Notch Wear Research Articles

Improving surface integrity of GH4169 alloy through magnetic-assisted cutting

GH4169 alloy presents superior properties such as high strength and resistance to high temperature, but possesses poor machinability. To ameliorate the problem and improve the machined surface integrity of GH4169 alloy, this paper focused on the application of magnetic-assisted cutting (MAC) for GH4169 alloy. In the MAC process, a permanent magnetic field (the magnetic field intensity is 0.25 T) was applied to the workpiece material during cutting, and its impact on chip morphology, tool damage and surface integrity was investigated. By comparing to traditional cutting (TC), the introduction of a magnetic field results in a reduction in the chip thickness and minimizes chip serration, leading to smoother cutting process and reduced fluctuations in cutting forces. Meanwhile, the introduction of magnetic field resulted in a substantial decrease in the notch wear and abrasion of cutting tool, and mitigated the excessive growth of built-up edge (BUE), which improved the tool life and machined surface integrity. By analyzing the machined surface at the end of TC and MAC, it was found that the surface roughness at the end of MAC was reduced by 22.4 %. Meanwhile, the cavity, side flow and debris of BUE, which tend to occur in the machined surface during the TC process, are effectively suppressed after MAC. Furthermore, Microstructural analysis of the machined surface indicated an enhancement in the dislocation density on the machined surface layer, suggesting the magnetoplastic effect of the magnetic field on GH4169 alloy.

Enhancement of ceramic tool behaviour with textured grooves during machining of Inconel® 718

Inconel® 718, known for its excellent mechanical properties in extreme conditions, presents machining challenges due to its low machinability. The chip formation process, influenced by its high ductility and low thermal conductivity, leads to material adhesion and high cutting forces. Ceramic tools have been proposed to mitigate these inconveniences. Textured cutting tools have emerged as a promising solution, aiming to optimise tool-chip contact and, with it, the tribological conditions and the cutting forces. This study investigates the influence of textured grooves on ceramic tools when turning Inconel® 718. Two groove inclinations, 0° and − 25° relative to the cutting edge, were tested. Texturing was performed using a laser station. Experimental results showed improved tool wear characteristics with textured tools, indicating favourable chip extraction and reduced material adhesion. Cutting forces were notably lower with textured tools compared to the reference tool, attributed to reduced notch wear and altered chip flow. Chip morphology analysis revealed differences in chip shape and thermal stability between the reference and textured tools. In conclusion, textured tools, particularly those with − 25° inclined grooves, demonstrated enhanced performance in machining Inconel® 718.

Influence of the substrate treatment on the surface integrity and cutting performance of CVD coated inserts

To investigate the influence of substrate treatment on the surface integrity and cutting performance of CVD TiN/MT-TiCN/α-Al2O3/TiN coated inserts, four different process routes were designed to produce the coated inserts. The results indicate that the surface treatment can prominently influence the cutting performance. Compared with the typical production process (route 2), the process (route 4) involving polishing rake face and grinding flank face resulted in a 23.3 % enhancement in tool life during continuous turning and a 17.5 % improvement during interrupted turning. This enhancement was due to the smooth rake face (Sa 123 µm) and the improved coating adhesion on the flank face attained through route 4, which delayed the crater wear during continuous turning and notch wear during interrupted turning.

Effects of magnetic intensity on the machining quality and tool damage in nickel-based superalloys subjected to magnetic-assisted cutting

Nickel-based superalloys are widely used in engine components due to their excellent high-temperature strength. However, their low plasticity and low thermal conductivity pose significant challenges in machining, leading to poor quality of machined parts and severe tool wear. Magnetic-assisted machining has received considerable attention as a clean and effective machining method, but its application to nickel-based superalloys is rarely reported, necessitating further exploration of its potential. This study focuses on GH4169 alloy and explores the effects of magnetic-assisted cutting (MAC) with varying intensities on the machining quality and tool wear. The experimental results indicate that the introduction of a magnetic field improves the machining quality by reducing tool wear and built-up edge adhesion. Additionally, both the plasticity and thermal conductivity of GH4169 alloy are improved under the effect of magnetic field, resulting in an 11.4 % decrease in cutting temperature. However, when the magnetic intensity ranges from 0.03 T to 0.12 T, secondary serration of the chip edges manifests, resulting in notch wear on the tool nose and a deterioration of surface quality. This secondary serration is attributed to the combined effect of tool nose radius and material plasticity under the magnetic field. As the magnetic field intensity increases further, the secondary serration gradually diminishes, and the surface roughness can be reduced by 26.5 % compared to traditional cutting. This study analyzed the relationship between machined surface, tool wear, chip morphology and magnetic field, and revealed the reasons for the differences in machining quality at different magnetic field intensities. These findings provide more possibilities for future applications of magnetic-assisted cutting to improve the machining quality of nickel-based superalloys and other difficult-to-machine metals.

Effects of chip breaker groove and tool nose radius on progressive tool wear and behavior when turning GH3536 nickel-based superalloys

Nickel-based superalloys are typically challenging to machine and often exhibit severe tool wear during the turning process, thus attracting substantial research attention. This study not only explores the tool wear mechanisms when turning GH3536 nickel-based superalloys but also introduces a focus on the role of tool geometry configuration. Tools with different chip breaker groove structures and nose radii were investigated, with results indicating the tool wear mechanisms were predominantly abrasive and adhesive. For the 04HA chip breaker, which has a 9° rake angle and a "V"-shaped bottom, there is a single point of impact with the chip during cutting, while the 04VP3 chip breaker, with a 15° rake angle and a flat bottom, has two points of impact with the chip during cutting, increasing chip deformation and favoring chip breaking, thereby suppressing the formation of built-up edge. Additionally, changes in the nose radius influenced the degree of work hardening and consequently influence the severity of notch wear, with the nose radius also impacting the chip flow angle. Based on this finding, a theoretical mathematical model describing the initial chip flow angle was established and validated. Additionally, an examination of the effects of varying operating parameters on tool life was conducted, revealing that cutting speed was the most significant factor affecting tool life, followed by feed rate and depth of cut.

Wear behavior of ultrafine WC-Co cemented carbide end mills during milling of Inconel 718

Two innovative ultrafine cemented carbide end mills, denoted C1 and C2, were synthesized through spark plasma sintering, featuring compositions of WC-8Co-0.4VC-0.4Cr3C2 and WC-40(Ti,W)–8Co-0.4VC-0.4Cr3C2, respectively. Their wear behaviors were delved into during the precision machining of Inconel 718, and distinct disparities in wear evolution and tool longevity were unveiled. C1 exhibits exceptional wear resistance, surpassing C2 by a striking margin of 7.4–9.5, depending on the cutting speed employed. The sharp cutting edge of C1, characterized by a single hard phase of WC, minimal grain size, and high hardness, demonstrates excellent wear resistance and deformation resistance, thereby minimizing the onset of notch wear. In contrast, C2 experiences severe adhesive and diffusive wear phenomena, which culminate in substantial flank wear and cutting edge chipping. The addition of 40 wt% of (Ti,W)C exacerbates adhesion, flaking, and notch wear during machining. The prolonged and intensified adhesive wear witnessed in C2 leads to the deterioration of the tool surface and the formation of deep wear craters on the flank face. A comparison evaluation involving the prepared novel tools and commercially available end mills reveals that C1 boasts a longer tool life that outstrip those of its commercial counterparts by approximately 1.7–3.5 times under identical cutting conditions.

Pemesinan Paduan Ti-6Al-4V ELI

Titanium alloy material Ti-6Al-4V ELI (Extra Low Interstitial) is a type of alloy that has very similar properties to Ti-6Al-4V (Grade 5) alloy, which is the most widely used material, but only differs in terms of properties. his tenacity. Ti-6Al-4V ELI has higher ductility and better fracture toughness. In addition, this material also has a good ability to work at high temperatures without losing its main properties. The main properties of this material are corrosion toughness at high temperatures and excellent weight to strength ratio. Referring to these advantages, the alloy material of the Ti-6Al-4V ELI type has been developed in many fields including the field of planting materials in the medical field, the aircraft industry, applications in the field of military weapons, the manufacture of racing vehicle components and also high pressure vessels for storing materials. low-temperature (cryogenic) liquid nitrogen [16].. During the machining process of titanium alloy, many things become obstacles because this material is a material that is difficult to machine. This is because the titanium alloy has high hardness, there is often a reaction between the cutting tool and the workpiece material during the cutting process, and there is an accumulation of high temperatures in the cutting area. Factors cutting speed and feed rate are the two dominant factors on the formation of cutting tool wear, both wear on the face or crater side. Damage to the cutting tool is also followed by damage to the surface of the workpiece being machined or the surface quality of the workpiece. The dominant wear that occurs in the rib face area is wear due to adhesion, notch wear, while wear in the crater area is diffusion that occurs during the machining process. Meanwhile, the cutting temperature has a direct impact on the surface quality of the workpiece being machined. The factor of high cutting speed with low feed rate is a combination of factors that provide good cutting force. Meanwhile, insert type cutting tools that have a hard coating, such as TiN, TiAlN and TiCrN play a significant role in the formation of tool wear. Likewise, hard coated tools provide better performance compared to uncoated insert tools. Machining with the Minimum Quantity Lubrication (MQL) method gives better results compared to dry machining and machining using flooded cooling.Keywords: machining, Ti-6Al-4V ELI, cutting tool, materials.

Mechanical behavior, tribological properties, and thermal stability of (AlCrNbSiTiVZr)N high entropy alloy nitride coatings and their application to Inconel 718 milling

(AlCrNbSiTiVZr)N high entropy alloy nitride coatings were deposited on silicon wafers and WC substrates using a radio-frequency magnetron sputtering system with nitrogen flow rates of 0, 10, 15, and 20 sccm (coating codes: N0, N10, N15, and N20, respectively). The coatings were subsequently annealed in a vacuum at 950 °C for 1 h (coating codes: HN0, HN10, HN15, and HN20). The effects of the nitrogen flow rate on the composition, microstructure, mechanical properties, and tribological properties of the coatings were systematically examined. The N0 and N10 coatings had amorphous structures, whereas the N15 and N20 coatings had FCC structures. Among the as-deposited coatings, the N20 coating exhibited excellent mechanical properties and a superior tribological performance. All the annealed coatings showed an FCC structure and formed a V2O5 solid lubricant layer in ball-on-disk sliding tests. The lubricant layer reduced the coefficient of friction and led to a smooth friction curve. The annealed coatings additionally showed a high hardness, good adhesion strength, and excellent thermal stability. The mechanical and tribological properties of the HN20 coating were particularly impressive. In Inconel 718 milling trials, the N20-coated cutter showed an excellent machining performance, with significantly reduced flank wear, notch wear, and built-up edge adhesion.

A Comparative Performance Investigation of Single- and Double-Nozzle Pulse Mode Minimum Quantity Lubrication Systems in Turning Super-Duplex Steel Using a Weighted Pugh Matrix Sustainable Approach

This study investigates the performance comparison of machining of UNS S32750 super-duplex stainless steel under single- and double-nozzle pulse mode minimum quantity lubrication (MQL) conditions. The pulse mode MQL system delivers lubricant pulses at specific intervals. The Taguchi L9 design, with three factors and their three levels, was taken to perform the CNC turning experiments under both single-nozzle and double-nozzle MQL cooling environments. The surface roughness (Ra), tool-flank wear (VB), tool-flank temperature (Tf), power consumption (Pc), and material removal rate (MRR) are evaluated and compared as performance indicators. In comparison to single-nozzle MQL, the responses of Ra, VB, Tf, and Pc were found to be decreased by 11.16%, 21.24%, 7.07%, and 3.16% under double-nozzle conditions, respectively, whereas MRR was found to be 18.37% higher under double-nozzle conditions. The MQL pulse time was found to be an important variable that affects Ra, VB, Tf, and MRR significantly. Under both cooling scenarios, common wears such as abrasion, built-up edges, adhesion, and notch wear are detected. Furthermore, the Pugh matrix-based sustainability evaluation results revealed that the double-nozzle MQL technique was superior to single-nozzle MQL, achieving improved sustainability for machining super-duplex stainless steel.

Cutting Performance and Wear Behavior of Self‐Developed Silicon Nitride Ceramic End Mills with Optimized Structure for High‐Speed Machining of GH4099

Ceramic tool materials possess a wide range of potential in machining nickel‐based superalloys due to their superior wear resistance, high‐temperature hardness, and strong chemical stability. Herein, a structural optimization scheme of self‐developed silicon nitride ceramic end mill based on stiffness enhancement and performance improvement is proposed, and the key geometric angular parameters scope of the self‐developed ceramic end mills are prioritized via the finite‐element simulation method. Through precision grinding manufacturing and sandblasting pretreatment, the cutting performance and tool wear behavior of three optimized self‐developed silicon nitride ceramic end mills (called S4‐1, S4‐2, S4‐3 respectively) are comprehensively analyzed in comparison, including cutting force, milling temperature, surface quality, and tool life. The results indicate that the cutting force and cutting temperature of all the optimized ceramic end mills are effectively restrained compared with the nonoptimized ceramic tool(S4), and the final workpiece surface roughness is significantly reduced. Further, better surface quality can be obtained by optimized ceramic mills. In terms of tool life, ceramic end mill with optimized construction in best can be increased by up to 1.9 times. The wear mechanism and pattern of the three optimized ceramic milling tools are similar, which is adhesive wear, diffusion wear, and notch wear. Overall, the effectiveness of the optimization scheme for ceramic end mill is successfully verified.

Analysis of tool wear and surface roughness in machining of AISI 4462 duplex stainless steel

Abstract Machining is one of the most precise manufacturing methods used in the manufacturing of machine parts. In machining, significant tool wear is observed due to cutting tool-to-workpiece contact. Controlling tool wear and minimizing the effect of tool wear in this method is an important research topic. In this study, machinability tests were carried out on AISI 4462 duplex stainless steel materials, which are in the hard-to-cut material class. In the experiments, the changes in tool life and surface roughness were analyzed by using 150, 180, and 210 m/min cutting speeds; 0.1 mm feed; and 0.8 mm depth of cut. Increasing cutting speed significantly increased wear and reduced tool life. However, experiments with cutting speeds of 180 m/min and 210 m/min had the same tool life values. In addition, significant notch wear and BUE formation were observed on the tool surface. Besides, it was determined that the surface roughness deteriorated due to tool wear. In addition, surface deterioration due to chip wrapping was also observed in many passes.

Investigation of Cutting Performance of Nano/Layered Hard Coatings in Face Milling of AISI D2 Steel

In the die-molding industry, milling steels in a hardened condition is common. Tool wear and cutting-forces occurring during this process must be considered for better surface quality. The cutting performance of nano-layered AlTiN/TiN coated carbide cutting-tools in AISI D2 face-milling was evaluated in this work. Single-layer hard-coated carbide cutting-tools and uncoated cutting-tools were used to compare cutting performance testing. All cutting-speeds nano-layer AlTiN/TiN coated carbide cutting tool presented longer cutting-length than TiAlN and TiN coated ones and uncoated tool. Notch wear is an overriding wear mechanism, followed by build-up edge formation for all cutting-tools. Using a nano-layer AlTiN / TiN hard-coating, cutting-force values were lowered in all experiments.

On the Influence of Binder Material in PCBN Cutting Tools for Turning Operations of Inconel 718

Inconel 718 is a highly valued material in the aerospace and nuclear industries due to the fact of its exceptional properties. However, the processing of this material is quite difficult, especially through machining processes. Machining this material results in rapid tool wear, even when low material removal rates are considered. In this study, instrumented turning experiments were employed to evaluate the machinability of Inconel 718 alloy using PCBN tools while assessing the usage of two distinct binder phases, TiN and TiC, for those cutting tools. It was found that the tool life was highly sensitive to the cutting speeds but also affected by the workpiece mechanical properties. At lower cutting speeds, notch wear significantly impacted the tool integrity, whereas at higher cutting speeds, flank wear was the primary failure mode of the tool. The flank wear of the tools with TiN-based binder outperformed TiC by almost 30%, presenting a more consistent behavior when machining.

The correlation of surface roughness and tool edge condition under sustainable cryogenic machining

This paper investigates the correlation between surface roughness of Inconel 718 and tool edge condition of ball nose inserts when milled at high speed. The cutting parameters were varied as follows; cutting speed: 120–140 m/min, feed rate: 0.15–0.25 mm/tooth, and axial depth of cut: 0.3–0.7 mm. For a sustainable machining approach, the experimental works were carried out under a smooth supply of cryogenic coolant which is a mix of liquid CO2, gas CO2, and compressed air. The experimental results revealed that the range of surface roughness obtained is from 0.114 to 0.197 µm. Along the cutting process, the tool wear patterns such as the abrasion, chipping, and the intermittent build-up-edge near the depth of cut cause the rapid increase of tool wear as well as the roughness of the machined surface with a significant correlation between them. However, the roughness was slowly reduced and became stable with the increase of notch wear. The finding could be used as a prediction reference for monitoring surface roughness and tool wear progress under cryogenic conditions. It also provides foundations for further research on machinability under this sustainable approach.

The effects of cryogenic cooling on tool wear and chip morphology in turning of tantalum-tungsten alloys Ta-2.5W

Tantalum‑tungsten alloy is particularly difficult to cut due to its high plasticity. Environmentally friendly liquid nitrogen cooling and hybrid minimum quantity of lubricant-low temperature CO2 (MQL + CO2) technology can improve the machinability of ductile materials. In this paper, the experimental and numerical turning of tantalum‑tungsten alloy Ta-2.5W were carried out under cryogenic cooling conditions. The effects of liquid nitrogen cooling and MQL + CO2 cooling on the wear mechanism of cutting tools and the formation mechanism of chips were studied. The Rehbinder effect induced by the surfactant in MQL + CO2 system was analyzed. The results show that the cutting tool life can be effectively improved by 50 % in turning of Ta-2.5W under both cryogenic cooling conditions. Different from the flank wear dominated by adhesive wear under water-based emulsified cutting fluid, the tool failure was mainly caused by the notch wear under cryogenic cooling conditions. The chips in turning of high plastic Ta-2.5W showed a “pomelo-meat shaped” morphology with non-uniformed and non-periodic folds. Rehbinder effect was induced by the surfactant in MQL + CO2 system, which transformed the “pomelo-meat shaped” chips into “layered-rock shaped” chips. Under this effect, the machinability of tantalum‑tungsten alloy was effectively improved with a reduction of chip thickness and increment of the tool life.

Suppressing notch wear by changing the tool path in the side milling of a Ti-6Al-4 V alloy

Suppressing notch wear by changing the tool path in the side milling of a Ti-6Al-4 V alloy

Effect of Sintering Parameters on the Mechanical Properties and Wear Performance of Alumina Inserts

The sintering temperature and holding time have a significant impact on the densification of a ceramic compact. In this study, alumina inserts were made with varying sintering temperatures and holding times. The procedure began with the compacting of alumina powders inside a mould with trapezium and round shapes. These inserts were then sintered between 1200 °C and 1400 °C for 5 to 9 h holding time. The sintered samples underwent analysis based on the shrinkage size, density, and microstructure. The sample with the highest density was chosen for additional machining tests. The results showed that the alumina shrinkage ranged from 3 to 6%, with a maximum relative density of 91.3% recorded when the sintering parameter was applied at 1400 °C and a 9 h holding time. The transition of the grain growth was observed depending on the sintering temperature and heating duration. When machined with AISI 1045 carbon steel, the sintered alumina inserts achieved a maximum tool life of 35 s at a cutting speed of 350 m/min. The sintered inserts exhibited brittle characteristics with a dominant notch wear and abrasive mechanisms.

The effect of pulsating lubrication method on rake face cutting tool during end milling of inconel 718

Inconel 718 is widely used in components under harsh conditions. The abrasiveness of the carbide particles, poor heat conductivity and built-up edge (BUE) formation are common issues which warrant further investigation. In this work, the failure mode of a TiAlN/AlCrN-coated tungsten carbide (WC) tool during milling of Inconel 718 using different lubrication strategies, namely pulsating lubrication (PLS) and flood-coolant (FC), were compared. The effects of the pulsating water stream at 2000 pulse/min, when applying lubrication pressures at 8 bar, were discussed. Reduction of BUE at the tool tip was observed. The study revealed that this approach is better in delaying pitting, notch wear formation and flaking damage. Hence, the service life of a cutting tool can be extended when compared to the flood-coolant strategy.

A systematic investigation of the tribological behaviour of oxides formed on AlSiTiN, CrAlTiN, and CrAlSiTiN coatings

Changes with temperature in the microstructure and oxide formation of AlSiTiN, CrAlTiN, and CrAlSiTiN coatings were systematically studied using various characterisation techniques. By correlating these results with their tribological behaviour seen in the reciprocating sliding tests, it was concluded that SiO2 was more lubricous than Cr2O3, and provided better wear protection. Although an increase in the amount of SiO2 produced in the tribo-layer resulted in a greater lubricating effect, Cr2O3 produced a much lesser of such benefit. The effect of SiO2 as lubricant was also seen in machining. In the machining of stainless steel at 100 m/min, where flank and notch wear was due to abrasion and mechanical cracking, the CrAlSiTiN coated tools with the highest hardness, H/E, and H3/E2 exhibited the highest wear resistance. However, AlSiTiN coated tools demonstrated reduced flank wear and the lowest wear in machining at 200 m/min. The formation of SiO2 could account for this low level of wear.

Mill condition monitoring based on instantaneous identification of specific force coefficients under variable cutting conditions

Following the necessity of increased performance and availability requirements for manufacturing systems, research is becoming more and more attracted by monitoring solutions for cutting tools. In this paper, a robust unsupervised strategy for milling tool wear monitoring under variable process parameters and lubrication conditions is presented. The proposed method is completely unsupervised, thus not requiring any kind of training procedure, and is validated on different machine tools. The solution is based upon the online estimation of specific force coefficients (SFC) from instantaneous cutting forces in high-feed milling of Ti6Al4V workpiece. This avoids the need for continuously variable feed per tooth during cutting tests, necessitated for the application of reference literature approach. For this purpose, a novel high-feed mill mechanistic model was conceived and developed. Five run-to-failures were performed in different lubrication conditions – cryogenic and traditional lubrication – with different cutting speeds (50 m/min, 70 m/min and 125 m/min) on two different machine tools. Principal Component Regression was introduced in order to deal with the variability of the estimated coefficients. Self-starting tabular cusum control charts were implemented and demonstrated high accuracy and reliability in the prediction of notch wear phenomena as well as chipping of tool cutting edges for all the cases considered. The solution detected an out-of-control conditions ranging from 166μm to 499μm of maximum flank wear for the analysed tests. The mean prediction error with respect to the 600μm threshold is of −45% with a peak of −72%, whereas reference literature algorithms reach −57% and −66%, respectively. A sensitivity analysis of control chart threshold was performed with reference to the maximum flank wear at the detection point. In a supervised scenario, the threshold can be increased to obtain a less conservative approach: for instance, a mean prediction error of −41% was reached by doubling the threshold.