A2 Tool Steel Research Articles

Optimization of Process Parameters of Wire Electric Discharge Machining Process for Machining AISI A2 Tool Steel

Optimization of Process Parameters of Wire Electric Discharge Machining Process for Machining AISI A2 Tool Steel

Multi-response optimization of M2 steel coatings deposited by co-axial laser cladding on A2 steel tool surfaces

Laser cladding is a highly effective technique used in additive manufacturing to enhance the surface properties of workpieces. It is employed to improve wear resistance, corrosion resistance, and high-temperature resilience of materials. This study explores the utilization of laser cladding technology to repair the surface of AISI A2 tool steel by applying a coating of M2 steel. Sixteen experiments were designed using an orthogonal methodology to investigate the intricate relationship between various processing parameters, including laser power, scan speed, powder feed rate, and overlapping ratio. These parameters were examined in conjunction with key mechanical properties of the coating, such as micro-hardness, friction-wear characteristics, and shear bond strength.Additionally, analytical techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) were employed to gain insights into the microstructure of the coatings and elucidate the underlying failure modes. Shear testing of the coatings indicated a tendency towards a brittle fracture mode within the coating, with the dominant wear mechanism involving a combination of abrasive and oxidative wear.Finally, a TOPSIS-Grey Relational Analysis (GRA) method was utilized to identify the optimal process parameters. These optimal parameters were determined to be a laser power of 1200 W, a scan speed of 5 mm/s, a powder feed rate of 14 g/min, and an overlapping ratio of 30 %. Subsequent validation experiments carried out with these parameters demonstrated superior performance compared to the optimal group identified in the orthogonal experiment.

Gas atomization of A2 tool steel: Effect of process parameters on powders' physical properties

In this study, powders of the A2 tool steel were produced by close-coupled gas atomization using argon gas aiming their use in additive manufacturing (AM) technologies. The effects of melt overheating and gas atomization pressure on their physical properties were analyzed. The powders were separated into different particle size ranges, and a complete morphological characterization was carried out. The effect of back pressure was verified due to a substantial increase in the gas-to-melt mass flow rates ratio (GMR) with increasing gas pressure. Atomization gas pressure showed a slightly more significant influence on particle size distribution; however, the melt overheating effect was also significant. As the GMR increases, the median particle size decreases to a certain threshold. Above this, particle size cannot be considerably reduced with increasing GMR.

Corrosion rate and surface hardness optimization in wire electrical discharge machining of AISI A2 tool steel in various conductive states and mediums

The current work focuses on optimizing the material characteristics such as surface hardness and corrosion rate on the surface of the machined specimens of A2 Tool Steel (A2TS) under various conditions like normal conductive state (NCS) and superconductive state (SCS) in flushing and submergible medium. The machining parameters such as voltage, current, pulse-on, pulse-off, wire-feed, wire-tension, and fluid-pressure are considered for experimentation through orthogonal array L18 using the Taguchi method. The surface morphology of machined specimens surface is examined using energy dispersive x-ray analysis (EDAX), x-ray diffraction (XRD), and Scanning Electron Microscope (SEM). The experimental results reveal that voltage, pulse off, and fluid pressure increase while corrosion rate decreases and similarly, the increases in voltage, pulse-on, and wire feed the surface hardness increases in various states and mediums. The conductive states and mediums improved the material characteristics, such as corrosion rate and surface hardness of A2TS. The oxide layer (ferric oxides) formation reduces in SCS A2TS machined in submergible as elemental reaction with environment reduced with formation of chromium compounds. The bonding strength of the SCS A2TS material increased during re-solidification of machined specimens in submergible increases the surface hardness as a result, carbon content will increases. These results are noticed from EDAX, XRD and SEM analysis. An improvement of corrosion rate between NCS A2TS and SCS A2TS in flushing medium is 57.59% and in submergible medium is 59.35% respectively. The progress of surface hardness between NCS A2TS and SCS A2TS in flushing medium is 2.58% and in submergible medium is 4.93%, respectively.

Towards additively manufacturing excavating tools for future robotic space exploration

AbstractMultiple metal alloys, that is, Ti‐6Al‐4 V, 316 L stainless steel, MS1 maraging steel, A2 tool steel, Inconel 625 with TiC and TiB2 reinforcement, and AMZ4 bulk metallic glass, were additively manufactured through laser powder bed fusion and tested as potential excavating tools for future robotic spacecraft landing on icy planetary bodies. Mechanical specific energy as a function of blade hardness was measured for each excavating tool as it trenched through soft and hard salt, where the salt is a regolith simulant for extraterrestrial ice. A2 tool steel, MS1 maraging steel, and bulk metallic glass cutting tools were shown to perform well in the experiments. A method for using the cutting tool as a sensor was also demonstrated.

Aluminium bronze-steel sliding contact in packaging applications: Failure analysis and lab-scale tribological tests

This study focuses on components for a pressing device involved in a sliding contact. In particular, the tribosystem consists of a pin (AISI A2 tool steel) and a guide plate (UNS C95500 aluminium bronze) coupled under a counterformal line contact.Firstly, the main wear mechanisms in the pin/guide plate contact were identified by failure analysis on real components after field operation, in order to define the conditions for lab-scale dry sliding tests (block-on-ring). Adhesive wear of bronze (leading to material transfer on steel) and two-body abrasion due to hard carbides from tool steel were the main wear mechanisms in field operation. Secondly, lab-scale tests were carried out for studying the influence of (i) applied load, (ii) sliding speed and (iii) bronze microstructure (as-cast condition or precipitation hardened) on tribological behavior.Tribological laboratory tests showed that the coefficient of friction of the bronze/steel couple was more influenced by applied load and sliding speed than by bronze heat treatment conditions. The wear behavior of bronze is mainly influenced by its work hardening capacity as well as by its ability to form a stable and protective copper oxide surface layer.

Improving the Stability and Critical Speed of Rotor Bearing System By Using External Damping Source

The presented study has the aim of finding out the relationships between input variables and process parameters that describe mathematical models, also to estimate the impact of independent parameters on the Heat Affected Zone (HAZ). In the presented paper, A2-Tool Steel material is the utilized workpiece material, whereas copper is the electrode material. RSM, which is the abbreviation of Response Surface Methodology, is used for identifying the impact of controllable parameters; such controllable effects consist of pulse current, pulse on time, and pulse off time on HAZ. It has been noticed that the model has been developed by RSM adequacy is suitable since the coefficient related to the determination is considered closest to one for HAZ, whereas the highest percentage of error between experimental and predicted data is (-13.829%). From ANOVA, the pulse current has the most significant factor affected by HAZ with 67.219% contribution.

Regression and Statistical Analysis of Process Parameters on Heat Affected Zone in Electrical Discharge Machining of Tool Steel

The presented study has the aim of finding out the relationships between input variables and process parameters that describe mathematical models, also to estimate the impact of independent parameters on the Heat Affected Zone (HAZ). In the presented paper, A2-Tool Steel material is the utilized workpiece material, whereas copper is the electrode material. RSM, which is the abbreviation of Response Surface Methodology, is used for identifying the impact of controllable parameters; such controllable effects consist of pulse current, pulse on time, and pulse off time on HAZ. It has been noticed that model has been developed by RSM adequacy is suitable since the coefficient related to the determination is considered closest to one for HAZ, whereas the highest percentage of error between experimental and predicted data is (-13.829%). From ANOVA, the pulse current has the most significant factor affected on HAZ with 67.219% contribution.

Electrically-Assisted Manufacturing for Reduction in Forging Forces of Bearing Steels

The aerospace industry regularly uses three high-strength steel alloys in the manufacture of their bearings: M50, M50 NiL, and Pyrowear P675. The high strength of these alloys causes increased force, friction, and temperature rise during forging operations, resulting in residual stresses and creating issues with distortion and springback in subsequent machining operations. Electrically-assisted manufacturing (EAM) has been studied for reduction or elimination of these issues in magnesium, aluminum, and titanium alloys as well as A2 tool steel and 304 stainless steel. This research determined the threshold current densities for EAM of Pyrowear P675, M50, and M50 NiL steels. Threshold current densities were determined for each material at 33, 48, and 37 A/mm2 respectively. Once the test reached this threshold a significant reduction in yield stress occurred and the samples had an increase in hardness near the exterior, the authors assess the probability of a phase change due to resistive heating during this forming operation.

Enhancement the Thermal Effects Produce by EDM Using Hybrid Machining

The present work is aimed to improve the thermal effects of electrical discharge machining (EDM) by EDM/ECM hybrid process. A hybrid method of EDM-ECM combined processing involve EDM shaping as well as electrochemical machining (ECM) finishing, also, they are conducted in sequence one same machine tool, same electrode, yet on the different dielectric. Concerning the process of EDM, the material will be removed via the vaporization and melting throughout all electric discharges. Thus, thermally damaged layers make the machined surface. In this study, the used workpiece material is the A2-Tool Steel material, while the electrode material is copper. The influence of controllable parameters could be identified via RSM, which is an abbreviation for Response surface methodology, these controllable effects include: pulse current, pulse on time, pulse off time, gap, voltage, and electrolyte concentration on white layer thickness (WLT) and Surface Roughness (SR). It has been noticed that model adequacy is acceptable because the coefficient of determination is closest to one for WLT and SR, in addition to that, the generated surface doesn’t have thermally affected layers as the SR and recast layers which have been generated via EDM are removed entirely through ECM finishing.

Identification of abrasion regimes based on mechanisms of wear on the steel stylus used in the Cerchar abrasiveness test

The wear of tools in rock excavation is a challenging and costly issue. To predict the added costs arising from wear, field and laboratory investigations can be conducted during the early stages of a project. Accordingly, a measure of particle abrasivity is needed. Abrasivity is defined as the capability of different kinds of soils and rocks to cause abrasive wear of metallic surfaces. The Cerchar abrasiveness test is a well-recognized lab test for assessing rock abrasivity. The Cerchar Abrasiveness Index (CAI) is determined by measuring the crater diameter [mm] produced by a conical steel stylus moving under a fixed load and sliding distance. Many authors have been trying to correlate CAI with rock properties, but no consensus has been achieved. The main reason for this difficulty arises from the effects of the microstructural complexity of rocks and their tribological response. This investigation proposes a new approach based on the use of a scanning electron microscope to identify the wear mechanisms acting on the Cerchar stylus (AISI A2 tool steel) during testing, and comparing these observations to the corresponding CAI values for nine different rock types (0.1 < CAI < 6). The observed wear mechanisms were classified into two extremes (mild and severe) with a transition region between them. The mild regime is characterized by the polishing action of rocks (CAI ≤ 1.8). The severe regime is characterized by microcutting with extensive plastic deformation (CAI ≥ 3.1). The reliability of the current findings is discussed in the light of a theoretical conversion of CAI values into their respective wear coefficients. Our proposed approach of using wear coefficients is expected to provide better correlation between the results of the Cerchar laboratory test and real drilling rates.

Surface Integrity and Metallurgical Characteristics of the EDMed Work Surfaces of A2 Tool Steel (SAE 304SS), Inconel 601 and Ti-6Al-4V: a Comparative Analysis

In the present work, a comparative analysis of surface integrity and metallurgical characteristics of the EDMed work surfaces of A2 tool steel (SAE 304SS), Inconel 601 and Titanium alloy (Ti-6Al-4V) has been attempted. Experiments have been conducted at different values of peak discharge current to study morphology as well as topographical features of the EDMed work surface in terms of surface roughness, surface crack density and thickness of the white layer. XRD analysis has also been carried out to understand metallurgical features (phases and precipitates, material migration) of the EDMed work surface. Results have been interpreted with relevance to EDS and micro-indentation hardness test data. The effect of peak discharge current on the EDMed work surface topography has also been examined. It was found that peak current has imposed a positive effect on surface crack density as well as white layer thickness irrespective of the work material chosen. Compared to 304SS and Inconel 601, cracks thus developed are more severe for the EDMed surface of Ti-4Al-6V due to formation of a hard TiC layer. The white layer is non-uniformly deposited over the EDMed surface of Ti-6Al-4V compared with 304SS and Inconel 601.

Optimization of cutting parameters in Dry Turning of AISI A2 Tool Steel using Carbide Tool by Taguchi Based Fuzzy Logics

AISI A2 tool steel is generally used for the machine tool parts, blades, punches and forging dies. This paper discusses the applications of Taguchi method with fuzzy logic to optimise the machining parameters for dry turning of AISI A2 tool steel using carbide inserts. Combined effects of the cutting parameters, namely cutting speed, feed rate, depth of cut and nose radius, on the surface roughness and cutting force components, were explored by analysis of variance (ANOVA) and optimization of process parameters were carried out by using fuzzy logic A Multi Response Performance Index (MRPI) was used for optimization. The relationship between the results shows that the overall process is mainly influenced by cutting speed and feed rate.

Multi-criteria decision making with PCA in EDM of A2 tool steel

In this investigation, experiments have been conducted with the help of full factorial design methodology in the Electro Discharge Machine (EDM) for machining of A2 tool steel. A cylindrical copper (99.9% pure) rod of 20 mm diameter has been selected as the electrode or tool material for machining. Four significant process parameters of EDM process such as discharge current (Ip), spark on time (Ton), duty cycle (Tau) and discharge voltage (V) have been studied in this research investigation. The effects of these parameters have been considered on the responses of EDM process such as Material Removal Rate (MRR) and Electrode Wear Rate (EWR) both in qualitative and quantitative terms. For qualitative analysis, main effect plots have been drawn, while for quantitative analysis ANOVA has been carried out. The significance of process parameters at 95% confidence interval has been found out through F-distribution and t-distribution values. ANOVA results revealed Ip and Ton as to be the major contributing process parameters for the considered EDM responses. Ip was found to have an 87.90% contribution towards MRR whereas Ton was having a 50.91% contribution towards TWR. Principal Component Analysis (PCA) has been implemented to find out the best trade-off between the responses MRR and EWR. The best process parameter setting for multi-criteria decision making among the answers such as MRR and EWR was found to be: Ip= 16A, Ton=500µs, Tau= 80%, V= 40volts.

Experimental Investigation of Process Parameters in Drilling EDM using RSM and ANN in Air Hardened Tool Steel (AISI A2)

The present work is to investigate the effect of significant process parameters on responses and to validate the developed ANN model with the experimental data. To achieve this, 30 number of experiments were carried out on Air Hardened Tool Steel (AISI A2) suspended in deionized water dielectric with copper as tool electrode by using full factorial central composite experimental design based Response Surface Methodology (RSM). The Air hardened tool steel is chosen as the specimen due to its wide range of applications such as in large blanking dies, master hubs, precision tools and coining dies. The various process parameters which can be varied such as Pulse on time, Pulse off time, Peak Current and Voltage are chosen as input parameters. For the selection of dominant process parameters, preliminary experiments were carried out. The output responses viz., Material Removal Rate, Tool Wear Rate, Taper Angle, Circularity and Perpendicularity were measured and analyzed using Design Expert software analytically as well as graphically in order to evaluate the performances of the EDM process. Regression model is developed for predicting Material Removal Rate, Tool Wear Rate, Taper Angle, Circularity and Perpendicularity, in terms of interactive and individual terms of machining parameters through RSM, utilizing relevant experimental results as obtained through experimentation. The research outcome identifies significant parameters and their effects on process performances on AISI A2 tool steel. The adequacy of the above proposed model is also tested using analysis of variance (ANOVA) method. Surface plot for the responses (Material removal rate, Tool wear rate, Taper angle Circularity and Perpendicularity) were obtained considering the significant parameters. The program is developed in MATLAB using Neural Networks based back propagation algorithm and the results are compared with the experimental data. A validated mathematical model will be useful for the Industrial applications to predict the responses without performing unnecessary experiments for AISI A2 tool steel. This leads to increase the performance and economic productivity of drilling EDM process.

Analysis of the Effect of Ultrasonic Vibrations on the Performance of Microelectrical Discharge Machining of A2 Tool Steel on the Diesel Engine Performance

The application of ultrasonic vibrations to a workpiece or tool is a novel hybrid approach in microelectrical discharge machining. The advantages of this method include effective flushing out of debris, higher machining efficiency and lesser short-circuits during machining. This paper presents a systematic analysis of the influence of kinetic effects of the ultrasonic vibrations on the material removal rate (MRR) and tool electrode wear rate (TWR). The tool wear ratio was estimated for the process at all processing conditions. The maximum variation in tool wear ratio is observed to be 82%. Therefore, MRR and TWR were independently analyzed by using three scientific tools: i) AOM plots, ii) interaction plots and iii) three-dimensional scatter plots. The increase in MRR is 47% corresponding to an increase in the maximum power of vibrations by 30%. The ultrasonic vibrations are found to be very effective at higher machining depths for achieving stable machining conditions. Regression equations were developed for MRR and TWR with capacitance, ultrasonic vibration factor, feed rate and machining time.

Development of AISI A2 Tool Steel Beater Head for an Impact Crusher in a Sinter Plant

Failure analysis of a tool steel (AISI A2) beater head of an impact crusher and development of suitable heat treatment process to improve its performance have been presented. The beater heads were failing prematurely by brittle fracture from its pin-hole locations. The investigation consisted of visual inspection, fractography, chemical analysis, characterization of microstructures using optical and scanning electron microscopes (SEM), EDS analysis, and determination of micro-hardness profile. Microstructural characterization using SEM and EDS analysis revealed significant amount of coarse continuous Cr-carbide networks in the martensite matrix. It increased hardness (64 HRC) as well as heterogeneity of the matrix as depicted by the micro-hardness profile, and decreased the toughness (3 J) since coarse carbide networks are very hard and brittle. The austenitizing temperature as well as tempering temperature of heat treatment was found lower at the manufacturer’s end. The new recommended heat treatment resulted in lower amount of discontinuous Cr-carbides along with significant amount of fine precipitates uniformly distributed throughout the matrix which led to an optimum combination of both hardness (59 HRC) and toughness (6.5 J) required for the application. The beater heads manufactured following the recommended heat treatment exhibited better performance (life increased by 4 times) compared to the earlier ones.

Comparison of the tribological behavior of steel–steel and Si3N4–steel contacts in lubricants with ZDDP or ionic liquid

Tribological evaluations were conducted on lubricating base oils of different viscosity grades with and without an anti-wear (AW) additive in lubricating steel-steel and ceramic-steel contacts. Two AW additives were applied: a conventional secondary zinc dialkyldithiophosphate (ZDDP) and an oil-miscible phosphonium-phosphate ionic liquid (IL). Tests were carried out using reciprocating ball-on-flat sliding at room temperature. The flat material was AISI A2 tool steel, and the ball material was either AISI 52100 bearing steel or silicon nitride. Four lubricants were tested: Chevron SAE 15W40 and 0W30 base oils, and the 0W30 base oil plus 1 wt% ZDDP or IL. For the steel–steel contact, the lower-viscosity 0W30 base oil resulted in a higher wear rate than did the 15W40 base oil, as expected. Both the ZDDP and the IL substantially reduced wear, and the IL-additized 0W30 base oil was the best performer. For the ceramic–steel contact, the ZDDP provided moderate wear protection for both ball and flat. In contrast, the IL reduced the steel flat wear more effectively but increased the ceramic ball wear rate. Cross-sectional transmission electron microscopy (TEM) examination and x-ray photoelectron spectroscopy (XPS) chemical analysis were used to reveal the thickness, nanostructure, and composition of the tribofilms formed by ZDDP and IL on the steel and silicon nitride surfaces.

High speed ball nose end milling of hardened AISI A2 tool steel with PCBN and coated carbide tools

High speed machining (HSM) of tool steels in their hardened state is emerging as an attractive approach for the mold and die industry due to its potential for significant cost savings and productivity improvement. An experimental study was conducted to investigate the tool wear mechanism and surface integrity in high speed ball nose end milling of hardened AISI A2 tool steel using coated tungsten carbide and polycrystalline cubic boron nitride (PCBN) tools. It is found that coated carbide tools can only be used at low speed (120m/min) while high content PCBN tools are suitable for HSM range (470m/min). PCBN tools produce a damage free workpiece with better surface finish and less work hardening. Despite the higher tool cost, HSM with PCBN tools lead to reduction in both total cost and production time per part.

Process capability study of laser assisted micro milling of a hard-to-machine material

Laser assisted micro milling (LAMM) is capable of generating three-dimensional micro scale features in hard-to-machine materials. This paper compares the process capability of LAMM with conventional micro milling of a hardened tool steel. In particular, the potential advantages of LAMM over micro milling with respect to cutting forces, tool wear, material removal rate, burr formation and surface roughness are investigated when micro milling hardened A2 tool steel (62 HRC). The results show that LAMM has significant advantages over micro milling, especially in terms of cutting forces, material removal rate and tool wear. The average reduction in the resultant cutting force is found to be up to 69% with laser assist. In addition, tool wear is found to be substantially less with laser assist even when the material removal rates are increased by a factor of six over the tool manufacturer recommended cutting conditions.