Development of High-Speed Steels for Cast Metal-Cutting Tools

Author(s):  
Alexander S. Chaus ◽  
J. Chovanec ◽  
M. Legerská
2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.


Author(s):  
Mitsuru Hasegawa ◽  
Tatsuya Sugihara

Abstract In cutting of Ti-6Al-4V alloy, the cutting speed is limited since a high cutting temperature leads to severe tool wear and short tool life, resulting in poor production efficiency. On the other hand, some recent literature has reported that various beneficial effects can be provided by forming micro-textures on the tool surface in the metal cutting process. In this study, in order to achieve high-performance machining of Ti-6Al-4V, we first investigated the mechanism of the tool failure process for a cemented carbide cutting tool in high-speed turning of Ti-6Al-4V. Based on the results, cutting tools with micro textured surfaces were developed under the consideration of a cutting fluid action. A series of experiments showed that the textured rake face successfully decreases the cutting temperature, resulting in a significant suppression of both crater wear and flank wear. In addition, the temperature zone where the texture tool is effective in terms of the tool life in the Ti-6Al-4V cutting was discussed.


Author(s):  
Anatolii Chumak ◽  
Sergey Klimenko ◽  
Sergei Klimenko ◽  
Andriy Manokhin ◽  
Artem Naydenko ◽  
...  

Finishing methods of machining of superhard composite’s working elements based on cubic boron nitride BL group are considered. The results of the microgeometry formation research of the cutting inserts’ surfaces during machining by free powders of synthetic diamond, grinding wheels and a method of vibro-magnetic-abrasive machining (VMAM) are presented. It is shown that during VMAM the friction between the inserts’ surfaces and the abrasive particles result in microremoval of the material, which reduces the roughness of the cutting inserts’ surfaces. It is established that additional fine grinding with 14/10 mkm synthetic diamond powder provides the absence of microgeometry defects of the cutting inserts’ surfaces left by pre-machining. The result of high-quality rounding of cutting edges and the formation of surfaces of cutting inserts with less roughness is an increase in strength and wear resistance of metal-cutting tools in high-speed machining under conditions of significant loads.


Author(s):  
N.V. Ferdinandov ◽  
D.D. Gospodinov

Purpose: To present a technology for hardfacing of metal-cutting tools by arc welding in vacuum. Design/methodology/approach: The experiments were carried out using an installation for arc welding in vacuum. Objects of research were metal cutting tools (lathe knives), made of high-speed steel HS6-5-2 on a base metal of structural steel C45. The structure, hardness and wear resistance after hardfacing and after a triple tempering at 560°C have been determined. The heat resistance of the obtained instruments has been examined. Findings: The microstructural analysis showed that the structure of the built-up layer consisted of martensite, retained austenite and carbides. This was confirmed by the values of measured hardness after welding which were about 63-64 HRC. The triple tempering led to an increase in hardness by 3-4 HRC. It was found that the built-up layers (cutting edges of tools) retain their hardness (HRC=63-65) up to a temperature of 615-620°C, which shows that the heat resistance of the build-up layers was similar to that of the hardened and tempered tools of the same steel. The built-up work-pieces (excluding heat treated) and the reference knife showed the same cutting qualities at cutting speeds in the range of 55 to 120 m/min. It has been found that triple tempering after hardfacing led to increased wear resistance and consequently the durability of the tool also increased due to the higher hardness. Practical implications: The practical application is related to the production of metalcutting tools. Originality/value: The proposed technological method allows to produce defects free built-up layers. The cutting properties of the built-up in vacuum layers are comparable to or better than those of new tools made of steel HS 6-5-2.


1959 ◽  
Vol 81 (2) ◽  
pp. 139-147 ◽  
Author(s):  
B. T. Chao ◽  
K. J. Trigger

A substantial reduction in power consumption, an increase in tool life, more effective utilization of cutting fluids, and improved surface finish on the machined workpiece have been achieved by suitably controlling the length of tool-chip contact. Reasons for these findings are discussed in terms of basic variables in chip formation mechanics. Artificially restricted contact tools open new avenues for metal cutting research. Machining data obtained with such tools provide further evidence of the invariant behavior of the dynamic shear stress of metals under high-speed cutting conditions, and unfold interesting information on the intricate nature of tool-chip contact.


2015 ◽  
Vol 788 ◽  
pp. 325-329
Author(s):  
Alexander G. Ovcharenko ◽  
Andrey Yu. Kozlyuk ◽  
Mikhail O. Kurepin

Abstract. A promising method for improving wear resistance of metal cutting tools including pre-heating and a subsequent impact of the pulsed magnetic field of high intensity on the cutting tool is proposed. The experimental setup and methods of research are described. Experimental studies of surfaces of carbide reversible cutting plates of the VK8, T15K6 alloy and drills of high speed steel R6M5 to assess the effectiveness of the proposed method were performed. An increase in wear resistance of cutting tools made of the T15K6 hard-alloy plates by 30% and made of the VK8 alloy plates by 13% was revealed while wear resistance of drills made of steel R6M5 increased on average by 58% The proposed method can be of practical interest for hardening the surface of other types of tools and machine parts for further experimental verification.


2013 ◽  
Vol 652-654 ◽  
pp. 2218-2221 ◽  
Author(s):  
Li Bao An ◽  
Chun Guang Lu

Metal cutting indicates a specific category of processes in which unwanted material is removed from workpeice by single- or multi-point cutting tools for making products meeting prescribed specifications. Parameter optimization in metal cutting plays an important role in satisfying quality requirements of machined parts at low production cost or time. It requires optimal selection of cutting speed, feed rate, depth of cut, and the number of passes. A brief review of recent progress on the optimization of cutting parameters is introduced in the present work. Some new machining practices expending in recent years are involved including hard turning, dry cutting, high speed machining, machining of difficult-to-machine materials and composites. Modeling skills for creating optimization models and optimization techniques for solving optimal or near-optimal solutions are summarized and analyzed.


1959 ◽  
Vol 81 (3) ◽  
pp. 263-279 ◽  
Author(s):  
D. M. Eggleston ◽  
R. Herzog ◽  
E. G. Thomsen

Orthogonal-cutting experiments using SAE 1112 free-cutting steel, 2024-T4 and 6061-T6 aluminum alloys, and alpha-brass (85 Cu-15 Zn) at feeds of 0.002 to 0.010 ipr, were performed on a lathe with 18-4-1 high-speed-steel cutting tools. The mean cutting speeds and rake angles for SAE 1112 varied from 33.7 to 170.8 fpm and 5 to 40 deg, respectively, while the remainder of the alloys were tested at conditions yielding a continuous chip without a built-up edge at speeds ranging from approximately 470 to 790 fpm. It was found that the angle λ between the shear plane and the resultant tool force R was only approximately constant for each test condition and varied with cutting speed. Hence the equation λ = ϕ + β − α = const and the linear relationship between ϕ and β − α are only approximately satisfied. Furthermore, neither the Ernst and Merchant minimum-energy criterion, nor the Lee and Shaffer nor the Hill ideal plastic-solid solution, is in agreement with all the experimental observations.


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