Al2O3／TiB2／SiCW陶瓷刀具加工镍基合金时的磨损机理研究

研究了Ａｌ２Ｏ３／ＴｉＢ２／ＳｉＣＷ陶瓷刀具加工Ｉｎｃｏｎｅｌ７１８镍基合金时的切削性能和磨损机理。结果表明；在低速切削条件下，Ａｌ２Ｏ３／ＴｉＢ２／ＳｉＣＷ和硬质合金刀具的抗后刀面磨损的能力相差不大；而在高速切削条件下，前者的抗后刀面磨能力远高于后者。     

新型复相陶瓷刀具材料JX-2-I协同增韧补强机理的研究

本文研制成功了一种新型陶瓷刀具材料——SiC晶须（SiCw）增韧和SiC颗粒弥散增韧Al2O3陶瓷刀具JX－2－Ⅰ，该刀具材料具有高的抗弯强度和断裂韧性等优点；对比A（Al2O3）、AP（Al2O3／SiCp）、AW（Al2O3／SiCw）、JX－1（Al2O3／SiCw）和JX－2－1（Al2O3／SiCp／SiCw）等陶瓷材料的力学性能可以看出，在JX－2－Ⅰ材料中具有明显的增韧补强叠加效应；本文在热失配分析和微观结构观察的基础上详细研究了JX－2-Ⅰ刀具材料的增韧补强机理，系统研究了JX－2—Ⅰ中各种增韧补强机理之间的协同效应。     

磁化高速钢刀具的磨损性能研究

本文对非磁化和磁化高速钢刀具分别切削大理石和45号钢时的磨损性能进行了试验研究,研究了磁化对刀具抗磨损能力的影响规律,并初步探讨了刀具的磁化机理。     

磁力研磨镍基高温合金实验研究

针对镍基高温合金(Inconel718)机械加工后表面质量难以满足使用要求的问题,基于磁力研磨法,选用雾化快凝法制备的Al_2O_3系球形磁性磨料,对Inconel718合金样件进行表面光整加工。采用梯度研磨法提高加工效率,并结合正交试验优化加工参数。结果表明,Inconel718合金表面粗糙由原始的0.359μm下降到0.023μm,达到镜面效果;表面微裂纹和微观形貌得到明显改善,提高了零件的抗疲劳强度和寿命。为磁力研磨在镍基高温合金光整加工中的推广应用提供了理论和技术支持。     

新型陶瓷刀具的切削性能研究

本文研究了山东工业大学机械工程学院研制的新型陶瓷刀具材料（包括ＪＸ－２，Ｈ５，Ｈ１３和Ｈ２１等）分别切削铸铁（ＨＴ２０）淬火４５号钢和难加工材料ＧＨ９９时的切削性能，探讨了各陶瓷刀具的抗磨损能力，实验研究了切削速度和进给量对刀具磨损的影响，并对切削条件进行了优化。     

磁力研磨对Inconel718合金表面质量的影响

为改善镍基高温合金Inconel718制造零部件的表面质量,降低其表面粗糙度,基于磁力研磨加工方法,选用雾化快凝法制备的Al_2O_3球形磁性磨料,对Inconel718合金样件进行光整加工。探究了主轴转速、进给速率、加工间隙和磨料填充量对Inconel718合金表面粗糙度的影响,获得了较佳的磁力研磨参数:主轴转速1000 r/min,进给速率10 mm/min,加工间隙2mm,磨料填充量2.5 g。在优化的工艺参数下对Inconel718合金样件磁力研磨20min,试样的表面粗糙度由原始的0.359μm下降到0.036μm,达到镜面效果。由此表明,磁力研磨对Inconel718合金具有良好的光整加工效果。     

氧化对Al_2O_3－TiB_2陶瓷刀具材料磨损特性的影响

研究了Ａｌ_２Ｏ_３－ＴｉＢ_２陶瓷刀具材料的高温氧化特性以及氧化对刀具耐磨性能的影响。结果表明：随ＴｉＢ_２含量的增加，Ａｌ_２Ｏ_３－ＴｉＢ_２的氧化活化能降低，抗氧化能力下降．Ａｌ_２Ｏ_３－ＴｉＢ_２刀具材料在加工淬火钢时，因切削高温的氧化作用在刀具表面生成的ＴｉＯ_２既可减轻刀具的粘结磨损，又能起到固体润滑剂的作用，从而降低摩擦系数，因而提高刀具的耐磨性能。当切削速度大于１５０ｍ／ｍｉｎ时，随ＴｉＢ_２含量的增加，刀具抗磨损能力显著提高。     

磨料对Inconel718镍基高温合金磁力研磨效果的影响

选择粒度均为W7(即直径5~7μm)的Al_2O_3和SiC两种球形复合磁性磨粒分别对Inconel718镍基高温合金进行磁力光整加工,工艺条件为:以46#机械油作为研磨液,主轴转速1 000 r/min,进给速率10 mm/min,加工间隙2 mm,磨料填充量2.5 g。从工件表面粗糙度和微观形貌两方面对比分析了两种磨粒对Inconel718合金研磨效果的影响。结果表明,在Al_2O_3磨粒的研磨下,工件表面粗糙度从0.560μm降至0.049μm,表面微观形貌得以改善,达到镜面效果;而在SiC磨粒的研磨下,工件的表面粗糙度由原始的0.493μm降至0.124μm,表面微观形貌变化不大。Al_2O_3磨粒对Inconel718的研磨效果优于SiC磨粒。     

钢铁冶金用炭素材料(二)(续15)

钢铁冶金用炭素材料（二）（续１５）刀具及其切削参数加工石墨电极时使用硬质合金（如牌号ＹＧ８）或高速钢（如牌号Ｗ１８Ｃｒ４Ｖ）制成的车刀及铣刀进行切削。高速钢刀具坚韧性好、刃磨方便、价格较低，但红硬性稍差，只能耐５００－６００℃。硬质合金刀具具有良好的...     

Sialon陶瓷刀具高速切削高温合金Inconel 718的切削性能和磨损机理的研究

本实验研究两种商业Sialon陶瓷刀片(牌号为KY1540、CC6060,分别是肯纳和山特维克公司生产)高速切削高温合金Inconel718的切削性能和磨损机理.采用XRD和SEM分析刀片的物相成分和显微结构,结果表明KY1540和CC6060主要的物相成分是α-和β-Sialon.通过测量切削长度和后刀面的磨损量,结果表明,在实验条件下由于CC6060具有较高的高温硬度,导致它的后刀面磨损量低于KY1540.两种刀片的磨损后刀面通过扫描电镜观察,发现两种刀片的磨损形式主要是沟槽磨损和后刀面磨损,磨损机理主要是磨粒磨损和粘结磨损.     

Cutting performance,failure mechanisms and tribological properties of GNPs reinforced Al2O3/Ti(C,N) ceramic tool in high speed turning of Inconel 718

Cutting performance and failure mechanisms of graphene nano-platelets (GNPs) reinforced ceramic cutting tool ATG (short for Al₂O₃/Ti(C,N)/GNPs) in continuous dry turning of Inconel 718 up to a cutting speed of 500 m/min were investigated in comparison with those of commercial Sialon tool KY1540. The results show that ATG tool shows similar cutting performance with KY1540 tool at the speed range of 150–300 m/min, but greatly outperforms KY1540 when the cutting speed range of 400–500 m/min for higher hardness, wear resistance, chemical inertness and fracture toughness. Flank wear, notch wear, chipping and flaking are the reasons for tool failure of ATG. The wear modes are related to cutting speed, and adhesion wear is found to be the dominant failure mechanism of ATG. It is believed that GNPs play a significant role in improving mechanical properties and tribological properties which contributed to excellent resistance to abrasive wear and fracture. Turning Inconel 718 in dry and high speed via using ATG ceramic tool is an efficient and eco-friendly method.     

Performance of Si3N4/(W,Ti)C graded ceramic tool in high-speed turning iron-based superalloys

A Si₃N₄/(W, Ti)C graded nano-composite ceramic tool was fabricated and its performance in high speed turning iron-based alloys GH2132 was investigated compared with homogeneous and commercial ceramic tools. The chip morphology, cutting forces, cutting temperature, tool life and failure mechanisms and machined surface roughness were recorded and analyzed. The results showed that with the increasing cutting speed the resultant cutting force shows a tendency to first increase and then decrease while the cutting temperature increases gradually. Straight continuous chips, bending continuous chips, twist continuous chips and snarled chips form in turn. Saw-tooth chips tend to form when the cutting speed is more than 200?m/min. The graded tool shows longer tool life especially at the cutting speed of 150 and 200?m/min compared with the homogenous and commercial ceramic tools. Tool failure modes mainly include grooving on the rake face, notching on the flank face, abrasion and adhesion. The grooving on the rake face tends to decrease while notching on the flank face tends to increase as cutting speed increases. Surface roughness of the machined iron-based super-alloys is relatively high due to the serious adhesion. Better surface roughness can be got using the graded tool.     

Cutting performance of microwave-sintered sub-crystal Al2O3/SiC ceramic tool in dry cutting of hardened steel

Tool life and failure mechanisms of a microwave-sintered sub-crystal Al₂O₃/SiC ceramic tool (AS) in dry turning hardened steel were studied. The AS tool with plane face shows better cutting performance and wear resistance than the commercial ceramic tool SW500 and cemented carbide tool YG8 at both low and high cutting speeds. It's suitable for dry cutting at high speed (210–270 m/min), the cutting distance is 5–8 times longer than that of other two tools. The results indicate that the ceramic tool fabricated by this pressureless sintering technology can satisfy the requirements of high-speed machining. Wear forms of AS tool at low cutting speed are slight crater wear and groove wear, which were mainly caused by abrasion. At high cutting speed, tool failure forms are cater wear, groove wear and slight chipping caused by severe abrasion and adhesion.     

油-水、乳-水体系开孔转盘塔流体力学性能的研究

本文通过油-水、乳-水体系对开孔转盘塔进行试验,研究了塔型、体系改变对分散相滞存率X、特性速度(?)及泛点操作转速n_(?)的影响.实验结果表明:(1)对给定的体系、塔型,操作转速不变时,两相流率、滞存率及特性速度可以用Logsdail提出的半经验式:进行关联;(2)低转速下操作RPDC可获得良好的液液分散效果;(3)最低切割转速n_(?)(在此转速下小孔能切割分散相液滴)可以用下式估算:     

高压水射流除锈装置及试验研究

高压水射流除锈与切割应用关键要解决灵敏调控、执行机构设计、安全、运行可靠等问题,实现商品化.笔者从船舶除锈和岩石切割两大用途出发,研制了70MPa、2m~3/h、55kW高压水射流成套装置.本装置集高压泵、阀、密封和水射流技术为一体,由往复泵、安全阀、调压阀、截止阀、控制阀、喷枪、旋转喷头、磨料射流系统和绞盘等组成.经船厂对A、B、C、D四级锈蚀钢板除锈和上船除锈,除锈质量符合ISO8501-1:1988标准中Sa2.5级需求,除锈速度0.8m~2/min,效率高,无粉尘污染,完全满足船舶工业需求.同时以100MPa以内不同压力对石灰岩、混凝土进行切割试验表明该装置的切割功能具备了应用的条件.本文从设计和试验两方面论述了装置参数优化与型式特点、各参量与除锈、切割的关系,进而分析磨料射流除锈新工艺替代喷砂除锈工艺的必然趋势.     

高速切削关键技术

论述了高速切削的高速主轴单元、高速进给系统、高速CNC控制系统、高性能刀具系统、机床支承技术、辅助单元技术以及高速切削加工理论等高速切削的关键技术的现状与最新进展。     

Effects of Ni content on microstructure,mechanical properties and Inconel 718 cutting performance of AlTiN-Ni nanocomposite coatings

AlTiN-Ni coatings with various Ni contents (0–3?at%) were deposited using cathodic arc evaporation. X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, a nanohardness tester, scratch-adhesion tester, and cutting tester were used to examine the microstructure, mechanical properties, and cutting performance of the coatings. The AlTiN coatings exhibited a columnar structure, while the AlTiN-Ni coatings exhibited a nanocrystal structure due to the formation of nc-AlTiN/Ni nanocomposite coatings. The nanohardness of the AlTiN-Ni coatings decreased from 26.2?GPa to 20.9?GPa as the Ni content increased from 0 to 3?at%. At an Ni content of 1.5?at%, the coating possessed a high toughness and sufficient adhesion strength; however, these dropped drastically for the AlTiN-Ni coating with 3?at% Ni owing to the presence of amorphous Ni. The results for the Inconel 718 turning indicated that the wear mode is adhesion at the rake face, abrasion and adhesion (built-up edge) at the flank face, and chipping at the cutting edge. Compared to AlTiN-Ni₃ and AlTiN-coated tools, the lifetime of the AlTiN-Ni_1.5 coated tool increased to 160% at a cutting speed of 40?m/min. This was attributed to less adhesion at the rake face and chipping at the cutting edge, due to the nanocrystal structure and higher toughness of the AlTiN-Ni_1.5 coating.     

Applicability of DLC and WC/C low friction coatings on Al2O3/TiCN mixed ceramic cutting tools for dry machining of hardened 52100 steel

The present work examines the applicability of DLC and WC/C low friction coatings on Al₂O₃/TiCN based mixed ceramic cutting tools for the dry and hard turning of AISI 52100 steel (62 HRC). The characterization of coated tools reveals that the coatings retain very low values of surface roughness, whereas the DLC coating exhibits much higher microhardness when compared to the WC/C coating. On the other hand, the WC/C coating exhibit a coarse surface morphology virtually due to the tungsten doping. Later, continuous turning tests were executed with the help of coated and uncoated cutting tools under dry cutting conditions, and their performance was investigated in terms of machining forces, cutting temperature and tool wear. Coating delamination by flaking and peeling is quite prominent in the case of both the coatings; however, it is less severe for the WC/C coated tool. The coatings help to reduce machining forces, cutting temperatures and tool wear, but the performance of coated tools converge towards uncoated tool as the cutting speed, and feed rate is increased. Both the coatings prevent the development of cracks near the cutting edge with WC/C coating exhibiting superior wear behavior basically due to its multilayered structure and better thermal stability. Moreover, the tested low friction coatings don't serve as thermal barriers and only the lubrication generated due to graphitization at the chip-tool interface is mostly responsible for the improved machining performance.     

TiB2涂层刀具制备及干铣削Ti-6Al-4V磨损行为研究?

由于切削过程中产生高温、刀具粘结与氧化严重,钛合金切削尤其是干切削,一直是刀具行业的重大挑战之一,而在刀具表面添加涂层是提高钛合金切削刀具寿命的有效途径。利用脉冲磁控溅射技术制备了TiB2涂层刀具,以相同基体的无涂层刀具为对照,干铣削Ti-6Al-4V钛合金,切削速度从30~100 m/min变化,研究TiB2涂层刀具的切削性能与失效机理。所制备的TiB2涂层具有(100)择优取向的六方晶体结构,组织致密。涂层硬度可高达4000 HV。切削实验发现,在30 m/min的低速时,TiB2涂层刀具的切削寿命超过无涂层刀具57%之多,当切削速度加倍到60 m/min时,刀具寿命未见下降。当切削速度增加到100 m/min时,TiB2涂层刀具与无涂层刀具切削寿命相当。TiB2涂层刀具表面氧化所产生的B2O3液化膜,起自润滑作用,可充分减少钛合金的粘结,降低摩擦力。因此,在TiB2或B2O3消失之前,TiB2涂层刀具均有良好表现。在100 m/min时,切削高温造成B2O3强烈挥发,且TiB2被氧化为多孔疏松的TiO2,刀具寿命急剧下降到无涂层刀具的水平。     

Effects of drilling parameters and aspect ratios on delamination and surface roughness of lignocellulosic HFRP composite laminates

Hemp fibre‐reinforced polycaprolactone (HFRP) composite has inherent good mechanical properties and benefits which include remarkably high specific strength and modulus, low density, and renewability. No doubt, these properties have attracted wider applications of HFRP composite in engineering applications. This paper presents an investigation on the influence of drilling parameters and fibre aspect ratios, AR (0, 19, 26, 30, and 38) on delamination damage factor and surface roughness of HFRP composite laminates utilising high speed steel twist drills under dry machining condition. Taguchi's technique was used in the design of experiment. The results obtained show that increase in cutting speed reduces delamination factor and surface roughness of drilled holes, whereas increase in feed rate causes increase in both delamination factor and surface roughness. Feed rate and cutting speed had the greatest influence on delamination and surface roughness respectively when compared with aspect ratio, while an increase in fibre aspect ratios leads to a significant increase in both delamination factor and surface roughness. The optimum results occurred at cutting speed and feed rate (drilling parameters) of 20 mm/min and 0.10 mm/rev, respectively, when drilling sample of AR 19. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42879.