Browsing by Author "Kailas, S.V."

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Effect of Laser Surface Modification on Texture, Roughness, Wettability and Surface Energy of Hastelloy C22, C276 & X
(Trans Tech Publications Ltd, 2024) Suvin, P.S.; Singh, A.; Depu Kumar Patro, B.; Edachery, V.; Kailas, S.V.; Horng, J.H.
Hastelloy is a nickel-chromium-molybdenum-iron-based alloy and a member of the ‘superalloy’ family. Hastelloy has exceptional properties like high strength, wear resistance and hightemperature stress-corrosion resistance. Therefore, Hastelloy is used in gas turbines, power plants, metal injection molding, etc. Many industrial applications are related to the properties of the surface. Wettability is a key surface property that affects applications like lubrication, adhesion, coating, heat conduction, etc. Laser Texturing is an excellent method to modify the surface properties of materials like metal, polymers and ceramic. In the present study, a carbon dioxide laser created unidirectional textures on Hastelloy (C22, C276, X). Different sets of unidirectional textures were formed by changing the laser power and frequency. Various roughness parameters were compared for every laser parameter. In this paper, the effective change in wettability properties of Hastelloy (C22, C276, X) after the Laser texturing process for a range of power and frequency were studied under DI water and glycerol as test fluids. Results show that the contact angle of the test fluid increases as the laser power increases, and the contact angle decreases as the laser frequency increases for all three superalloys. The surface energy of a given set of samples was also measured using the recorded contact angle of DI water and Glycerol by the OWRK equation. Similar trends were found in surface energy for all three Hastelloy. © 2024 Trans Tech Publications Ltd, Switzerland.
Effect of Surface Topography and Roughness on the Wetting Characteristics of an Indigenously Developed Green Cutting Fluid (GCF)
(CRC Press, 2023) Edachery, V.; Ravi, S.; Badiuddin, A.F.; Tomy, A.; Suvin, P.S.; Kailas, S.V.
The production of cutting fluids from petroleum-based products has resulted in significant improvements in the current and rising machining sector. However, the majority of cutting fluids are costly, harmful, and unsustainable mineral base oils. A vital concern lies in their improper disposal, as it can cause pollution of groundwater, as well as pollute agro-based farm products. To counter these hazardous effects, the synthesis of an eco-friendly alternative was crucial. By mixing nontoxic emulsifiers and natural ingredients, a coconut oil-based Green Cutting Fluid (GCF) was created. Many of the defining requirements of commercial formulations are satisfied by GCF while yet being ecologically friendly. This study’s goal is to determine how surface topography and roughness affect the GCF’s ability to wet surfaces made of EN31 steel, titanium alloy Ti6Al4V, and aluminum alloy AA5052. Also, experiments are conducted to determine an optimum concentration of usage of the GCF for the aforementioned surfaces. The findings provide strong, clear proof that the GCF is a practical, long-term replacement for mineral oil-based cutting fluids for its superior wetting qualities and advantages for the environment. © 2024 selection and editorial matter Ravi Kant, Hema Gurung and Shashikant Yadav; individual chapters, the contributors.
Evaluation of a comprehensive non-toxic, biodegradable and sustainable cutting fluid developed from coconut oil
(SAGE Publications Ltd, 2021) Suvin, P.S.; Gupta, P.; Horng, J.-H.; Kailas, S.V.
The evolution in development of cutting fluid from petroleum based products have brought about remarkable changes to the present and growing machining industry. Most of the cutting fluids are made of mineral base oils which are toxic, non-biodegradable and unsustainable. A major issue lies in their inappropriate disposal which results in surface water and groundwater contamination and consequently, agricultural products and food contamination. Hence, the objective of this study is to develop an alternative, sustainable, non- toxic and completely bio-degradable cutting fluid to replace the mineral oil based cutting fluid. A Green cutting fluid [GCF] was prepared by combining nontoxic emulsifiers and natural additives. GCF meets many of the characteristic specifications of commercial formulations with the added advantage that it is eco-friendly. Toxicity test for cutting fluids has been carried out using fish toxicity test (OECD -203). The GCF with green additives has an LC50 value ?1064 mg/L. Commercial cutting fluid (CCF) has an LC50 value less than 100 mg/L These tests show that commercial cutting fluids are highly toxic, while the GCF can be considered as non-toxic. Biodegradability test was done using BOD-COD technique and found GCF as biodegradable and CCF as non-biodegradable. The ASTM D4627 corrosion tests infer that the GCF with grade 3 has better anticorrosive characteristics when compared to grade 4 of most CCF samples tested this could be possibly by the effect of natural additives in GCF. Drilling experiments were carried out to evaluate the machining performance of cutting fluids. Results from the drilling tests comparing the axial force/cutting force and torque showed that the performance of the GCF was comparable to that of the CCFs. Nevertheless, GCF formulation with non- toxic emulsifiers and natural additives is a good basis for further development and use of non-toxic tribological products. © IMechE 2020.
Finite element simulation of exit hole filling for friction stir spot welding - A modified technique to apply practically
(2014) Malik, V.; Sanjeev, N.K.; Hebbar, H.S.; Kailas, S.V.
Friction Stir Spot Welding (FSSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and/or a probe. Though it has proven its potential in joining difficult to weld materials, one of the drawbacks of process is prevalence of exit hole at the end of the process. In the recent past new techniques have been developed to eliminate this draw back by filling this unwanted hole. Determining the appropriate tool design and parameters to fill a hole for given situation is a challenge. The article demonstrates the effective method of obtaining these desired parameters a priory. A three dimensional (3D) model is developed in finite element (FE) commercial code DEFORM 3D/Implicit. It was found that internally filleted shoulders help in filling of holes. The obtained optimized process parameter (tool rotation speed of 900rpm, plunge velocity of 30mm/sec and plunge depth of 0.2 mm) for AA2024 plate (5mm thick) have potential to reduce number of experiments. � 2014 The Authors.
Finite element simulation of exit hole filling for friction stir spot welding - A modified technique to apply practically
(Elsevier Ltd, 2014) Vinayak, V.; Sanjeev, N.K.; Hebbar, H.S.; Kailas, S.V.
Friction Stir Spot Welding (FSSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and/or a probe. Though it has proven its potential in joining difficult to weld materials, one of the drawbacks of process is prevalence of exit hole at the end of the process. In the recent past new techniques have been developed to eliminate this draw back by filling this unwanted hole. Determining the appropriate tool design and parameters to fill a hole for given situation is a challenge. The article demonstrates the effective method of obtaining these desired parameters a priory. A three dimensional (3D) model is developed in finite element (FE) commercial code DEFORM 3D/Implicit. It was found that internally filleted shoulders help in filling of holes. The obtained optimized process parameter (tool rotation speed of 900rpm, plunge velocity of 30mm/sec and plunge depth of 0.2 mm) for AA2024 plate (5mm thick) have potential to reduce number of experiments. Â© 2014 The Authors.
Green lubricants in action: a comprehensive performance evaluation of groundnut oil-based cutting fluids in metal machining processes
(Institute of Physics, 2024) Srinivas, M.S.; Kumar, D.; Suvin, P.S.; Kailas, S.V.; Pawar, S.R.; Roy Choudhury, M.
As industries worldwide seek environmentally sustainable solutions, the metalworking sector faces a growing need for eco-friendly alternatives to traditional cutting fluids. This abstract introduces the concept of an innovative approach to cutting fluid technology—the use of groundnut oil as a base material for machining fluids. Derived from peanuts, groundnut oil presents a renewable and biodegradable alternative to petroleum-based counterparts, addressing concerns related to resource depletion and environmental impact. A comprehensive performance evaluation of groundnut oil- based cutting fluid has been carried out by series of critical tests such as separation testing, particle size and stability testing, frictional testing, corrosion testing and drilling testing. The results of these tests collectively contribute to a comprehensive understanding of groundnut oil-based cutting fluids, shedding light on their potential as sustainable and high-performance alternatives in metalworking. The zeta potential for the prepared green cutting fluid has been found to be 49.10 mV. The dimensions of the dispersed particles in a fluid of the cutting fluid have been found as 250-260 nm. The environmentally friendly cutting fluid exhibits favourable outcomes in corrosion resistance, frictional performance, and drilling efficacy during testing. © 2024 The Author(s). Published by IOP Publishing Ltd.
Investigations on the effect of various tool pin profiles in friction stir welding using finite element simulations
(2014) Malik, V.; Sanjeev, N.K.; Hebbar, H.S.; Kailas, S.V.
Friction stir welding (FSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and a pin/probe. The shoulder applies a downward pressure to the work piece surface, generates heat through the friction and leads to plasticization of materials in the vicinity of pin. During traverse the rotating tool mixes the adjacent material in the stir zone, creating a joint without fusion. The welding tool pin profile plays a major role in obtaining desirable weld. At present, research efforts are being made to gain a better understanding of the process, to explore different tool configurations, to optimize the set of process parameters and to widen the applicability of FSW and it variants. In this regard, having reliable finite element model that is capable of simulating FSW with minimal possible simulation time can turn out handy to reduce the number of physical experiments required in such studies and applications. The current work investigates a model based approach in knowing the effect of various tool pin profiles on temperature, stir zone and power consumed for welding. A three-dimensional (3-D) model is developed in finite element (FE) commercial code ABAQUS/Explicit using the Coupled Eulerian-Lagrangian (CEL) formulation, the Johnson-Cook material law and Coulomb's law of friction. The obtained results help in arriving at better tool designs. � 2014 Published by Elsevier Ltd.
Investigations on the effect of various tool pin profiles in friction stir welding using finite element simulations
(Elsevier Ltd, 2014) Vinayak, V.; Sanjeev, N.K.; Hebbar, H.S.; Kailas, S.V.
Friction stir welding (FSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and a pin/probe. The shoulder applies a downward pressure to the work piece surface, generates heat through the friction and leads to plasticization of materials in the vicinity of pin. During traverse the rotating tool mixes the adjacent material in the stir zone, creating a joint without fusion. The welding tool pin profile plays a major role in obtaining desirable weld. At present, research efforts are being made to gain a better understanding of the process, to explore different tool configurations, to optimize the set of process parameters and to widen the applicability of FSW and it variants. In this regard, having reliable finite element model that is capable of simulating FSW with minimal possible simulation time can turn out handy to reduce the number of physical experiments required in such studies and applications. The current work investigates a model based approach in knowing the effect of various tool pin profiles on temperature, stir zone and power consumed for welding. A three-dimensional (3-D) model is developed in finite element (FE) commercial code ABAQUS/Explicit using the Coupled Eulerian-Lagrangian (CEL) formulation, the Johnson-Cook material law and Coulomb's law of friction. The obtained results help in arriving at better tool designs. Â© 2014 Published by Elsevier Ltd.
Machining of hard materials using textured tool with minimum quantity nano-green cutting fluid
(Elsevier Ltd, 2021) Gajrani, K.K.; Suvin, P.S.; Kailas, S.V.; Pradhan, K.P.; Ravi Sankar, M.R.
Metal cutting causes severe friction and heat generation in the machining zone. Previously, petroleum-based cutting fluids were applied for reducing friction and machining temperature at the machining zone. Nowadays, nano-cutting fluids are preferred owing to their higher thermal conductivity and better lubricating ability. However, during machining of hard materials (hardness, ?50 HRC), the effectiveness of these nano-cutting fluids is limited, as they rarely reach to the cutting edge of cutting tool because of high normal stresses. In this regard, the combination of rake face micro-textured cutting tool with indigenously synthesized nano-green cutting fluids under in-house developed minimum quantity cutting fluid (MQCF) environment is accomplished for hard machining experiments. For comparison, hard machining experiments are also performed under dry machining, green cutting fluid and nano-green cutting fluid (NGCF) with untextured cutting tools. Detailed analysis shows significant improvement in hard machining performance using combination of micro-textured tools with NGCF corresponding to forces, chip-tool interface friction, workpiece surface roughness and chip morphology. It is attributed to better infiltration of NGCF in-between chip-tool interface by virtue of micro-textures present on the cutting tool rake face. Further, the proposed analytical model captures the effect of textures on the tool surface in the same way as reduced contact tools. It is in a good agreement with corresponding experimental cutting forces. © 2021 CIRP
Surface modification of steels using friction stir surfacing
(Trans Tech Publications Ltd ttp@transtec.ch, 2012) Janakiraman, S.; Reddy, J.; Kailas, S.V.; Bhat, K.
Friction stir surfacing is done to deposit commercial pure Al on medium carbon steel under open atmosphere conditions. Roughness of the substrate, normal load and tool rotation are the variables. Deposition is analysed with respect to continuity, width, composition and phase parameters. Good deposition is observed under a limited set of load and rotation speed. The deposit contains a mixture of steel and aluminium particles. Â© (2012) Trans Tech Publications.
Tailoring surface characteristics of bioabsorbable Mg-Zn-Dy alloy using friction stir processing for improved wettability and degradation behavior
(Elsevier Editora Ltda, 2021) Rokkala, U.; Bontha, S.; Ramesh, M.R.; Balla, V.K.; Srinivasan, A.; Kailas, S.V.
Magnesium (Mg) and its alloys are currently under consideration for use as temporary implants. However, early degradation and maintaining mechanical integrity is a significant concern. Surface modification techniques are used to improve mechanical and corrosion properties of Mg based alloys. In the present study, friction stir processing (FSP) was used to tailor the surface characteristics of Mg-1Zn-2Dy (wt.%) alloy for temporary implant applications. The FSPed alloy was characterized using EBSD to understand the influence of FSP on crystallographic texture, grain size and grain boundaries and thereby their effect on corrosion, wettability and hardness. Results showed that the grain size of stir zone (SZ) was refined to less than 3 ?m, as a result of dynamic recrystallization (DRX) during FSP and the FSPed alloy exhibited better wettability than as-cast alloy. An increase in the hardness (11.7%) and elastic modulus (6.84%) of FSPed alloy were also observed. Electrochemical corrosion and weight loss methods were conducted in Dulbecco's Modified Eagle's Medium (DMEM) with, 10% Fetal Bovine Serum (FBS) physiological solution. The lower degradation rate (0.72 mm/yr) of FSPed alloy has been attributed to the fine grains and evenly distributed secondary phase particles. Further, the influence of grain boundary characteristics and crystallographic texture on the corrosion behavior have been investigated. © 2021 The Author(s).
Wetting behaviour of a Green cutting fluid (GCF); influence of surface roughness and surface energy of AA5052, Ti6Al4V and EN31
(Elsevier Ltd, 2022) Edachery, V.; Ravi, S.; Badiuddin, A.F.; Tomy, A.; Kailas, S.V.; Suvin, P.S.
Green Cutting fluids (GCFs) are biodegradable and eco-friendly alternatives that can be employed in metalworking processes. They facilitate better tool service life and surface quality by removing the heat built, reducing coefficients of friction at tool-chip, and tool-work interfaces, flushing away the chip and preventing the formation of Built-up edges (BUEs). Conventionally, mineral oil (MO) based CFs are used, which can cause serious health hazards in humans as well as negatively impact the environment. Sustainable Green-cutting fluids (GCF) were found to be the solution for reducing the issues raised by the MO-based cutting fluids. The GCF used in the present study was synthesized using coconut oil (Cocos Nucifera) as the base, which is a clean, bio-degradable and eco-friendly substitute for petroleum-based mineral oils. This work is focused on experimentally determining the effectiveness of green cutting fluids on surfaces of (Aluminium)AA5052, (Titanium alloy)Ti6AL4V and Steel(EN31) with various surface topographies. In order to do so, the wetting properties were measured by a stable contact angle Î¸ between the solidâ€“liquid surface and the vapour-liquid interface. Wettability responses from the roughened surfaces in the range of 0.06â€“2.1 Âµm was evaluated using a profilometer and contact angle goniometer. Results show that the wetting characteristics of GCF are comparable to that of the MO-based CFs and can be a viable alternative, thus reducing the adverse effects on the environment. In conclusion, this study shows the potential of GCFas an alternative to MO-based cutting fluids used in machining operations in the manufacturing industries. Â© 2022