高性能材料刀具及其切削性能研究

发布时间：2018-06-17 19:21

本文选题：Ti(C + N)基金属陶瓷　；参考：《合肥工业大学》2015年博士论文

【摘要】：Ti(C，N)基金属陶瓷材料在高温下因其具有优良的耐磨性和良好的化学稳定性而广泛应用于切削刀具；但是Ti(C舯基金属陶瓷属于硬脆性材料,如何增加其强韧性以提高刀具寿命一直是广大材料及切削加工研究者需要面对的难题。聚晶立方氮化硼(简称PCBN)刀具具有硬度高、化学惰性良好而稳定等优点,其在加工高硬度材料方面具有明显的优势,如何正确应用PCBN刀具切削铁基粉末冶金件以实现其价值最大化显得尤为重要。本文在概述刀具材料发展的基础上针对这些问题进行了以下实验研究：(1)Ti(C,如基金属陶瓷刀具的研究：用粉末冶金法、真空烧结工艺制备了TiC原始粒度不同的两组Ti(C,N)基金属陶瓷材料。对TiC粉末粒度提高Ti(C,N)基金属陶瓷材料强韧性的机制进行了分析研究。得出纳米TiC原始粉末制备的Ti(C,N)基金属陶瓷具有更小的晶粒度,同时具有更好的材料综合性能。纳米TiC原始粉末制备的金属陶瓷组织的晶粒细化,抗弯强度和硬度更高,但微米TiC原始粉末制备的金属陶瓷中粘结相平均自由程较大,从而韧性高。(2)在测试这两组Ti(C,N)基金属陶瓷刀具材料的机械力学性能时,用自制的刀具进行实际切削实验,切削实验结果表明：Ti(CN)基金属陶瓷刀具切削正火态45号钢时,后角α=5°的刀具耐用度最好,刀具的使用寿命最长；纳米Ti(C,N)基金属陶瓷刀具寿命比微米Ti(C,N)基金属陶瓷刀具寿命长。对Ti(C,N)基金属陶瓷刀具的磨损形态和磨损机理进行了进一步的分析研究得出两种金属陶瓷刀具的磨损机理基本相同,在刀具的后刀面磨损中共同存在着磨粒磨损、粘结磨损、扩散磨损和氧化磨损四种磨损形式,其中主要磨损形式是扩散磨损和氧化磨损。(3)利用大型商业有限元仿真软件Abaqus对正交金属切削过程进行建模和数值仿真计算；借助仿真模型研究前角和切削速度对切削过程的影响,分析复杂的切削过程,并且利用切削试验,对切削力和剪切角两个重要仿真参数进行了验证。仿真技术更直观的揭示了切削状态；为制备工业上实用的高性能的材料刀具提供了实验和理论上的指导；为新刀具的开发降低了成本,提高了效率。(4)PCBN刀具切削铁基粉末冶金件——发动机气门座圈的实验研究。得出了以下结论：V581铁基粉末冶金材料在密度、硬度、硬质粒子硬度(HV0.1)和压溃强度方面均明显优于ZN-1材料；切削三要素中,切削深度对切削力的影响最大,进给量次之,切削速度最小;实验表明,三方向切削力中以径向力Fy最大,比轴向力Fx大近2倍；PCBN刀具切削粉末冶金件的磨损形态主要为：前刀面月牙洼磨损、后刀面磨损和微崩刃；PCBN刀具的破损形态主要为：刀尖断裂、前刀面剥落。实验中刀具前刀面主要磨损形态为脱落,后刀面在切削过程中发生了严重的化学磨损。由于粉末冶金材料中含有大量的硬质粒子,所以机械磨损始终存在于刀具磨损中。
[Abstract]:Ti (C, N) based cermet is widely used in cutting tools at high temperature because of its excellent wear resistance and good chemical stability. But Ti (C based cermet is a hard brittle material. How to increase its strength and toughness to improve tool life has been a difficult problem for large material and cutting researchers. " Cubic boron nitride (PCBN) tool has many advantages, such as high hardness, good chemical inertness and stability. It has obvious advantages in the processing of high hardness materials. It is very important to use PCBN tool to cut iron based powder metallurgy parts correctly to realize its maximum value. This article is based on the development of tool materials. The following experimental studies have been carried out: (1) Ti (C, such as the study of basic cermet cutters: two groups of Ti (C, N) cermet with different TiC original granularity were prepared by powder metallurgy and vacuum sintering process. The mechanism of TiC powder grain size to improve the strength and toughness of Ti (C, N) based ceramic materials was analyzed and studied. The Ti (C, N) cermet prepared by powder has smaller grain size and better comprehensive material properties. The grain of the cermet is refined, the bending strength and hardness are higher, but the average free range of bond phase in the micrometer TiC raw powder is higher, and the toughness is high. (2) it is measured. When the mechanical properties of the two groups of Ti (C, N) foundation ceramic tool materials were tested, the actual cutting experiments were carried out with self-made tools. The results showed that when Ti (CN) foundation ceramics cutters were cutting normalizing No. 45 steel, the tool durability of the posterior angle alpha =5 degree was the best and the service life of the tool was the longest; the nano Ti (C, N) foundation was the tool life of the ceramic tool. Life is longer than micrometer Ti (C, N) based cermet cutters. The wear morphology and wear mechanism of Ti (C, N) based ceramic cutters are further analyzed and studied. The wear mechanism of the two kinds of ceramic tools is basically the same. Four types of wear are damaged, among which the main wear forms are diffusion wear and oxidation wear. (3) modeling and numerical simulation of orthogonal metal cutting process by large commercial finite element simulation software Abaqus are used to study the influence of the front angle and cutting speed on the cutting process, and the complex cutting process is analyzed, and the use of the cutting process is analyzed. Two important simulation parameters of cutting force and shear angle are verified by cutting test. The simulation technology reveals the cutting state more intuitively; provides experimental and theoretical guidance for the manufacture of practical high performance material tools; reduces the cost and improves the efficiency for the development of new tools. (4) cutting iron base powder by PCBN cutters. The experimental study of metallurgical parts - engine valve seat ring is carried out. The following conclusions are drawn: V581 iron based powder metallurgy material is obviously superior to ZN-1 material in density, hardness, hard particle hardness (HV0.1) and crushing strength; in the three elements of cutting, the cutting depth has the greatest impact on the cutting force, the feed amount is the second, the cutting speed is the least; the experiment table is the least. In the three direction, the maximum cutting force in the three direction is 2 times larger than the axial force, which is nearly 2 times larger than the axial force; the wear form of the PCBN cutting tool is mainly: the wear of the crescent surface of the knife surface, the wear of the knives and the micro avalanche edge, and the breakage form of the PCBN cutter mainly is the fracture of the knife tip and the flake of the front knife. The main wear form of the tool front face in the experiment is the form of the main wear of the tool front face in the experiment. There is a serious chemical wear in the cutting process. Because of the large number of hard particles in the powder metallurgy material, the mechanical wear is always in the tool wear.
【学位授予单位】：合肥工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG711

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