High Speed Steel Research Articles

Influence of Cutting Parameters on the Service Life of Twist HSS Drill Bit When Drilling C35 Steel

This work aims to understand the influence of cutting parameters on the twist high-speed steel (HSS) drill bits wear when drilling C35 steel before and after quenching. An experimental investigation has been conducted using the planning experience methodology (L8) on C35 steel in the annealed and hardened states. The input parameters are cutting regime elements, cutting speed (Vc), feed rate (f), and drill diameter (D), while the output parameters are the tool wear related to its tool life. The most interesting phenomenon is the controversial effect of cutting speed when drilling C35 steel in hardened conditions. The drilling life increases with increasing cutting speed for different cutting regimes (1 to 8). In addition, the 20 mm diameter drill related to the high value of the depth of cut (f) has given better life before and after hardening, contrary to the literature on cutting tool life. The analysis of variance (ANOVA) has showed that the feed rate (f) is the most significant factor in the annealed state while it is the depth of cut (ap) in the hardened state. The correlation coefficients R2 determined by the ANOVA before, and after quenching, are very satisfactory, and testify the good adequacy of the proposed model.

Characterisation of Metal Debris in Grinding and Flotation Circuits

An extensive body of work exists on the impact of grinding media composition on media wear, valuable mineral surface chemistry and subsequent separation from gangue species. However, the literature is limited in describing what happens to metal (either tramp metal from upstream processes, or grinding media debris) in the grinding and flotation processes. This study aims at characterisation and deportment of metal debris within the grinding and flotation circuits of three Australian concentrators. The results show a remarkable range of “metallic” morphologies and sizes, with a considerable amount of metal debris circulating in the hydrocyclone/mill circuit while fine fractions proceed to downstream flotation. Chemical and mineralogical characterisation revealed notable metal debris contribution from upstream equipment such as loader teeth and high speed steel tools, coupled with mild steel grinding media. Surface chemistry and mineral association analysis suggest sulphide mineral oxidation at reactive metal debris surfaces, causing possible limitation of flotation performance and process economics.

Microstructure and mechanical properties of borided AISI T1 high-speed steel by dehydrated paste-pack boriding

Microstructure and mechanical properties of borided AISI T1 high-speed steel by dehydrated paste-pack boriding

Microstructure Evolution and Wear Resistance of Laser-Clad M2 High-Speed Steel Coatings

Microstructure Evolution and Wear Resistance of Laser-Clad M2 High-Speed Steel Coatings

Application of Adaptive Materials and Coatings to Increase Cutting Tool Performance: Efficiency in the Case of Composite Powder High Speed Steel

The paper proposes a classification of adaptive materials and coatings for tool purposes, showing the ability to adapt to external heat and power influences, thereby improving tool life. Creating a cutting tool made of composite powder high speed steels containing refractory TiC, TiCN, and Al2O3 compounds for milling 41CrS4 steel demonstrated the effectiveness of the adaptive materials. The tool material characteristics under the external loads’ influence and the surface layer adaptation to the heat–power exposure conditions were shown by the temperature field study using a semiartificial microthermocouple method (the level of fields is reduced by 20%–25% for 80% HSS + 20% TiCN), frictional interaction high-temperature tribometry (the coefficient of friction did not exceed 0.45 for 80% HSS + 20% TiCN at +20 and 600 °C), laboratory performance tests, and spectrometry of the surface layer secondary structures. Spectral analysis shows the highest spectrum intensity of TiC2 after 5 min of running in. After 20 min of milling (V = 82 m/min, f = 0.15 mm/tooth), dicarbide decomposes and transits to thermally stable secondary phase films of good lubricity such as TiO (maximum) and TiN (partially). There was an increase in tool life of up to 2 times (>35 min for 80% HSS + 20% TiCN), and a decrease in the roughness of up to 2.9 times (Ra less than 4.5 µm after 25 min of milling).

Performance analysis of centrifugal-cast single-point cutting-tools developed from scrapped tools

ABSTRACT Single-point cutting tools were developed adopting a novel technique involving centrifugal casting using scrapped and discarded tools without any compositional adjustments. These tools included single-point cutting tools, drills, milling cutters, etc., and were melted in an induction furnace and cast in a vertical rotating mold. Single-point cutting tools were developed from these cast bars. The cutting ability of these developed tools was compared with that of conventional high-speed steel (HSS) tools that were procured from the market, for cutting of mild steel (A36) workpiece under identical tool geometry and cutting parameters. The cutting ability of the conventional HSS tool and the developed tool was observed to be comparable in terms of tool wear. Further, the surface-finish, force required for cutting and chip-configuration were more or less identical. The performance of the developed tool is comparable with the conventional cast HSS tool within the cutting velocity of 52.77 m/min and yields the most encouraging results, putting these tools at par with those available in the market. Thus, the novel technique adopted is claimed to be a viable method for developing single-point cutting tools without going for stringent methods of compositional adjustments and the costly forging methods for compaction.

Multicomponent Internal Standard Methods for Determination of Vanadium, Chromium, Nickel, and Copper in Tool Steel Samples in Continuum-light-source Flame Atomic Absorption Spectrometry

This paper suggests an improved method for the sample preparation to quantify vanadium, chromium, nickel and copper in tool steel and high-speed steel by using flame atomic absorption spectrometry. The suggested method prepared two specimen solutions containing different internal standard elements: one included nickel for the quantifications of vanadium or copper and cobalt for the quantification of chromium and another included cobalt and phosphoric acid for the quantification of nickel, after the sample was digested with an acid mixture of hydrofluoric acid, nitric acid and phosphoric acid by using a microwave oven. A multi-wavelength high-resolution spectrometer system was employed to be simultaneously measured absorption lines for several pairs of an analyte and an internal standard element, such as vanadium and nickel, chromium and cobalt, nickel and iron, cobalt and phosphorus oxide, and copper and nickel. The internal standards contributed to more accurate and precise quantification of vanadium, chromium, nickel, and copper in tool steel and high-speed steel samples.

Mechanical and high-temperature tribological properties of CrAlN/TiSiN multilayer coating deposited by PVD

Hard nitride coatings have the prospect of acting as protective layers for cutting tools because of their excellent mechanical properties and wear resistance. To enhance the mechanical, tribological, and high-temperature oxidation properties, the structural design of the coating is important. In this study, TiSiN, CrAlN/TiSiN bilayer and CrAlN/TiSiN multilayer coatings were deposited on the surface of high-speed steel by multi-arc ion plating technology. The microstructure, phase composition, mechanical properties and high-temperature tribological properties of prepared coatings were analyzed. Results indicated that the TiSiN and CrAlN/TiSiN bilayer coatings contain TiN phases and the CrAlN/TiSiN multilayer coating contains three main phases of TiN, AlN and CrN. The CrAlN/TiSiN multilayer coating possesses a denser microstructure than the other two coatings. The multilayer structure improves the cohesive and bonding strength of the coating by reducing the shear stress. The CrAlN/TiSiN multilayer coating exhibits a stable coefficient of friction and excellent wear resistance during high-temperature friction. The formation of TiO2 and Al2O3 oxide layers on the surface of the coating in a high-temperature environment contributes to the desired tribological properties of the coatings.

Modification of cast alloys nanostructured material

The third article of the series devoted to the application of nanomaterials and nanotechnologies in industry in general and, first of all, in metallurgy, materials science and foundry is presented. This article deals with the use of nanomaterials for the improvement of ferrous and non-ferrous alloys by micro-alloying and modifying methods, as well as the synthesis of new composite materials. The results of research on C-B-Fe composites obtained at the Belarusian State Technological University, a method for modifying gray cast iron with micro-additives of abrasive slurries of high-speed steels, proposed by specialists of BNTU and OJSC «MTW», and aluminum alloys modified with nanostructured carbideand nitride-containing powders developed by Belarusian, Bulgarian and Russian scientists are presented.

Structure and Properties of a Local Diffusion Discrete Coating Applied to High Speed Steel

Investigations of metallographic and mechanical properties of local diffusion discrete oxide coating on high-speed steel Р6М5 have been carried out. It was found that the technology of discrete oxidation makes it possible to increase the hardness by 31% in relation to the uncoated material, and the wear resistance of the cutting tool with oxidation is 1.5-3 times higher than that of the tool hardened by the standard ion-plasma technology.

Milling of Electron Beam Melting Ti-6Al-4V by HSS Instrument with Combined Surface Treatment

Despite the advanced development in the field of creating new hard-alloy and ceramic tool materials, the use of modern high-speed steels has not yet lost its relevance, and it is especially true for the production of small batches of costly specialized tools, especially since modern strengthening technologies can make it competitive. For example, additive production systems associated with laser or electron beam manufacturing methods create products, including Ti-6Al-4V alloy, with low surface quality, and it is still necessary to apply the additional cutting treatment. The features of milling titanium alloy obtained by the electron beam melting method were revealed. It is determined that the force parameters differ from those in the processing of metal obtained by traditional technologies. Thus, the component of cutting tangential force FT increases by approximately 15%. At the same time, a 20% drop in the radial force FR observed

Machining Temperature and Accuracy of Magnesium Alloy AZ31 with Deep-Hole Small Drilling

In recent years, magnesium-based materials have become expected to replace conventional engineering plastics as next-generation industrial materials to protect the global environment. However, in the production technology, problems of cracking and unstable accuracy in drilled hole shapes persist in plastic molding and machine tool processing; many studies have been conducted to address these problems. In dry machining ignition can be caused by the material, so wet machining is the prevalent method. However, it is necessary to establish a machining method with improved environmental parameters, considering the impact of oil mist and waste oil treatment on woks. In this study, the relationship between machining temperature and the accuracy of hole shapes in magnesium alloy AZ31 is investigated with four types of drills: high-speed steel, cemented carbide (K-Base), diamond-like carbon (DLC; K-Base), and TiN-coated cemented carbide (K-Base). The drill tip angle is set to 116°, 118°, or 120°. The work material used is the extruded AZ31 magnesium alloy. To evaluate the hole shape accuracy, squares of 80 × 80 mm are used. The cutting temperature is measured over an area of 12 × 30 mm. The work material is drilled using a dry method with a 3-mm-diameter drill having the aspect ratio (L/D) of 10. The tool protrusion length of 50 mm and cutting speed of 20 m/min are fixed, and the tool feed rate and drill step amount are changed. The experiment is repeated 3 times. The burr generated around the loophole on the back surface of the test material after the test is evaluated with a criterion burr height H of 0.02 mm. Furthermore, the average roughness (Ra) of the centerline is measured on the inner surface of the hole with a contact-type roughness meter. The results show that when using the three drill point angles of 116°, 118°, and 120° in the drill step, no burrs form at the exit of the drill hole. Carbide tools form burrs when the feed rate exceeds 30 mm/min and the step amount exceeds 20 mm. TiN tools are highly accurate up to a tip angle of 118°, while DLC tools have lower cutting forces and yield better finished surfaces than the other tools.

Temperature effect on nanostructured wear-resistant coating on the surface of a band-saw cutting tool

The article presents the results of study of temperature effect on microstructural and thermophysical properties of developed nanostructured wear-resistant coating with high strength characteristics, resistance to shock and vibration loads on the surface of metal saw band for industrial instrumental and high-speed steel treatment. Studies are shown on the example of one of the cutting on band-cutting machines, using closed band saws as cutting tools made of spring-spring steels with obtained carbide cutting edges. It is known that the operating conditions of a band saw include such characteristics as increased vibration resistance, resistance to alternating and dynamic loads, as well as increased wear resistance. This article presents the results of the thermal effect on the characteristics of the developed wear-resistant nanostructured coating on the surface of the cutting edge of a band saw tooth for metalworking.

Nanostructured wear-resistant coating for the composite turning inserts

The article presents the results of study of microstructural and strength properties of developed nanostructured wear-resistant high-hardness coating with high strength characteristics, resistance to shock and vibration loads on the surface of cutting inserts for instrumental and high-speed steel turning treatment. The specificity of the turning operating conditions of the composite cutting tool inserts shows that the cutting inserts working surface should have such characteristics as high hardness, strengths, increased vibration resistance, resistance dynamic loads and thermal shock, as well as increased wear resistance. Therefore, one of the ways to solve this problem proposed in the report is applying a wear-resistant hard oxide phase nanostructured coating on the surface of the cutting edge of the composite cutting inserts. Technological modes were selected for the wear-resistant hard protective coating which provides high microhardness due to the nanostructure by magnetron sputtering deposition of the developed compositions that have high adhesion to substrates made of composite cutting turning inserts. The results are shown on the example of high-speed turning of 30KhGSA by using composite turning inserts with developed nanostructured wear-resistant hard protective coating.

Solid-state phase transformation of ductile cast iron during electroslag remelting cladding

ABSTRACT A bimetallic composite roll with the cladding layer of high-speed steel (HSS) and the roll core of ductile cast iron (DCI) was manufactured by the electroslag remelting cladding (ESRC) technology, and the changes in the graphite morphology, matrix structure, and mechanical properties of the DCI core before and after the ESRC process were compared. The DCI core was first heated to a very high temperature and then cooled down to room temperature during ESRC which led to a deteriorative graphite morphology with a low spheroidisation rate, a large size, and a nonuniform distribution and also caused a solid-state phase transformation of the matrix structure from lamellar pearlite + few carbides to bainite + large amounts of carbides. Based on the changes of graphite sphericity, matrix structure, carbides content, the tensile strength and impact toughness of DCI before and after the ESRC process changed from 458 MPa, 3.02 J/cm2 to 417 MPa, 5.74 J/cm2, respectively.

Uncovering process-structure relationships associated to the hot isostatic pressing of the high-speed steel PMHS 3-3-4 through novel microstructural characterization methods

Gaining insight into the many agents that determine the underlying material microstructure is essential to engineer new and efficient solutions. Tool steels resistant to abrasive wear are particularly interesting because it is possible to tailor their macroscopic properties by adjusting some of the primary carbide phase features: micromechanical properties, volume fraction, size, and shape. For many popular ledeburitic cold-work and high-speed tool steel alloys, there is a generally good understanding of the effects of the HIP temperature, pressure, and holding time on these traits. Nevertheless, there is still no thorough investigation on the influence of powder size distribution on the primary carbide phase. To that end, we employ in this work novel microstructural characterization methods that shed light on the nature and extent of its influence. We show that powder size has an enduring effect on primary carbide geometric features associated with the solidification process during powder atomization. This work contributes significant process-structure links, which uncover new opportunities for microstructural design.

Design of a TiAlON multilayer coating: Oxidation stability and deformation behavior

During the cutting of high-speed steel, thermal and mechanical loads occur. Thin hard coatings like TiAlN deposited by physical vapour deposition (PVD) are applied on the tool surface to prevent wear and oxidation. In the scope of this article, a multilayer coating concept was developed to improve the cutting performance of the tools. It consists of a Ti bond coat, a TiN/AlN nanolayer as an interlayer and an oxynitride TiAlON toplayer. The manuscript presents results of the investigation on the influence of the oxygen content in the reactive gas flow during an industrial direct current/high power pulsed magnetron sputtering hybrid process on the coating properties and on the oxidation stability. The reaction layer forming after the PVD process under ambient atmosphere on the surface of hard coatings has a thickness of a few nanometers. The chemical composition of the coatings and of the reaction layer were measured using electron probe micro analysis (EPMA) and X-ray photoelectron spectroscopy (XPS), respectively. At a high oxygen content of y(O / (O + N) = 85% the oxynitride TiAlON shows the presence of both, crystal and amorphous phases, as proven by transmission electron microscopy. As investigated by nanoindentation, indentation hardness, indentation modulus and resistance against plastic deformation decrease with increasing oxygen content in the coatings. When the oxygen content increases from y = 49% to y = 85%, the oxidation stability decreases. This might be caused by a decreased aluminum ratio of the reaction layer of x(Al / (Al + Ti) = 73% compared to x = 49%.

Tribological behavior comparisons of high chromium stainless and mild steels against high-speed steel and ceramics at high temperatures

High-temperature tribology, which is often involved during hot metal forming, is controlled via oxidation on a rubbing surface. However, for high chromium stainless steel (ST), where oxidation is strongly inhibited, the effect of counterface materials on tribological behavior is yet to be elucidated. In this study, the effects of counterfaces on the tribological behavior of 253MA ST and mild steel (MS) are investigated via a ball-on-disc test at 900 °C using a 20 N load. The results reveal that high-speed steel (HSS) experiences severe abrasive wear with MS and causes severe sticking problems with ST. Si3N4 and SiC present substantially stronger abrasive wear resistance than HSS with MS, and the friction coefficients are dependent on the type of ceramic. Both ceramics can facilitate the establishment of a thick tribo-oxide layer (> 3 µm) on ST to prevent sticking; however, this is accompanied by severe pull-out and fracture wear. The effects of the counterface on the mechanical properties of the tribo-oxide layer, near-surface transformation, and the responses of the tribo-oxide layer to friction and wear are discussed. This study contributes to the understanding of interfacial tribological behaviors when different types of tools are used on MS and ST.

Optimization of Technological Parameters and Application Conditions of CMQL in High-Speed Milling 300M Steel

In order to study the influence of different lubrication conditions on cutting force, surface roughness and work hardening, single factor milling tests on 300M steel were carried out under five lubrication conditions of dry cutting, cryogenic cold air cutting, water mist cooling cutting, oil mist friction-reducing cutting and Cryogenic Minimum Quantity Lubrication (CMQL) cutting. Through orthogonal test under CMQL cutting condition, the influence of process parameters, such as cold air temperature, cold air pressure and cutting fluid dosage on workpiece surface quality and tool wear was studied, and the process parameters were optimized. Through the results of single factor and orthogonal tests, it is found that compared with other cutting conditions, CMQL cutting condition can get lower surface finish, work hardening and smaller cutting forces. And compared with other influencing factors, cold air pressure was the most important influencing factor in high-speed milling 300M steel under CMQL cutting condition, and its optimal value was 0.6 mpa.

Повышение эффективности концевого алмазного абразивного инструмента на металлической связке за счет совершенствования технологии изготовления

Introduction. Difficult-to-machine materials with enhanced physical and mechanical properties are increasingly being used in various industries. Such materials are used in mechanical engineering for the manufacture of parts and assemblies of machines and mechanisms, in the production and processing of food products where increased operational requirements are required. In modern production, along with traditional methods of intensifying technological operations, combined and hybrid processing technologies are used. For the finishing of products, abrasive grinding with a diamond tool is used. One of the problems hindering the wide practical application of this method in industry is the fact that it has a high prime cost caused by the cost of materials used in the manufacture and the laboriousness of the tool shaping process. This leads to the need to develop a new technology for manufacturing diamond tools. The purpose of the work is to increase the efficiency of the end diamond abrasive tool with a metal bond by using carbon steels as a body material, increasing the strength of the connection between the body and the diamond-bearing part, as well as choosing an effective tool manufacturing technology. Research methodology. To gain this task, a technology for manufacturing end diamond abrasive tools is developed and tested. Allowing using the technology of capacitor welding to connect the diamond-bearing part with the shank and use medium-carbon hardened high-quality steels with a hardness of 45-60 HRC as the shank material. The strength of the connection of the body with the working diamond-bearing part of the grinding head samples is determined by tensile testing on a 1958U10 tensile machine with maximum load 100 kN. The quality of the joint is assessed visually by the presence of discontinuities in the joint, as well as by examining the microstructure and measuring the microhardness of the weld and heat-affected zones. The microhardness of the welded joint is measured using an HMV-G21ST semi-automatic microhardness tester (Shimadzu, Japan) at a load of 50 g. Results and discussion. Thus, the results of comparative studies allow us to assert that the strength of the connection between the shank and the working diamond-bearing part according to the proposed technology surpasses similar characteristics of the strength of the connection between the shank and the diamond-bearing layer of grinding heads obtained by the method selected by the prototype. Conclusions. The proposed technology for the manufacture of diamond heads increases the strength of the connection between the body and the diamond-bearing working part, reduces the cost of manufacturing the grinding heads due to the use of hardened medium-carbon steels as the material of the tool body instead of high-speed steel grades, the technology is simplified and the possibility of automating the manufacture of tools appears.