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氮化硅陶瓷球研磨去除机制试验与仿真研究 总被引:1,自引:0,他引:1
为研究研磨过程中氮化硅陶瓷球的材料去除形式及磨损行为,结合陶瓷材料动态压痕断裂力学理论,进行陶瓷球研磨加工试验,采用超景深三维显微镜和扫描电镜对研磨后陶瓷球表面进行观察,同时建立单颗金刚石磨粒冲击作用有限元模型并进行仿真研究。试验结果表明:氮化硅陶瓷球表面材料去除以脆性断裂去除和粉末化去除为主,陶瓷球表面残留有大量贝壳状缺陷和呈簇状随机分布的粉末化材料区域;研磨过程中,陶瓷球表面存在擦伤、划伤和凹坑等缺陷;磨粒冲击作用时,表面材料会受微切削作用产生破碎去除,同时也会受挤压作用产生脆性断裂去除,当磨粒以滚动方式作用在陶瓷球表面时,陶瓷球表面更容易形成粉末化去除,且材料去除率更高。仿真结果表明:各磨粒冲击作用方式产生的最大等效应力由大到小的顺序为滚动磨粒变切深、滚动磨粒定切深、磨粒挤压、滑动磨粒定切深,其中,滚动磨粒变切深产生的亚表面裂纹最深。 相似文献
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为探究磨料对氮化硅陶瓷球精研加工的影响,从而提高氮化硅陶瓷球的表面质量和材料去除率,以基液种类、磨料种类和研磨盘转速为主要影响因素设计正交试验,并分析各因素对表面粗糙度Ra的影响程度。以表面粗糙度Ra和材料去除率为评价指标,通过单因素试验优化研磨参数。根据正交试验结果,得到精研加工过程中各影响因素对于表面粗糙度Ra的影响程度,从大到小排列依次为:磨料种类>基液种类>研磨盘转速。综合考虑陶瓷球精研加工的要求,确定最佳的研磨参数组合为:煤油基液、碳化硅磨料以及150 r/min的研磨盘转速。在金刚石、碳化硅、氮化硼、氧化铬和氧化铁这5种磨料中,氧化铁磨料修复粗研过后的氮化硅陶瓷球表面缺陷的效果最好。 相似文献
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采用集群磁流变效应研磨加工工艺进行SrTiO3陶瓷基片研磨加工,分析了研磨盘材料、磨粒种类、研磨压力和磨粒团聚等因素对SrTiO3陶瓷基片表面粗糙度和表面完整性的影响。
结果表明:磁流变效应研磨工作液中的SiC、Al2O3和CeO2等磨料的大尺寸磨粒在SrTiO3陶瓷基片研磨加工表面产生的局部大尺寸划痕破坏了加工表面的完整性;采用铸铁研磨盘和SiO2磨料的磁流变研磨工作液研磨加工后,原始表面粗糙度Ra从约1.7854μm下降到0.6282μm,并且表面完整,SrTiO3材料与SiO2磨料之间存在的化学机械研磨过程促进了研磨加工表面性能的改善;研磨压力也是影响研磨加工表面粗糙度和大尺寸划痕的主要因素之一,研磨压力取较小值(1.875kPa)为宜。
相似文献
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超精研是轴承滚道的最后一道工序,其加工的质量直接影响轴承的成品质量。精研润是该工序产生的一种怒性表面缺陷,本文对精研瘤的成因以及消除方法提出了一些新的见解。一、精研瘤的成因精研启产生于轴承套圈沟道的超精研过程中,其形状是一种白色点状突起物。有研究认为是切屑与磨粉条和力强而产生。我厂用扫描电子显微镜对精研瘤的形貌及成分进行分析。1.精研瘤有一条慧星尾巴似的划痕,如同“富拉”逐渐切入工件表面,当研削力和摩擦阻力相平衡财,这颗“唐粒”就嵌入工件表面,成为精研瘤,2.在越精研沟道时,磨粒尺寸为10~14μm,而… 相似文献
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采用激光在Al2O3/TiC陶瓷刀具前刀面加工出不同的表面织构,制备出纳米织构陶瓷刀具及微纳米复合织构自润滑陶瓷刀具,并与传统陶瓷刀具进行干切削45淬火钢试验比较.结果表明:纳米织构陶瓷刀具不能够有效降低切削力、改善刀具黏结现象,但是可以减小刀具前刀面磨损凹坑,减少磨粒磨损;微纳米复合织构自润滑陶瓷刀具能够有效降低切削力,减小刀具磨损,改善刀具的切削性能. 相似文献
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陶瓷球研磨装置设计和试验 总被引:4,自引:0,他引:4
为提高陶瓷球研磨加工效率,本文对陶瓷球三磨过程及研磨装置进行了理论分析。据此确定了研磨的设计指标,提出了新的陶瓷球研磨方法锥形研磨法。 相似文献
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铌酸锂晶体的研磨亚表面损伤深度 总被引:1,自引:0,他引:1
针对光学材料研磨过程引入的亚表面损伤层(SSD)深度对工件的抛光工序效率和表面质量的影响,探索了光学材料在研磨过程中的亚表面损伤规律。采用角度抛光的方法测量了软脆材料铌酸锂(LN)晶体的损伤层深度,分析了研磨方式、磨粒粒径和研磨压力对工件亚表面损伤层的影响规律。结果表明:研磨方式对损伤缺陷的影响最为显著,相同研磨条件下游离磨料研磨后的损伤层深度约为固结磨料研磨的3~4倍,游离磨料研磨后工件亚表面存在多处圆弧形裂纹,固结磨料研磨后主要显现细小裂纹和"人"字型裂纹;当磨粒粒径从W28下降到W14后,游离研磨的亚表面损伤层深度下降至原来的45%,而固结研磨的损伤层深度下降至30%;另外,研磨压力的降低有利于减小工件的亚表面损伤。该研究对LN晶体研磨方式及研磨工艺的选择具有指导意义。 相似文献
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The particle size effect on abrasive wear of high-chromium white cast iron mill balls 总被引:3,自引:0,他引:3
Granite grinding tests, under dry and wet conditions, were performed to assess the influence of abrasive particle size to the wear behavior of martensitic high-chromium white cast iron mill balls. The tests were performed, at first, using raw granite particle sizes between 0.074 and 19.1 mm, and then with coarse and fine granite fractions obtained after screening the raw granite in a 3.36 mm sieve. It is demonstrated that the relative particle/ball size relationship is the determining parameter to ball wear. The highest ball wear rates were observed for fine granite grinding under dry (120 mg/cycle) and wet (129 mg/cycle) conditions. The lowest wear rate (ca. 50 mg/cycle) was observed for coarse granite grinding (dry and wet). These different results were attributed to the different size relationships between grinding body diameter and granite particles size. For wet-grinding of raw granite, the mineral components may influence significantly the wear behavior. Feldspar can act as a bonding agent, gluing fine quartz particles to the coarse granite and to the balls surface and turning the dependence of the relationship between the relative sizes of ball and granite particle less important to the wear process. This explains why wet-grinding of raw granite results in a ball wear two times greater (106 mg/cycle) than dry-grinding (51 mg/cycle). 相似文献
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Jorn Larsen-Basse 《Wear》1985,105(3):247-256
It has previously been proposed that preferential removal of the cobalt binder is an important mechanism in the abrasive wear of cemented carbides in the WC-Co family. It is here demonstrated that binder extrusion occurs also in metal-to-metal sliding wear contacts. The wear scar generated by sliding a hardened steel ball repeatedly over a polished WC-Co surface was studied by scanning electron microscopy. The extruded cobalt fragments accumulate at surface defects, such as cracks caused by the sliding loaded ball, and gradual microfragmentation of the carbide grains follows. The energy required to extrude the cobalt and to cause the gradual change in surface layer microstructure is provided by the frictional forces. 相似文献
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The ball‐crater micro‐scale abrasive wear test can be applied to coated samples and small bulk samples. The surface condition
of the ball influences the magnitude and the reproducibility of the measured wear coefficient. Use of a polished new ball
in the test may give uncertain or anomalously low wear coefficients, particularly for relatively soft specimens. This effect
is explained in terms of the ease of entrainment of abrasive particles into the contact area. Reproducible results are obtained
with pre‐conditioned balls with slight surface pitting, and the use of such balls is recommended for routine testing.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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The relative significance of corrosive and abrasive wear in ore grinding is discussed. Laboratory marked ball wear tests were carried out with magnetic taconite and quartzite under different conditions, namely dry, wet and in the presence of an organic liquid. The effect of different modes of aeration and of pyrrhotite addition on the ball wear using mild steel, high carbon low alloy steel and austenitic stainless steel balls was evaluated. Results indicate that abrasive wear plays a significant role in ore grinding in the absence of sulfides, and rheological properties of the ore slurry influenced such wear. The effect of oxygen on corrosive wear becomes increasingly felt in the presence of a sulfide mineral such as pyrrhotite. Wear characteristics of the three types of ball materials under different grinding conditions are illustrated. 相似文献
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Partap Singh Samra Sehijpal Singh Lakhvir Singh 《Machining Science and Technology》2019,23(1):153-169
The advanced ceramics have emerged as a successful alternative to the conventional materials used in ball bearing industry. However, extreme hardness and lower toughness of the ceramic balls make their finishing a challenging task. To address this problem, a novel process is developed and results are presented in this article. The process is termed as magnetically assisted lapping (MAL) wherein the lapping and the polishing action are supported by magnetic levitation. The process parameters are identified. The capability of the process in terms of surface finish, roundness and material removal rate of alumina balls is assessed. The process is carried out in two stages. In the first stage, the main focus is on material removal and sphericity while the second stage focuses on achieving nano level surface finish. A very high material removal rate of 2.5 µm/min is achieved in the first stage. In the second stage, diamond abrasive powder (0.25–1 µm) mixed with silicone oil is used as a polishing medium for fine finishing of balls. The final surface finish of 20?nm and roundness of 0.23 µm is achieved which meets the requirement of G10 grade bearings (as per ISO3290). Atomic force microscope images show remarkable improvement of the surface up to 8?nm. The developed process is capable of producing nanometric finish in quite lesser time as compared to conventional and eccentric lapping processes. The underlying mechanism of material removal is proposed with the help of scanning electron microscope and atomic force microscope images. 相似文献
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硬盘巨磁电阻磁头的超精密抛光工艺 总被引:1,自引:0,他引:1
硬盘巨磁电阻磁头的抛光可分为自由磨粒抛光和纳米研磨,在自由磨粒抛光中,精确控制载荷和金刚石磨粒的粒径,可以避免脆性去除实现延性去除。通过控制抛光过程中的抛光盘表面粗糙度、金刚石粒径大小及粒径分布和载荷等进行滚动磨粒和滑动磨粒比例的调控,获得较好的磁头表面质量和较高的材料去除率。在自由磨粒抛光阶段,先采用铅磨盘抛光,然后用锡磨盘抛光,以纳米研磨作为最后一道抛光工序对磁头表面进行研磨,获得了亚纳米级粗糙度的磁头表面。用两种工艺制作的纳米研磨盘进行加工,分别获得了0.37nm和0.8nm的磁头表面粗糙度,去除率分别为5.3 nm/min和3.9nm/min。 相似文献