半自磨机中φ20mm钢球开裂原因分析

某公司生产的φ120 mm轧制钢球用于半自磨机中磨矿,使用过程中碎球率较高,采用金相分析、SEM、XRD等手段对钢球开裂原因进行分析。结果表明:钢球开裂原因一方面为钢球内部晶粒粗大;另一方面钢球内残留奥氏体含量较高,在使用过程中转化为马氏体,内应力增大,撞击、摔落过程中产生晶间裂纹,造成钢球沿晶断裂。     

高温轴承钢钢球表面缺陷分析

7/8″(22.225 mm)高温轴承钢钢球在精研工序检查中发现,有若干钢球表面有微小的黑点和麻点。采用碳硫分析仪、等离子光谱仪、洛氏硬度计、维氏硬度计、金相显微镜、激光共聚焦显微镜及能谱仪对钢球的原材料、显微组织、硬度等进行检验分析,以确定其表面缺陷性质及产生的原因。结果表明:钢球表面点状或麻点状小黑点缺陷为腐蚀斑点,并非钢球加工过程中产生的机械加工缺陷。黑点缺陷是由于钢球存放的库房环境比较潮湿而腐蚀的,是钢球疲劳剥落的疲劳源,必须预防和控制。     

大型轴承钢球热处理过程中瞬态温度和应力分布

推导了轴承钢球的热传导方程,采用球贝塞尔函数给出了热处理过程中钢球瞬态温度分布的解答,应用弹性力学热应力理论得出了热处理过程中钢球径向和切向应力公式,并以半径50mm的大型轴承钢球为例,对钢球应力分布进行了分析.热处理过程中钢球的表面温度变化剧烈；靠近钢球中心位置为三向拉应力,并且同时达到最大值,开裂容易从中心部位开始发生.靠近钢球表面位置处于二向应力状态,径向应力为0 Pa,切向应力为压应力并达到最大值,导致钢球在锻造过程中产生的表面裂纹扩大,并导致钢球开裂.细化钢球中间部位晶粒,减少在锻造过程中钢球上的裂纹,放缓钢球的加热速度能减少热处理过程中钢球的开裂.     

小直径钢球表面缺陷检测机设计

钢球是滚动轴承的重要零部件,表面缺陷会影响工作精度。国内钢球表面缺陷的检测主要依靠人工目测,人工检测容易受到人为因素影响,检测效率低。该课题研究设计了一款钢球表面缺陷检测设备,完成了辊式筛选装置、图像获取装置、钢球不良品筛选装置的机构设计,并对辊式筛选装置进行了运动分析和计算。该设备能够实现钢球的自动上料,分级,检测,筛选不良品等功能,完成钢球表面缺陷的检测。     

其它

钢球企业将调整产品价格由于钢材及原材料屡屡涨价,导致钢球成本急剧增加,给钢球生产企业带来了巨大压力。为此,国内十大钢球厂厂长最近在无锡召开的每年一度的"十大钢球厂厂长联谊     

安徽省企业标准皖Q/XZ04—87《锻压钢球》标准水平评价会召开

为了提高安徽省钢球锻造技术水平,促进钢球的锻造生产,创钢球部优产品,安徽省锻压学会根据《安徽省工业企业标准化管理暂行办法》的规定,并受有关部门委托,于1990年7月4日在合肥红旗钢球厂主持召开了安徽省企业标准——皖Q/XZ04—87《锻压钢球》标准水平评价会。出席会议的有安徽省标准计量局、安徽省乡镇企业局、合肥市经委、合肥市     

附加回火对风电轴承钢球压碎载荷值的影响

在影响风电轴承钢球压碎载荷值的诸多因素中,磨削应力是降低风电轴承钢球压碎载荷值的主要因素之一。本文选用三种规格的风电轴承钢球进行不同的附加回火工艺试验,研究结果表明:在风电轴承钢球初研后增加附加回火工序能有效地减小钢球的磨削应力,提高风电轴承钢球的压碎载荷值。获得风电轴承钢球最佳附加回火工艺。     

耐磨贝氏体钢球开裂原因分析及工艺改进

耐磨钢球是球磨机的必需备件,耐磨钢球的质量直接影响生产效率和效益。高质量的耐磨钢球,磨球磨耗系数低,有利于提高球磨机的效率,减少停机更换磨球次数,有利于降低综合生产成本,提高整体经济效益。Mn—B合金贝氏体钢球是一种低合金高强度的耐磨钢球,具有低成本、强度高、耐磨效果好等特点,它的屈服强度超过1000MPa,适合工业生产应用。     

大型轴承钢球开裂分析

对大型轴承钢球在淬火过程中的开裂进行了失效分析,采用宏微观形貌、化学成分、金相显微组织分析、硬度测试、SEM微观断口形貌等手段,分析了钢球开裂的原因.结果表明,钢球开裂为淬火开裂,淬火温度过高是导致淬火钢球开裂的主要原因.     

轧制参数对钢球螺旋孔型斜轧工艺的影响

采用螺旋孔型斜轧工艺加工轴承钢球,其模具加工、调试安装复杂且耗时。针对该问题,利用有限元软件Deform,对轴承钢球轧制过程进行了仿真模拟,并采用控制变量法的思想,通过改变单一参数研究了棒料尺寸、轧制温度、轧辊倾斜角度对钢球轧制成形的影响规律,从而为钢球的斜轧工艺设计提供一定的参考。研究结果表明:棒料尺寸对钢球外形影响最大,棒料尺寸不足会造成钢球带有环带沟,棒料尺寸过大会导致钢球表面金属堆积;轧制温度对轧制力影响最大,轧制温度的提高有利于降低轧制力,但会导致钢球表面的脱碳及氧化皮现象严重,因此应尽可能采用较低的轧制温度;当轧辊倾角小于轧辊螺旋升角时,在轧制过程中容易出现钢球无法旋转的情况,因此应尽可能使轧辊倾角与轧辊的螺旋升角保持一致。     

Investigation on the Surface Coating of Grinding Balls

As an important means 1'Or preparing new'materials, mechanical alloying has been paidmore attention[1--6]. ln genera1, mechanicalalloying can be realized through the strong in"teraction between powders and grinding balls irla high-energy ball miller, where the metal pow--ders underg() cold welding and refinement. At1-ter repeated extruding and cold welding, acoating with a certain thickness tbrms on thesurface oI' the balls and the walls of the vessel.Hashimoto et al.[7j Studied the coating p…     

真空消失模铸造低合金余热淬火马氏体球墨铸铁磨球

介绍了采用真空消失模铸造（EPC）低合金余热淬火马氏体球墨铸铁窘球的工艺、窘球的组织、力学性能、生产成本以及使用性能，并与采用金属型铸造的相同材质的磨球进行了对比。工业实验表明：采用真空消失模铸造的低合金余热淬火马氏体球墨铸铁磨球的耐磨性约是采用金属型铸造的低铬铸铁磨球的2倍。     

基于双目视觉的机械手捡球机器人设计

为解决人工捡球费力费时的问题,设计了一种双目视觉识别定位、机械手捡拾和自主避障的轮式智能捡球机器人。该机器人通过双目摄像头和Lab VIEW平台,实现对小球图像的实时采集与处理;运动控制系统采用以STM32F411为主核心的NUCLEO-F411RE嵌入式开发板,实现对各个模块的驱动;通过五自由度机械手实现小球的捡拾;通过红外传感器检测周围环境,实现自主避障;由计数器统计捡球数量,通过手柄模块人机交互辅助完成卸载过程。仿真结果表明:该机器人能够完成高尔夫球、乒乓球、网球等多种小型球类的捡拾任务。     

On the charging and interaction of two conductive balls

The recharging processes of charged conductive balls at their potentials balancing and also the charging of the balls from one and the same voltage source are considered. The charges obtained by every ball are calculated. At that, the phenomenon of mutual electric induction, due to which an infinite number of charges-images is formed in every ball, is considered. The interaction forces of balls with different radii connected to one and the same voltage source and having identical potentials are calculated. It was shown that, at the removal of balls with different radii from each other, the force of their interaction passes through a local maximum. It was also shown that, when taking account of the images, only the first order in some cases is a sufficiently good approximation. Experimental measurement results of the interaction force of the balls that are in good agreement with the theoretical ones are presented.     

我国金属矿山球磨机磨球的应用现状及选材

对国内目前使用的磨球材质进行分类,并结合湿式球磨机的工况特征对这些磨球的使用状况进行分析,为湿式球磨机中使用的磨球材质的选择提供参考意见.     

薄壁管小弯曲半径数控绕弯成形芯模效用的实验研究

薄壁管数控弯曲中带芯头的柔性芯模是提高薄壁管件成形极限和成形精度的关键因素。文章建立了绕弯过程芯模(包括芯棒和芯头)的理论解析模型,包括了芯模直径d、芯棒伸出量e、芯头个数n、芯头厚度k、芯棒/芯头孔心间距p及芯棒圆角半径r等参数的选取公式的推导,获得了不同弯曲规格下的芯模参数取值范围,验证了解析模型的合理性;实验研究了芯模参数对管材失稳起皱、壁厚减薄和截面畸变的影响规律。通过分段抽芯的工艺方法,完成了38mm×1mm×38mm(1D)高难度不锈钢管件的弯曲。     

Study of the milling parameters optimization in the direct carburization of WO3 by mechanical alloying

The mechanical alloying method allows obtaining tungsten carbide by direct carburization of tungsten trioxide. The parameters that have a determining role on the kinetic reactions are the temperature and the pressure of the process. The milling installation must maintain a low pressure by removing the carbon dioxide released during the carburizing reaction.In a planetary balls mill, the energy developed during a ball impact was determined via a simplified computational modeling and depends on the mass of balls and on the speed of balls reached during the milling process. The energy dissipated during impact increases exponentially with the speed rotation of the mill and with the balls diameter.Tests were carried out in a planetary balls mill equipped with bowls lined with tungsten carbide and filled with tungsten carbide balls of 10- and 12-mm diameter. Two levels of filling of the bowls, 150 g and 200 g of balls were also tested. The balls/milled powder ratio was kept at 10:1 in all tests. To monitor the carburizing reaction, samples were taken every 3 h of grinding. They have been investigated by X-ray diffraction to determine the phases in presence. The morphology of the particles was studied by scanning electron microscopy and the particle size was investigated by laser granulometry in liquid medium.To determine the effect of various milling parameters on the temperature during a milling cycle, a temperature-monitoring device was created and installed on the grinding bowl. The obtained values demonstrate that the diameter of the balls and the filling degree of the bowl have an important role in the evolution of the temperature during milling.     

A novel technique for reducing macrosegregation in heavy steel ingots

Solid steel balls were added to the melt during the pouring process. A reference 500 kg steel ingot with no addition of solid balls was poured to provide a realistic comparison with the typical macrosegregation found in conventional industry heavy ingots. The experiments show that by adding solid balls the degree of macrosegregation is reduced, the formation of A-type segregation is prevented, a generally refined microstructure is obtained and the mechanical properties are improved. Numerical simulation of the solidification process confirms that the addition of solid balls increases the cooling rate, imposing large temperature gradient which refine the microstructure and alleviate the extent of macrosegregation.     

氧化锆陶瓷磨球的滚制成型法制备技术与性能研究

研究了滚制成型法制备氧化锆陶瓷球坯工艺及烧结温度对陶瓷磨球体积密度、压碎强度和自磨损性能的影响.结果表明,凝胶固相合成法生产的亚微米级3mol% Y_2O_3-ZrO_2陶瓷粉体适用于滚制成型法制备体积密度高、圆度好、大小均匀的球坯.在1500 ℃保温2 h的烧结条件下得到的微晶氧化锆陶瓷磨球在快速研磨机中的自磨损率最低,其微观结构均匀,晶粒尺寸约0.5 μm,体积密度为5.97 g/cm~3,φ2.75 mm和φ6.36 mm陶瓷磨球的平均压碎强度分别达到326和1377 kg.     

Structure and phase state of Zr-1% Nb and Zr-2.5% Nb alloys loaded by spherically converging shock waves

Four balls made of zirconium-niobium alloys are loaded by spherically converging shock waves of various intensities and then studied from layer to layer by X-ray diffraction, optical metallography, transmission electron microscopy, and microhardness measurements. The phase and structural states of the balls are found to depend on the loading conditions and the depth of layer location in a ball. The ω phase is retained in the near-surface layers of the balls only after low-intensity loading, and its content increases with the niobium content in an alloy. The high-rate plastic deformation of the balls, which have a fine-grained structure in the initial state, during loading under our experimental conditions is shown to occur via slip and the formation of adiabatic shear bands.