M2 Tool Steel Research Articles

Enhancing Quality Control: Image-Based Quantification of Carbides and Defect Remediation in Binder Jetting Additive Manufacturing.

While binder jetting (BJ) additive manufacturing (AM) holds considerable promise for industrial applications, defects often compromise part quality. This study addresses these challenges by investigating binding mechanisms and analyzing common defects, proposing tailored solutions to mitigate them. Emphasizing defect identification for effective quality control in BJ-AM, this research offers strategies for in-process rectification and post-process evaluation to elevate part quality. It shows how to successfully process metallic parts with complex geometries while maintaining consistent material properties. Furthermore, the paper explores the microstructure of AISI M2 tool steel, utilizing advanced image processing techniques like digital image analysis and SEM images to evaluate carbide distribution. The results show that M2 tool steel has a high proportion of M6C carbides, with furnace-cooled samples ranging from ~2.4% to 7.1% and MC carbides from ~0.4% to 9.4%. M6C carbides ranged from ~2.6% to 3.8% in air-cooled samples, while water-cooled samples peaked at ~8.52%. Sintering conditions also affected shrinkage, with furnace-cooled samples showing the lowest rates (1.7 ± 0.4% to 5 ± 0.4%) and water-cooled samples showing the highest (2 ± 0.4% to 14.1 ± 0.4%). The study recommends real-time defect detection systems with autonomous corrective capabilities to improve the quality and performance of BJ-AM components.

Effects of yttrium doping on high-temperature oxidation, friction, and wear properties of CrAlN films

This study investigates the deposition of CrAlYN nanomultilayer films with different yttrium (Y) contents on M2 tool steel and single-crystal Si wafer using unbalanced magnetron-sputtering ion-plating technology. Transmission and scanning electron microscopic and scanning morphologies, x-ray diffraction pattern, energy dispersive spectra, nanoindentation, high-temperature oxidation, and high-temperature tribological analyses show that CrAlYN nanomultilayer films have a face-centered cubic (fcc) crystal structure with a modulation period of CrN/YN+AlN/CrN/AlN. CrAlYN films exhibit optimal mechanical performance when Y content is 1.13at%. However, a substantial drop occurs when Y content increases to 2.67at%. As Y content increases, the high-temperature oxidation resistance, friction, and wear of CrAlYN films first increase and then decrease. Notably, films with the Y content of 1.13at% have optimal resistance to high-temperature oxidation, friction, and wear.

Study of the effect of asymmetric rolling followed by ion nitriding on the hardness and structure of HSS M2 tool steel

Study of the effect of asymmetric rolling followed by ion nitriding on the hardness and structure of HSS M2 tool steel

Influence of the heat treatment on the mechanical and tribological properties of cryogenically treated AISI M2 steel

Cryogenic treatments are known to increase the wear resistance and toughness of steel. However, the literature reports some contradictory results. This work aims to investigate and determine the optimum cryogenic parameters combined with cycles of quenching and tempering of AISI M2 tool steel to increase wear resistance and toughness. Charpy specimens were austenitized (1185 °C, 1200 °C or 1215 °C), quenched to room temperature, cryogenically treated to −196 °C (20 h or 28 h), and subjected to double tempering (520 °C, 535 °C or 550 °C). A Taguchi L9 DoE approach was used to determine the optimum set of heat treatment cycles. Mechanical and tribological properties were investigated in terms of wear, impact, hardness, and microhardness tests. The results show that austenitization temperature (AT), tempering temperature (TT), and cryogenic treatment (CT) time are interdependent. Depending on the AT and TT parameters used, CT can improve, have little influence, or even deteriorate the mechanical and tribological properties of AISI M2 steel. The amount of retained austenite after CT ranged from 4.3 to 7.6%. Cryogenic treatment improves wear resistance and impact toughness simultaneously.

Effect of surface wetting on tribological behavior for laser textured steel using ionic liquid-based lubricants

In this study, the effect of surface wettability on the tribological performance is evaluated through a ball-on-flat reciprocating wear test. The substrate material, M2 tool steel, is laser processed and then functionalized with fluorocarbon and nitrile chemistry to achieve distinct oleophobicity and oleophilicity, respectively, but with a similar nanoscale surface texture. The poly-alpha-olefin (PAO) base oil is used as the baseline lubricant, and ammonium- and phosphonium-based oil-miscible ionic liquids (ILs) are used as additives. The interaction between the nanoscale textured steel surface and ionic liquid-based oils is investigated. A set of reciprocating wear tests are performed to identify the wear and frictional mechanisms of the tribosystem consisting of the surface-engineered, flat M2 tool steel specimen and a standard, surface-polished steel ball. Results show that the oleophobic flat surface results in a lower friction, while the oleophilic surface modification leads to a better wear protection to the flat surface. Ammonium-based IL provides the highest friction reduction, while the phosphonium-based IL provide an improved wear protection. Click here and insert your abstract text.© 2023 Society of Manufacturing Engineers (SME). Published by Elsevier Ltd. All rights reserved.This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under responsibility of the Scientific Committee of the NAMRI/SME.

Tribological behavior of steel-based composite coatings produced by cold spray

This study investigates the microstructure, the mechanical properties, the topography and the tribological behavior of a composite coating obtained by cold spray, as a potential candidate for its use in internal combustion engines in the automotive sector. The coating consists of a 410 L matrix and M2 tool steel reinforcements. For comparison, a single component 410 L cold sprayed coating and a wire arc coating, used in some of today's car engines, are also studied. Post-spraying, the coatings underwent specific surface finishing. Their microstructure and topographies were observed. A lubricated reciprocating sliding test was performed, resulting in an exceptionally low friction coefficient and negligible wear, even in harsh conditions for the composite coating. The analyses revealed that the surface finish creates protuberances due to the presence of hard M2 particles, activating a series of mechanisms bringing to the stabilization of a tribofilm. This can be considered responsible for the exceptional tribological properties observed. This study proposes the application of surface textures with protuberances, in particular, their use in lubricated contacts in presence of fully formulated oils, and how cold spray is a suitable process to easily produce them.

Improving mechanical properties of carbon and tool steels via chromizing

ABSTRACT Steels are commonly used in high-performance demanding applications due to their favourable mechanical properties. Various surface engineering techniques have been developed for steels, among which chromizing is an affordable high-throughput case-hardenig process for improved surface hardness and wear resistance while retaining the substrate ductility and toughness. In this work, tribological testing along with nano- and micro-indentation and morphological and composional characterisation were used to understand the effects of the chromizing process on the AISI 1095 carbon steel, 52100 bearing steel and A2, D2 and M2 tool steels. The results of this study demonstrate that the chromizing treatment of low-cost 1095 and 52100 steels significantly improves their wear and hardness properties to a level comparable to the more costly tool steels. While chromizing also increased the hardness of the tool steels, it had little improvement on the wear resistance for the D2 and M2 tool steels.

Role of surface wetting on tribological behavior for laser nanotextured steel using ionic liquid lubricants

This research evaluates the effect of surface wettability on the tribological performance through ball-on-flat tribology testing. The substrate material, M2 tool steel, is laser processed and then functionalized with fluorocarbon and nitrile chemistry to achieve distinct oleophobicity and oleophilicity, respectively, but with a similar nanoscale surface texture. The baseline lubricant is poly-alpha-olefin (PAO) oil, and ionic liquids (ILs) are used as additives for this study. The interaction between the nanoscale textured steel surface and ionic liquid-based oils is investigated. A set of reciprocating wear tests are performed to investigate the tribological behavior of the tribo-system consisting of the surface-engineered, flat M2 tool steel specimen and a standard, surface-polished steel ball. Results show that the oleophobic flat surface results in a lower friction, while the oleophilic surface modification leads to a better wear protection to the flat surface. Ammonium-based IL provides the highest friction reduction, while the phosphonium-based ILs provide an improved wear protection.

Utilising H/E to predict fretting wear performance of DLC coating systems

Diamond-like carbon coatings have previously been studied as a protective coating for fretting wear protection providing low friction and low wear. H/E ratio has been used as a metric to rank coating performance in sliding wear, but this has not been applied to gross-slip fretting. Three DLC coating systems (a-C:H, Si-a-C:H, a-C:H:W top layers) on hardened M2 tool steel were studied using a bespoke electrodynamic shaker with a 10 mm 52100 steel ball as the counterface. This work has shown that H/E ratio can be used to predict wear performance in gross-slip fretting; the highest H/E ratio a-C:H performed best with low friction and wear.

Tribological Performance of a Composite Cold Spray for Coated Bores

The tribological performance of a thermal sprayed, mirror-like surface with localized protuberances was investigated through tribotests and computational simulation. A composite coating with a 410L steel matrix and M2 tool steel hard particles was applied by the cold spray process as a bore coating for combustion engines. The presence of protuberances promoted the quick formation of an antifriction tribofilm when tested with an SAE 0W-16 containing ZDDP and MoDTC, which significantly reduced the asperity friction in comparison to the conventional engine coated bores in reciprocating tribological tests. An in-house computational model using deterministic numerical methods was used for the mixed and hydrodynamic lubrication regime. Lubricant film thickness and friction were simulated for a piston ring versus the proposed coating. The computer simulations showed that the protuberances reduced the hydrodynamic friction by increasing the otherwise very thin oil film thickness of mirror-like surfaces. Although not intuitive, this result was caused by the reducing of the oil film shear rate.

Improving knife milling performance for biomass preprocessing by using advanced blade materials

Mechanical preprocessing of biomass, including size reduction, is a crucial step in converting biomass into biofuel. However, feedstock inevitably contains abrasive intrinsic and extrinsic inorganics that may cause excessive tool wear in preprocessing. This work demonstrates that performance of a knife mill can be significantly improved by applying a more wear-resistant blade material. A series of full-scale knife mill tests were performed for size reduction of forest residue using blades of tungsten carbide (WC–Co), iron-borided tool steel, and diamond-like carbon (DLC) coated tool steel. Blade material loss was quantified in correlation to the amount of feedstock processed and wear mechanisms were investigated via worn surface characterization. While the thin DLC coating was removed quickly, the WC-Co and iron-borided blades improved the tool life by 8X and 3X compared with the M2 tool steel blades (baseline), respectively. The in-situ throughput and power consumption measurements provided additional insights. The WC-Co and iron-borided blades had ∼3X higher throughput than the baseline blades by the end of the test with lower normalized power consumption. The experimental results were then used as input for a techno-economic analysis, which suggested that the more wear resistant blades could cut the knife milling cost by $2–3 per ton of biomass processed with downtime reduced by 65–85%.

EXPERIMENTAL STUDY ON THE SURFACE ROUGHNESS AND OPTIMIZATION OF CUTTING PARAMETERS IN THE HARD TURNING USING BIOCOMPATIBLE TiAlN-COATED AND UNCOATED CARBIDE INSERTS

Machining of difficult-to-cut materials has always been a focus of research. In terms of surface roughness, it is one of the most important machinability indicators used to evaluate the performance of machining processes. This research aims to investigate the effect of biocompatible TiAlN-coated and uncoated carbide inserts, as well as the effect of cutting parameters such as feed, rotational speed, and depth of cut on surface roughness in the hard turning of M2 tool steel at 64 HRC. The central composite design is used to create the experimental layout. Surface roughness values are measured using separate experiments for coated and uncoated inserts. A quadratic model is selected, and an analysis of variance (ANOVA) is performed to test the adequacy of the developed model. From the ANOVA, it is found that feed and rotational speed are the most significant parameter while hard turning with TiAlN-coated and uncoated inserts, respectively. Cutting parameters are ranked according to their importance using the Pareto chart. The composite desirability function is employed to determine the optimal setting of cutting parameters to minimize the surface roughness and a confirmation experiment is conducted to validate the optimization results. Confirmation results are very close to the predicted value and the error between experimental and predicted results are 7.93% and 9.36% with TiAlN-coated and uncoated carbide inserts, respectively. TiAlN-coated carbide insert gives better surface roughness compared to an uncoated carbide insert.

Effects of TiN/CrN, CrAlN, and TiN Coatings on the Performance of AISI M2 Tool Steel

The aim of this study is to investigate the effects of various ceramic-based coatings on the performance of AISI M2 high-speed steel punch used in the nut piercing process. AISI M2 punches were coated with TiN, TiN/CrN, and CrAlN utilizing a physical vapour deposition method. The total stroke number of the punches was used to evaluate the tool life of TiN, CrAlN, and TiN/CrN coated AISI M2 punches. AISI M2 punch coated with TiN/CrN was able to work up to greater stroke numbers than punches coated with TiN and CrAlN. Hardness and wear tests were performed to study the wear resistance of TiN/CrN and CrAlN coatings under relatively normal load conditions compared to actual working conditions (impact loading conditions) in the piercing process. The hardness and wear resistance of the CrAlN coating were greater than those of the TiN/CrN coating. The wear performance of the CrAlN coating was higher at normal loads and sliding speeds while the tool life of the TiN/CrN-coated punch was better under impact loading conditions.

Determination of the Elastic Modulus of Wear Resistant Coatings by Quantitative Acoustic Microscopy

Abstract For the quality assessment of coatings there is an increasing need of test methods which are able to fulfil the requirements to a high reliability of the test results. The exact knowledge of the coating properties and their objective assessment helps the coating industry for an optimum coating development as well as the user which will use the coated parts under a specific purpose. As part of an European project four laboratories deal with the determination of elastic moduli of hard coatings by means of quantitative acoustic microscopy. On titanium nitride coatings and C doped chromium coatings on M2 tool steel basic and continuing research studies were accomplished, guidelines have been developed and proofed in round-robin tests.

Enhancement of thermal and mechanical stabilities of silicon doped titanium nitride coating by manipulation of sputtering conditions

This study investigates the influence of substrate (AISI M42 tool steel) bias voltage (from −30 to −80 V), on the mechanical properties of magnetron sputtered TiSiN coating derived from Ti and Si targets. Thermal stability, microstructure (crystallite size, microstrain, lattice constant), morphology and mechanical (hardness, Young's modulus, residual stresses) properties, of the deposited TiSiN coatings, were investigated with synchrotron powered X-ray diffraction (SR-XRD), X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and nanoindentation techniques. Rietveld analysis, of the in-situ SR-XRD, in the temperature range of 25–800 °C, demonstrated cubic TiN form in (Ti,Si)N solid solutions, with TiO2 and Ti2O3 identified at lower bias voltages. Density functional theory supplemented the experimental results.Increase in the bias voltage resulted in: (i) a decrease in Si content, (ii) significant smoothening of surface morphology, (iii) change in the phase composition and microstructure, (iv) improved oxidation resistance and thermal oxidation threshold, and (v) hardness and Young's modulus of the coatings increased up to 50% to 33 GPa and 450 GPa, respectively.

Influence of substrate bias on the scratch, wear and indentation response of TiSiN nanocomposite coatings

TiSiN coatings were synthesised onto AISI M42 tool steel substrates via closed field unbalanced magnetron sputtering ion plating , using bias voltages of −40 and −50 V. The aim of this study is to investigate the underlying deformation mechanisms of TiSiN coatings, prepared at two different substrate bias voltages, following scratching, wear and indentation tests . A graded columnar microstructure evolved in these coatings. A hardness value of ~30.2 GPa was determined in the coating prepared at the lower bias voltage (i.e., −40 V), which was correlated to the fine nanocomposite structure and the presence of a high compressive residual stress. Of note, for the coating deposited at −40 V enhanced scratch adhesion strength , i.e., higher critical loads (L c1 and L c2 ) against cohesive and adhesive failure were determined with the higher H/E r and H 3 /E r 2 values. The improved scratch resistance was ascribed to the hierarchical structure that hindered crack propagation in the TiSiN coatings during progressive loading. An approximately 21% decrease in wear rate was obtained at the lower bias voltage, which was attributed to the slightly lower Si concentration (~8.3 at.%) and, in turn, higher hardness. Deformation behaviour under indentation loading was dominated by shear sliding along the columnar grain boundaries. • ~20% increase in L c1 was found in the TiSiN coating with the lower Si content. • The scratch resistance was enhanced by the coating's hierarchical structure. • ~21% reduction in wear rate was achieved in the coating with the lower Si content. • Indentation deformation was governed by columnar shear sliding.

High-temperature tribology of Hf doped c-Al0.64Ti0.36N cathodic arc PVD coatings deposited on M2 tool steel

Hard coatings are continuously improved due to the industrial needs and urgency to reduce the environmental impact of manufacturing processes. For these reasons, scientists seek hard coatings resistant to high mechanical and thermal loads under extreme working conditions (i.e., dry machining), which is why Hf and other rare earth metals have been added to the metastable c-AlxTi(1-x)N nitrides. In the present investigation, Hf-doped c-Al0.64Ti0.36N was deposited in a 2- & 3-axis rotation system using a semi-industrial coater. For this purpose Hf-pins were fixed in Al/Ti targets that produced coatings with ~0.2 at. % Hf-contents homogeneously dispersed. Hf effect on the crystalline state and microstructure, mechanical properties, high-temperature resistance, and the tribological performance of the coating in an Ar-jet at 900 °C were analyzed. It was found that the Hf-doped Al0.64Ti0.36N 5.07 μm thick-layer was mainly cubic fcc + traces of the hcp phases and displayed higher mean hardness (36 GPa) and E-module (416 GPa) than the coating without Hf (h = 32 GPa and E = 402 Pa). The Hf-containing nitride oxidizes dynamically during the high-temperature tribology testing and produces t-Ti2O3 & o-Al2TiO5 after short exposure periods (2.5–5 min), which strongly affected the CoF, before evolving to thermodynamically stable α-Al2O3 & anatase TiO2 between 10 & 30 min in the Ar-flow, thus resulting in the relative stability of the CoF. The mechanical evaluation of the oxidized coatings indicates that a specific oxide thickness must be reached to avoid catastrophic system damage at high normal loads.

Wear resistance of direct-energy–deposited AISI M2 tool steel with and without post-heat treatment

Wear resistance of direct-energy–deposited AISI M2 tool steel with and without post-heat treatment

Experimental investigations of wire lag phenomena on wire electrical discharge machining of M2 tool steel

A detailed experimental research study on wire lag phenomena, gap force, and wire lag compensation has been carried out on M2 tool steel material to overcome the error in dimensional accuracy for circular or curved profile job cutting in the wire electrical discharge machining. The design of experimental planning was made based on Taguchi methodology to determine the effect of the WEDM input control parameters on the wire lag related to different machining criteria, as well as the material removal rate, surface finish characteristic in terms of Ra values, spark gap, and specific energy consumption in this research work. The frequency, pulse on time, peak current, wire feed, workpiece height and wire tension, cutting diameter, and the span in between wire guide and job surface are considered as input control parameters for the present study. Parametric analysis shows that wire lag increases with workpiece height and wire lag compensation value increase rapidly with the decrease of job diameter. Parametric analysis is also carried out for MRR, surface roughness, spark gap, and specific energy consumption for optimum output. A further key finding is identified that the energy utilization efficiently increases with larger height job cutting in the WEDM process.

Influence of Mo Doping on the Microstructure, Friction, and Wear Properties of CrAlN Films

In this study, closed-field unbalanced magnetron sputtering ion-plating technology is used to deposit CrAlMoN and CrAlN nanomultilayer films on the surfaces of M2 tool steel and single-crystal Si. Energy-dispersive spectroscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, x-ray diffraction, scratch tester, nanoindenter, and pin-on-disk wear tester are used to study the influence of Mo doping on the composition, microstructure, mechanical properties, and friction properties of CrAlN films. Results show that CrAlMoN films have a nanomultilayer structure, CrN/Mo2N/CrN/AlN, with a modulation period of 10.5 nm. After Mo doping, the face-centered cubic structure of CrAlMoN films remains the same as that of CrAlN films. The chemical valence of each element in CrAlN films does not change with Mo doping. At room temperature, the wear resistance of CrAlMoN films is significantly improved compared with that of CrAlN films. This is attributed to the significant antifriction effect of MoO3 that forms on CrAlMoN films doped with Mo during the friction process.