Applied Mechanics and Materials Vols. 592-594

Abstract: In the present paper, analysis of coal cutting has been carried out by conical pick which was developed by cast iron mixed with 21% (by weight) mild steel. The conical tip of pick was coated with material LH710 (hardness 40 RC) which is basically an alloy of Fe, Mn, Cr and Ni. The coal sample was cut linearly by using shaper machine. Parameters as depth of cut, amount of coal removed and temperature generated during cutting were analyzed for different tilt angle of tool and best compromise was found out among them.

Abstract: In this present work, Investigation was carried on the surface of laser dressed super abrasive grinding wheel to study the topography of the super abrasive wheel surface, the residual stress distribution on the laser dressed surface of the wheel and to analyse the heat affected zone of the wheel surface. To investigate all this terms the experimental study of Scanning Electron Microscope and Raman Spectroscopy on the laser dressed wheel surface were done and objective of this work is also to show the effectiveness of laser dressing by measuring the surface roughness of the workpiece before and after laser dressing operation.

Abstract: As the population of the world is continuously increasing, the demand of the mechanical manufactured products is also increasing. Machining is the most important process in any mechanical manufacturing, and in machining two factors i.e. Material removal rate (MRR) and Surface roughness (SR) are the most important responses. If the MRR will be high, the product will get desired shape in minimum time so the production rate will be high, but we could not scarify with the surface finishing also because in close tolerance limit parts like in automobile industry if the surface is rough exact fit cannot take place. So here aim is to maximise MRR and minimise surface roughness and process control variable are taken to be transverse speed, standoff distance, abrasive flow rate, and water pressure. Here Grey relational analysis is used to convert multi responses into single response and optimal parameter setting and most significant parameter is found with the help of S/N ratio.

Abstract: This paper revolves around the idea of finding the strength enhancement of pure ‘Al’ compacts processed through Equal-Channel Angular Pressing (ECAP) process which ultimately results in fine grain structure of the material processed. The material initially prepared through conventional powder metallurgical route is processed in an ECAP die with a channel angle of 110⁰. The tensile test and micro-structural evaluation is done following the ECAP process and it is found that there was a substantial enhancement in the tensile properties and Ultrafine Grain (UFG) structure is obtained due to the Severe Plastic Deformation (SPD) phenomenon taking place during the process. The pore closure behavior is also analyzed using the TEM micrographs after each pass in ECAP die and promising results are obtained when the material is processed through different routes. The dislocation cell structure is also found to get refined after each pass through the die. The pore closure behavior is also confirmed using the DEFORM 3D software when the aluminum is simulated under similar conditions.

Abstract: In this study the combined effect of thermal environment and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated plates are numerically analyzed. The finite element modeling of laminated composite plates and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the present finite element analysis is demonstrated by comparing the interlaminar stresses developed due to mechanical loadings derived using the present FEM with those of available literature. Various parametric studies are also performed to investigate the effect of thermal environment on interlaminar stresses generated in asymmetric cross-ply composite laminated plates of different length to thickness ratios (L/H) and boundary conditions with identical mechanical loadings. It is observed that the elevated thermal environment under identical mechanical loading lead to higher interlaminar shear stresses varying with length to depth ratio and boundary conditions in asymmetric cross-ply laminated composite plates.

Abstract: Wire Electrical Discharge Machining (WEDM) is an very accurate non-traditional machining process for producing parts with accurate dimensions and complex shapes. The performance of WEDM is measured by evaluating the parameters like Material Removal Rate (MRR), Surface Roughness (Ra), cracks, voids, pores and recast layer. In this paper, an attempt is made to improve the machining performance by adding multi wall carbon nanotube (MWCNT) with dielectric fluid. The MRR, Ra and surface characteristics are compared with surface that is machined using dielectric fluid with and without MWCNT. The results show that addition of MWCNT improves the MRR and surface finish.

Abstract: One of the interests in machining is to attain better surface roughness with dimensional accuracy. Polymer composites has been continuously dispatching the conventional materials. Polymer based composites have superior mechanical strength and stiffness such as strength-to-weight ratio, high stiffness-to-weight ratio. Polymer composites are the one which are produced closer to the required shape and further machining is often necessary to achieve the expected surface characteristics. This study targets the machining of hybrid polymer, made in the form of round rod, using general purpose resin and cashew nut shell liquid with varying proportions of CSNL by volume fraction up to 30%. Machining is carried out and the study includes the influence of the various process parameters such as cutting speed and feed with depth of cut kept constant and their importance in deciding the surface roughness. Surface roughness was measured after machining under specified measuring conditions using Talysurf.

Abstract: Monel 400 is a cuprous nickel alloy which is very well-known for its resistivity towards physical and chemical strength. It is probably one of the hardest and most non-corrosive materials known in industrial as well as research field. These properties have enhanced its applications in various fields such as aerospace industries, marine industries, automotive industries etc. Monel 400 alloys are too hard to machine using conventional machine tools and methods as it work hardens rapidly on its surface. Authors concluded that electrochemical machining is the choice of machining of these materials. The present work is carried out to analyze the impact of ECM process parameters such as applied voltage (V), inter-electrode gap (IEG) and electrolyte concentration (EC) on material removal rate (MRR) and surface roughness (R_a). An aqueous sodium nitrate (NaNO₃) is used as basic electrolyte in the electrochemical machining of Monel 400 alloys. Response surface methodology (RSM) based central composite design (CCD) is used as experimental strategy. Effects of process parameters as well as their interactions are analysed and the process parameters are optimized.

Abstract: A safe and healthy work piece is important for sustainable manufacturing process. Green laser surface hardening is a heat treatment process on a part of its application does not use water or oil as quenching media, because it is self-quenching and less detrimental to the environment. Since it is an energy saving process it is fast being adopted by manufacturing industries. Quenching media used in conventional heat treatment process for a sudden cooling of the heated work piece to get hard structure transformation. Unfortunately the reactions of quenchant with hot working also have several negative health, production cost, and environmental impact.This paper focuses the experimental investigation into the roller of green surface hardening on energy saving, the production cost of the industrial components. A comparative study of surface hardening under conventional and laser sources was conducted using similar components. The results show that the quality of hardening improved in laser hardening but the process time increased marginally at one stage and reduced at other shapes of manufacturing. In analyzing the process cost laser hardening show cast saving notably.

Abstract: Electric discharge machining (EDM) is a non-conventional machining process in which material removal take place by a series of electric spark generated between the small gap of both electrode and both immersed in dielectric medium. The gap conditions of EDM significntly affect the stability of machining process. Thus, the machining performance would be improved by removing the debris from the machining gap fastly. In view of this, the objective of present work was to investigate the effect of magnetic field on the material removal rate (MRR) and surface roughness (SR), in conjunction with the variation of electrical parameters like pulse on-off times and gap current, while keeping other electrical parameters and work piece/ tool material constant. Experimental results showed that the magnetic field assisted EDM improves the process stability. Moreover, the EDM process with high efficiency and quality of machined parts could fulfill the requirements of modern manufacturing industries.