Monel K-500 Research Articles

Influence of WEDM input variables on the machinability of Ni–Cu superalloy

ABSTRACT The study investigates the influence of Wire-cut Electrical Discharge Machining (WEDM) input variables on the Ni–Cu superalloy, crucial in marine environments. Input variables include Input current (Ic), Pulse on Time (TON), Pulse off Time (TOFF), Servo Voltage (SV), and Wire Feed (WF) rate, while output variables are Machine Speed (Mc), Kerf Width (K), and Material Removal Rate (MRR). Utilizing an L16 orthogonal matrix, experiments were conducted. The Taguchi method examines single output variables, while the Grey Relational Grade Algorithm (GRA) assesses multi-objective outputs. GRA identifies optimal input combinations, crucial for maximizing the machining performance. ANOVA of GRA results highlights Pulse on Time (TON), Input current (Ic), and Servo Voltage (SV) as significant factors affecting Mc, K, and MRR. This analysis underscores their importance in optimizing the WEDM process for Ni–Cu (MONEL K-500 superalloy).

Laser-based directed energy deposition of Monel K-500 and Stellite 6 multi-materials

ABSTRACT Laser-based directed energy deposition (L-DED) offers significant advantages for repairing metal structures, particularly in the marine and offshore industry where corrosion-resistant materials like Monel K-500 (a Ni-Cu alloy) lack strength and wear resistance. This study addresses this issue by producing Monel K-500 with high-strength Stellite 6 (a Co-Cr alloy). Two types of multi-material samples were created using L-DED: interlayered and mixed powder samples. The interlayered samples experienced cracking at the material interface, while the mixed powder samples were crack-free and exhibited improved mechanical properties, with yield strength increasing from 208.3 MPa to 490.2 MPa and ultimate tensile strength from 429.7 MPa to 887.0 MPa compared to single Monel K-500 samples. This research demonstrated the potential of in-situ alloying during the L-DED process to enhance alloy properties and highlighted the challenges of abrupt compositional changes leading to cracking, suggesting mitigation strategies for successful production.

Multi-objective optimization of an EDM process for Monel K-500 alloy using response surface methodology-multi-objective dragonfly algorithm

Monel K-500 is a high-performance superalloy composed of nickel and copper, renowned for its exceptional strength, hardness, and resistance to corrosion. To machine this material more precisely and accurately, Electrical Discharge Machining (EDM) is one of the best choices. In EDM, material removal rate (MRR) and electrode wear rate (EWR) are crucial performance parameters that are often conflicting in nature. These parameters depend on several input variables, including peak current (Ip), pulse on time (Ton), duty cycle (Tau), and servo voltage (SV). Optimizing the EDM process is essential for enhancing performance. In this research, a set of experiments were conducted using EDM on Monel K500 alloy to determine the optimal process parameters. The Box–Behnken design was used to prepare the experimental design matrix. Utilizing the experimental data, a second-order mathematical model was developed using Response Surface Methodology (RSM). R2 value is found to be 99.40% and 96.60% for MRR and EWR RSM-based prediction model, respectively. High value of R2 is indicated is indicated good adequacy for prediction. The mathematical model further used in multi-objective dragonfly algorithm (MODA): a new meta-heuristic optimization technique to solve multi-objective optimization problem of EDM. The MODA is a very useful technique to achieve optimal solutions from the multi decision criteria. Utilizing this technique, a set of non-dominated solutions was obtained. Further, the TOPSIS method was used to determine the most desirable optimal solution, which was found to be 0.0135 mm3/min for EWR and 6.968 mm3/min for MRR. These results were obtained when the optimal process parameters were selected as Ip = 6 A, Ton = 200 µs, Tau = 12, and SV = 41.6 V. Operators can machine Monel K500 by selecting the above-mentioned optimal parameters to achieve the best performance.

A Comparative Analysis of a Microstructure and Properties for Monel K500 Hot-Rolled to a Round Bar and Wire Deposited on a Round Surface

Metal manufacturing processes based on deformation (forging, rolling) result in a fine grain structure with a complex dislocation substructure, which positively influence mechanical properties. Casting and additive manufacturing (powder- or wire-based) usually produce a coarse grain structure with a poorly developed dislocation substructure, which negatively affect mechanical properties. Heat treatment may alter phase balance and stimulate precipitation strengthening; however, precipitation kinetics depends on the dislocation substructure. In this paper, a comparative study of the microstructure and strength is presented for Monel K500 alloy containing 63 Ni, 30 Cu, 2.0 Mn, and 2.0 Fe (wt.%), and microalloyed with Al, Ti, and C hot-rolled to a round bar and deposited on a round surface using wire additive manufacturing (WAAM) technology. An increased dislocation density and number density of fine precipitates resulted in 8–25% higher hardness and 1.8–2.6 times higher compression yield stress in the hot-rolled alloy compared to these in the WAAM-produced alloy. However, due to a high work hardening rate, only 3–10% cold deformation was necessary to increase the strength of the WAAM alloy to this of the hot-rolled one. Age hardening heat treatment, through the intensification of the precipitation strengthening mechanism, reduced the value of cold deformation strain required to equalise the properties. Based on the obtained results, a new technology consisting of additive manufacturing, heat treatment, and cold deformation can be proposed. It can produce WAAM components with strength and hardness improved to the level of hot-rolled components, which is a significant development of additive manufacturing.

Boronizing of Monel K500 alloy: Microstructural characterization and modeling of boron diffusion

In this study, the thermochemical treatments were carried out using the powder-pack boronizing method at temperatures ranging from 1123 K to 1223 K for durations of 2 to 6 h, with the aim of improving the surface properties of Monel K500 alloy. Microstructural investigation of the boride layers, conducted using optical microscopy (OM) and scanning electron microscopy (SEM), revealed a needle-like layer structure with high porosity homogeneously distributed on the surface. The results of XRD analysis showed that the boride layer contained different nickel borides (Ni2B, Ni3B, Ni4B3 and NiB12), iron borides (Fe2B and Fe3B) and complex borides (Fe4.5Ni18.5B6 and Fe3Ni3B). The presence and amount of elements in the boride layer were determined by EDS analysis. This study focused mainly on diffusion kinetics studies of boronized Monel K500 alloy. Growth kinetics of the boride layer were investigated using three different approaches such as parabolic growth model, regression model and mean diffusion coefficient (MDC) model. Boron activation energy values were calculated and found to be quite similar, at 266.14 kJ mol−1 and 266.17 kJ mol−1 using the MDC model and parabolic growth model, respectively. These values were compared with similar results reported in the literature.

Evaluation of nano fluids in minimum quantity lubrication hard machining of Monel K500 material for high heat-resistant application

Evaluation of nano fluids in minimum quantity lubrication hard machining of Monel K500 material for high heat-resistant application

Synergistic effect between cavitation erosion and corrosion of Monel K500 alloy in 3.5 wt% NaCl solution

Cavitation erosion-corrosion simultaneously damaged the material through mechanical attack and electrochemical corrosion. In this work, experiments were performed on Monel K500 alloy in deionized water and 3.5 wt% NaCl solution using an indirect ultrasonic vibration system to investigate the synergistic effect between cavitation erosion and corrosion. Mass loss measurement and surface topography observation were used to identify the different stages of cavitation erosion. The electrochemical properties at different cavitation stages were analyzed by EIS technique. Results showed that the synergistic effect between cavitation erosion and corrosion exacerbated cavitation damage, and the weight loss rate in 3.5 wt% NaCl solution was about 10% higher than that in deionized water. The increase in ion diffusion and oxygen supply caused by violent agitation accelerated the surface corrosion process, resulting in corrosion-enhanced erosion. Mechanical damage to the material surface during the cavitation process also accelerated the corrosion process, indicating that cavitation-enhanced corrosion was the primary synergistic mechanism. Pure cavitation accounted for 90.75% of total mass loss, suggesting that mechanical deterioration dominated the overall cavitation erosion and corrosion process. Cavitation-enhanced corrosion accounting for 96.12% of the synergistic effect，was the main synergistic mechanism.

Effect of Ti on stress corrosion cracking behavior and mechanism of Monel K500 alloy in flowing seawater

Purpose The purpose of this paper is to investigate the effect Ti on stress corrosion cracking (SCC) and flow accelerated stress corrosion cracking (FA-SCC) behavior and mechanisms of Monel K500 alloy. Design/methodology/approach Monel K500 alloy with different Ti contents was designed. A metallurgical microscope (XJP-3C) and scanning electron microscopy (EV0 MA15 Zeiss) with an energy dispersive spectroscopy were used to analyze the microstructure of the Monel K500 alloy. In situ electrochemical tests were carried out in static and flowing seawater to study FA-SCC behavior. Findings The number of TiCN particles in the alloy increased as the increase of Ti content. The static corrosion and SCC of Monel K500 alloy are reduced as the content of Ti increases. Generally, the SCC of alloys was caused by the synergistic effect of the anodic dissolution at exposed metal matrix and the pit corrosion of metal matrix adjacent to TiCN particles, which was further accelerated by flowing. Originality/value The corrosion behavior and mechanism of Monel K500 alloy with different Ti contents in a complex flowing seawater environment are still unclear, which remain systematic study to insure the safe service of the alloy.

Investigations of performance characteristics on direct metal laser sintered MONEL K-500 superalloy

MONEL K-500 superalloy is difficult to manufacture precisely in traditional manufacturing processes like casting, forming and machining. The direct metal laser sintering (DMLS) process is one of the best metal additive manufacturing processes used in this work. In this work, Laser Power (LP), Scan Speed (SS), Hatch Distance (HD) and Layer Thickness (LT) are used as DMLS process parameters. L09 Orthogonal array is used for printing the MONEL K-500 metal parts. The performance characteristics like ultimate tensile strength (UTS) and surface toughness (Ra ) are improved by 2% and 17% for the Taguchi optimum parameter levels. Contour plots explained the interaction effects of DMLS process parameters on performance characteristics. The better microstructural characteristics obtained the higher optimum parameter level.

Effect of grain structure on the mechanical properties of a Monel alloy fabricated by laser-based directed energy deposition

Monel K-500 is a Ni–Cu alloy widely used in the marine and offshore industry due to their superior resistance to corrosion in seawater and hence easily degraded. To address this problem, laser-based directed energy deposition (LDED) is used to repair or refabricate these high-value worn parts. To optimize the mechanical properties of repaired parts, the commonly applied solution and aging is not ideal because it also changes the properties of the base materials. Consequently, in situ control of the grain structures during the LDED process becomes an effective approach for high-performance repair. In this study, we fabricated a duplex grain structure with small grain size and low texture intensity using low laser power and scanning velocity. The duplex microstructure consists of short columnar grains and zigzag-distributed fine equiaxed grains. The formation of this grain structure is dependent on both the solidification and recrystallization mechanisms. The strength of this grain structure is improved to 523.5 MPa without the sacrifice of ductility, which is instead 20% higher than that of the counterpart consisting of typical columnar grains due to the grain refinement and crack toughening. The mechanical properties of the alloy with the duplex grain structure are even comparable to heat-treated Monel K-500 fabricated by wire arc additive manufacturing. This work provides valuable insights into the in situ optimization of the microstructure and mechanical properties of LDED-fabricated parts.

Measurement of flank wear in turning of Monel K500 material based on novel image processing technique

In this article, a novel method for calculating the amount of flank wear that occurs during the turning of the nickel-based superalloy Monel K500 is presented. In order to determine how much flank wear the worn-out insert has sustained, a technique known as the Modified MSER (Maximally Stable Extremal Regions) was applied to it. In this particular piece of research, the algorithm known as the Modified MSER is referred to as the Flank Net. When the data generated by Flank-Net and the flank wear analysed by a tool maker's microscope were compared, an average percentage error of 4.038 percent was found to have been created by Flank-Net. As a result of the strong work-hardening tendency of the Monel K500 and the poor heat conductivity of the material, rapid tool wear has been observed. This has an influence on the dimensional and geometrical precision of the machined products. As a result, research was conducted to investigate the effect that the machining parameters have on tool wear. The experimental trials were navigated with the assistance of the L9 orthogonal array.

The effect of Ni201 transition layer on the corrosion, wear and synergetic cavitation erosion-corrosion behavior of CMT-Monel K500 coating

The Monel K500 modified coating with Ni201 as the transition layer was prepared on the 304 stainless steel substrate by cold metal transfer (CMT) technology. Different from the Monel K500 coatings with direct deposition, the Ni201 transition layer can effectively block the diffusion of Fe and other elements in the substrate and avoid the deterioration of corrosion resistance of Monel K500 coating caused by galvanic corrosion in artificial seawater, which showed the highest polarization resistance and the strongest passivation tendency. In addition, the diffusion of Ni atoms in the transition layer compensated and stabilized the alloy element composition of the Monel K500 coating, making it have a finer microstructure and show higher microhardness and wear resistance. After 10 h- cavitation erosion (CE), the Monel K500 coating with transition layer showed the lowest mean depth erosion rates (MDER) of 2.2 ± 0.09 μm/h as it maintains the highest self-healing ability and integrity of passive film during the long-term synergistic effect of cavitation erosion and corrosion (SCEC). The introduce of the Ni201 transition layer can effectively improve the corrosion-cavitation and wear properties of CMT-Monel K500 surface modified coating, and then effectively prolong the service life of seawater overflow components such as butterfly valves, pump bodies, hydraulic turbines and heat exchangers, which has great application potential in the field of tribo-corrosion in ocean engineering.

Stress corrosion cracking behavior and mechanism of aging treated Monel K500 alloy in flowing seawater

Stress corrosion cracking behavior and mechanism of aging treated Monel K500 alloy in flowing seawater

Strengthening mechanisms in Monel K500 alloyed with Al and Ti

Monel alloys containing 63Ni–30Cu (wt%) are often used in applications requiring simultaneously high strength and corrosion resistance. Additions of Ti, Al and C to Monel K500 lead to formation of TiC, Ni3Al and Ni3Ti particles, which provide precipitation strengthening effect following heat treatment. The traditional heat treatment schedule includes solution annealing above 1000 °C and aging in the 400–600 °C temperature range. However, no correlation exists between the alloy composition and the heat treatment schedule (holding temperature and time) required to obtain the optimum microstructure and mechanical properties. This may result in excessive alloying, energy loses during heat treatment, and higher product costs. In this work, we investigate the effect of solution annealing part of heat treatment schedule on microstructure (particularly, particle precipitation and grain growth), hardness and strength. For hot rolled samples, solution annealing followed by aging was shown to result in lower strength compared to aging without annealing. The analysis of strengthening mechanisms carried out utilising our theory for calculation of solute atom concentrations has explained the strength variation with heat treatment and has shown (i) a lower strength after annealing and aging being related to dissolution of fine (< 20 nm) TiC particles, (ii) Ti- and Al-rich precipitates to provide a larger strengthening than Ti and Al solute atoms, (iii) Al to be a more effective strengthening agent than Ti, and (iv) the majority of Al to remain in solution for both processing schedules, this indicates potential for mechanical properties improvement via optimisation of the heat treatment schedule aiming to generate more Al-rich precipitates.

INVESTIGATION OF CHIP MORPHOLOGY ON TURNING OF MONEL UNDER NANOGRAPHENE AND NANO CuO COOLANTS

This paper deals with experimental investigation on chip formation of machining of Monel K500 and its characteristics are studied. Two different nanocutting fluids namely nanoCuO and nanographenes are used for turning operation and the performance of the two cutting fluids is evaluated and the corresponding responses are recorded for the selection of better cutting fluid. This experiment is carried out with the help of SEM which picturizes the microstructure and surface distribution of the chips. The various output responses like chip thickness, chip compression ratio, and surface roughness are portrayed. The desirable effects on the properties of the machined material obtained by the variation of process parameters like cutting speed, cutting depth, and feed rate are analyzed. Results show that the thickness of chips (corresponding metal removal rate) is reduced considerably by 10–15% and the surface roughness is reduced by 20–30% when nanographene cutting fluids are used.

Effect of TiC precipitation on the corrosion behavior of Monel K500 alloy in 3.5 wt.% NaCl solution

The microstructure of Monel K500 alloy was investigated consisting of (Ni-Cu-Al) solid solution matrix distributed with TiC precipitates. The semi-coherent interface was formed between the precipitates and the matrix, which reduced the phase boundary energy, resulting in the preferential corrosion of matrix instead of the interface in 3.5 wt.% NaCl solution. Immersion experiment combined with electrochemical test exhibited the uniform corrosion behavior of the alloy, covered with passivation film consisted of surface polycrystal layer and inner amorphous layer. Moreover, the accumulation of CuO in the film with time, led to generation of microcracks as well as deterioration of corrosion resistance.

Microstructure and mechanical properties of a Monel K-500 alloy fabricated by directed energy deposition

Directed energy deposition (DED) is a mainstream metal additive manufacturing technique that can fabricate near-net-shape components and repair damaged parts with a high build rate. Monel K-500 is a Ni-based alloy widely used for marine and offshore applications because of its excellent corrosion resistance and good combination of strength and ductility. In this study, laser-assisted DED (L-DED) was used to print Monel K-500 parts from powder. The key process parameters, including the laser power and scanning speed, were optimized to obtain single beads with desirable geometry and blocks with nearly full density (≥99%). The block samples printed by L-DED exhibit ∼20% higher ultimate tensile strength and ∼60% higher elongation to failure than their conventional cast counterparts. From the microstructure examination, it is found that the parts printed with a low laser power have fine grains and an alternating equiaxed/columnar-grain sandwich structure with high tensile strength. In contrast, those printed with a high laser power have coarse columnar grains with a strong <001> texture but low tensile strength. The mechanism accounting for the grain structure evolution was studied by computational fluid dynamics and cellular automata simulations. The anisotropy in mechanical properties is mainly attributed to the difference in grain boundary strengthening effects. Moreover, the increase in hardness and tensile strength of the heat-treated samples is attributed to the precipitation hardening effect. This work exemplifies how the process parameters can be tuned to control the grain texture to achieve superior mechanical properties for parts of Monel K-500 and other metals printed by L-DED.

Performance analysis of electrode materials in electro discharge machining of monel K-500

The present work focusses on the electrical discharge machining (EDM) of Monel K 500 super alloy with different electrodes. The study’s objective is to examine the effects of process parameters and electrode materials (Cu, W-Cu, and graphite) in terms of surface quality, material removal rateand electrode wear. In this context, EDM experiments have been designed and performed using the L27 standard orthogonal array of the Taguchi method with a statistical approach. The outcomes of this study reveal that the current plays an important role to improve the EDM machining performance of Monel K 500. The surface quality is approximately 11.62% and 55.52%, respectively better when Monel K-500 alloy is machined with copper electrodes compared to those in W-Cu and graphite electrodes. Moreover, The W-Cu electrode’s wear is approximately 15.73% and 21.05%, respectively less than those of graphite and Cu electrodes in optimum processing conditions. Graphite electrodes are better than Cu and W-Cu electrodes in terms of material removal rate. The statistical results also show that the estimation equations developed to select the optimum production conditions to give high accuracy results.

Multi response optimization of machining parameters for an annealed Monel K 500 alloy in drilling using Machine learning techniques and ANN

Manufacturing companies are focusing on continuous process development to thrive in today’s quality-conscious market. It is particularly relevant to investigate machining processes for advanced materials such as superalloys. Drilling is a major operation that is used in the majority of manufacturing processes. Hence, this research work is focused on investigating the drilling performance of the Monel K500. The output responses under consideration are metal removal rate (MRR), surface roughness, and tool wear. Various contemporary techniques were utilized in this work, namely machine learning methods, artificial neural networks, principal component analysis, and grey relation analysis using uncoated, coated, and HSS (high-speed steel) drills. After annealing, the softened material can be easily machined to increase the MRR and decrease tool wear and surface roughness. The experimental results show that, after annealing, the surface roughness values for HSS drills have been reduced by 23.86%, uncoated drills by 27.29%, and coated drills by 29.27%, respectively. Moreover, tool wear values for HSS drills decreased by 28.51%, uncoated drills by 34.7%, and coated drills by 33.71%, based on the relative error approach. MRR values for HSS drills increased by 20.51 %, uncoated drills by 23.08%, and coated drills by 23.5%, respectively. For PCA (principal component analysis), feed (47%), and for GRA (gray relation analysis), feed (40.1%) will be the significant parameter followed by speed, and both methods have identified the same experimental run values for optimization of cutting parameters. The theoretical values were predicted using machine learning methods, which utilized the Python language using the Google Colab and then validated with experimental values. The predicted values obtained by the decision tree are close to the measured values as compared to support vector regression and K-nearest neighbor based on relative error. The estimated values obtained by the ANN (artificial neural networks) approach, using Easy NN plus software, match well with the actual values, with a slight deviation.

Cavitation erosion mechanisms of HVOF-sprayed Ni-based cermet coatings in 3.5% NaCl environment

Monel K-500 is a nickel-based alloy that is a widely used material in industries like hydraulic, chemical and marine. In its marine application, such as in seawater, Monel alloy suffers from high cavitation and corrosion. In one of the approaches to control these degradations, thermal spray coatings are recommended to enhance the resistance against these degradations. The current study assesses the synergic effect of cavitation erosion (CE) and corrosion on two HVOF-sprayed nickel-based cermet coatings, WC-10Ni5Cr (WC-NiCr) and WC-18Hastelloy C (WC-H), on Monel K-500 substrate. CE tests were conducted for 15 h in a corrosive (3.5% NaCl) environment. It was observed that WC-NiCr coating reduced the CE losses in Monel alloy by 45%. In pure cavitation (DI water) conditions, the better CE of a coating originates from its better combination of microhardness and indentation toughness. Whereas, in a corrosive medium, the CE behavior of a coating depends upon its electrochemical properties too. Electrochemical corrosion test on both the coatings revealed that WC-NiCr coating had better corrosion results than that of WC-H coating due to its higher corrosion potential (Ecorr) value and slightly lower corrosion current density which may influence the CE performance of the investigated coatings. In-depth study of the erosion mechanism for each of the coatings was conducted using Scanning Electron Microscopy (SEM). It was observed that due to the effect of the corrosive medium, several pits and pores were generated over the coating surface. These defects provided additional nucleation sites for CE in the coatings resulting in a high level of erosion losses in the coatings. Considering the effects of cavitation and corrosion simultaneously, HVOF-sprayed WC-NiCr coating is recommended to enhance the cavitation-corrosion resistance in Monel K-500 alloy.