纳米粒子润滑油的抗磨减摩机理

使用扫描电镜、能量色散谱、X射线光电子能谱仪和原子力显微镜研究了纳米粒子润滑油的抗磨减摩机理.结果表明:纳米粒子通过"微抛光"作用、"微滚珠"承载作用、填充修复作用、大小粒子协同作用以及在摩擦表面形成新的金属元素的单质和氧化物膜等达到抗磨减摩效果.     

纳米耐磨和减摩复合镀层的研究

分析了将纳米三氧化二铝(Al2O3)和聚四氟乙烯(PTFE)颗粒加入常规电刷镀液中制备纳米耐磨和减摩复合镀层的组织、显微硬度、耐磨性和摩擦因数。结果表明：纳米颗粒的加入使复合镀层组织明显细化和致密。随着纳米Al2O3颗粒含量的增加，复合镀层的显微硬度和耐磨性有明显的提高，纳米PTFE的加入有助于减少复合镀层的摩擦因数。     

摩擦学涂层技术在模具减摩抗磨中的应用

针对模具恶劣的工况条件，介绍了涂层材料体系及匹配原则，综述了应用于模具行业中的摩擦学涂层技术，展望了摩擦学涂层的最新进展。     

磁性润滑脂抗磨减摩性能的试验研究

以Fe3O4磁性微粒为添加剂制备了一种磁性润滑脂,在摩擦磨损试验机上考察了其摩擦学特性,并分析了其抗磨减摩机制.结果表明:Fe3O4磁性润滑脂对负荷的适应性较好,特别是在较大载荷、中高转速情况下,具有很好的抗磨性.     

复合陶瓷强化挤压模具钢抗磨减摩研究

本文对复合陶瓷强化挤压模具钢抗磨减摩进行了研究，利用比拟试验研究了在蓖麻油 硬脂酸钙润滑下，有色金属铜（H62）、钢（20）试样与复合陶瓷强化9CrSi环配副的摩擦磨损特性，并与未采用陶瓷强化的钢（H62）、钢（20）/9CrSi环摩擦副进行比较，分析了其减摩抗磨机理，试验结果表明：复合陶瓷强化挤压模具能显著减少摩擦系数，降低磨损量，适合应用于挤压模。     

二冲程汽油机油采用减摩抗磨添加剂的试验研究

本文通过对几种典型的发动机润滑油添加剂的对比试验，研究了此类减摩抗磨添加剂在二冲程汽油机油中的使用效果，试验结果表明某些添加剂在专用摩擦磨损试验机上的试验结果和发动机台架试验结果存在明显差异，据此本文提出了选用润滑油添加剂的建议。     

不同工况条件下纳米添加剂抗磨减摩性能分析

通过在PLINT试验机进行试验,研究在不同法向载荷、频率、浓度条件下纳米氧化铝添加剂的抗磨减摩性能。结果显示在试验范围内,频率的增加会导致摩擦因数减小,磨斑体积也随之减小,磨损减弱;法向载荷的增加会导致摩擦因数增大,但随着自修复反应的发生,磨斑体积随之变小,磨损减弱。     

羟基硅酸镁和MoDTC复合添加剂的减摩抗磨性能

采用MMW-1A型立式万能摩擦磨损试验机分别考察羟基硅酸镁超细粉体以及羟基硅酸镁超细粉体复合MoDTC作为基础油PAO4添加剂的摩擦学性能,借助金相系统显微镜、扫描电子显微镜(SEM)以及能量色散谱仪(EDS)对摩擦表面进行观察表征及组成分析。结果表明:羟基硅酸镁超细粉体可改善PAO4的减摩抗磨性能,但摩擦表面仍存在明显划痕及凹坑;质量分数0.25%的羟基硅酸镁超细粉体与0.3%的MoDTC组成的复合添加剂,可明显改善PAO4的减摩抗磨性能,相比于PAO4基础油和仅添加质量分数0.25%的羟基硅酸镁超细粉体的润滑油,摩擦因数分别降低了32.75%和17.87%,磨斑直径分别下降了53.16%和32.04%;复合添加剂对磨斑表面形貌的改善效果更为显著,其在摩擦表面形成了一层富含C、O、Mo、S、Mg、Si等元素的修复层,且2种添加剂在摩擦过程中优势互补,起到了相互促进的协同作用。     

NANOSTRUCTURED CUTTING TOOLS COATINGS FOR MACHINING TITANIUM

Innovative nanostructured tool coatings were developed in order to machine titanium-based alloys. Two dedicated coatings, AlSiTiN and TiCN, were applied by PVD on WC-Co tool inserts, developing nanostructured layers exhibiting superior performances, laboratory tests results being confirmed by machining experiments. Coatings surface qualification included tribological evaluation by ball-on-disc set-up, ball-erosion test, nanoindentation, scratch test, surface texture analysis and SEM observation with EDS analysis. The results have been compared to machining performances in wet and MQL turning, showing a marked pattern of agreement among different indexes.     

AN 'EFFECTIVE CUTTING TOOL THERMAL CONDUCTIVITY' BASED MODEL FOR TOOL-CHIP CONTACT IN MACHINING WITH MULTI-LAYER COATED CUTTING TOOLS

This paper presents a new modeling approach, based on Oxley's predictive model, for predicting the tool-chip contact in 2-D machining of plain carbon steels with advanced, multi-layer coated cutting tools. Oxley's original predictive model is capable of predicting machining parameters for a wide variety of plain carbon steels, however, the tool material properties and their effects are neglected in the analysis. In the present work, the effect of the tool material, more particularly, the effect of multiple coating layers and the individual coating thicknesses on the tool-chip contact length in orthogonal machining is incorporated. The results from the model predict the tool-chip contact length with respect to major cutting parameters such as feed and rake angle, work material parameters such as the carbon content in the steel, and varying thicknesses and combinations of coating layers. This model enables more precise cutting tool selection by predicting the relative tribological impact (in terms of tool-chip contact length) for a variety of multi-layer coated tools.     

FINITE DIFFERENCE METHOD-BASED SIMULATION OF TEMPERATURE FIELDS FOR APPLICATION TO ORTHOGONAL CUTTING WITH COATED TOOLS

A finite difference method was proposed to model the effect of a variety of tool coatings on the magnitude and distribution of temperatures through the tool-chip contact region and the coating/substrate boundaries. For each workpiece-tool pair tested the intensity of uniformly distributed heat flux and relevant analytically obtained values of the heat partition coefficient were assumed to change with variations of cutting speed and the corresponding friction. In this case the simulation of an orthogonal machining of AISI 1045 steel was performed using special computing algorithm with elementary balances of induced energies (MBE). It is concluded that the temperature contours obtained reflect favorable the specific contact conditions existing at the tool-chip interface and substantial differences can arise from coating effects.     

FINITE DIFFERENCE METHOD-BASED SIMULATION OF TEMPERATURE FIELDS FOR APPLICATION TO ORTHOGONAL CUTTING WITH COATED TOOLS

ABSTRACT

A finite difference method was proposed to model the effect of a variety of tool coatings on the magnitude and distribution of temperatures through the tool-chip contact region and the coating/substrate boundaries. For each workpiece-tool pair tested the intensity of uniformly distributed heat flux and relevant analytically obtained values of the heat partition coefficient were assumed to change with variations of cutting speed and the corresponding friction. In this case the simulation of an orthogonal machining of AISI 1045 steel was performed using special computing algorithm with elementary balances of induced energies (MBE). It is concluded that the temperature contours obtained reflect favorable the specific contact conditions existing at the tool-chip interface and substantial differences can arise from coating effects.     

低压水射流辅助聚晶金刚石刀具车削硬质石材

提出了低压水射流辅助聚晶金刚石刀具切削硬质石材的加工方法。分析了低压水射流参数、加工工艺参数和刀具的弹性对切削过程、切削力和加工表面质量的影响，研究了水射流辅助聚晁金刚石刀具切削硬质石材的加工机理和加工工艺。     

新型陶瓷涂层硬质合金刀具的涂层机理和切削性能

以异丙醇铝为前驱物,将溶胶-凝胶工艺应用于硬质合金刀片涂层,研制成功一种新型的陶瓷涂层刀片,从而为涂层刀具制造展示了一种全新的涂层方法。使用浸渍提拉法对刀具基体进行涂层,然后经凝胶、干燥和1200℃热处理后可以得到厚度适宜的α－Al2O3涂层,涂层完整,无宏观缺陷,并且在初步的切削试验中显示出一定效果。涂层在1140℃左右转化成α－Al2O3,在1200℃烧结致密,而在1250℃以上涂层发生明显收缩,晶粒明显长大,最终的涂层为多晶体结构,涂层界面未生成弱化相,硬质合金中的部分钴元素扩散到涂层中,有助于提高涂层和基体间的粘结强度。切削试验的结果表明,所得涂层能有效地阻止前刀面上的粘结磨损,从而提高了刀具的使用寿命。     

高硬度石材的超低温切割加工

提出了一种花岗岩、大理石等高硬度石材的超低温切割加工方法,即利用超低温液华丽形成局部超低温切割区域,以改善切割性能和增加刀具耐用度。实验结果表明,该方法比现有普通采用的水冷却切割石材的方法,成倍地提高了刀具耐用度,并避免了污水对环境的污染。     

nm硬质合金刀具切削性能的研究

在切削试验研究的基础上,对比了ｎｍ硬质合金刀具与普通硬质合金刀具的切削性能。试验结果表明,ｎｍ硬质合金刀具由于晶粒细化可以改善刀具的切削性能,提高抗破损性和刀具寿命。ｎｍ硬质合金可为自动化生产提供一种性能优良的刀具材料,有广泛的推广前景。     

陶瓷刀具切削加工时的磨损和润滑及其与加工对象的匹配研究

分析了陶瓷刀具发展及其应用过程存在的问题，综合评述了陶瓷刀具切削加工时的磨损和润滑的研究进展，提出了陶瓷刀具与加工对象存在合理的匹配问题。指出了在实际应用中，应根据所加工的工件材料选择合适的陶瓷刀具材料，并应根据陶瓷刀具组分中是否含有高温下易与工件发生扩散及化学作用的组分来确定合理切削用量。     

PREDICTION OF TOOL LIFE IN MACHINING WITH RESTRICTED CONTACT TOOLS

A semi-empirical method is described for predicting tool life in orthogonal machining with restricted contact tools. The method uses a well established machining theory to predict cutting forces, tool-chip contact length and cutting temperatures for the corresponding plane face tool i.e. tool having the same cutting edge geometry but no restricted contact. These predicted parameters and a set of empirical relations are then used to calculate the cutting temperatures and tool life for the restricted contact tool. A comparison has been made between predicted and experimental results obtained from the literature and from tests carried out by the authors.