离子镀TiAlN工具涂层的微结构与切削性能

研究并比较了TiAlN和TiN涂层的成分、微结构、力学性能与抗氧化性及涂层铣刀的高速切削性能和涂层钻头的切削性能。结果表明,TiAlN和TiN涂层同为单相的NaCl型结构,并都呈现择优取向的柱状晶,TiAlN涂层的硬度远高于TiN涂层的硬度,TiAlN涂层的抗氧化温度明显高于TiN涂层的抗氧化温度。在高速铣削条件下,TiAlN涂层铣刀的后刀面磨损速率仅为TiN涂层铣刀的约四分之一。在钻孔数相同时TiAlN涂层钻头的磨损量也显著低于TiN涂层钻头。TiAlN涂层刀具的使用寿命显著高于TiN涂层刀具。     

球头铣刀高速切削Inconel 718的刀具磨损研究

为了实现航空高温合金的高速高效加工,通过对Inconel718的铣削试验,分析了涂层球头铣刀切削高温合金时的加工性能。试验结果表明,乳化液在90m/min的切削速度下仍然具有较好的冷却润滑作用。通过对TiAlN涂层和TiAlN+Al2O3涂层刀具的对比试验,证明TiAlN涂层具有优异的耐磨性,可显著提高加工高温合金时的刀具寿命。     

硬质合金铣刀涂层性能的试验研究

针对涂层材料改善刀具切削性能这一问题,本文采用常速试验和高速试验的方法,对比分析了七种涂层材料对铣刀切削性能的改善程度。试验结果表明:涂层性能优越与否与切削速度有很大关系,AlCrN和TiAlCN涂层铣刀更适合高速切削;而AlTiN涂层铣刀不适合高速切削;TiN涂层铣刀无论在常速和高速切削时性能均表现不佳,高速切削时磨损相对更快;CrN+TiN复合涂层抗氧化能力较好,但抗磨能力相对较差。     

不同涂层刀具切削淬硬H13钢加工性能研究

为了研究不同涂层刀具切削淬硬H13钢的切削性能,进行了多层Ti化合物涂层、TiAlN涂层以及MTTiCN厚Al_2O_3TiN涂层材料刀具车削加工淬硬H13钢试验,分析了不同的涂层材料刀具与切削力、切削温度、涂层刀具磨损以及刀具寿命的关系。研究得出:多层Ti化合物涂层刀具受到三个方向的力都大于其它两种涂层的刀具,而且切削温度最高;用TiAlN涂层刀具切削时温度最低;切削过程中三种刀具后刀面磨损程度不同,发现多层Ti化合物涂层刀具磨损最为严重,寿命最短;MT-TiCN厚Al_2O_3Ti N涂层材料刀具比多层Ti化合物涂层刀具寿命长30%;TiAlN涂层刀具的切削寿命最长比多层Ti化合物涂层刀具寿命长45%。     

Hardness properties and high-temperature wear behavior of nitrided AISI D2 tool steel, prior and after PAPVD coating

Wear experiments in the range of 25–600 °C have been conducted on samples of D2 tool steel in different conditions involving unnitrided, nitrided and nitrided and coated with Balinit^® A (TiN) and Balinit^® Futura (TiAlN) deposited industrially at Balzers (Amherst, NY, USA), by means of PAPVD. The results indicate that coating the nitrided D2 tool steel substrate with these two films gives rise to an improvement of 97% (TiN) and 99% (TiAlN) in the wear behavior at the test temperature of 300 °C, in comparison with the uncoated substrate. However, at a temperature of 600 °C, besides oxidation of the coatings, the mechanical strength of the substrate decreases giving rise to fracture and delamination of the films. At this temperature the uncoated substrate exhibited the highest resistance to sliding wear, presumably due to the formation of a well bonded surface glazed layer which gives rise to a significant reduction in the friction coefficient. The indentation experiments that were conducted with the nitrided steel substrate and the coated systems indicates that the nitriding process applied to the D2 steel prior to PAPVD coating provides a satisfactory load support which contributes to the improvement of the coated systems capability to withstand indentation loads at room temperature. In this regard, the coated system with a TiAlN coating displayed a better behavior than that shown by the system with a TiN coating. An experimental procedure is proposed in order to predict the hardness profile of the nitrided tool steel, along the cross section of the material, just from hardness measurements taken on the surface of the sample, employing different indentation loads.     

离子镀TiCN和TiN工具涂层的微结构与切削性能

采用电弧离子镀技术在硬质合金铣刀和钻头上镀覆了TiCN和TiN涂层,研究并比较了两种涂层的微结构与力学性能,以及涂层铣刀的高速切削性能和涂层钻头的切削性能。结果表明,TiCN和TiN涂层同为单相的Na-Cl型结构,并都呈现(111)择优取向的柱状晶,TiCN涂层的硬度为34.6GPa,远高于TiN涂层25.1GPa的硬度。在高速铣削条件下,TiCN涂层铣刀的后刀面磨损速率仅为TiN涂层铣刀的约三分之一。TiCN涂层钻头在钻孔数为TiN涂层钻头两倍时的磨损量仍低于TiN涂层钻头。TiCN涂层的高硬度及在较高切削线速度下的减摩作用是这种涂层刀具寿命提高的重要原因。     

Characteristic evaluation of friction and wear in the C-N and TiN coated gear

C-N films were deposited on the 20CrMo alloy steel substrate by the Plasma Source Ion Implantation (PSII) method and TiN films were coated on the same material by the Physical Vapor Deposition (PVD) method. It was found that friction coefficient of C-N coating were relatively lower than TiN coating. And with the load increased, the friction coefficients of C-N coating and TiN coating were both decreased. Then the author puts forward the test rig, working under the conditions of 1,800 rpm, 20 N·m for 100 h. The observations by microscope showed the wear reduced. The antiwearing performance enhanced prominently. But the TiN coated gear had a more serious friction phenomenon than C-N coated gear. This is caused by that coating of TiN, which was made at a high temperature about 500°C. The high temperature led to the substrate intenerated and the surface hardness had decreased from 850 HV to 630 HV. PSII method eliminates the tempering problem of the coating of C-N films, which had better wear resistance than TiN films. The friction and wear resistance of gears which coated by C-N films ameliorated significantly.     

Wear mechanism of coated tools in the turning of ductile cast iron having wide range of tensile strength

In this study different specimens of ductile cast iron with tensile strength ranking from 400 MPa to 675 MPa were turned with K15 carbide, TiN coated and TiAlN coated tool in order to investigate wear mechanism and performance. Cutting forces and cutting temperature were similar for both coated tools, however flank wear and BUE were the lowest on the TiAlN coated tool, for this reason the TiAlN coated tool is suitable in the machining of ductile cast iron. The proposed tool wear mechanism is based on like-intermittent cutting caused by the pass from hard matrix to the soft graphite occasioning wear by adhesion. The analysis of the flank wear on coated tools is proposed by means of the wear curves in logarithmic scale instead of the usual linear scale. In this way, the change in wear rate is easily observed. This phenomenon was related with the wear out of the coating layer. The partial loss of the coating layer on cutting edge was confirmed by the EDS mapping images and SEM photographs.     

High-Speed Machining of Malleable Cast Iron by Various Cutting Tools Coated by Physical Vapor Deposition

The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron.However,the machining adaptability of various coating materials to malleable cast iron has been insufficiently researched.In this paper,turning tests were conducted on cemented carbide tools with different coatings(a thick TiN/TiAlN coating,a thin TiN/TiAlN coating,and a nanocomposite(nc)TiAlSiN coating).All coatings were applied by physical vapor deposi-tion.In a comparative study of chip morphology,cutting force,cutting temperature,specific cutting energy,tool wear,and surface roughness,this study analyzed the cutting characteristics of the tools coated with various materials,and established the relationship between the cutting parameters and machining objectives.The results showed that in malleable cast iron machining,the coating material significantly affects the cutting performance of the tool.Among the three tools,the nc-TiAlSiN-coated carbide tool achieved the minimum cutting force,the lowest cutting tempera-ture,least tool wear,longest tool life,and best surface quality.Moreover,in comparisons between cemented-carbide and compacted-graphite cast iron machined under the same conditions,the wear mechanism of the coated tools was found to depend on the cast iron being machined.Therefore,the performance requirements of a tool depend on multiple factors,and selecting an appropriately coated tool for a particular cast iron material is essential.     

TiN涂层高速钢刀具的磨损特性及磨损规律

探讨了ＴｉＮ涂层高速钢刀具的磨损特性和磨损扩展规律,分析了涂层在各磨损阶段所起的不同作用,并说明了使用涂层刀具时应注意的一些问题。     

Approach for Polishing Diamond Coated Complicated Cutting Tool: Abrasive Flow Machining(AFM)

Lower surface roughness and sharper cutting edge are beneficial for improving the machining quality of the cut?ting tool, while coatings often deteriorate them. Focusing on the diamond coated WC?Co milling cutter, the abrasive flow machining(AFM) is selected for reducing the surface roughness and sharpening the cutting edge. Comparative cutting tests are conducted on di erent types of coated cutters before and after AFM, as well as uncoated WC?Co one, demonstrating that the boron?doped microcrystalline and undoped fine?grained composite diamond coated cutter after the AFM(AFM?BDM?UFGCD) is a good choice for the finish milling of the 6063 Al alloy in the present case, because it shows favorable machining quality close to the uncoated one, but much prolonged tool lifetime. Besides, compared with the micro?sized diamond films, it is much more convenient and e cient to finish the BDM?UFGCD coated cutter covered by nano?sized diamond grains, and resharpen its cutting edge by the AFM, owing to the lower initial surface roughness and hardness. Moreover, the boron incorporation and micro?sized grains in the underly?ing layer can enhance the film?substrate adhesion, avoid the rapid film removal in the machining process, and thus maximize the tool life(1040 m, four times more than the uncoated one). In general, the AFM is firstly proposed and discussed for post?processing the diamond coated complicated cutting tools, which is proved to be feasible for improving the cutting performance     

Comparative evaluation of machinability characteristics of Nimonic C-263 using CVD and PVD coated tools

Machining of Nimonic C-263 has always been a challenging task owing to its hot strength, low thermal conductivity, tendency to work harden and affinity towards tool materials. Although coated tools have been used to overcome some of these challenges, selection of coated tool with appropriate deposition technique is of immense significance. The current study attempts to comparatively evaluate various performance measures in machining of Nimonic C-263 such as surface roughness, cutting force, cutting temperature, chip characteristics, and tool wear with particular emphasis on different modes of tool failure for commercially available inserts with multi-component coating deposited using chemical vapour deposition (CVD) and physical vapour deposition (PVD) techniques. Influence of cutting speed (V_c) and machining duration (t) has also been investigated using both coated tools. The study demonstrated remarkable decrease in surface roughness (74.3%), cutting force (6.3%), temperature (13.4%) and chip reduction coefficient (22%) with PVD coated tool consisting of alternate layers of TiN and TiAlN over its CVD coated counterpart with TiCN/Al₂O₃ coating in bilayer configuration. Severe plastic deformation and chipping of cutting edge and nose, abrasive nose and flank wear along with formation of built-up-layer (BUL) were identified as possible mechanisms of tool failure. PVD coated tool successfully restricted different modes of tool wear for the entire range of cutting speed. Superior performance can be attributed to the hardness and wear resistance properties, thermal stability due to presence of TiAlN phase and excellent toughness owing to PVD technique and multilayer architecture.     

Using Barkhausen noise to measure coating depth of coated high<Emphasis Type="Bold">-</Emphasis>speed steel

Coated high-speed steel tools are widely used in machining processes as they offer an excellent tool life to cost ratio, but they quickly need replacing once the coated layer is worn away. It would be therefore useful to be able to measure the tool life remaining non-destructively and cheaply. To achieve this, the work presented here aims to measure the thickness of the coated layer of high-speed cutting tools by using Barkhausen noise (BHN) techniques. Coated high-speed steel specimens coated with two different materials (chromium nitride (CrN), titanium nitride (TiN)) were tested using a cost-effective measuring system developed for this study. Sensory features were extracted from the signal received from a pick-up coil and the signal features, Root mean square, peak count, and signal energy, were successfully correlated with the thickness of the coating layer on high-speed steel (HSS) specimens. The results suggest that the Barkhausen noise measuring system developed in this study can successfully indicate the different thickness of the coating layer on CrN/TiN coated HSS specimens.     

Optical Detections From Worn and Unworn Titanium Compound Surfaces

Wear-induced roughness in terms of grooves, sharp ridges, and edges leads to scattering of the reflected light and leads unavoidably to a reduction of the optical signals in a standard specular geometry. However, by using a double-layer system consisting of titanium aluminum nitride (TiAlN) on top of a titanium nitride (TiN) layer we obtain an increase in the reflected light as a result of wear. The relative change of reflectance of light from the tribological TiAlN coated surface to the underlying layer of TiN is similar for non-worn surfaces and for surfaces exposed to an abrasive wear process. The induced roughness reduces the signals from worn samples, in a standard specular geometry, by up to 30% compared with unworn samples. Our model system of TiAlN coatings on top of ‘optical’ signal layers of TiN deposited on a 100Cr6 steel substrate, was exposed to a reciprocating wear process with up to 10⁵ repetitive cycles in a linear tribometer. The worn TiAlN layers of thicknesses up to 3 μm, with strongly developed grooves and ridges, were subsequently used for the reflectance measurements. The results show that optical reflectance monitoring is a potential technique for intelligent determination of a residual thickness of realistic tribological coatings prior to complete wear.     

Wear behaviors of single-layer and multi-layer coated carbide inserts in high speed machining of hardened AISI 4340 steel

Flank wear progression and wear mechanisms of uncoated, coated with PVD applied single-layer TiAlN, and CVD applied multi-layer MT-TiCN/Al₂O₃/TiN cemented carbide inserts were analyzed during dry turning of hardened AISI 4340 steel (35 HRC). Experimental observations indicate that by applying a coating to the uncoated insert the limiting cutting speed increase from 62 to 200 m/min, which further extends up-to 300–350 m/min when using multi-layer coating scheme. Relatively lower wear rate seen when using single-layer TiAlN coated inserts. However, after removal of the thin layer of coating the wear rate increase rapidly, subsequently dominates the wear rate of multi-layer coated inserts. Cutting forces; especially axial and radial components have also shown the similar behavior and increase rapidly when the tool failure occurs. Flank wear, crater wear and catastrophic failure are the dominant forms of tool wear. Digital microscope and SEM images coupled with elemental analysis (EDAX) have been taken at various stages of tool life for understanding the wear mechanisms.     

Ti/TiN复合膜工艺优化及性能研究

利用正交试验和极差分析方法，分析了多弧离子镀Ti／TiN复合膜中工艺参数（弧电流、氮气分压、基体负偏压、钛过渡层厚度）对Ti／TiN复合膜的纳米硬度和膜与基体的结合力的影响及主次关系，并通过正交试验对工艺参数进行了优化。研究表明，氮气分压和弧电流是影响Ti／TiN复合膜纳米硬度的2个最主要因素，膜层与基体的结合力随着弧电流的增加而下降；升高基体负偏压，虽然可以提高Ti／TiN复合膜纳米硬度和膜与基体的结合力，但是高负偏压将急剧升高基体温度，可能导致基体退火；沉积一定厚度的钛过渡层可以显著提高TiN膜层与基体的结合力。     

高速铣削硬态40CrNiMoA的试验研究

针对硬态40CrNiMoA（47HRC），在干切和空气油雾环境下，选用黛杰整体硬质合金（K30）涂层（涂层材料为TiAIN）立铣刀在Mikron UCP710高速加工中心上作了试验研究。并通过试验结果对两种铣削环境下的铣削力作了比较，得出不同铣削参数和铣削环境下高速铣削硬态40CrNiMoA（47HRC）铣削力的变化规律。     

纳米TiN改性金属陶瓷刀具的磨损性能研究

研究了纳米TiN改性TiC金属陶瓷刀具（纳米改性金属陶瓷刀具，下同）与普通Ti（C，N）基金属陶瓷刀具及硬质合金刀具在切割正火态45钢时的磨损曲线及磨损机理。结果表明：纲米TiN改性TiC基金属陶瓷刀具的效果明显；与硬质合金刀具相比，纳米改性金属陶瓷刀具优良的综合性能使其具有更同的耐磨性。刀具的失效形式主要是磨损及崩刃。     

Investigation of the performance of carbide cutting tools with hard coatings in hard milling based on the response surface methodology

Machining of hard materials has become a great challenge for several decades. One of the problems in this machining process is early tool wear, and this affects the machinability of hard materials. In order to increase machinability, cutting tools are widely coated with nanostructured physical vapor deposition hard coatings. The main characteristics of such advanced hard coatings are high microhardness and toughness as well as good adhesion to the substrate. In this paper, the influence of hard coatings (nanolayer AlTiN/TiN, multilayer nanocomposite TiAlSiN/TiSiN/TiAlN, and commercially available TiN/TiAlN) and cutting parameters (cutting speed, feed rate, and depth of cut) on cutting forces and surface roughness were investigated during face milling of AISI O2 cold work tool steel (～61 HRC). The experiments were conducted based on 3¹³ factorial design by response surface methodology, and response surface equations of cutting forces and surface roughness were obtained. In addition, the cutting forces obtained with the coated and uncoated tools were compared. The results showed that the interaction of coating type and depth of cut affects surface roughness. The hard coating type has no significant effect on cutting forces, while the cutting force F _z is approximately two times higher in the case of uncoated tool.     

Influence of cutting speed on cutting force,flank temperature,and tool wear in end milling of Ti-6Al-4V alloy

Tool wear is one of the most important problems in cutting titanium alloys due to the high-cutting temperature and strong adhesion. Recently, the high-speed machining process has become a topic of great interest for titanium alloys, not only because it increases material removal rates, but also because it can positively influence the properties of finished workpiece. However, the process may result in the increase of cutting force and cutting temperature which will accelerate tool wear. In this paper, end milling experiments of Ti-6Al-4V alloy were conducted at high speeds using both uncoated and coated carbide tools. The obtained results show that the cutting force increases significantly at higher cutting speed whether the cutter is uncoated carbide or TiN/TiAlN physical vapor deposition (PVD)-coated carbide. For uncoated carbide tools, the mean flank temperature is almost constant at higher cutting speed, and no obvious abrasion wear or fatigue can be observed. However, for TiN/TiAlN PVD-coated carbide tools, the mean flank temperature always increases as the increase of cutting speed, and serious abrasion wear can be observed. In conclusion, the cutting performance of uncoated inserts is relatively better than TiN/TiAlN PVD-coated inserts at a higher cutting speed.