邯钢2180冷轧工作辊磨削工艺优化

为适应高档板材生产的需要,冷轧工作辊必须获得更高的表面精度和表面质量。通过失效模式分析和因果图筛选出轧辊磨削过程中主要影响因子为砂轮、磨削液、磨削程序结构和磨削参数。依据辊系粗糙度、表面质量精度要求、磨削效率,制定了工作辊的砂轮使用规范和选用了合适的磨削液。通过优化磨削程序结构和参数匹配,冷轧工作辊表面质量已达到O5级别,工作辊辊形公差控制在0.002 mm以内,粗糙度均匀性控制在±0.1μm,满足高品质汽车板生产用轧辊需要。     

高表面质量带钢轧辊磨削工艺研究

轧辊磨削是影响带钢表面质量的关键工艺过程,磨削工艺优化需考虑磨削程序架构和关键参数两个方面与磨削效果之间的关系.文章结合高表面质量带钢对轧辊磨削过程的要求,从实际生产出发明确了磨削工艺的调整原则.分析了磨削程序、参数设置对轧辊表面质量的影响特点,发现程序架构是影响轧辊磨削质量的主要原因.研究结果对冷轧带钢轧辊磨削具有指导意义.     

轧辊磨床静压托瓦防水装置的改造与实现

针对德国轧辊磨床设计缺陷导致轧辊磨削加工过程中设备液压系统内混入大量的磨削液和磨削颗粒、托瓦和液压系统油泵严重磨损的现状,利用聚四氟乙烯胶板和简易的加紧装置,对磨削加工的轧辊轴颈进行有效防护,防止磨削液和磨削颗粒进入设备液压系统,从而保护设备.     

走刀痕缺陷产生的原因与控制

轧辊磨削质量直接影响冷轧带钢的质量。从磨削加工的特点入手，分析了走刀痕产生的原因，认为磨床设备精度差、砂轮材质不均、砂轮修磨形状不良、轧辊辊型偏差大、磨削参数不匹配、磨削液循环过滤不良都会导致走刀痕。举例说明了不同分布特征走刀痕缺陷的控制方法。磨削参数不匹配导致的走刀痕，主要通过调整各个磨削阶段的磨削压力、砂轮转速和横移速度、增加磨削道次来改进磨削质量。若辊型偏差大于50μm,主要通过优化磨削进给量或分段控制磨削参数的方法，将辊型偏差控制在20μm以内，然后再采用正常的磨削参数进行磨削，控制走刀痕的产生。     

铝箔轧辊剥落原因及对策

影响铝箔轧辊寿命因素有两个：一是磨削时的磨损，二是在轧制过程中表层剥落。分析剥落的原因，采取相应的措施就能提高轧辊的寿命。     

我国电工钢近年进出口状况

热轧板带的凸度和板形主要取决于轧辊的机械磨削、轧辊温升、轧辊磨损以及轧辊的弹性弯曲变形有叠加作用。轧辊弹性弯曲变形又受机架负载（轧制力）和轧辊反向弯曲力的影响。目前控制板形的方法主要有可反复移动的CVC工作辊、弯辊。PC辊和轧辊分段冷却几种。     

热连轧粗轧辊磨损的有限元数值模拟和工艺优化

针对轧钢厂GCr15轴承钢240 mm × 240 mm方坯粗轧阶段轧辊磨损较严重的情况,采用Archard磨损数学模型模拟分析了轧件压下量、轧辊硬度、热传导系数及摩擦因子在一道次成形后对轧辊磨损规律的影响。模拟结果表明,轧辊硬度越高,轧辊抗磨损能力越强;热传导系数对轧辊磨损的影响较小;当摩擦因子f＞0.25时,其摩擦因子对轧辊磨损量变化明显;当轧件压下量在△h＜50 mm 时,轧件压下量对轧辊的磨损量影响显著。根据所得结果,结合现场轧制工艺和轧辊材质,将使用的球墨铸铁Ⅰ轧辊[抗拉强度≥400 MPa,硬度HRC值40,热传导系数18 kW/（m²·℃）,摩擦因子0.3]改成球墨铸铁Ⅱ轧辊[抗拉强度≥500 MPa,硬度HRC值45,热传导系数17kW,/（m²·℃）,摩擦因子0.2],并将压下量由70 mm降至50 mm,使轧辊单槽过钢量由优化前10000 t提高至优化后的18000~20000 t。     

2050粗轧机组轧辊磨损预报模型的开发及应用

热轧生产作为板带轧制的首道工艺，轧辊异常消耗与磨削次数影响着机组的生产能力，同时影响板形，迫切需要建立磨损情况的准确预报。以唐钢2050粗轧机组为研究对象，充分考虑粗轧工艺特点，结合实际工况，分析了轧辊磨损机理。为更好地了解轧辊沿长度方向上各点的磨损情况，对轧辊进行了划分条元，同时利用划分条元建立了单位辊间压力的理论模型。针对工作辊与支撑辊的不同磨损情况，建立了区别于不同轧辊的磨损理论模型，同时根据辊间压力模型与轧辊磨损模型，开发了一套粗轧机组轧辊磨损预报模型软件。该软件可以显示轧制一定里程后轧辊各个样本点的磨损情况，形成轧辊磨损规律曲线。同时采用离散分段法分别计算支撑辊和工作辊磨损量分布，为后续轧制工艺提供了精确的轧辊磨损预报，确保轧件产品的质量，同时提高了机组的轧制稳定性与轧制效率。     

冷轧高端电镀铬基板表面粗糙度控制研究

根据高端电镀铬基板后步工序的要求,结合鞍钢冷轧现有设备,研究了轧机轧辊粗糙度配置、轧辊磨削、干平整等工艺对于钢板表面粗糙度的影响,使得平整后表面粗糙度达到了0.1μm以下,表面光泽度达到了400,表面反射亮点满足要求,成功开发出具有鞍钢特色的高端电镀铬冷轧基板。     

影响热轧轧辊原始辊型精度的因素分析

保证轧辊的原始辊型是计算精确热态辊型的基础。以某钢厂2 250mm热轧宽带钢精轧机组轧辊原始辊型保持为研究背景,研究了轧辊下机温度、磨前强度、磨削热、磨后空冷温度对热轧轧辊原始辊型精度的影响。将研究成果应用到实际生产中后,磨削后的原始辊型精度得到保障。     

Profile and Flatness Control Technology With a Long Shifting Stroke on Wide Non-Oriented Electrical Steel Sheets

 In order to solve the difficult profile and flatness control problem of wide non-oriented electrical steel sheets, the factors such as the relationship between strip crown control and strip width, the relationship between the maximum wearing value of work roll and the number of a rolling campaign and the wear contour change of work roll were analyzed on the basis of industrial test. Through analyzing the rolling process characteristics of non-oriented electrical steel sheets, the ASR (asymmetry self-compensating work rolls) shape control technology and its roll shifting strategy of the wider non-oriented electrical steel sheets was proposed and developed. When the technology was applied, the number of the wide non-oriented electrical steel (23 mm×1280 mm) in one rolling campaign rose from 40 coils of the trial production to 70 coils of the industrial production, the ratio of the measured strip crown less than 45 μm was increased from 500% to 949%, and the ratio of the measured strip crown more than 60 μm was decreased from 200% to 07%.     

锻造半高速钢冷轧工作辊的试制

整体锻造半高速钢(%:0.74C,0.87Si,4.92Cr,1.05Mo,0.41V)Φ540mm×1530mm冷轧工作辊的试制工艺为:电弧炉冶炼+电渣重熔,锻造成型,双频感应加热表面温度1090℃淬火,520℃高温回火而制成。采用逐层磨削法测得轧辊硬度分布曲线,轧辊表面硬度HSD92,HSD90以上的淬硬层深度为25mm,HSD87以上的淬硬层深度为35mm。轧辊组织为回火马氏体基体上分布有着细小弥散的碳化物。     

1 250 mm热带轧机辊型曲线优化设计

 针对港陆1 250 mm热带轧机,通过对带钢凸度在机架间进行合理分配确定各机架的带钢入出口凸度范围,采用一种基于影响函数法的辊型曲线优化设计算法优化了现场辊型曲线,对优化后的辊型曲线进行了模拟计算和现场实际生产实验。结果表明,优化后的辊型曲线改善了辊间压力的分布情况,降低了轧制末期工作辊边部对支撑辊的磨损,提高了支撑辊轧制质量。现场生产实验的带钢凸度介于40~60 μm,满足生产要求。     

基于GM-AGC的中厚板轧机同板差原因分析及改进

基于GM-AGC的控制方程,分析了轧机刚度、轧件塑性系数偏差对厚度控制调整量的影响,讨论了咬钢冲击、油膜厚度、偏心、轧制力偏差等造成钢板同板差的原因。采用轧机刚度非线性回归、轧件塑性系数实时计算和头部沉入、轧辊偏心、油膜厚度的补偿等措施,在国内某3 500 mm轧机上,实现了厚度10～30 mm的钢板同板差控制在40μm之内。     

Experimental Investigation of Shear Capacity of Precast Reinforced Concrete Box Culverts

This study presents an experimental program to investigate the shear capacity of precast reinforced concrete box culverts. Each culvert was subjected to monotonically increasing load through a 254?mm×508?mm (10?in.×20?in.) load plate in order to simulate the HS20 truckload per AASHTO 2005. Instrumentation included strain gauges, high-resolution laser deflection sensor, and automated data acquisition. Four tests were conducted on 1.22?m×1.22?m×1.22?m (4?ft×4?ft×4?ft) box culverts. The location of the load plate was varied to identify the position, which introduces the maximum shear stresses. Laser sensor data and dial gauge readings were recorded to measure the deflection profile of the box culvert. Strain gauges were placed on the steel reinforcement to measure axial strain at locations of maximum positive and negative bending moments. The test results include reporting the loads at which each crack initiated and propagated. The displacement profile of the top slab from the laser instrumentation output along with the load versus maximum deflection for each culvert is also reported.     

砂磨次数对钛白初品质量的影响

以钛白辊压初品为原料,不同粒径氧化锆珠为研磨介质,通过卧式砂磨机研究了砂磨次数对钛白初品性质的影响。试验结果表明:随着砂磨次数的增加,浆料的p H和黏度基本不发生改变,粒度D50逐渐减少,粒度≤1μm的百分比逐渐增加,浆料颗粒长径比缓慢减少,球形度逐渐改善,团聚体数量和尺寸减少,白度L值和亮度缓慢增加。氧化锆珠粒径0.4 mm相对0.6 mm和1.8 mm能获得更好的粒度、白度L值和亮度值。     

复合助磨剂对钢渣超微粉助磨效果

以乙二醇与三乙醇胺为原料、无水乙醇为溶剂配制复合助磨剂。将复合助磨剂分别与滚筒渣、脱硫渣和热闷渣进行混合后,利用行星式球磨机进行粉磨。研究钢渣的化学成分与矿物组成、不同助磨剂对钢渣超微粉粒度分布的影响、复合助磨剂对钢渣超微粉的作用机理。结果表明,当乙二醇、三乙醇胺与无水乙醇按体积比2∶2∶2配制复合助磨剂,以钢渣∶复合助磨剂质量体积比为450 g∶6 mL时,钢渣超微粉的粒度分布最佳,即d90为9.14~9.28、d50为3.31~4.20、d10为0.99~1.04和d90-d10为8.11~8.24 μm,其中复合助磨剂对脱硫渣的助磨效果最佳。     

Microstructure of shot-blasting casting roll and effect on strip solidification during strip-casting process

In the strip-casting process,the surface topography of the casting roll has a significant influence on the solidification microstructure and surface quality of the as-cast strip. Shot-blasting treatment is an important way to achieve a suitable surface topography on the casting roll. In this study,a casting roll of beryllium copper alloy was shot blasted using steel pellets in the laboratory,resulting in a randomly distributed discontinuous peak and dent surface topography,in which cold deformation-slip bands and fine-deformation twins were formed. The thickness of the deformed copper alloy was about 100 μm during the shot-blasting process,and the copper hardness value increased significantly within 40 μm of the surface,with a maximum increase of more than 20% compared to the mean substrate hardness value. Within 60-100 μm of the surface,the hardness at the peak position was still higher than the copper substrate mean value,but the hardness at the dents was not,which was mainly due to the copper alloy slip and twinning deformation mechanisms. The surface hardness was similar to that of the substrate after the shot-blasted sample had been subjected to thermal shock. The molten steel first chilled and nucleated at the surface peaks of the casting roll;furthermore,fine dendrites grew and crossed over the middle of the dents. Therefore,the peak intervals of the shot-blasted surface are an important factor in solidification quality control.