Applied Mechanics and Materials Vols. 813-814

Abstract: Present investigation deals with the effect of varying process parameters on the characterization of plasma sprayed fly ash - Al₂O₃ composite coatings using Taguchi’s experimental design method to conduct experiments and optimization of process parameters. Parameters such as standoff distance, powder feed rate and current density were considered for the optimization of bond strength, porosity and hardness. The significance of the parameters and their optimum level is determined by using ANOVA. Experiments were carried out to validate the effect of optimum process parameters on response characteristics and found that selected optimal combination of process parameters is able to achieve the best results.

Abstract: In conventional casting, the riser is separated from the casting and remelted for further use. If the riser can be configured to house a product, it can save energy for separately melting in making that product. In present work the separated riser is used as a raw material for another product without subjecting it to melting. A green sand mould consisting of a cubical pattern and LM 4 grade aluminium metal were used for the experiment. The riser used was designed to embody a cylindrical rod of 3.5 cm diameter. For the product given out by the riser used in this research energy saving to the tune of 23.5 % could be achieved. If this is extended to annual production of 98,593,122 tons of castings in the world, the cumulative energy savings amount to 17840 GWh, minimizing 7671200000 tons of CO₂ per year. Hence such innovations can be explored more deeply for industrial implementation.

Abstract: The paper present the effect of current flow and Deep Cryogenic Treatment (DCT) on the Surface Roughness (SR) of AISI D3 steel machined using EDM. The EDM tool is modified using deep cryogenic treatment to obtain positive results. Cryogenic treatment is a add on process over conventional heat treatment processes which converts retained austenite to martensite along with formation of nano sized carbide. The treatment enhance the properties of materials like wear resistance, hardness, dimensional stability, thermal conductivity and tool consumption rate which are recognized as a important factors in industries. The results show that increase in current level enhance the surface roughness, while deep cryogenic treated electrodes produces less surface roughness as compared to that of non-cryogenic treated electrodes.

Abstract: This paper presents a prediction and evaluation of surface roughness based on Taguchi’s method and the analysis of variance (ANOVA). The experiments were conducted on aluminium 6061 reinforced with 5% SiC to study the surface roughness under various cutting conditions. The objective was to establish a correlation between current, pulse on time flushing pressure with the surface roughness in the metal matrix composite (MMC). The correlation was obtained by multi-variable linear regression and compared with the experimental results.

Abstract: The main objective of the present work is the study the experimental and numerical study of multi hole extrusion process for making circular rods. The pure lead is used as extrude material for extrusion. The die consists of 5 holes with 5mm diameter. For prediction work, process has simulated using a Finite Element Method (FEM) code metal forming software DEFORM-3D®. All the experimental work and simulation are done at ambient conditions. The maximum load and maximum ram displacement are calculated for circular rods during the experimental work. From the results, it is noted that the behavior of load vs displacement is almost same for both experimental and numerical study of multi hole extrusion process. This study becomes illustration the behavior of the other tough materials by which one can understand the extrusion behavior of nonferrous materials.

Abstract: Micro manufacturing has received good attention globally in terms of its manufacturing methods and processes. One of the most popular micro manufacturing processes is micro forming. Although there were efforts made to realize micro extrusion for industrial application, the technology itself was seen as being insufficiently mature and unlike conventional methods, there is no in-depth knowledge. It has become essential to develop a proper understanding which in turn could be used to develop dedicated processes for the manufacturing of metallic micro components. In this work, an attempt has been made to realize this special application of metal forming. A novel experimental setup consisting of forward extrusion assembly and a loading set-up has been developed to obtain the force-displacement response. The effects of minaturization on micro components and the material behavior during forward extrusion are investigated. As per industrial requirement and application of micro part in micro manufacturing process, grain size is an important factor. In this context the effect of grain size is also studied in this work. The realization of such a productive forward extrusion assembly poses significant advantages when compared to the conventional manufacturing technologies in the production of micro parts.

Abstract: Friction at die/billet interface is a complex phenomenon affected by various operating and process parameters in metal forming industries. In presence of lubricating layer at the interfacial contact friction effect is reduced and enhances tool life and surface quality of product. The lubricant viscosity is strongly dependent on pressure and temperature during deformation of hard material and an accurate prediction of lubricants viscosity leads to realistic results in the work zone. Therefore, the paper incorporates numerical simulation of friction at the die/billet interface in hydrostatic extrusion of tungsten alloy 93W for three different lubricants whose rheology is represented by a Non-Newtonian friction model. The billet heating effect is incorporated in the investigation and results show that the co-efficient of friction varies in a range (0.058 to 0.062) along the work zone for various lubricating conditions in hydrostatic extrusion process.

Abstract: — Continuous casting of steel is a process in which liquid steel is continuously solidified into semi-finished or finished product (slabs, blooms or billets). There are many problems associated with continuous casting shop which affect the casting process. A major problem is associated in continuous casting shop is breakout of molten steel. Breakout leads to temporary shutdown of caster, damage of machinery due to splash of molten steel, capital loss, safety hazards etc. In Bokaro steel plant a logical based breakout prediction system is used to predict the breakout. This system sometimes generates false alarm and sometimes even fail to generate an alarm before breakout. Also the logical model has lot of dependence on specific equipment, process and calibration. Neural network can be implemented for a better breakout prediction system. So, in this paper a back-propagation neural network model is developed for predicting the existence of primary cracks that might lead to a breakout. The network gets its input temperatures from thermocouples which are attached to the wide and narrow sides of the mould. The output of the neural network is either logic 1 (for presence of crack) or logic 0 (for no crack). Testing the network shows excellent result as evident from the confusion matrix and performance plot. The neural network model is validated by simulating in MatLab/Simulink. The developed network may be used effectively in predicting breakouts during continuous casting. Such effective prediction can go a long way in reducing production losses in steel manufacturing.

Abstract: The equal channel angular extrusion (ECAE) is one of the most important methods used for bulk metal forming. In which die angles are the most importent parameter. This paper attempts to determine the effect of different die angles during ECAE process for 6062 aluminum alloy deformation. Numerical simulations are performed for ECAE process on cylindrical billet of 6062 aluminum alloy at a constant frictional coefficient (μ) of 0.08 and punch speed of 15 mm/sec. Die has made with inner corner angles of (φ) =105^°, 115^°, 125^°and 135^° by fixing the outer corner angle (ψ) of 6^°, punch is designed with a radii (R) of 4.75mm and height of 50mm. From the simulation results, tha data has been obtained in the form of load stroke behavior, and energy consumend during the punch stoke. It is observed that the maximum load and more energy consumption during the process is noted for lower angle.

Abstract: In this paper, a combination of taguchi method and grey taguchi method has been studied for optimization of the hot forging of medium carbon micro-alloyed (MC–MA) steel. The influence of forging parameters viz. forging temperature, percentage reduction and cooling rate are investigated for the responses tensile strength and impact strength after forging operation. In order to optimize the responses simultaneously, Grey Relational Analysis (GRA) is employed along with Taguchi method. Through GRA, grey relational grade is used as a performance index to determine the optimal setting of process parameters for above mentioned responses simultaneously. Analysis of variance (ANOVA) is employed to determine significant parameters. The results indicated that the cooling rate has a remarkable effect on the tensile strength and impact strength at room temperature. Optimization of the parameters simultaneously leading to a higher tensile strength and impact strength and it is also verified through a confirmation experiment for validation of these results.