多楔楔横轧轧制力在线测试系统

针对目前多楔轧制规律比较复杂现状，设计了H630轧机轧制力在线测试系统，该系统可以在线准确测出单楔与多楔轧制过程中轧制力变化规律。同时采用Ansys／Ls—Dyna3D有限元软件对轴类零件楔横轧制过程进行模拟，并对轧制力变化规律进行较系统的分析，分析结果与实验测试结果基本一致。     

阀门零件加工组装新方法

阀门零件加工组装新方法大连前进工业总公司崔杰１．双头螺柱装卸工具双头螺柱常用于中小口径阀门的阀体与阀盖的连接，用传统的方法装卸双头螺柱比较麻烦，为此特制了一种专用工具（图１）。安装双头螺柱时，先扭动大扳手，将双头螺柱旋入螺母内，使螺钉、钢球、螺母和双...     

轴承钢球毛坯热斜轧成形过程数值模拟

轴承钢球毛坯螺旋孔型斜轧工艺设计和变形行为较为复杂,传统的解析计算和物理试验方法不能有效揭示其轧制变形机理。探讨总结了钢球毛坯热斜轧成形主要建模技术与方法,基于SIMUFACT有限元软件平台首次建立了钢球毛坯热斜轧成形三维热力耦合有限元仿真模型。基于有限元模拟结果详细分析了轴承钢球毛坯热斜轧成形过程等效应变、应力、温度和轧制力能参数的分布与演变规律,证明钢球毛坯斜轧心部疏松或空洞缺陷的产生是由其在轧制过程承受的循环交变切应力、较高水平的横向拉应力和由多向拉应力引起的较大负静水压应力(正的平均应力)共同作用的结果。     

巧制双头螺栓安装工具

当碰到需要拧双头螺栓而又无现成的安装工具时,虽可用手钳临时应付,但效率低,且易损坏螺栓螺纹,本文介绍一种简易双头螺栓安装工具如下: 1.制作 如图所示,根据双头螺栓规格,找一相应螺母1,另找一只方孔完好的废套筒,再找一直径合适的钢球,按图示将套筒与螺母焊接牢固即可(为保护螺母螺纹,焊接时应先套入一个螺栓,然后再焊)。 2.原理及使用 先将双头螺栓挂在机体上,再将此工具套在风板机或摇手柄板头上并对准双头螺栓,顺时针旋转即可将双头螺栓旋入工件螺孔,由于螺栓端面与钢球是点     

铝板带轧制油中添加剂的综合评价与实验研究

在基础油中使用不同类型、不同含量的添加剂进行铝板带的冷轧工艺润滑与退火实验，获得了各种添加剂的轧制润滑特征曲线。并通过实验研究全面评价了铝轧制油中常用的脂肪酸、脂肪醇、脂肪酸酯等添加剂的性能，包括基本理化性能、油膜强度、轧制变形区摩擦系数、轧制压力及退火性能等，最终推荐了综合性能好的添加剂．其中：含有椰油醇的轧制油润滑作用效果最佳。实验结果还表明：添加剂的使用并非含量越高越好。上述评价实验结果为铝材轧制润滑正确选择添加剂提供了参考依据。     

影响斜轧钢球质量的因素分析

斜轧钢球内部疏松问题是制约钢球质量提高的一大隐患。基于斜轧成形原理,对影响钢球质量的主要因素进行了分析。通过分析钢球在成形过程中的受力变形,发现影响变形抗力的最大因素是钢球的变形速度,而钢球内部的应力状况直接影响钢球内部质量。基于DEFORM-3D软件,在不同轧辊倾角、导板距和轧辊转速条件下对钢球轧制过程进行了仿真试验,找到这些因素对钢球受力的影响规律。该项研究为解决钢球斜轧过程中形成的内部疏松问题提供理论依据。     

球磨钢球斜轧孔型的设计

球磨钢球与其他零件轧制生产一样，轧制过程的顺利与否、轧件质量的优劣，其主要关键之一是合理的孔型设计。介绍斜轧钢球孔型设计基本参数的选取。     

楔横轧轧制力矩规律有限元分析与实验测试

采用二次开发的有限元命令流程序，较系统地分析了轧制过程中轧制力矩的变化规律，阐明各工艺参数对轧制力矩的影响规律；利用计算机数据采集测试系统，在线测试展宽角对轧制力矩影响规律，测试结果与理论分析结果一致。研究结果为大型楔横轧机研制中力能参数的确定提供了重要的理论依据。     

中厚板轧制过程的三维显式动力学有限元分析

运用显式动力学有限元方法对中厚板轧制过程进行模拟计算.通过分析计算结果得出,在稳定轧制阶段,轧件沿截面高度方向应力和应变呈不均匀分布状态.绘制测试节点的速度时程曲线,分析沿轧件应力应变场分布不均的原因.计算出不同轧制压下率下的轧制压力分布曲线,并分析轧制压力的分布特点.分析结果与实验研究的结论相符合,表明显式动力学有限元法的可靠性.     

《滚动轴承钢球振动（速度）技术条件》编制说明

1 制定思路 对于小尺寸段（配d≤60mm的轴承）钢球，首先收集大量的国内不同厂家生产的、不同精度等级的钢球样品和少量的国外钢球样品；同时收集加工质量较好的轴承内、外圈各10套，作为“标准套圈”，以及少量加工质量中等的内、外套圈；其次在BVT-1A型轴承振动（速度）测量仪和SBV-1型钢球振动（速度）测量仪上进行合套测振和单粒钢球测振。通过测试、分析、比较，研究钢球振动对轴承振动的影响规律。对于大尺寸段（配d≥65mm的轴承）钢球，采用“先检测某批次钢球振动速度，然后用BVT-6型轴承振动（速度）测量仪跟踪该批钢球所装轴承的振动速度值”的方法，并结合小尺寸段钢球的研究结果。     

陶瓷球轴承内部结构参数优化设计及其性能试验研究

氮化硅陶瓷是一种较好的滚动轴承材料,在此提出了陶瓷球轴承内部结构参数优化设计的基本原则,建立了其优化设计的数学模型,通过对钢球轴承和陶瓷球轴承的性能对比试验,证明了陶瓷球轴承的高速性能要优于钢球轴承,并验证了陶瓷球轴承优化设计原则。     

Rolling contact fatigue performance of detonation gun coated elements

Rolling contact fatigue performance of thermal spray coatings has been investigated using an experimental approach. A modified four ball machine which simulates a rolling element bearing was used to examine the coating performance and failure modes in a conventional steel ball bearing and hybrid ceramic bearing configurations. Tungsten carbide (WC-15% Co) and aluminium oxide (Al₂O₃) were thermally sprayed using a super D-Gun (SDG2040) on M-50 bearing steel substrate in the geometrical shape of a cone. A coated cone replaced the upper ball that contacts with three lower balls. The rolling contact fatigue (RCF) tests were performed under immersed lubricated conditions using two different lubricants. Fatigue failure modes were observed using a scanning electron microscope. Microhardness measurements of the coating and the substrate and elastohydrodynamic fluid film thickness results are included. The results show the requirement for significant optimization of the coating before use in rolling element bearing applications. The coating was fractured in a delamination mode. Test results show an optimization in coating process is required before these coatings can be used for rolling contact applications. WC-Co coatings perform better than Al₂O₃ coatings in rolling contact.     

Occurrence of Wall Slip in Elastohydrodynamic Lubrication Contacts

Preliminary experimental work has been carried out to identify some of the boundary slip phenomena of highly pressurised polybutenes in an elastohydrodynamic lubrication (EHL) conjunction. The movement of the oil is signified using an entrapment that can be readily formed by the impact of a steel ball against a layer of oil on a glass block in an optical EHL test apparatus. The post-impact lateral movement of the entrapment was investigated under the conditions: (i) pure rolling, (ii) pure glass block sliding (steel ball stationary) and (iii) pure ball sliding (glass block stationary). It was observed that under pure rolling the entrapped oil travels within the contact region at the entrainment speed, which is correlated with EHL theory. Under pure glass block sliding conditions, the speed of the entrapped oil core is less than the entrainment speed, and in the extreme cases, this core can be nearly stationary. Under pure ball sliding conditions, the oil core moves at a speed greater than the entrainment speed. The observation indicates that the oil/steel ball interface can sustain higher shear stress than the oil/glass (chromium coated) interface and there is a boundary slip in terms of relative sliding at the latter interface under the experimental conditions. Furthermore, the amount of slip increases with an increase in the pressure. These experiments provide evidence of the existence of wall slippage, which leads to the abnormal EHL film profile characterised with an inlet dimple as reported earlier.     

斜轧半钢磨球及力学性能试验

研究了斜轧半钢磨球的制坏方法、思制工艺及力学性能，所得结果对斜轧半钢磨球的开发应用具有一定的指导意义。     

直线滚动导轨反向器回珠曲线曲率半径的优化设计

直线滚动导轨中钢球的运动是很复杂的,一般情况下,滚动体绕自身轴线转动,同时又绕反向器沟道轴线公转.在滚动的同时,滚动体沿滚道还伴随有一定的滑动.通常直线滚动导轨中钢球的运动是三维的,若接触角不等于零.钢球会有绕垂直于接触面的滑动,成为自旋滑动.高速运转时,钢球还可能有因陀螺力矩而产生的运动.直线滚动导轨的结构参数,工作条件,润滑状况以及制造精度都会影响其内部的运动学关系.综合考虑结构参数以及润滑状况对直线滚动导轨运动的影响,对反向器的回珠曲线进行多目标函数的优化设计,使得钢球能从受载区向非受载区平稳过渡.     

钢珠对磁力抛光工艺影响规律的实验研究

磁力抛光机利用磁场的力量,引导磨具(磁针)做快速旋转运动而抛光工件。为了使磁力抛光机对45钢轴的抛光效果及效率更佳,从理论上分析了磁力抛光的工作原理、磁力抛光过程中磨具的运动方式和影响磁力抛光效率的因素,提出加入钢珠会提升抛光效果及效率,并对45钢轴进行磁力抛光实验。实验结果表明:加工频率、磁针长度均对抛光效果及效率有不同程度的影响;加入钢珠后,抛光效果及效率都有提升;最佳磁针与钢珠的质量混合比例为1∶3。     

Surface strength of silicon nitride in relation to rolling contact performance measured on ball-on-rod and modified four-ball tests

Silicon nitride (Si₃N₄) has been used in various rolling contact applications in turbomachinery, automotive and power industry. It is favoured to replace conventional steel due to its low density, low friction, corrosion resistance and good performance under extreme condition. However, a major limitation of its wider application is its high material and machining cost, especially the cost associated with the finishing process. In the present study, a low cost sintered and reaction bonded silicon nitride (SRBSN) is used to study the surface machining effects on its rolling contact performance. Attempt has been made to link the surface strengths of Si₃N₄ derived from half-rod and C-sphere flexure strength specimens to the rolling contact lifetimes of Si₃N₄ rod and ball specimens. The rolling contact fatigue tests are carried out on ball-on-rod and modified four ball machines. Three types of surfaces with coarse, fine and conventional finishing conditions are examined. Flexure strength tests on half-rod and C-sphere show an increasing surface strength from specimens with coarse, fine to conventionally machined conditions. During rolling contact fatigue test of as-machined specimens, there are no failures observed on both ball-on-rod and four ball tests after 100 million stress cycles. However, there is a trend of decreasing wear volumes measured on the contact path of rods and balls with coarse, fine and conventional conditions. In four ball test, spall failures are observed on pre-crack specimens. There is a trend of increasing rolling contact fatigue lifetime from pre-cracked specimens with coarse, fine to conventional machining conditions.     

沟球断面环件冷辗扩三维有限元模拟与工艺设计

沟球断面环件冷辗扩是滚珠轴承套圈制造新工艺。以有限元软件Abaqus为平台,根据冷辗环机实际工作条件,建立从矩形断面毛坯冷辗扩成形沟球断面环件的三维弹塑性动力显式有限元模型。通过动力显式有限元数值模拟,研究沟球断面环件冷辗扩变形过程,揭示出该环件冷辗扩中直径增长和圆度变化规律。基于数值模拟结果,优化设计矩形断面环件毛坯尺寸和冷辗扩工艺参数。在D56G90冷辗环机上进行沟球断面环件冷辗扩试验,验证了数值模拟结果,并采用矩形断面环件毛坯成功冷辗扩出了沟球断面轴承套圈。     

Fretting wear behaviour of polymethylmethacrylate under linear motions and torsional contact conditions

The fretting wear behaviour of PMMA against a rigid counterface has been investigated under various contact zone kinematic conditions. A specific device has been used in order to achieve load axis spin or stationary rolling motions in a contact between a PMMA flat and a steel ball. Wear processes under such conditions have been investigated by means of laser profilometry and in-situ optical observations of the contact area during tests. Very different wear patterns were produced depending on the contact kinematics. For stationary rolling conditions, the progressive accumulation and compaction of debris induced the formation of a single ripple located in the middle of the contact. Very little debris was found to be eliminated from the contact and the resulting wear was quite low. On the other hand, little accumulation of debris was observed for torsional contact conditions and the wear was drastically enhanced. These results are analysed by considering the effects of contact zone kinematics on particle detachment and third body elimination.     

Influence of adsorbed fluids on the rolling contact deformation of MgO single crystals

Basic phenomena associated with rolling contact deformation were studied using MgO as a model bearing material. A hardened steel ball was rolled on MgO single crystals in slow speed reciprocating motion and in high speed circular motion. The resulting deformation was studied by dislocation etch pit techniques. The presence of adsorbed fluids, such as silicone oil, white mineral oil and toluene, with slow speed sliding caused a dramatic change in slip mode and premature surface spalling compared with similar experiments in air or under water. In contrast dimethyl formamide inhibited these slip processes. The results are consistent with the dependence of dislocation mobility on adsorbed species. High speed hydrodynamic rolling with mineral oil lubrication produced a different slip phenomenon entirely than that produced by slow speed rolling. The slip bands resembled those produced in tensile tests and all slip apparently initiated at subsurface sites.