High Speed Steel Research Articles

Study on Microstructure, Mechanical Properties, Tribological Properties and Service Performance of CrAlN and CrAlBN Coatings Deposited on Powder Metallurgy High-Speed Steel (PM-HSS) and Shaper Cutter by Arc Ion Plating Technique

CrAlN and CrAlBN coatings were prepared on the surface of high-speed steel and shaper cutter by physical vapor deposition (PVD) technique using arc ion source. In the process of coating preparation, the adhesive layers were deposited by low bias voltage (−40 V) and the working layers are deposited by high bias voltage (−130 V). The effects of the addition of B element on the microstructure, hardness, elastic modulus and wear resistance of CrAlBN coating were studied. The results show that B element and its compounds exist in amorphous form in the coating, resulting in lattice distortion of the coating, increase of coating hardness to 37.1 GPa, and decrease of elastic modulus to 406.2 GPa. The addition of B element increases the uniformity of the columnar structure distribution and decreases the width of the columnar structure and grain size. The resistance to elastic deformation and plastic deformation of CrAlBN coating is improved, the wear resistance is improved. The performance of CrAlN and CrAlBN coatings on shaper cutter was studied. It was found that the main failure mode of shaper cutters is boundary wear and the wear mechanism of coatings had changed obviously. CrAlBN coating is mainly due to fatigue induced failure, accompanied by some diffusion wear. The addition of B element makes the CrAlBN coating have excellent resistance to oxidative wear, abrasive wear and diffusion wear during cutting. The results show that the addition of B element can improve the microstructure and mechanical properties of CrAlN coating, and the preparation of CrAlBN coating on the surface of the shaper cutter can significantly improve the service life of the coated shaper cutter, which has significance for the development of the shaper cutter industry.

Synthesis and characterization of titanium-titanium nitride deposition on SS-CRM 487/1 high speed tool steel

ABSTRACT The present study uses DC magnetron sputtering for synthesis of a TiN and Ti-TiN bilayer on the surface of SS-CRM 487/1 high-speed tool steel. This coating is deposited on the substrate at 400°C. The deposited substrate is characterised by different experimental techniques. The scanning-electron microscopy (SEM) is used for film morphology, cross-sectional examination, and worn-out surfaces. The profilometer is used for measuring the film thickness and roughness. However, the nano-indentation is used to extract the intrinsic hardness and young’s modulus evaluation. The ball on-disc sliding test under dry conditions is employed for tribological properties of deposited high-speed tool steels. The test results indicate the improvement in the wear resistance for the Ti-TiN bilayer except four bilayers as no of layer increases.

Machinability studies of Al–4Mg/ in-situ MgAl2O4 nano composites: measurement of cutting forces and machined surface roughness

Abstract The present research is to study the dry turning machinability characteristics of in situ Al-4Mg/MgAl2O4 nanocomposite by High-Speed Steel tool. The influence of various machining process parameters, such as feed rate, depth of cut and cutting speed on the surface roughness and cutting force of the nanocomposites was measured while performing dry turning. From the turning operation results, it is noticed that up to 100 m/min, the cutting force increased and with further increases in cutting speed, the cutting force starts decreasing up to 150 m/min. Using a scanning electron microscope, the type of chips and built-up edge (BUE) development were studied. Formations of BUE were noticed to be higher at low cutting speeds (50 m/min) and lower at high cutting speeds (150 m/min). At a given depth of cut and feed rate, with an increase in cutting speed, the length of the chip and chip curls increased. Further, higher 2 wt.% of in-situ MgAl2O4 addition changes long-curled chips to segmental type chips. With a feed rate of 0.14 mm/rev, the Al-4Mg / 1wt% MgAl2O4 nanocomposite showed the lowest surface roughness value of 2.4 µm proving usage of high speed steel can provide better surface finish while turning Al-4Mg / MgAl2O4 nanocomposite.

Characteristics and Formation Mechanism of Oxide–Sulfide Complex Inclusions in High-Speed Railway Wheel Steel

Characteristics and Formation Mechanism of Oxide–Sulfide Complex Inclusions in High-Speed Railway Wheel Steel

Ssessment of cutting fluids supplying method influence on contact processes when drilling stainless steel 12Х18Н10Т

The authors have considered the process of blind holes processing during drilling operations when processing stainless steel 12Х18Н10Т. Spiral drills made of high-speed steel were used as cutting tools. There are some typical problems in this process such as difficulty of removing chips and cutting fluids supply to the machining zone. One more problem is that while removing chips along spiral grooves, they rub against the surface of the hole and thus become deformed, which results in the deterioration of surface quality. Therefore, a comparative assessment of various coolants influence was carried out depending on the method of their supply under closed cutting conditions.

Enhancing the Cooling Efficiency of Aluminum-Filled Epoxy Resin Rapid Tool by Changing Inner Surface Roughness of Cooling Channels.

In low-pressure wax injection molding, cooling time refers to the period during which the molten plastic inside the mold solidifies and cools down to a temperature where it can be safely ejected without deformation. However, cooling efficiency for the mass production of injection-molded wax patterns is crucial. This work aims to investigate the impact of varying surface roughness on the inner walls of the cooling channel on the cooling efficiency of an aluminum-filled epoxy resin rapid tool. It was found that the cooling time for the injection-molded products can be determined by the surface roughness according to the proposed prediction equation. Employing fiber laser processing on high-speed steel rods allows for the creation of microstructures with different surface roughness levels. Results demonstrate a clear link between the surface roughness of cooling channel walls and cooling time for molded wax patterns. Employing an aluminum-filled epoxy resin rapid tool with a surface roughness of 4.9 µm for low-pressure wax injection molding can save time, with a cooling efficiency improvement of approximately 34%. Utilizing an aluminum-filled epoxy resin rapid tool with a surface roughness of 4.9 µm on the inner walls of the cooling channel can save the cooling time by up to approximately 60%. These findings underscore the significant role of cooling channel surface roughness in optimizing injection molding processes for enhanced efficiency.

Microstructure and antibacterial properties of AlCrTiZrWN high-entropy alloy nitride synthesized using HiPIMS under various N2/Ar flow ratios

This paper reports on the use of high-power impulse magnetron sputtering (HiPIMS) to deposit (AlCrTiZrW)Nx high-entropy alloy (HEA) nitride films to a thickness of 1 μm on SKH-9 high-speed steel, SUS304 stainless-steel, and Si wafers. The primary aim was to elucidate the effects of N2/Ar flow ratio (from 10/100–150/100 sccm) on the structure of the resulting materials and antibacterial properties. Co-sputtering was performed using multiple simultaneous targets to overcome the difficulties in manufacturing HEA targets at industrial scales. XRD analysis revealed a FCC structure with (111) orientation under nitrogen gas flow of 70 sccm. Increasing the nitrogen flow to 90 sccm shifted the preferred orientation to the (200) direction. The highest water contact angle (113°) and highest hardness value (27.6 GPa) were achieved under a nitrogen flow of 70 sccm, while the best Rp value (22.7 × 105 Ω‧cm2) was achieved under 110 sccm. The antibacterial performance of the coated samples exceeded that of uncoated SUS304 stainless-steel. Overall, the incorporation of nitrogen had positive effects on HEA film properties.

Effect of nano-SiC on microstructure evolution and enhanced high wear resistance mechanism of laser surface alloyed M42 high-speed steel

M42 high-speed steel is one of the main materials for preparing bimetallic band saw parts. In this paper, nano-SiC particles of different densities (0–1.00 mg/mm2) were precoated on the surface of M42 high-speed steel samples, then, the samples were prepared by laser alloying. The matching relationship between the quantity, size, and type of martensite and MxCy carbides in laser alloyed samples play a decisive role in improving wear resistance. It is found that under the optimized particle density of 0.75 mg/mm2, compared with M42 high-speed steel, the hardness was increased by 50%, the wear rate decreased by 84.7%. The matching relationship between Martensite and MxCy carbides formed by laser alloying of nano-SiC particles on the improvement of wear resistance was elucidated.

Simulation and Optimization of Surface Roughness and Process Performance during Machining of HSS by Micro-WEDM Technology.

When machining high-speed steels (HSS) with micro-wire electrical discharge machining (micro-WEDM), high surface quality is achieved as standard. The value of the roughness parameter Ra is less than 0.2 μm. However, the problem is the performance of the electroerosion process (MRR), which is low. This problem is related to the mechanical and physical properties of the HSS in combination with the setting of the main technological parameters (MTP). The proposed solution to eliminate this problem relies on the selection of proper procedures for the determination of optimization criteria in relation to Ra and MTP, with the inclusion of properties of the machined material. The solution consisted in the identification of four significant physical (ρ, κ) and mechanical (Rm, HRC) indicators of HSS properties, on the basis of which a suitable combination of the process output parameters Ra and MRR can be determined through established mathematical regression models using simulation and optimization. In the next step, the proper values of the MTP output process parameter settings, which correspond to the optimized output parameters Ra and MRR during machining of HSS by micro-WEDM technology, were then obtained by the same approach.

Effect of Tempering on Structure and Properties of Plasma Surfacing of R2M9U High-Speed Tool Steel

Effect of Tempering on Structure and Properties of Plasma Surfacing of R2M9U High-Speed Tool Steel

Effect of Cryogenic Time on Wear Resistance of M2 High Speed Steel

The wear resistance, residual austenite volume and carbon content in martensite of M2 steel were studied by means of universal vertical friction and wear testing machine, X-ray diffractometer (XRD), scanning electron microscope (SEM) and digital Rockwell hardness tester. The results show that a large number of fine carbide particles in M2 steel martensite are precipitated by cryogenic treatment and distributed uniformly and diffusely in the structure. With the increase of cryogenic time, the residual Austenite volume of M2 steel gradually decreases, while the Martensite volume increases, resulting in the wear resistance and Rockwell hardness increasing first and then decreasing. After 24 hours of cryogenic treatment of M2 steel, its wear resistance increased by 310%, hardness increased by 3.6%. Therefore, 24 hours is confirmed as the best cryogenic treatment time for the wear resistance and hardness of M2 steel.

Study on Forming Mechanism of the Recast Layer on the Workpiece Surface during Micro EDM.

In comparison to conventional EDM, micro EDM distinguishes itself through its brief discharge duration, narrow discharge channel radius, and concentrated energy density. However, there remains a paucity of comprehensive research on the surface formation characteristics in this domain. This paper delves into the formation mechanism of the recast layer in micro EDM workpieces, scrutinizing the primary factors that influence the formation process and the morphological attributes of the recast layer. We conducted a series of single-pulse experiments and micro EDM trials. Utilizing surface fitting tools, our experimental findings facilitated the derivation of a relational expression between the recast layer thickness of high-speed steel and the discharge parameters in micro EDM. Notably, when the energy is below 100 μJ, the recast layer thickness remains under 10 μm. Specifically, at an energy level of 16 μJ, opting for a smaller capacitance of 2200 pf and a higher voltage of 120 V in micro EDM results in a thinner recast layer. This study serves as a cornerstone for future efforts aimed at controlling and assessing the surface morphology of micro EDM.

Effect of In Situ NbC-Cr7C3@graphene/Fe Nanocomposite Inoculant Modification and Refinement on the Microstructure and Properties of W18Cr4V High-Speed Steel.

A novel graphene-coated nanocrystalline ceramic particle, iron-based composite inoculant was developed in this study to optimize the as-cast microstructure and mechanical properties of W18Cr4V high-speed steel (HSS). The effects of the composite inoculant on the microstructure, crystal structure, and mechanical properties of HSS were analyzed using transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The (002-) and (020) crystal planes of the Fe3C and Cr7C3 phases, respectively, were collinear at two points in the reciprocal space, indicating a coherent relationship between the Fe3C and Cr7C3 phases in the tempered modified HSS. This contributed to an improved non-uniform nucleation rate and refining of the HSS grains. The mechanical properties of the modified steel exhibited a general improvement. Specifically, the modification treatment enhanced the hardness of HSS from HRC 63.2 to 66.4 and the impact toughness by 48.3%.

Cutting edge preparation of micro end mills by PVD-etching technology

AbstractMicromilling tools face significant challenges in achieving cutting edge preparation by mechanical processes due to their small size. To address these limitations, a new approach for cutting edge preparation of micro end mills by physical vapor deposition (PVD) etching technology is presented. By adapting the etching strategy, which is conventionally used as pre-treatment process for PVD technology to clean and condition the surface of cemented carbide substrate, cutting edges of micromilling tools were successfully modified. The high-energy process variation by Advanced Arc-Enhanced Glow Discharge (AEGD) offers the possibility of achieving high material removal rates on the tool surfaces and thereby altering the cutting edge geometry. Fundamental investigations on material removal as well as on the effects on surface topography, sub-surface properties, and coating adhesion of a subsequently applied PVD coating are performed. To influence the topography and the cutting edge geometry, the preparation time tp and bias voltage UB were selected. Subsequently, the machining performance of the modified tools is evaluated in a micromilling process of the hardened powder-metallurgical high-speed steel AISI M3:2 with a hardness of 62 ± 1 HRC. For this purpose, micro end mills of cemented carbide with a diameter of D = 1 mm were conditioned, achieving asymmetric geometric properties of cutting edges with varying average cutting edges rounding of $${\overline S}$$ S ¯ = 5.8 … 14.8 µm and a form-factor of K = 2.0 … 2.7. Based on the application tests a positive influence on the process forces was found. Thus, an efficient approach to cutting edge preparation can be identified by specifically designing ion etching in the PVD coating process.

Investigation of the Mechanical and Tribological Properties of Diamond-Like Carbon Films on YG8 and High-Speed Steel Substrates with W Buffer Layers

Investigation of the Mechanical and Tribological Properties of Diamond-Like Carbon Films on YG8 and High-Speed Steel Substrates with W Buffer Layers

Effect of Tungsten Carbide Additions on the Microstructure, Mechanical, and Tribological Properties of M2 High-Speed Steel Matrix Composites

Effect of Tungsten Carbide Additions on the Microstructure, Mechanical, and Tribological Properties of M2 High-Speed Steel Matrix Composites

Effect of Alloying and Microalloying Elements on Carbides of High-Speed Steel: An Overview

In high-speed steel, carbides are essential phase constituents, which have a direct impact on engineering performance and qualities of high-speed steel. The formation, morphology, and distribution of carbides are dictated by alloying elements. In this paper, various types of carbides in high-speed steel are presented. The effects of different alloying elements such as C, W, Mo, Cr, and V on the formation of carbides in high-speed steel are discussed. Research progresses on carbide improvement by microalloying elements such as N, B, Mg, and rare earth (RE) elements are reviewed. It is reported that Cr promotes the precipitation of M2C, N enhances the formation of fibrous M2C, Mg effectively shatters the large-size carbide grid, Nb refines granular carbide MC, and rare earth elements encourage the formation of M6C, resulting in irregular M2C lamellae. The incorporation of microalloying elements improves the distribution and size of carbides and also refines the solidification structure of high-speed steel.

Structure and mechanical properties of TiCN-ZrCN multilayer coatings

The present study is focused on the design, deposition and characterization of nanoscale multilayer TiCN/ZrCN coatings obtained by cathodic-arc PVD technique. The multilayer coatings with the bilayer period’s thickness of 12 nm, 20 nm and 32 nm were deposited on stainless steel and high-speed steel substrates at temperature of 320°C in a mixture of N2 and CH4 gases. Scanning electron microscopy equipped with energy dispersive x-ray spectroscopy, was employed to investigate the top surface morphology, cross-sectional morphology, bilayer thickness and structure of the coatings. Mechanical properties were investigated via Calotester, Nanoindentation tester, Scratch tester and Tribometer. The SEM/EDS cross-sectional analysis revealed a columnar morphology and well expressed multi-layered periodic structure. All the multilayer samples demonstrated an increase in hardness and well fracture resistance ability in comparison to TiCN and ZrCN monolayer coatings. The highest nanohardness of 41GPa and better wear resistance for the coatings with bilayer period of 12 nm was determined. The results of the study show that a reduction in the thickness of the individual sub-layers has a significant impact on the mechanical properties of the coatings.

Impact of Boundary Parameters Accuracy on Modeling of Directed Energy Deposition Thermal Field

Within the large Additive Manufacturing (AM) process family, Directed Energy Deposition (DED) can be used to create low-cost prototypes and coatings, or to repair cracks. In the case of M4 HSS (High Speed Steel), a reliable computed temperature field during DED process allows the optimization of the substrate preheating temperature value and other process parameters. Such optimization is required to avoid failure during the process, as well as high residual stresses. If 3D DED simulations provide accurate thermal fields, they also induce huge computation time, which motivates simplifications. This article uses a 2D Finite Element (FE) model that decreases the computation cost through dividing the CPU time by around 100 in our studied case, but it needs some calibrations. As described, the identification of a correct data set solely based on local temperature measurements can lead to various sets of parameters with variations of up to 100%. In this study, the melt pool depth was used as an additional experimental measurement to identify the input data set, and a sensitivity analysis was conducted to estimate the impact of each identified parameter on the cooling rate and the melt pool dimension.

Low friction behaviors of self-assembled GO/CMWCNTs composite films on high-speed steel

To reduce the energy loss of high-speed steel (HSS) rolls during the rolling process, coatings with effective friction reduction qualities were studied. In this paper, the magnetic stirring was used to prepare the composites of graphene oxide and carboxylated multi-walled carbon nanotubes (GO/CMWCNTs) with various mass ratios. By using 3-(aminopropyl)triethoxysilane (APTES) as a transition layer on hydroxylated-treated HSS, Si-O and C-N bonds were formed to obtain the assembled GO/CMWCNTs films. The results of the friction tests with Al2O3 ceramic balls indicate that the assembled GO/CMWCNTs-2 (1:2) films have an optimum friction reduction effect with the coefficient of friction of about 0.06 (about 83% lower than bare steel). Analysis of the wear mark surface reveals that the reason for the low friction behaviors is the formation of GO/CMWCNTs lubricating films with more sp2 content at the friction interface. The lubricating mechanism of the self-assembly films is to produce a stable multilayer film stacking system with layers joined by covalent bonds.