冷轧薄钢板"湿法"平整的轧制压力计算

平整是使冷轧薄钢板获得合理表面形貌的关键工艺。平整轧制压力的预测与控制直接影响钢板平整后的表面质量。本文作者采用刚性、弹塑性、全滑动和边界润滑等不同模型，进行了平整轧制压力预测模型的理论分析与模拟实验研究。结果表明：当矿井下量小于5%后，轧辊的弹性变形和钢板的弹性恢复对轧制压力的影响很大，不能忽略；采用边界润滑弹塑性模型计算得到的平整轧制压力较边界润滑刚性模型更接近实验值（相对误差减小约20%）。     

Lubrication of Aluminum Rolling by Oil-in-Water Emulsions

The dynamic concentration model for lubrication by oil-in-water emulsions proposed by Wilson el al. (1) is applied to strip rolling to derive a relatively simple equation for inlet film thickness. The predictions of the new model are supported by rolling experiments using emulsions as lubricants, where the film thickness is inferred from the surface roughness that is generated on the workpiece during rolling. The experiments also seem to suggest that the efficiency of oil droplet capture increases with increasing rolling speed.     

铜带轧制变形区摩擦润滑状态研究

观察分析了轧制变形区形貌特征,研究了不同方向粗糙度对轧制润滑的影响。在轧制变形区并存边界润滑和流体动压润滑;轧辊与轧制的塑性挤压边界接触是获得高光亮表面的必要条件。轧后轧件表面粗糙度Ｒａ和丰满度Ｋ趋向于满足一定润滑条件的最佳值。     

Starvation Behavior in Cold Rolling of Aluminum with Oil-in-Water Emulsion

Reich, et al. ( 1 Reich, R., Panseri, N. and Bohaychich, J. 2001. “The Effects of Lubricant Starvation in Cold Rolling of Aluminum Metal When Using on Oil-in-Water Emulsion,”. Lubrication Engineering, 57: 15–18.  [Google Scholar] ) reported that the rolling force for the cold rolling of aluminum increased when starvation occurred in the oil-in-water (O/W) emulsion used as the rolling fluid. They reported that the starvation occurrence was dependent on the emulsion concentration and the size of the oil droplets, but the thickness of a starved lubricant film was independent of the rolling speed. However, from their experimental results, the cause of the increase of the rolling force and the quantitative inlet oil film thickness at the entrance between the roll and the workpiece for the O/W emulsions cannot be understood. In this study, the aluminum rolling experiments using O/W emulsions with different concentrations were carried out in order to reproduce the increase of the rolling force. Experiments were carried out using a laboratory mill with two high rolls. The workpiece material was an aluminum A1050-H. Commercial rolling oil was used as base oil for the aluminum emulsion. The rolling force was measured during the rolling and the appearance of the workpiece after rolling was taken. Moreover, the effect of the surface roughness of the rolls on the increase of the rolling force was investigated. The increase of the rolling force was reproduced in the aluminum rolling with the O/W emulsion using the laboratory rolling mill. It was observed that the increase of the rolling force occurred after the oil starvation, and it depended on the oil starvation, the oil film thickness, the surface roughness of the roll, the rolling speed, and the reduction in thickness.     

铁路客车滚动轴承挡边结构的研究

本文应用弹性流体动力润滑理论,对铁路客车用圆柱滚子轴承的挡边和滚子端面形状进行了讨论。并从理论上提出了常用结构形状的最佳几何参数。     

The Effectiveness of Boundary and Hydrodynamic Lubrication when Cold Rolling Aluminum Metal

How hydrodynamic and boundary lubrication affect a lubricant's film strength when cold rolling aluminum was studied using a laboratory mill. The film strength of the lubricant was determined by increasing the amount of reduction until a rapid rise in load and temperature produced a herringbone pattern on the surface of the metal. The hydrodynamic lubrication was changed by increasing the viscosity of the base oil or by increasing the rolling speed. The boundary lubrication was changed by increasing the concentration of the additives or by changing the type of additives. The results of the test showed that either increasing the amount of the hydrodynamic lubrication or increasing the amount of the boundary lubrication were effective ways to increase the film strength of the lubricant; however, the effectiveness of each decreased as the calculated film thickness of the lubricant increased. It is proposed that this can be explained by the decrease in contact area between the work roll asperities and the surface of the sheet as the thickness of the lubricant film increases.     

国内外冷轧机垂直振动问题研究进展

以冷轧机系统的垂直振动现象为研究对象,结合近年来国内外冷轧机垂直振动问题研究的成果,对带钢冷轧机垂直振动的成因、危害、主要影响因素、解决办法等方面进行了初步的研究与探讨.为解决当前国内冷轧机振动问题提供一些借鉴,并提出了未来轧机振动的研究方向和重点.     

基于弹性流体动压润滑条件的滚动轴承耐磨损设计

分析了弹性流体动压润滑的理论和条件,阐述了基于弹性流体动压润滑的圆柱滚子轴承耐磨损设计的方法和步骤。     

A Two-Wavelength Model of Surface Flattening in Cold Metal Rolling with Mixed Lubrication

A new model of surface flattening is developed for cold metal rolling in the mixed regime. Longitudinal surface roughness is modeled by two separate wavelengths. The new model follows the asperity crushing analysis of Sutcliffe (1999) for unlubricated rolling but additionally includes a hydrodynamic model to account for the effect of the lubricant. The effect of various parameters including speed, reduction in strip thickness, roughness wavelength and lubricant properties is examined. The results show similar behavior to previous models of mixed lubrication, with a speed parameter A_s having the most influence, and confirm the results for unlubricated rolling that the short wavelength components of the surface roughness persist more than the long wavelength components. The predicted changes in roughness are in good agreement with experiments.     

Mixed Lubrication of Strip Rolling

An analytical model for strip rolling operating in the mixed regime is developed. The model combines analysis for the influence of bulk plastic deformation on the effective hardness of the strip asperities with an approach to allow for the influence of roughness on lubricant flow. An approximate correction for thermal effects is also included. The predictions of the model are compared with experimental measurements of film thickness and slip.     

Lubrication of Strip Rolling in the Low-Speed Mixed Regime

An analytical model for strip rolling in the low-speed mixed lubrication regime is developed. An average Reynolds equation for longitudinal saw-tooth surfaces under conditions of high fractional contact area, is combined with an analysis for asperity flattening under conditions of bulk plastic flow, to treat lubrication in the mixed regime. Analyses for the inlet zone and work zone and the influence of pressure on viscosity are included in the model. The model indicates that hydrodynamic lubrication effects are important at much lower speeds than previously considered possible. The film thickness predicted by the model is somewhat smaller than that measured using the oil drop method in rolling aluminum alloy with a mineral oil.     

热轧带钢还原冷轧后的表面及横截面形貌

对Q215热轧带钢试样进行还原处理后,利用四辊轧机对其进行五道次冷轧试验,采用扫描电镜对还原后及不同道次冷轧后试样的表面和横截面形貌进行了观察。结果表明:还原后热轧带钢表面出现的裂纹、气泡和气孔等缺陷在冷轧过程中得到有效消除,裂纹宽度减小并趋于闭合,但五道次冷轧后,带钢表面仍然残留裂纹痕迹,且裂纹间距增大;带钢表面脱碳层厚度逐道次减小,试样表面形貌得到改善,表面质量不断提高。     

1750mm冷连轧不锈带钢高效轧制的跟踪实现

跟踪功能是冷连轧线高效轧制、稳定运行的基础。针对1750mm不锈钢冷连轧生产线的快节奏特点,进行轧线跟踪逻辑分区,焊点跟踪用于实现对中心区域带钢焊点的精确定位,并提供精确的钢卷跟踪信息。提出了跟踪逻辑队列概念,建立轧制数学模型共享区和队列存储区,进而实现跟踪数据处理,最终设计了适合于工业生产实践的跟踪功能模块。现场应用表明,该跟踪模块设计人性化,跟踪精度高,在线状态信息反馈更为及时和准确,为冷连轧过程控制系统各项功能的投入提供了保证,有效地提高了轧制节奏和生产效率,满足自动化生产的需求,具有良好的实际应用价值。     

基于改进型混合膜润滑模型的金属轧制过程的数值仿真

根据 Wilson和 Chang的粗糙度补偿模型和 Von Mises均匀变形模型 ,在轧制过程中 ,一种新的混合膜润滑模型被建立。一个更精确的平均雷诺方程被用来计算液体动压力。随变形而变化的屈服应力也在模型中被考虑。并编制了程序用来计算接触面积 ,膜厚和流体动压力。该模型使用较少的假设 ,且更切合实际 ,收敛快。它能应用于较宽速度范围的轧制状态     

Numerical Analyses of Hydrodynamic Lubrication and Dynamics of the Rolling Piston and Crankshaft in a Rotary Compressor

In this article, numerical analyses of hydrodynamic lubrication and dynamics of the crank, rolling piston, and vane were carried out to study the tribological performance of a rotary compressor. Dimensionless Reynolds equations of journal and thrust bearings in dynamic load condition were derived and solved numerically. To deal with the lubrication of the rolling piston, the effect of the nonuniformity of tangential velocity over the bearing surface on the Reynolds equation was taken into account. In addition, combined with the analyses of dynamics and kinematics of the crank, piston, and vane, the angular velocities of the crank and piston as well as the motion mode between the piston and vane were studied. Analysis results illustrate characteristic oil film pressure distributions of the crank and piston bearings, which are different from that of common journal bearings. Under the influences of dynamic load and eccentricity of the cam, the wedge effect as well as the stretch and squeeze effect contribute greatly to hydrodynamic pressure. The relative motion mode between the piston and vane tip is not always pure sliding but accompanies rolling in some cases, which depends on the magnitude of the friction coefficient between the piston and vane tip. The analysis results are helpful for the improvement of rotary compressor design.     

板带冷轧机颤振抑制策略研究

以冷轧机系统的垂直振动为研究对象,提出冷轧机颤振的评价指标,结合近年来国内外冷轧机垂直振动问题的研究成果,对冷轧机颤振的抑制策略进行分析探讨。     

Operating Limits for Acoustic Measurement of Rolling Bearing Oil Film Thickness

An ultrasonic pulse striking a thin layer of liquid trapped between solid bodies will be partially reflected. The proportion reflected is a function of the layer stiffness, which in turn depends on the film thickness and its bulk modulus. In this work, measurements of reflection have been used to determine the thickness of oil films in elastohydrodynamic lubricated (EHL) contacts. A very thin liquid layer behaves like a spring when struck by an ultrasonic pulse. A simple quasi-static spring model can be used to determine the proportion of the ultrasonic waves reflected.

Experiments have been performed on a model EHL contact between a ball and a flat surface. A transducer is mounted above the contact such that the ultrasonic wave is focused onto the oil film. The reflected signals are captured and passed to a PC for processing. Fourier analysis gives the reflection spectrum that is then used to determine the stiffness of the liquid layer and hence its thickness. In further testing, an ultrasonic transducer has been mounted in the housing of a deep-groove ball bearing to measure the film generated at the outer raceway as each ball passes. Results from both the ball-flat and ball bearing measurements agree well with steady-state theoretical EHL predictions. The limits of the measuring technique, in terms of the measurable rolling bearing size and operating parameters, have been investigated.     

冷轧塑性加工中的摩擦性质

根据轧制时轧件金属发生塑性变形特点及摩擦副间的介质实际情况,经理论分析认为冷轧塑性加工中的摩擦性质是混合摩擦或边界摩擦,并得到了实验的验证。     

小模数渐开线花键冷挤成型研究及挤轮设计

通过对小模数花键冷挤轧成形过程分析,指出冷挤小模数花键的可行性,其工艺明显优于传统加工方法,加工精度、齿面强度和效率均得到很大提高。针对实际的成形条件,详述了滚轧轮的设计方法,为小模数花键零件的研究和生产提供了一种实用、高效、可靠的成形工艺。     

1420mm冷轧机组吹扫器对钢带质量的影响

通过改进1 420 mm冷轧机组吹扫器结构,使钢带表面的乳化液斑、黑带明显减少,提高了钢带的表面质量。