刀具在高速切削时的磨损机理研究

分析了高速切削时刀具的磨损形态,综述了典型高速切削刀具材料在高速切削时的磨损机理,讨论了高速切削铸铁时,陶瓷刀具、金属陶瓷刀具的磨损寿命.     

硬质合金刀具切削Ti6Al4V的磨损机理及特征

为研究硬质合金刀具在不同切削速度下切削钛合金时,刀具材料中的合金成分对刀具磨损机理及特征的影响,采用YG8、YT15和YW2三种牌号的硬质合金刀具进行干切削Ti6Al4V试验。研究切削速度分别为48 m/min、71 m/min、100 m/min时,三种硬质合金刀具的磨损形貌与磨损机理,分析在低、中、高速切削时三种刀具的磨损机理对其磨损速度的影响。结果表明:低速切削时三种刀具均以黏结磨损为主;高速切削时YG8刀具仍以黏结磨损为主,YT15刀具在发生黏结磨损的同时会产生一定程度的扩散磨损和氧化磨损,YW2刀具的磨损中黏结磨损、扩散磨损和氧化磨损占据同样地位;高速切削时选用YW类刀具更为适合。     

高速铣削刀具磨损研究进展

介绍高速切削的特点、应用现状和加工时刀具遇到的问题,针对刀具磨损机理(刀具材料、切削参数、冷却方式、铣削方式)和刀具磨损监测等方面,综述了近几年高速铣削难加工材料时刀具磨损的研究进展,并对其发展趋势进行了讨论。     

陶瓷刀具高速干切削等温淬火球铁(ADI)磨损性能研究

采用陶瓷刀具(CC650)对等温淬火球墨铸铁(以下简称AD I)进行干式高速切削试验,用带有X射线能谱分析的扫描电镜观察刀具表面的磨损形貌,并对刀具磨损微区和工件表面成分进行定性分析,用X射线衍射仪对刀具、工件和切屑等试样进行物相分析,研究高速切削时陶瓷刀具磨损性能及磨损机制。结果表明:切削速度是影响刀具寿命的主要因素;CC650刀具高速干切削AD I时形成的刀具主后刀面和前刀面的磨损形态基本类似中、低速条件下磨损形态,主要区别在其磨损区域紧靠切削刃,最大磨损部位位于切削刃附近;CC650刀具高速切削AD I时切削温度高,其磨损是机械磨损与化学磨损综合作用的结果,磨损机制主要包括磨料磨损、扩散磨损、粘结磨损和微崩。     

涂层刀具磨损对工件表面质量的非线性影响关系

在高速硬态切削过程中,涂层刀具高速切削失效形态分为非正常磨损（破损）与正常磨损两种。刀具非正常磨损失效发生在低速切削时,而高速切削过程中的刀具失效形式倾向于后刀面磨损、边界磨损和切削刃斜面磨损等多种一常磨损彤式的组合。本文通过涂层刀具高速车削45#钢的试验,研究了刀具磨损对工件表面质量的影响。试验表明：提高切削速度,工件已加工表面质量并未随刀具磨损情况加剧而呈线性下降,刀具磨损对已加工表面质量负面影响作用的减轻,使表面质量在一定程度上得到了改善。     

不同介质下高速切削高温合金时刀具磨损的研究

针对在不同的低温冷风方式下高速切削加工高温合金材料时涂层硬质合金刀具和陶瓷刀具磨损的微观形貌,对刀具磨损机理进行研究,揭示低温冷风方式下高速切削时涂层硬质合金刀具和陶瓷刀具磨损的规律。     

CN35硬质合金涂层刀具高速车削淬硬钢的磨损与破损形态

借助于扫描电镜照片和能谱分析,对高速车削淬硬45钢时CN35硬质合金涂层刀具的失效形态及其机理进行了观察和分析。结果显示,在高速切削条件下,涂层刀具的失效形态主要分为破损与磨损两种,刀具正常磨损失效过程仍然遵循常规切削条件下三个阶段的程序。刀具破损失效发生在低速切削阶段,且随着切削速度的提高,破损部位由后刀面转移到前刀面;高速切削时,刀具失效形式倾向于后刀面磨损、边界磨损和切削刃斜面磨损,因高热、粘结、疲劳、氧化、扩散和热裂等原因造成刀具切削功能丧失。     

高速切削高碳当量合金灰铸铁制动盘的PCBN刀具磨损分析与工艺改进

采用PCBN刀具对高碳当量合金灰铸铁进行高速切削实验,通过IM3000光学显微镜、LSM700 3D测量激光显微镜、S-4800Ⅱ场发射扫描电镜对产生崩裂破损的刀具进行观察与分析。结果表明：高速切削后PCBN刀具表面同时存在磨粒磨损、黏结磨损和氧化磨损三种磨损形式;高速切削加工含有过多高塑、韧性游离铁素体的制动盘时,刀具前、后刀面黏结物均有增多,导致刀具表面出现严重的黏结磨损,并且伴有大面积切削刃崩刃;恶化的切削条件使得刀具表面过早出现磨损与裂纹,从而在切削时引起刀具振动,最终导致PCBN刀具崩裂破损。为了改善切削加工条件,通过改进刹车盘的铸造工艺减少铁素体数量,改进后的制动盘铸态组织以珠光体为主,有效减少了刀具的崩刃概率,提高了生产效率。     

钛合金零件高速铣削刀具磨损的试验研究

高速铣削钛合金时,由于切削区内的切削温度高,加剧了刀具的磨损。通过对钛合金TC4的高速铣削实验,得出带TiA lN涂层的硬质合金刀具切削钛合金TC4时的刀具磨损的变化规律和刀具耐用度公式。通过对刀具磨损特性的分析,研究结果主要是刀具表面层的粘结相Co在高温下丧失对WC颗粒的结合强度,磨损机理以高温下的粘结层撕裂磨损为主。     

高速车削300M高强度钢涂层刀具失效机理研究

选用不同涂层刀具进行高速切削300M钢试验,利用工具显微镜和电子扫描显微镜(SEM)观察刀具磨损形貌,并利用线扫描进行元素扩散分析,揭示刀具失效机理。研究结果表明:金属陶瓷基涂层刀具高速切削时,切削速度不宜超过240m/min;硬质合金基涂层刀具可在300m/min以上高速切削300M钢,其中CVD-Ti CNAl2O3厚涂层的高速切削性能更高,切屑塑形变形较小;涂层刀具切削300M钢的主要磨损形式是前刀面磨损和后刀面磨损,涂层剥落、崩刃、微裂纹、粘结磨损、磨粒磨损、氧化磨损、扩散磨损是刀具失效的主要原因。     

高温合金高速加工技术及刀具材料研究

总结了高速切削加工的特点及发展趋势,介绍了高温合金高速加工及其刀具材料的研究现状,并重点讨论了加工高温合金时刀具材料的选用、匹配、加工参数、损坏机理及存在的问题等。     

绿色加工中刀具磨损对表面粗糙度影响的研究

在切削镍基高温合金材料过程中,由于不稳定因素造成已加工表面粗糙度很难控制,尤其是刀具磨损直接影响着表面粗糙度。通过对冷风油雾、冷风和常温油雾等不同冷却切削条件下刀具磨损和工件表面粗糙度微观形貌的实验,研究了高速切削镍基高温合金材料时,在不同冷却切削条件下刀具磨损对工件表面粗糙度的影响,揭示了用冷风高速切削提高表面加工质量的规律。     

Suppression of notch wear of a whisker reinforced ceramic tool in air-jet-assisted high-speed machining of Inconel 718

This paper describes the notch and flank wear specific to a SiC whisker reinforced alumina tool in air jet assisted (AJA) turning of nickel-base superalloy Inconel 718 at high cutting speeds. An AJA machining experiment has revealed that the air jet applied to the tool tip in addition to coolant dramatically reduces the depth-of-cut notch wear. As a result, the width of flank wear, but not the size of notch wear, determined the life of a ceramic tool in AJA machining of Inconel 718. This is a reason for the large extension and small variation of the tool life when high speed AJA machining is adopted. The maximum tool life length reached 2160 m at a cutting speed of 660 m/min under the given cutting conditions. Finally, the mechanisms of the notch and flank wear of a SiC whisker reinforced alumina tool in AJA machining are discussed from the viewpoints of tribochemical reactions and tool wear anisotropy.     

车铣复合加工的刀具磨损强度分析

在车铣复合加工中心上,进行了车铣加工高强度钢工件材料的刀具磨损强度实验,分析了车铣切削用量对刀具磨损强度的影响.研究表明,在影响车铣刀具磨损的切削用量中,切削速度对车铣刀具的磨损强度影响最大.并以车铣刀具的磨损实验为基础,以切削速度为变量,建立了车铣高强度钢的刀具磨损强度分析模型.     

高速加工切削用量选择分析

高速加工切削用量的选择主要考虑加工效率、加工质量、刀具磨损和加工成本。不同刀具加工不同工件材料时,切削用量会有很大差异。切削用量的选择是高速加工中的重要内容,切削用量的大小对加工效率、加工质量、刀具磨损和加工成本均有显著影响。本文对高速加工的切削用量选择问题进行了分析,给出了若干原则和建议。     

陶瓷刀具材料切削加工G4335V高强钢时的耐磨性能研究

本文对Ａｌ２Ｏ３／ＴｉＣ陶瓷刀具材料切削加工Ｇ４３３５Ｖ高强钢时的切削性能和耐磨性进行了试验研究。结果表明：在低速切削条件下，Ａｌ２Ｏ３／ＴｉＣ陶瓷刀具和硬质合金刀具（ＹＴ１５）的抗后面磨损能力相差不大，而在高速切削条件下，前者的抗后面磨损能力远高于后者。Ａｌ２Ｏ３／ＴｉＣ陶瓷刀具前面的磨损形式主要为粘结磨损，后面的磨损形式主要为磨粒磨损。     

A comparative study of the tool–chip contact length in turning of two engineering alloys for a wide range of cutting speeds

Tool chip contact length is an important parameter in machining, as it provides an indication of the size of area of interaction between the hot chip and the tool surface and hence the interface heat transfer zone. Heat transfer and thermally activated wear modes usually dominate tool wear in the high speed machining of steels and machining of titanium alloys at most cutting speeds. In this study, existing models for the prediction of tool–chip contact length are reviewed and examined for their suitability in high speed machining of two widely used engineering alloys. Orthogonal turning tests for AISI 1045 steel and Ti6Al4V titanium alloy are conducted for a range of cutting speeds from conventional to high speeds. New contact length models are presented for both materials covering a wide range of cutting speeds. More significantly, these contact length models are appropriate for high speed machining where thermal loads significantly influence process performance. Additionally, the work discusses how the machinability of engineering materials influences the ability to predict contact length.     

MACHINABILITY STUDY OF CARBON/PEEK COMPOSITES

Composites are generally fabricated to near nett-shape, however, there is often a need to conduct some additional machining operations such as trimming of the edges. High tool wear and the need for good surface finish are some of the major concerns in machining. This study deals with the machining of Carbon/PEEK, a high performance thermoplastic matrix composite, which is being used extensively in aerospace industries because it is light and posses high specific properties compared to conventional metallic materials. The technique of the full factorial design of experiment is used to investigate the relative effects of the various machining parameters on the amount of tool wear and the surface quality of the workpiece.

Experimental results show that the cutting speed, depth of cut and feed-rate are the main factors that contribute to tool wear of the inserts. The surface finish is found to be independent of the machining parameters and much better than those obtained in the conventional machining of metals provided a critical cutting speed is exceeded. This critical cutting speed is found to be in the range of 70m/min to 75m/min. The cutting point temperature at this speed is found to have exceeded the glass transition temperature of the material, indicating that cutting is done in the rubbery regime. This leads us to conclude that the smooth surface finish of the workpiece is caused by some form of polymer softening action rather than determined by the tool geometry of the cutter.     

切削用量对铣削非标内螺纹刀具磨损的影响

与传统螺纹加工方法相比,铣削螺纹不仅具有较高的加工精度和加工效率,而且不受螺纹结构的制约,可较为自由地选取合理的加工参数。应用DEFORM-3D软件对铣削非标内螺纹刀具磨损进行仿真,运用正交仿真试验研究切削速度、最大切削厚度和径向切削深度等切削用量对刀具磨损的影响,并对加工参数进行了优化。结果表明:切削刃圆角处刀具磨损最严重,在研究范围内,径向切削深度对刀具磨损的影响最大。     

Wear Mechanism of Cemented Carbide Tool in High Speed Milling of Stainless Steel

Adhesion of cutting tool and chip often occurs when machining stainless steels with cemented carbide tools. Wear mechanism of cemented carbide tool in high speed milling of stainless steel 0Cr13Ni4 Mo was studied in this work. Machining tests on high speed milling of 0Cr13Ni4 Mo with a cemented carbide tool are conducted. The cutting force and cutting temperature are measured. The wear pattern is recorded and analyzed by high?speed camera, scanning electron microscope(SEM) and energy dispersive X?ray spectroscopy(EDS). It is found that adhesive wear was the dominant wear pattern causing tool failure. The process and microcosmic mechanism of the tool's adhesive wear are analyzed and discussed based on the experimental results. It is shown that adhesive wear of the tool occurs due to the wear of coating, the a nity of elements Fe and Co, and the grinding of workpiece materials to the tool material. The process of adhesive wear includes both microcosmic elements di usion and macroscopic cyclic process of adhe?sion, tearing and fracture.