High-speed Tool Steel Research Articles

レーザを用いた再溶融処理によるLMD肉盛層の内部欠陥除去

In recent years, Laser Metal Deposition (LMD), in which metal powders are injected into the molten pool created by laser irradiation and overlay welding is performed, has been attracting attention as a new technology for metal 3D printers. However, it is difficult to select the conditions for obtaining good quality in LMD using high-speed tool steel powder, and internal defects such as blowholes and lack of fusions are likely to occur. Therefore, laser remelting process was attempted to remove these internal defects in the overlay layer of high-speed tool steel. The purpose of this study is to perform laser remelting after LMD using the same equipment and to select remelting conditions that can remove internal defects. In the remelting process using the overlay layer of high-speed tool steel, the inter-pass temperature at which blowholes and lack of fusions could be removed without irregular surfaces was about 300～400℃. The remelting conditions were 2 kW laser power, 4 mm/s scanning speed, and 5 passes of laser irradiation × 4 times. Furthermore, the average hardness increased from 588 HV to 702 HV, and the non-uniformity of hardness was reduced.

Dynamic Alloying of Steels in the Super-Deep Penetration Mode.

The dynamic effects observed in collisions represent a specific area of high-energy interaction located at the boundary of mechanics, hydrodynamics, shock wave physics, and alternating high-pressure regions. The paper shows that in the volume of a solid metal body, as a result of dynamic alloying by a high-speed stream of powder particles in the super-deep penetration mode (SDP), fiber structures of altering material arise, forming the framework of the composite material. The stream of powder particles in the metal obstacle following the path of least resistance and the impact of shock waves on particles results in a volumetric framework from the products of interaction between the injected and matrix materials. When using SDP, defective structural elements (channeled)—germs of reinforcing fibers arise. At the subsequent heat treatment, there is an intensive diffusion. The growth process of reinforcing fibers shifts to higher temperatures (as compared to the standard mode), leading to an increase in the bending strength of the fiber material up to 13 times for W6Mo5Cr4V2 high-speed tool steel. As a result of the completion of the growth of reinforcing fibers in the volume of the W6Mo5Cr4V2 high-speed tool steel, the material’s bending strength in 1.2 times is realized. Simultaneously, it provides an increase of wear resistance 1.7–1.8 times.

Adapting the Surface Integrity of High-Speed Steel Tools for Sheet-Bulk Metal Forming

New manufacturing technologies, such as Sheet-Bulk Metal Forming, are facing the challenges of highly stressed tool surfaces which are limiting their service life. For this reason, the load-adapted design of surfaces and the subsurface region as well as the application of wear-resistant coatings for forming dies and molds made of high-speed steel has been subject to many research activities. Existing approaches in the form of grinding and conventional milling processes do not achieve the surface quality desired for the forming operations and therefore often require manual polishing strategies afterward. This might lead to an unfavorable constitution for subsequent PVD coating processes causing delamination effects or poor adhesion of the wear-resistant coatings. To overcome these restrictions, meso- and micromilling are presented as promising approaches to polishing strategies with varying grain sizes. The processed topographies are correlated with the tribological properties determined in an adapted ring compression test using the deep drawing steel DC04. Additionally, the influence of the roughness profile as well as the induced residual stresses in the subsurface region are examined with respect to their influence on the adhesion of a wear-resistant CrAlN PVD coating. The results prove the benefits of micromilling in terms of a reduced friction factor in the load spectrum of Sheet-Bulk Metal Forming as well as an improved coating adhesion in comparison to metallographic finishing strategies, which can be correlated to the processed roughness profile and induced compressive residual stresses in the subsurface region.

Duplex surface modification of tool steel - deposition of a WN film and subsequent electron-beam modification

In this study, we demonstrate a combined treatment technique of R18 high-speed tool steel comprising deposition of a WN coating followed by electron-beam surface treatment (EBT). In order to understand the influence of the deposited WN coating on the resultant structure and properties, an uncoated specimen was directly electron-beam treated under the same EBT technological conditions. The structure of the specimens was studied by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The microhardness was also investigated. The phase composition consisted of a double phase structure of Fe and M6C carbides in both cases. The microstructure was significantly finer in the case of an EBT of the steel with WN coating, leading to a much higher microhardness in comparison with the case without WN.

Impact of Deposition of the (TiBx/TiSiyCz) x3 Multilayer on M2 HSS on the Cutting Force Components and Temperature Generated in the Machined Area during the Milling of 316L Steel.

High-speed steel (HSS) tools account for 20 percent of the cutting tools materials’ global market. This is due to both their significant toughness and resistance to cracking, compared to cemented carbides. Covering steel tools with hard coatings clearly improves their mechanical properties, wear resistance, and significantly increases their durability. Physical vapor deposition methods are preferred for coating metal substrates, as they allow low temperature deposition. The most widely deposited coating materials are carbides, nitrides, and borides. They are combined with softer ones in the multilayer structure to promote increased resistance to cracking and delamination in comparison to monolayered structures. In this paper, the M2 steel end mills were coated by (TiBx/TiSiyCz) x3 multilayer by the pulsed laser deposition method. Coated and uncoated tools were tested in the cylindrical down milling of AISI 316L steel. Components of the cutting force and temperature generated in the machined area during dry milling were measured under two variants of operating conditions: V1 and V2. Tool wear mechanism was examined using scanning electron microscopy (SEM), accompanied by EDS analysis of worn areas. It was found that milling with higher speed (variant V2) is accompanied by lower cutting force components and a lower temperature generated in cutting area. The presence of the coating allowed lower cutting forces and temperature in the case of variant V1. The temperature measured during milling did not exceed 200 °C. The SEM observation of the edges of cutting tools indicated that the main mechanism of wear for both types of tools was abrasion. The built-up edge formation was observed in the case of tools tested at the V1 cutting parameters variant. It was assumed that it was the reason for higher cutting forces measured during milling according to this variant. The chemical composition of built-up edges was different for coated and uncoated tools. Tribo-chemical reactions were responsible for the reduction of the cutting force and temperature components observed during milling with a coated tool at V1 variant. Boron and titanium were the elements of the coating that enabled the tribo-oxidation reactions thanks to which friction was reduced. Our results show that this beneficial effect occurs with (TiBx/TiSiyCz) x3 coated tools, but can easily be lost with inadequately selected cutting parameters.

Design of cycle structure on microstructure, mechanical properties and tribology behavior of AlCrN/AlCrSiN coatings

AlCrN/AlCrSiN coatings with cycle structure, composed of fcc-CrN, hcp-AlN and amorphous Si3N4 phases, were fabricated to protect high speed steel (HSS) tools by high energy ion source enhanced multi-arc ion plating technology with Al70Cr30 and Al60Cr30Si10 alloying targets. With the increasing cycle structure, the crystal grains of AlCrN layers was refined from 60–110 nm to 8–15 nm, and the growth behavior transformed from (200)fcc to the coexistence of both (200)fcc and (111)fcc preferred orientation as demonstrated by GIXRD spectrum, calculated texture coefficient and HRTEM results. The HRTEM results investigated that the inter-planar spacing of CrN(111) was basically equal to that of AlN(0002) with parallel orientation relationship and the interface-1 between the substrate and adhesion layer with a semi-coherent appearance presented a specific orientation relationship. The coating with two cycle structure (Cycle 2) possessed better adhesion strength (HF1 grade, 62.7±1.3 N of Lc2), higher hardness (30.2±1.7 GPa), better fracture toughness (0.099 of H/E, 0.29 GPa of H3/E2 and 9.8±0.3 MPa m1/2 of KIC under 20 kgf loading), lower friction coefficient (0.54), less wear rate (4.2 × 10−16 m3/N·m) and longer service life (7.4 m).

Vol4 nim2-13 Topographic and dimensional study of thermostable polyurethane material mechanized by robotic machining

The thermostable polyurethane is a material used in the modeling sector and is currently replacing structural parts in control models of the automobile and aeronautics sector, for its ease of machining, in addition to providing good mechanical properties.  In this work a robotic machining of a commercial polyurethane material type Necuron® 651 has been experienced. Robotic machining offers a wide possibility of machining and modeling materials with the advantage of increasing the accessibility to pieces, compared to conventional machining centers of three or more axes. Machining has been carried out with a system consisting of a ABB® 6640-235 robot with a Peroni® high speed head and ABB rotary table. The disadvantage of robotic machining, caused by the lack of rigidity of the robot's morphology, are macro and micro-dimensional errors. Simple geometries with high speed steel tools have been made. The CAM programming has been obtained with the Software Powermill® of the company DELCAM, taking into account two types of strategies for limiting the freedom degree of the robot, to verify geometric results. Finally it has been measured and analyzed the surface generated by interferometer autofocus Alicona and has been measured the geogeometry of the samples in a coordinate measuring machine machine. The results show that both micro and macro errors are significantly reduced by making fixed one of the seven axes of the robotic system.

Experimental study of TiN, TiAlN and TiSiN coated high speed steel tool

In the machining process, high-speed steel cutting tool is important for fabricate the any product in the manufacturing sector. However, high-speed steel is still unable to meet the requirements in some conditions. Coating is one of the methods used to enhance the cutting tool performance. Tool coating extends tool life, improves cutting quality, and increases tool durability. The deposition and properties of coated molybdenum High speed steel tools are described in this experimental investigation.

Effect of Strain Rate on Compressive Properties of High-Speed Tool Steel

In the present study, the effect of strain rate on compressive properties of high-speed tool steel was experimentally investigated. It is not easy to obtain the stress-strain relationship under high-speed deformation since high-speed tool steel has very high strength. In order to carry out the impact compressive test of high-strength materials, we developed the split Hopkinson bar (SHB) compression test apparatus using cemented carbide for the elastic bar. The impact test was obtained at the strain rate of 103 s-1. The quasi-static test was carried out at strain rates of 10-3 to 10-1 s-1. Both tests were conducted under three temperature conditions, 298 K, 201 K, and 77 K. Within the set of experiments, almost all specimens showed an increase in flow stress with increasing strain rate (strain rate dependence of material strength) was confirmed. However, the impact test at 77 K showed that the effect of work softening was greater than the strain rate dependence of strength.

Multi-Criteria ranking algorithm for high quality of products in high performance drilling Operation: A case study for considering the Wide-Web and Cryo treated drills

Among the most commonly used tools in the industrial business, high-speed steel (HSS) tools rank first. A large web thickness and cryogenic treatment were used to obtain the most significant improvements in machining quality with the HSS tool. The results of this study are presented in this publication. Being stiffer in nature than normal drills, they have always had the ability to drill straighter, deeper, and more exact hole diameters than standard drills. Furthermore, wide-web drills often allow for feed rates that are approximately 20% faster than standard drills, and the strength of a wide belt makes it the ideal tool for deep cuts in hard materials. On the basis of a multi-criteria classification technique, this study discusses how to select the appropriate process parameter to obtain the highest possible level of drilling quality. These findings concern the optimization of drilling settings utilising a strategy to get the lowest possible deviation from cylindricity, surface roughness (Ra), roundness error, and burr. Cylindricity, surface roughness (Ra), roundness error, and burr are all considered in this study. Mistreating the L9 orthogonal die on the CNC milling machine resulted in a series of drilling trials, which were then recorded. The traces were made on the ZE41 block, which was produced by gravity die casting, with a cutting tool of a 4 mm diameter treated HSS drill, which was employed during experimental work in dry cutting circumstances to make the traces. The Combinative Distance-based ASsessment (CODAS) and ANOVA were used to determine the main spindle speed, feed rate, web thickness, Pont Angle, and Cryogenic Treated Drill Tools that had an impact on the response were determined. It is investigated whether information factors have a main or cooperative effect on normal reactions.

Optimization of magnesium ZK60A/SiC/B4C hybrid composite fabricated by friction stir processing

Friction stir processing (FSP) is a surface modification approach that may enhance microstructures, and remove processing flaws. Thereby to improve mechanical properties like strength, ductility, corrosion-resistant and fatigue, FSP was introduced. In this research, microstructural analysis, hardness, and optimization of developed magnesium hybrid composite were analyzed using process parameters i.e. tool tilt angle (10,20,30), %wt. of reinforcement (SiC/B4C), and rotational speed (600, 1000, 1400 rpm). High-speed steel (HSS) tool is used having a threaded pin with scrolled shoulder (TPSS). The results revealed that SiC and B4C particles are uniformly distributed in the Mg matrix. No defects were observed. To enhance the process variables, L9 orthogonal array was implemented. Weight percentage has more impact on hardness as compared to tool tilt angle and rotational speed. The acceptable mean value of hardness (µHD) is 90.35 HRB.

Diminution of chatter vibration in single point cutting tool holder using finite element analysis (FEA)

The present paper demonstrates the modal and harmonic response analysis of a single point cutting tool using the Finite Element Analysis (FEA). In this current research, the High-Speed Steel (HSS) tool holder has been coated using epoxy-granite for different square shanks. The coating ranges from 1 to 5 mm for both variable (a mm × a mm) and fixed (27 mm × 27 mm) square shank. Furthermore, the graphs between amplitude and frequency have been plotted for evaluating the damping ratio by using half power bandwidth theory. From modal and harmonic analysis, a maximum damping ratio of 0.2227 and 0.136 is achieved by using a 5 mm layer coating of epoxy-granite for variable (17 mm × 17 mm) and fixed (27 mm × 27 mm) square shank respectively. The amplitudes for variable and fixed square shanks utilizing 1 mm coating of epoxy-granite are relatively close i.e., 1.19E + 06 mm/s2 and 1.21E + 06 mm/s2 respectively. The damping ratio increases significantly for 1 mm coating in both variable and fixed square shanks (0.0900 and 0.0974) in comparison to the bare tool holder (0.0006).

Effect of MC-type Carbide on Belag Formation of High Speed Tool Steel

Effect of MC-type Carbide on Belag Formation of High Speed Tool Steel

Microstructural investigation on friction stir welded AA6063 pipe

Friction stir welding (FSW) is a solid-state joining technique that has came out as an excellent welding technology for almost all difficult to weld materials and for various weld joint configurations. However, pipe welding remains very challenging due to low contact surface area between the tool and pipes to be welded. In the present work, FSW was carried out on AA6063 aluminium pipes using high speed steel tool of tapered cylindrical tool pin geometry. During experimentation, the rotational speed of 1120 rpm was used while the pipes were rotated at a speed of 1.57 mm/s. Two passes of FSW were performed to weld the pipes and their effect were investigated on the microstructural evolution and the microhardness. The microstructural examination revealed the big sized tunnel defect in the cross-section of welded region in one pass welded sample. With repeated/second pass on the pipe the tunnel size was substantially reduced. Microstrucral characterization confirmed the presence of all characteristically different regions of FSW with refined and equiaxed grain structure in stir zone. Microhardness profile for both samples shows similar trend.

Microstructure and Machinability of Laser Cladding Co-WC on High Speed Steel Tools for Numerical Control Machine Tools

Microstructure and Machinability of Laser Cladding Co-WC on High Speed Steel Tools for Numerical Control Machine Tools

UDDEHOLM VANADIS 60 SUPERCLEAN

Abstract Uddeholm Vanadis 60 SuperClean is a cobalt-bearing high-speed tool steel that is produced by the powder metallurgy process. It is suitable for demanding cold work applications and for cutting tools, where the highest wear resistance and highest compressive strength are required at the same time. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on heat treating and machining. Filing Code: TS-823. Producer or source: Uddeholms AB.

Study on Equilibrium and Nonequilibrium Solidification of Boron-Containing High-Speed Tool Steel: Effect of Cooling Rate and Microstructure Investigation

Study on Equilibrium and Nonequilibrium Solidification of Boron-Containing High-Speed Tool Steel: Effect of Cooling Rate and Microstructure Investigation

Thermal Investigation on Coated and Uncoated HSS Twist Drill using ANSYS Software

Abstract: In drilling, a cylindrical hole is produced in workpiece, removing the material inside the workpiece. The cutting tool used in drilling operation is called ‘Twist Drill’; it rotates and allows the material to be removed from the workpiece in the form of chips and thus drill the hole. Cutting fluids or coolants are used to perform this operation smoothly. The coating on the drill bits helps to reduce friction in the cut and the heat buildup in the drill bit. Coating also helps in protecting against corrosion. The present work focuses on the features of uncoated High Speed Steel (HSS) Twist Drill bit and Titanium Nitride (TiN) and Titanium Aluminium Nitride (TiAlN) coated on HSS Drills. The workpiece material was Mild Steel and the drilling operation was done using normal machining condition i.e. in presence of coolant. The cutting parameters used are cutting speed (35.5 m / min), spindle speed (1500 rpm), feed rate (0.2 mm / rev.), depth of cut (10 mm). These parameters were kept constant. Temperatures were measured with the help of thermal imaging camera and with the help of ANSYS software thermal analysis were done. Experimental results showed that the average rise in temperature of uncoated HSS tool was higher as compared to TiN coated and TiAlN coated HSS tools. TiAlN coated drills showed the least average rise in temperature. Keywords: High Speed Steel (HSS) Drill, TiN and TiAlN Coated HSS Twist Drill, Mild Steel (MS), Thermal Analysis, ANSYS Software.

Improving the mechanical properties of tool steel by induction chemical-thermal treatment

The study results of the structure and microhardness of the surface layer of high-speed tool steel after induction chemical-thermal treatment in a gaseous nitrogen-containing medium at a temperature of 900–1100 °C were presented. Due to the strengthening treatment of products a gradient diffusion nitride layer with a thickness of about 200 μm and a surface microhardness of 1950±70 HV1 98 was formed.

Microstructure, Mechanical Properties, and Thermal Stability of Carbon-Free High Speed Tool Steel Strengthened by Intermetallics Compared to Vanadis 60 Steel Strengthened by Carbides

High speed tool steels are materials that exhibit superior mechanical properties (e.g., high hardness). They should also be resistant to thermal exposure to maintain high hardness during the machining process. In this paper, a C-free tool steel formed of Fe matrix and a Mo6Co7 intermetallic phase was studied. This steel was compared to the well-known Vanadis 60 steel containing Fe matrix and carbides. Microstructures were investigated by scanning (SEM) and transmission (TEM) electron microscopy, and the mechanical properties and thermal stability of both materials were compared. It was proven that the strengthening in the Vanadis 60 steel was mainly caused by the carbides, while the C-free steel was strengthened by the Mo6Co7 phase. The hardness values of both materials were comparable in the utilization state (approx. 950 HV). The hardness of Vanadis 60 steel decreased after several minutes of annealing at 650 °C under the value that enables material utilization. The hardness value of the steel strengthened by the intermetallics also decreased but significantly slower. Based on these results, the main finding of this study is that the C-free steel exhibited much better thermal stability and may be utilized at higher temperatures for longer periods of time than Vanadis 60.