主导因素.可以通过合理控制轧制压下率来平衡界面夹杂物和脱碳层对结合强度的竞争性影响.     

不锈钢夹层复合板的胶接强度

为了提高不锈钢夹层复合板的胶接强度,研究了表面处理、胶粘剂对不锈钢夹层复合板(铝蜂窝夹芯)胶接强度的影响.结果表明:不锈钢基材的表面处理是影响夹层复合板胶接强度的主要因素,盐酸-甲醛法处理的不锈钢板胶接强度最优,相同条件下,国产环氧胶膜夹层复合板胶接性能相对较好,最大胶接强度达到4.63 kN·m-1.     

高性能不锈钢冷轧轧制油的研制：Ⅰ基础油和助剂的筛选

不锈钢冷轧轧制生产工艺和工况(高速、高温、高压)比较苛刻,轧制不锈钢板带质量要求甚高,因而对不锈钢冷轧轧制油的性能要求很高。研究高性能不锈钢冷轧轧制油基础油和添加剂的配伍性,基于挥发性、表面张力和抗氧化能力3个指标筛选出最佳的基础油,基于抗老化性和黏度2个指标筛选出最佳的抗氧剂,基于磨斑直径与摩擦因数2个指标筛选出最佳的润滑剂;基于最大无卡咬负荷、烧结负荷和摩擦因数3个指标筛选出最佳的助剂。在此基础上,筛选得到了最佳的不锈钢冷轧轧制油配方。     

刀具用不锈钢带钢的试制

通过对3Crl13刀具用不锈钢冶炼、锻造、热轧及冷轧过程的控制，试制出3Cr13不锈钢带钢，摸索出合理的生产工艺，产品质量满足用户要求。     

双金属复合板冷轧变形行为的Avitzur上限模式分析

应用Avitzur上限理论建立双金属冷轧塑性变形模式的数学模型。应用此模型计算变形区域的速度场、能量消耗及轧制力的上限解等变形行为,给出相关参数的相应计算公式。应用这些理论公式对铝-钢复合板进行分析,计算与试验结果得到较好的吻合。分析模型能够很好地应用于模拟双金属冷轧过程,并能为双金属复合板的生产提供一些有益的理论依据。     

Analysis of asymmetrical clad sheet rolling by stream function method

A mathematical model for asymmetrical clad sheet rolling is proposed by using the stream function method and the upper bound theorem to investigate the plastic deformation behaviour of sheets at the roll-gap. The curvature and thickness ratio of the rolled product and rolling power, effected by various rolling conditions such as roll speed ratio, roll radius ratio, initial thickness ratio and flow stress ratio of sheets, total thickness reduction, etc., are systematically discussed. Furthermore, experiments on asymmetrical clad sheet rolling are also conducted by employing aluminum, copper, and mild steel as layers of clad sheets. It is found that the theoretical predictions of the thickness ratio of the rolled products, rolling force, and rolling power are in good agreement with the experimental measurements. Through the study, it becomes clear that the proposed analytical method is applicable to simulate the asymmetrical clad sheet rolling processes and is able to offer useful knowledge in manufacturing clad sheets.     

高性能不锈钢冷轧轧制油的研制：Ⅱ 性能测试*

轧制工艺的发展和市场对轧制不锈钢板带日益提高的质量需求使得轧制油的性能也提出更加严格的要求。在前期配方研发的基础上,对研制的最佳配方的高性能不锈钢冷轧轧制油的挥发性、冷却性、渗透性和退火清净性等性能进行研究,并对现场应用效果进行考察。结果表明,研究的轧制油产品的挥发性低、冷却性好,具有优异的渗透性和退火清净性,各项性能指标接近或者优于进口同类产品,可完全替代进口轧制油。     

柔性薄膜太阳能电池用不锈钢基板的成形技术

综述了不锈钢基底薄膜太阳能电池的研究进展及其不锈钢基板的国内外生产情况,并针对柔性薄膜太阳能电池对不锈钢基板的品质要求,介绍了不锈钢基板的成形过程,其中包括基板的轧制成形、光亮退火及拉伸矫直等一系列关键技术。     

铜覆铝板对称轧制复合工艺研究

运用四层对称轧制复合法对铜覆铝板的生产工艺进行了研究。与传统的二层非对称轧制复合法相对比发现,四层对称轧制复合法的生产效率提高了近1倍,制备的复合板较平直,同时,研究了轧制时组元的变形规律及其影响因素。     

The effect of roll and clad sheet geometry on the necking instability during rolling of clad sheet metals

Experimental evidence is presented showing that the rolling strain required to produce internal necking in clad sheet depends both on the volume fraction of each constituent in the clad and the geometry of the rolls. This result was not predicted by earlier localization analysis that approximates the stress/strain field in rolling with that of plane strain compression. The evolution of hardness during rolling and complementary finite element results point to redundant shearing of the soft phase as the reason for this behavior. Such redundant shear differentially strengthens the softer component of the clad and reduces the induced tensile stress in the harder component, delaying the localization. Therefore, unwanted strain localization in rolling of clad sheets can be delayed significantly by the use of small radius rolls in configurations such as a Sendzimir mill.     

Occurrence of surface defects on strips during hot rolling process by FEM

During a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions: (1) there are initial defects on continuous casting slabs that propagate and/or are inherited from those on the surface of rolled steels from upstream rolling processes; and (2) there are no initial defects on continuous casting slabs, and they consequently appear on the surface of rolled steels due to improper rolling technologies. In this paper, the authors present a new 3D finite element model coupled with constrained node failure to understand better the initiation and growth of surface defects on strips during the hot rolling process for case 2. The strip deformation processes were simulated for various rolling reduction ratios and friction coefficients between the roll and the strip. The occurrence of surface defects on strips was modeled under some rolling conditions. The plastic strain distribution in strips and the rolling forces were obtained. The risk of occurrence of surface defects on strips increases as the friction between the roll and strip increases for the same reduction ratio.     

Control of surface thermal scratch of strip in tandem cold rolling

The thermal scratch seriously affects the surface quality of the cold rolled stainless steel strip. Some researchers have carried out qualitative and theoretical studies in this field. However, there is currently a lack of research on effective forecast and control of thermal scratch defects in practical production, especially in tandem cold rolling. In order to establish precise mathematical model of oil film thickness in deformation zone, the lubrication in cold rolling process of SUS410L stainless steel strip is studied, and major factors affecting oil film thickness are also analyzed. According to the principle of statistics, mathematical model of critical oil film thickness in deformation zone for thermal scratch is built, with fitting and regression analytical method, and then based on temperature comparison method, the criterion for deciding thermal scratch defects is put forward. Storing and calling data through SQL Server 2010, a software on thermal scratch defects control is developed through Microsoft Visual Studio 2008 by MFC technique for stainless steel in tandem cold rolling, and then it is put into practical production. Statistics indicate that the hit rate of thermal scratch is as high as 92.38%, and the occurrence rate of thermal scratch is decreased by 89.13%. Owing to the application of the software, the rolling speed is increased by approximately 9.3%. The software developed provides an effective solution to the problem of thermal scratch defects in tandem cold rolling, and helps to promote products surface quality of stainless steel strips in practical production.     

An innovative development of a four-high foil rolling mill

During foil or ultrathin strip rolling, elastic deflection variation of the work rolls at the contact surface with the strip causes non-uniform thickness distribution of the product in the width direction, which possibly causes a central wrinkling or an edge fracture on the product. This study developed a four-high prototype rolling mill, comprising two work rolls fabricated from an ultrastrength alloy. This prototype rolling mill was composed of a housing frame set, a roll set, a roll gap adjusting mechanism, and a power transmission system. The finite element analysis was used for determining the frame dimensions and work roll diameters. Several experimental rolling passes of stainless steel strips were conducted using this self-developed prototype rolling mill to achieve a 0.05-mm-thick foil product.     

不锈钢-铝合金复层材料拉伸力学性能分析

针对半固态连接制备的不锈钢-铝合金复层材料，对不同相对厚度比的复层材料进行拉伸试验，将试验数据与混合法则相比较，并建立了屈服点、抗拉强度与相对厚度比之间的关系模型。在传统的混合法则基础上，建立了宽度方向应力与相对厚度比和拉伸应变之间的关系。研究结果表明：屈服点、抗拉强度与相对厚度比之间符合指数函数关系；在塑性变形阶段，试样宽度方向应力的绝对值随拉伸应变的增大而增大；不锈钢一侧宽度方向应力为拉应力，并随着相对厚度比的增大而减小；铝合金一侧宽度方向为压应力，其绝对值随相对厚度比的增大而增大。     

不锈钢复合板储罐泄漏的分析及改进措施

分析对不锈钢复合板储罐发生泄漏的原因,提出了不锈钢复合板现场制造储罐时关键工序及相应的改进措施。