D2 Cold Work Tool Steel Research Articles

Influence of cryogenic treatment and tempering temperature on microstructural evolution and dry sliding wear behavior of AISI D3 cold-work tool steel

Abstract AISI D3 cold work steel was shallow and deep cryogenically treated and double tempered at 150, 250, and 350 °C temperatures. Cryogenic processes transformed the retained austenite into martensite, while double tempering produced Fe, Cr, and W-rich carbides. The wear losses of cryogenically treated specimens decreased by up to 60% compared to conventionally heat-treated samples. Worn surfaces mainly experienced abrasive and adhesive wear mechanisms. Due to the formation of homogeneously dispersed fine carbides at 250 °C, oxidative wear occurred at the matrix phase, resulting in the lowest wear rate. The samples tempered at 150 °C suffered from the severe abrasive action of hard carbide particles, while the samples treated at 350 °C failed because of carbide coarsening.

Minimizing Tool Wear, Cutting Temperature and Surface Roughness in the Intermittent Turning of AISI D3 Steel Using the DF and GRA Method

Intermittent turning (IT) is characterized by a different context than continuous turning (CT). The cutting tool is shocked each time it goes off-load and engages a new surface. This interruption causes severe cutting conditions, which fatally affect the performance parameters. The purpose of this study is to assess the effects of four cutting factors, tool nose radius (r), cutting speed (Vc), feed rate (f), and depth of cut (ap), on the following output performance parameters: surface roughness (Ra), cutting temperature (T°), and cutting tool wear (VB) during turning (IT) AISI D3 cold work tool steel. A triple CVD (AI2O3/TiC/TiCN)-coated carbide cutting tool was used. A Taguchi L9 (3^4) experimental design was adopted for carrying out the experiments in intermittent turning. To improve the performance parameters based on three (3) highly particular scenarios that fulfill industrial criteria, the desirability function (DF) and the grey relational analysis method (GRA) were used. Finally, the optimization findings of the two strategies were compared in order to evaluate the performance of each method.

A Research on The Evaluation of Performances After Re-Sharpening of The End Mills

In this study, the performances of end mills used widely in machining were investigated in case of their reuse by sharpening. For this purpose, at the CNC vertical machining center, slot milling processes were carried out with HSS end mills (used once) on the AISI 1050 manufacturing steel having two different diameters and with carbide end mills (again used once) on the AISI D2 (2080) cold work tool steel having two different diameters. Machining experiments were made by using four different cutting speeds, four different feed and four different cutting depths. These end mills, afterwards, were re-sharpened by considering their original tool geometry and the machining experiments were repeated at the same conditions and their performances were evaluated in comparison with the performances of the new tool. In general, wear amounts in the sharpened tools were observed to be higher with respect to the new tools. In the HSS tools, no adverse effect of sharpening process was observed on the machining performance. In the carbide tools, especially from the point of surface quality for the tools having small diameter there is no adverse effect of re-sharpening and re-sharpening can be recommended with the condition of observing the surface quality in parallel to the increase in diameter.

The Effect of Cutting Parameters on White Layer Thickness and Surface Hardness in Wire EDM of Heat-treated D2 Cold Work Tool Steel

Bu çalışmada tel erozyon (WEDM) yöntemi kullanılarak Sverker 21 soğuk iş takım çeliğinin kesme parametrelerinin işleme sonrası malzemede oluşan beyaz tabaka ve kesme yüzeyi sertliğine etkileri incelenmiştir. Yüksek alaşımlı çeliğin kullanılmasındaki amaç; içerdiği alaşım elementi ve karbon oranına bağlı olarak yüksek sertlik, aşınma dayanımı ve tokluk özelliklerinden dolayı kalıpçılık endüstrisinde yaygın olarak kullanılmasıdır. Deneysel çalışmalarda hem ticari hem de ısıl işleme tabi tutulmuş soğuk iş takım çeliği kullanılmıştır. Kesme parametreleri olarak ticari numune ve ısıl işlem görmüş numune, iki ark arası süre (µs), voltaj (V), sıvı basıncı (bar), tel gerginliği (g), tel ilerleme hızı (m/min) kullanılmıştır. Deney tasarımı için Taguchi deney tasarım planı ve L18 ortogonal dizini kullanılarak malzemeler kesilmiştir. Sonuç olarak işlenmiş yüzey sertliği ve yeniden oluşan beyaz tabaka kalınlığı incelenmiştir. ANOVA yöntemine göre beyaz tabaka kalınlığı üzerindeki en etkili parametre % 57.236 ile ticari ve ısıl işlem görmüş numune parametresidir. Kesilen yüzey sertlik değerlerinde ise en etkin parametre % 98.627 oranında numune parametresi olmuştur.

Effect of ultrasonic peening on the surface properties of nano-layered CrN/CrAlN coating deposited by CAPVD method on D3 tool steel

Hard coatings are widely used in industrial applications to protect the workpiece from mechanical and chemical damage. Due to the high hardness and internal stress of most hard coatings, there is a deterioration in adhesion strength and coating performance. The aim of this study is to investigate the effect of the ultrasonic peening pre-treatment on the surface properties of a nano-layered CrN / CrAlN coating that is deposited on the AISI D3 cold-work tool steel. Cathodic arc physical vapor deposition (CAPVD) was used to apply the coating. To evaluate the surface properties of the coatings, Rockwell-C and Vickers microhardness testers, potentiodynamic polarization, and pin-on-disk were utilized. The obtained results show that the ultrasonic peening pre-treatment process has caused the compressive residual stress, reduced the surface roughness, and increased the surface hardness of the uncoated substrate. Ultrasonic peening pre-treatment of the D3 cold work steel samples has increased the wear resistance on the surface of the coated specimens by an average of 47% and, an ultrasonic power of 25% has the best conditions in terms of wear resistance. Also, in the peened sample with a power of 20%, the adhesion of the nano-layered CrN/CrAlN coating to the substrate is optimal (HF1 level), its average surface roughness has a minimum value (Ra=0.36 μm), and its corrosion resistance is improved about 33.2% rather than the base coated sample in the 3.5 wt.% NaCl solution.

Experimental and Statistical Investigation of Machinability of AISI D2 Steel Using Electroerosion Machining Method in Different Machining Parameters

This study investigated the effects of machining parameters on the experimental and statistical results using the electric discharge method in the machining of AISI D2 cold work tool steel. The design of the experiment was established using the Taguchi L18 method. The effect of the experiment parameters on the performance characteristics was analyzed by analysis of variance (ANOVA). As a result of the study, it was determined that increasing amperage and pulse time affected the surface roughness and hole diameter on the surface of the material. The lowest values for surface roughness, machining time, hole diameter, and crater diameter were determined as 2.085 μm, 47 minutes, 12.010 mm, and 81.007 μm, respectively. The highest wear amount was obtained as 0.604 grams with the processed parameters in the ninth experiment. When the signal‐to‐noise ratios were examined, the optimum combinations of the control factors for surface roughness, hole diameter, crater diameter, wear amount, wear rate, and processing time were determined as A1B1C3, A1B1C3, A1B1C3, A1B3C1, A2B1C1, and A1B3C3, respectively. According to the ANOVA results, the most important parameters affecting the test results for surface roughness, hole diameter, crater diameter, wear amount, material wear loss, and processing time were determined as amperage (49.34%), time‐on (59.38%), amperage (55.65%), time‐on (56.92%), amperage (51.42%), and amperage (78.02%), respectively. When the gray relational degree was calculated for the maximum and minimum values, the ideal factors for all output results were found to be the parameters applied in the third experiment.

Tribocorrosion behavior of surface-modified AISI D2 steel

Three different thermochemical coatings were obtained on the surface of an AISI D2 cold work tool steel under different process conditions through the use of boriding, titanizing, and borotitanizing (titanizing followed by boriding) treatments. The phases formed on the surface of the steel were identified using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray diffraction (XRD). The thicknesses of the layers were characterized and surface hardness profiles were constructed. Wear tests were carried out using a ball-on-disk type tribometer by applying 10 N load for a total sliding distance of 250 m against an abrasive WC ball in both ambient air and 3.5% NaCl. Microstructural studies revealed a boride layer composed of FeB + Fe2B with typical sawtooth morphology in the borided sample, a compact TiC layer on the surface of the titanized sample, and a complex polyphase layer consisting of TiB2, TiO2, Fe2B, and FeB in the borotitanized sample. Layer hardnesses ranged between 1647 and 2176 HV for the titanized sample and between 1720 and 2232 HV for the borotitanized sample. The TiC layer formed on the surface of the titanized sample was very thin compared to the layers grown on the borided and titanized samples and had an average hardness of 2447 HV. All coatings displayed reduced wear losses compared to the untreated AISI D2 steel, both in air and 3.5% NaCl. The coated samples exhibited better wear performance in 3.5% NaCl compared to ambient air due to the lubricating effect of the NaCl solution. The enhanced wear resistance of the coated samples was attributed mainly to their superior surface hardness.

The effect of vibration and cutting zone temperature on surface roughness and tool wear in eco-friendly MQL turning of AISI D2

Today, developments in technology have gained momentum more than ever, and the need for efficiency in production as well as in the ecological domain has increased significantly. Studies examining dry machining and coolant removal have been superseded by those presenting new cooling and lubrication techniques. The effects on surface roughness directly related to final product quality are being investigated in terms of tool life and employee health. This has resulted in more frequent use of the eco-friendly minimum quantity lubrication (MQL) technique, which has now become a major competitor to dry and coolant machining. In this study, AISI D2 cold work tool steel, a material widely used in the mold industry, was used as the workpiece. Tests were carried out under dry and MQL conditions and the temperature, cutting tool vibration amplitude, tool wear, surface roughness and tool life were evaluated. The experiments were carried out using two different cutting tool coating types (CVD-chemical vapor deposition and PVD-physical vapor deposition) and three different cutting speeds (60, 90 and 120 m/min) at a constant cutting depth (1 mm) and feed rate (0.09 mm/rev). Results revealed that tool wear, cutting temperature and cutting tool vibration amplitude were lower by 23, 25, and 45%, respectively, compared to dry cutting. Because of these improvements, the surface roughness of the workpiece was improved by 89% and tool life was increased by up to 267%.

Effect of machinability, microstructure and hardness of deep cryogenic treatment in hard turning of AISI D2 steel with ceramic cutting

This study examined the hard turning of AISI D2 cold work tool steel subjected to deep cryogenic processing and tempering and investigated the effects on surface roughness and tool wear. In addition, the effects of the deep cryogenic processes on mechanical properties (macro and micro hardness) and microstructure were investigated. Three groups of test samples were evaluated: conventional heat treatment (CHT), deep cryogenic treatment (DCT-36) and deep cryogenic treatment with tempering (DCTT-36). The samples in the first group were subjected to only CHT to 62 HRc hardness. The second group (DCT-36) underwent processing for 36h at −145°C after conventional heat treatment. The latter group (DCTT-36) had been subjected to both conventional heat treatment and deep cryogenic treatment followed by 2h of tempering at 200°C. In the experiments, Al2O3 + TiC matrix-based untreated mixed alumina ceramic (AB30) and Al2O3 + TiC matrix-based TiN-coated ceramic (AB2010) cutting tools were used. The artificial intelligence method known as artificial neural networks (ANNs) was used to estimate the surface roughness based on cutting speed, cutting tool, workpiece, depth of cut and feed rate. For the artificial neural network modeling, the standard back-propagation algorithm was found to be the optimum choice for training the model. Three different cutting speeds (50, 100 and 150m/min), three different feed rates (0.08, 0.16 and 0.24mm/rev) and three different cutting depths (0.25, 0.50 and 0.75mm) were selected. Tool wear experiments were carried out at a cutting speed of 150m/min, a feed rate of 0.08mm/rev and a cutting depth of 0.6mm. As a result of the experiments, the best results for both surface roughness and tool wear were obtained with the DCTT-36 sample. When cutting tools were compared, the best results for surface roughness and tool wear were obtained with the coated ceramic tool (AB2010). The macroscopic and micro hardness values were highest for the DCT-36. From the microstructural point of view, the DCTT-36 sample showed the best results with homogeneous and thinner secondary carbide formations.

Improvement of tribological behavior of H-13 steel by optimizing the cryogenic-treatment process using evolutionary algorithms

The effect of soaking temperature and duration of cryogenic treatment cycles were investigated for the hot die steel AISI-H13 to improve its wear resistance. The amount of wear, average friction coefficient, and maximum local contact temperature were investigated against the AISI D3 cold work tool steel (hardened and tempered) used as counter-surface for five conditions – varying the loading and sliding speed. Sliding parameter has great influence over wear rate when is compared to load effects. The wear detected on the surface analyzed is adhesive wear produced by deformation lips, surface cracks and fractured ridges. To achieve an increase of efficiency, Particle Swarm Optimization is preferred as it showed lower deviation than Bacteria Foraging Optimization in optimized results.

Applying a fuzzy interval ordered weighted averaging aggregation fusion to nondestructive determination of retained austenite phase in D2 tool steel

In the present paper, application of data fusion coupled with three electromagnetic nondestructive technologies (magnetic hysteresis loop, Barkhausen noise, and eddy current) has been explored to achieve higher accuracy and reliability of measurements. The ability of the proposed methodology has been evaluated for determining microstructural changes of D2 cold work tool steel during tempering with focus on decomposition of retained austenite and determination of this phase, quantitatively. The proposed data fusion method takes advantage of ordered weighted averaging aggregation operator and fuzzy defined interval to fuse the data produced by different experiments to obtain more accurate and reliable results. The fusion process also uses redundant information produced by applying different mapping functions modeled by neural networks. The results of the experiments revealed that applying data fusion to the outputs obtained from different experiments produces more accurate results compared to the situation that only outputs of one experiment are used.

Effect of Sub Zero Treatment on Microstructures, Mechanical Properties, and Dimensional Stability of AISI D2 Cold Work Tool Steel

AISI D2 tool steel has become important material in the industry, especially for mold and dies maker and also used for cutting tools. Conventional hardening process such as annealing and quenching is normally done for this kind of steel as it needs high hardness and wear resistance properties. To further improve its performance, sub-zero treatment can be performed. Quenching the steel in very low temperature e.g. liquid nitrogen, will help to remove unwanted retained austenite, thus provide better dimensional stability. In this study, AISI D2 tool steel samples were subjected to austenitizing temperature of 1030°C and then quenched using different quenching media i.e. air, oil, and liquid nitrogen. Vickers test result showed that after quenching process, the hardness for those samples were 762 HV, 822 HV, and 735 HV for air, oil, and liquid nitrogen quenched respectively. Microstructure analysis showed that retained austenite volume fraction after quenching process were 7.50%, 3.93%, and 3.18% for air, oil, and liquid nitrogen quenched respectively.

A comprehensive review on cold work of AISI D2 tool steel

As a common material in mould and die application, AISI D2 cold work tool steel has proven to be a promising chosen material in the industries. However, challenges remain in using AISI D2 through a modified version with a considerable progress having been made in recent years. This paper provides a critical review of the original as-cast AISI D2 cold work tool steel up to the modified version. The main purpose is to develop an understanding of current modified tool steel trend; the machinability of AISI D2 (drilling, milling, turning, grinding and EDM/WEDM; and the microstructure evolution and mechanical properties of these cold work tool steels due to the presence of alloy materials in the steel matrix. The doping of rare earth alloy element, new steel fabrication processes, significant process parameter in machinability and surface treatment shows that there have been few empirical investigations into these cold work tool steel alloys. This study has discovered that cold work tool steel will remain to be explored in order to survive in the steel industries.

Recrystallization, precipitation and flow behavior of D3 tool steel under hot working condition

Hot compression tests were performed on D3 cold-work tool steel at various temperatures of 800–1200°C and strain rates of 0.001–1s−1.The peak stress and strain of flow curves showed uncommon increase within the temperature range of 800–1000°C and strain rates of 0.001–0.1s−1. The dynamic precipitation of fine carbides was found responsible for the observed irregularities. Optical microscopy observations showed the highest rate of precipitation at about 1000°C. At high strain rates (0.1 or 1s−1), the precipitation temperature shifted to around 1100°C. Observations by optical and FESEM microscopes and EBSD measurements implied that dynamic precipitation could retard dynamic recrystallization at low temperatures and strain rates. Partial dynamic recrystallization mainly occurs by “continuous dynamic recrystallization” and partly by “discontinuous dynamic recrystallization” and “particle stimulated nucleation” mechanisms. More dissolution of carbides, less dynamic precipitation and considerable continuous dynamic recrystallization were the major microstructural phenomena at high temperatures (1100°C and 1200°C). The material constants in the hyperbolic sine constitutive equation were determined for low and high temperature regimes. The apparent activation energy for low and high temperature regimes was determined as 566kJ/moland 564kJ/mol, respectively.

Surface roughness analysis of greater cutting depths during hard turning

Abstract Literally, hard machining describes machining of parts having hardness over 45 HRC. Besides its advantages like high metal removal rate, easiness of adapting to complex part geometries, possibility of dry cutting; this operation, which can substitute grinding in most cases, has some disadvantages. One of them is the significant increase of surface roughness due to tool wear even when the tool life limit is not exceeded. In this study, considering hard turning praxes, higher depths of cut (0.5 to 1.0 mm) were examined when dry turning AISI D2 cold work tool steel, through-hardened to 62 HRC. TiN coated mixed ceramic inserts (Al2O3 + TiCN) were employed in the operations. Relationship between surface roughness and cutting parameters (cutting speed, feed and depth of cut) was modeled and analyzed using a Box-Behnken response surface methodology (RSM) design. A linear model best described this relationship. Despite the higher depths of cuts, the surface roughness values achieved were comparable to th...

Optimization of friction and wear characteristics of varied cryogenically treated hot die steel grade AISI-H13 under dry condition

Cryogenic treatment (CT) is a relatively new field, which has emerged during the last three decades of the twentieth century. However, its impact on material shaping and making tool life, and enhancement of their mechanical properties are quite remarkable. The selection of appropriate process parameters for CT is essential for cost reduction and optimum productivity. This study focuses on the influence of key parameters of CT cycles (i.e., soaking temperature and duration) on the friction and wear behavior of AISI H13 hot die steel under dry sliding conditions against hardened and tempered AISI D3 cold work tool steel (counter face) at varying sliding speeds and loads. Mathematical models have been developed for wear rate, the average coefficient of friction, and maximum contact temperature using the Box-Cox methodology. The developed mathematical models have been validated by comparing with the experimental results. Moreover, the optimum values of the process parameter have been employed to maximize the output and validate the same by confirmation of the experiments. To the best of our knowledge, this is the first study that demonstrates the modeling and optimization of sliding friction and wear characteristics of AISI H13 under varied CT cycles.

Metallurgical Characterization of a Weld Bead Coating Applied by the PTA Process on the D2 Tool Steel

Abstract In this investigation, a nickel-base powder mixed with tungsten carbide particles was applied by Plasma Transferred Arc welding (PTA) on the surface of the D2 cold work tool steel to improve surface quality and to extend its lifetime during applications. The Design of Experiment (DoE) method was applied to obtain the appropriate combination of hardfacing parameters and to run the minimum number of tests. Current, travel speed and preheat were considered as variable parameters. These parameters are important to reach a final layer with an appropriate bead geometry accompanied with good metallurgical properties. All samples were prepared for metallurgical investigations and the effect of process parameters on the weld bead geometry was considered. For each experiment run, weld bead geometry parameters were measured including dilution, penetration and reinforcement. Microstructures and the distribution of tungsten carbide particles after welding were analyzed by Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) equipped with an EDS microprobe. In addition, hardness tests were performed to evaluate the mechanical properties of the weld bead layers. Finally, among all the experiments, the best sample with appropriate bead geometry and microstructure was selected.

Punch structure, punch wear and cut profiles of AISI 304 stainless steel sheet blanks manufactured using cryogenically treated AISI D3 tool steel punches

Cutting edge geometry and punch wear are closely associated. Punch wear increases past shape errors. These basic defects may be found on the surface of the part and characterise its quality and accuracy. Punch errors are largely associated with punch wear and process parameters. The aim of this study was to investigate the effect of cryogenically treated punches on stainless steel sheet blanking shape errors. For this purpose, the blanking was carried out in a punch machine using 7- and 9-mm-diameter AISI D3 cold work tool steel punches and 1.5-mm-thick AISI 304 austenitic stainless steel sheets. One punch group was subjected to the cryogenic process at −145 °C in addition to the conventional heat treatment. The cryogenic process was carried out to improve the wear resistance and product quality. For this study, punch weight losses were measured and punch wear was evaluated through analysis of SEM and OM images. The rollover depth, burnish depth, fracture depth, burr height and angle of fracture of the selected parts were measured in the specified number of blanks. Results showed that the cryogenic process increased the wear performance of the punches and reduced the shape errors of the parts.

Performance of coated and uncoated mixed ceramic tools in hard turning process

The present contribution deals with the study of the effects of cutting speed, feed rate and depth of cut on the performance of machining which traditionally named “machinability”. The focus is made on the effect of the pre-cited cutting parameters on the evolution of surface roughness and cutting force components during hard turning of AISI D3 cold work tool steel with CC6050 and CC650 ceramic inserts. Also, for both ceramics a comparison of their wear evolution with time and its impact on the surface equality was proposed. The planning of experiments was based on Taguchi’s L16 orthogonal array. The analysis of variance (ANOVA), the signal-to-noise ratio and response surface methodology (RSM) were adopted. Consequently, the validity of proposed linear regression model was checked and the most important parameter affecting the surface roughness and cutting force components were determined. Furthermore, in order to determine the levels of the cutting regime that lead to minimum surface roughness and minimum machining force the relationship between cutting factors was analyzed. The results revealed that the surface quality obtained with the coated CC6050 ceramic insert is 1.6 times better than the one obtained with uncoated CC650 ceramic insert. However, the uncoated ceramic insert was useful in reducing the machining force.

Kinetics of vanadium carbide coating produced on AISI D2 steel by thermoreactive diffusion technique

AISI D2 cold-work tool steel is usually used for the purpose of hardness and wear resistance. Thermoreactive diffusion coating (TRD) treatment can be applied to this type of tool steel to improve the surface hardness. Since the rollers made of D2 tool steels are susceptible to wear fatigue, its surface hardness is of critical importance. A vanadium carbide coating was applied to the D2 tool steel samples by immersion in a borax liquid bath containing ferrovanadium, aluminum, and boric acid. Coating process and hardening heat treatment were carried out simultaneously in two steps. Firstly the samples were preheated up to 500°C and then TRD coating was performed on the samples at various temperatures for different times. Secondly the samples were undergone a mar-tempering heat treatment cycle in which the samples were austenitized in a BaCl2 molten bath at 1070°C for 30 minutes, oil quenched and then a two stage tempering treatment was applied to the quenched samples. The surface hardness of the coated sample was evaluated as 2300–3200 HV at various conditions while the hardness of the bulk was measured as 670–720 HV. XRD analysis of the coating showed that the main component was vanadium carbide (V8C7). Finally the kinetic study of coating was carried out based on determined rate curves, which showed that the diffusion of carbon atoms in the coating layer controlled the coating process.