陶瓷刀具在转包机匣镍基高温合金加工中的应用

采用陶瓷刀片进行了转包发动机薄壁机匣铣加工、车加工试验,研究了陶瓷刀片加工镍基高温合金的特点,优化了切削参数和走刀路线,分析了高速加工切屑形态,指出应用陶瓷刀具加工镍基高温合金最优的匹配性和最佳经济性,同时也是提高效率的有效途径。     

镍基高温合金高速切削加工性

镍基高温合金具有优良的高温强度以及良好的热稳定性和抗热疲劳性能,广泛应用于航空发动机、燃气涡轮机等领域。但其可加工性极差,切削过程中刀具迅速磨损,加工效率较低。本文介绍了镍基高温合金高速切削加工性的研究进展,重点阐述了适宜高速切削镍基高温合金的陶瓷和PCBN刀具及加工参数,并总结了切削过程中刀具的失效形式和磨损机理,以及利用辅助加工方法等实现陶瓷刀具对镍基高温合金精加工的可能性。为高速切削镍基高温合金加工刀具的快速选择及加工工艺的改进提供了参考。     

高温合金的切削加工

我厂在试制新产品时,遇到的难加工材料有铁镍基高温合金 Incoloy901(国内称N901)、镍基高温合金 C263和钴基高温合金 Haynes—25(简称 HS—25)等,当时试用 YG8、YA6、YW2等刀片加工 N901制成的零件,均不能胜任;用813刀片也因刀片寿命短、磨损大而不能满足精车时的精度要求。为了完成     

新型切削陶瓷

<正>目前可采用热压陶瓷刀片来加工镍基超强度合金。近年来这种切削陶瓷的加工效率提高了7倍。用陶瓷短纤维强化的ACMCS-7复合材料是改进这类工具材料迈出的新的一步,这种复合材料能有效地用于灰铸铁、可锻铸铁和各种硬度的合金钢的车、铣加工。通过     

高效铣削镍基高温合金GH4169的有限元数值模拟

在DEFORM软件中,根据实际加工情况建立整体硬质合金立铣刀加工镍基高温合金GH4169的三维有限元仿真分析模型。针对镍基高温合金GH4169加工效率低和切削刃磨损严重的问题,采用单因素试验法仿真探讨了切削用量(v、f_z、a_p、a_e)对切削力和切削温度的影响规律。获得了能有效提高镍基高温合金GH4169加工效率的切削用量,为实际加工中实现高效铣削镍基高温合金切削用量的选择提供依据。     

汽雾冷却下高速切削GH4169切削力和粗糙度试验分析

本文针对陶瓷车刀片在汽雾冷却下进行切削镍基高温合金GH4169单因素试验和正交试验进行分析研究。利用最小二乘法对所得试验数据进行线性回归分析,建立切削力和已加工表面粗糙度的经验模型,分析在汽雾冷却条件下使用陶瓷刀具的切削参数对切削力和已加工表面粗糙度的影响规律。通过正交试验结果分析出最优的切削参数,为进一步优化切削参数、研究刀片磨损机理提供参考依据。     

镍基高温合金斜角切削的仿真研究

针对难加工材料镍基高温合金切削力大以及难排屑等问题,在ABAQUS有限元分析软件中建立三维斜角仿真模型,模拟镍基高温合金的切削加工过程。研究斜角切削状态下镍基高温合金材料的去除机理和切屑形成,通过正交试验和单因素试验,分析在不同切削参数下流屑角以及三维切削力的变化情况。采用有限元分析方法对镍基高温合金的三维斜角切削过程进行仿真研究,降低了研究成本,为镍基高温合金高效切削加工提供了理论参考。     

陶瓷刀具的性能和实际应用技术

随着现代科技的发展，各种高强度、高硬度工程材料越来越多地被采用，这给切削加工带来了很大的困难。传统的硬质合金刀具难以胜任或根本无法实现对这类材料的加工，而陶瓷刀具有很高的耐磨性、红硬性，可以实现对多种难加工材料（淬硬钢、冷硬铸铁、镍基高温合金等）进行高速切削，生产效率比普通硬质合金刀具高３～８倍。根据我们的使用情况，对性能优越的陶瓷刀具进行分析并与普通刀具进行对比，优化了加工工艺参数。陶瓷刀具的切削性能使用Si３N４基系列的陶瓷刀具，其优点如下：①高硬度：该种刀片的室温硬度值已超过了最好的硬质合金…     

基于Deform-3D的Inconel 718镍基合金的车削仿真

Inconel 718镍基高温合金的力学、抗氧化、抗热变形的性能好,但是加工性能差,材料塑性大、导热系数低、加工硬化严重等问题制约了镍基高温合金的广泛使用.文中运用有限元软件分析和研究材料的切削性能、刀具选择以及切削参数等问题,对解决镍基高温合金难加工的现状提供了参考价值.     

镍基高温合金加工研究

简要介绍了镍基高温合金的物理性能和加工性能;进而介绍了国内外镍基高温合金切削加工的研究成果,主要分析重点集中在刀具材料的选择及切削性能的研究等方面;最后介绍了Inconel617切削加工性能和小孔加工工艺。     

加工镍基合金时切削力和切削温度的特点

本文研究了新型陶瓷刀具ＪＸ－２－Ｉ切削基合金时切削力和切削温度的特点。结果表明，在本试验条件下，切削温度较高，而且随切削速度的提高而呈快速上升的趋势，因此在切削基合金时必须使用冷却液；由于Ｉｎｃｏｎｅｌ７１８高温强度屈服拐点的影响而存在一个切削力最小的速度范围，据此可以选取合理的切削速度。     

Performance of PVD Coated Carbide Inserts When Machining a Nimonic (C-263) Alloy at High Speed Conditions

Physicals Vapor Deposition (PVD) coated carbide inserts were used to machine a nickel-base, C-263, superalloy under severe cutting conditions. Test results show that the TiN/TiCN/TiN coated, inserts with positive, honed and chamfered edges (Tool A) outperformed similar tools with double positive edges and no edge protection (Tool B) in terms of tool life as well as lower flank wear rate when machining under roughing conditions. The double positive edges of Tool B inserts are more susceptible to chipping action due to reduced tool-chip and tool-workpiece contact lengths/areas and associated increase in applied stresses at the cutting edge during machining. Increase in cutting conditions and variation of the cutting edge geometry did not increase the surface roughness value due to the elastic recovery of the C-263 alloy. Prolonged machining causes appreciable increase in the feed force due to the rapid work hardening of the nimonic alloy as well as the formation of hard burrs during machining     

MACHINING PARAMETERS OPTIMIZATION FOR ALUMINA BASED CERAMIC CUTTING TOOLS USING GENETIC ALGORITHM

Alumina-based ceramic cutting tools can be operated at higher cutting speeds than carbide and cermet tools. This results in increased metal removal rates and productivity. While the initial cost of alumina based ceramic inserts is generally higher than carbide or cermet inserts, the cost per part machined is often lower. Production cost is the main concern of the industry and it has to be optimised to fully utilize the advantages of ceramic cutting tools. In this study, optimization of machining parameters on machining S.G. iron (ASTM A536 60-40-18) using alumina based ceramic cutting tools is presented. Before doing the optimization work, experimental machining study is carried out using Ti [C,N] mixed alumina ceramic cutting tool (CC 650) and Zirconia toughened alumina ceramic cutting tool (Widialox G) to get actual input values to the optimization problem, so that the optimized results will be realistic. The optimum machining parameters are found out using Genetic algorithm and it is found that Widialox G tool is able to machine at lower unit production cost than CC 650 tool. The various costs affecting the unit production cost are also discussed.     

MACHINING PARAMETERS OPTIMIZATION FOR ALUMINA BASED CERAMIC CUTTING TOOLS USING GENETIC ALGORITHM

Alumina-based ceramic cutting tools can be operated at higher cutting speeds than carbide and cermet tools. This results in increased metal removal rates and productivity. While the initial cost of alumina based ceramic inserts is generally higher than carbide or cermet inserts, the cost per part machined is often lower. Production cost is the main concern of the industry and it has to be optimised to fully utilize the advantages of ceramic cutting tools. In this study, optimization of machining parameters on machining S.G. iron (ASTM A536 60-40-18) using alumina based ceramic cutting tools is presented. Before doing the optimization work, experimental machining study is carried out using Ti [C,N] mixed alumina ceramic cutting tool (CC 650) and Zirconia toughened alumina ceramic cutting tool (Widialox G) to get actual input values to the optimization problem, so that the optimized results will be realistic. The optimum machining parameters are found out using Genetic algorithm and it is found that Widialox G tool is able to machine at lower unit production cost than CC 650 tool. The various costs affecting the unit production cost are also discussed.     

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.     

Flake Formation in Phase Layers of a Cutting Ceramic

Flake formation (cracking) is observed in inserts of untreated cutting ceramic and also during diffusional strengthening of the inserts’ surface layer by nitrogen on heating in a muffle furnace to 450–500°C, with the creation of γ-phase (a protective layer), the removal of carbon from the atomic cells, and the formation of titanium nitride. Heat-treatment conditions for inserts of cutting ceramic are established such that the flake content at their surface is reduced. Treatment to prevent flake formation is proposed: heating in a sealed muffle furnace with a nitrogen atmosphere to 250–280°C at a pressure of 0.25 MPa. In this process, the titanium carbide at the surface of the inserts is converted to titanium nitride as a result of carbon diffusion, with the formation of a protective γ-phase layer. By removing carbon from the surface layer of the inserts and ensuring the diffusion of nitrogen into the cutting ceramic, with the formation of titanium nitride in the γphase, the durability and performance of the inserts are improved, along with their mechanical properties.     

新型陶瓷刀具材料的耐磨损性能

研究了近几年来所研制成功的几种新型陶瓷刀具材料切削加上高强钢、高温镍基合金、淬硬钢与铸铁时的耐磨性能。结果表明:加工不同材料时刀具的耐磨损能力不同,在实际应用时可根据需要选用合适的刀具材料。     

Effects of Cutting Parameters on Tool Insert Wear in End Milling of Titanium Alloy Ti6A14V

Titanium alloy is a kind of typical hard-to-cut material due to its low thermal conductivity and high strength at elevated temperatures, this contributes to the fast tool wear in the milling of titanium alloys. The influence of cutting conditions on tool wear has been focused on the turning process, and their influence on tool wear in milling process as well as the influence of tool wear on cutting force coefficients has not been investigated comprehensively. To fully understand the tool wear behavior in milling process with inserts, the influence of cutting parameters on tool wear in the milling of titanium alloys Ti6Al4 V by using indexable cutters is investigated. The tool wear rate and trends under different feed per tooth, cutting speed, axial depth of cut and radial depth of cut are analyzed. The results show that the feed rate per tooth and the radial depth of cut have a large influence on tool wear in milling Ti6Al4 V with coated insert. To reduce tool wear, cutting parameters for coated inserts under experimental cutting conditions are set as: feed rate per tooth less than 0.07 mm, radial depth of cut less than 1.0 mm, and cutting speed sets between 60 and 150 m/min. Investigation on the relationship between tool wear and cutting force coefficients shows that tangential edge constant increases with tool wear and cutter edge chipping can lead to a great variety of tangential cutting force coefficient. The proposed research provides the basic data for evaluating the machinability of milling Ti6Al4 V alloy with coated inserts, and the recommend cutting parameters can be immediately applied in practical production.     

Performance comparison of conventional and wiper ceramic inserts in hard turning through artificial neural network modeling

Hard turning with ceramic tools provides an alternative to grinding operation in machining high precision and hardened components. But, the main concerns are the cost of expensive tool materials and the effect of the process on machinability. The poor selection of cutting conditions may lead to excessive tool wear and increased surface roughness of workpiece. Hence, there is a need to investigate the effects of process parameters on machinability characteristics in hard turning. In this work, the influence of cutting speed, feed rate, and machining time on machinability aspects such as specific cutting force, surface roughness, and tool wear in AISI D2 cold work tool steel hard turning with three different ceramic inserts, namely, CC650, CC650WG, and GC6050WH has been studied. A multilayer feed-forward artificial neural network (ANN), trained using error back-propagation training algorithm has been employed for predicting the machinability. The input?Coutput patterns required for ANN training and testing are obtained from the turning experiments planned through full factorial design. The simulation results demonstrate the effectiveness of ANN models to analyze the effects of cutting conditions as well as to study the performance of conventional and wiper ceramic inserts on machinability.