Materials Science Forum Vol. 969

Abstract: Plasma Arc Welding (PAW) is more tolerant to joint misalignment than Laser Beam Welding (LBW) at a lower cost [1]. The present study deals with the assessment of mechanical and metallurgical properties of butt welded 1.6 mm thick austenitic stainless steel similar (SS304 and SS304) by using plasma arc welding technique. Similar butt-Welded joints were analyzed by using mechanical (Bend test, Erichsen cup test, tensile test) and metallurgical (Optical macroscopic and microscopic images) characterization methods. The bead width and depth of the butt welded 1.6mm thick butt joined SS304 was analyzed by macroscopic and microscopic images [2]. The Erichsen cup test was conducted on the weld specimens. The indentation was made on the weld specimens. In the similar metal joint the depth of indentation is high, which shows that the similar metal joint has better formability. This makes them appropriate for practicing in the aircraft industries (engine parts), automotive sector (engine-parts and assemblies) chemical processing, food processing, turbine buckets, pumps and valve parts [3]. Keywords: SS304, PAW, Butt weld, Erichsen Cup Test, Microstructure

Abstract: Dissimilar welding of 3mm thickness of AISI 304L austenitic stainless steel plate and AISI 430 ferritic stainless steel plates were performed by Tungsten Inert Gas welding without any filler material by using argon as shielding gas. Welding is carried out according to set of combinations of welding parameters such as welding current (levels of 135,140,145 Ampere), welding speed (levels of 105, 110, 115 mm/min) and shielding gas flow rate (of levels 5,10,15 Litre/min) obtained through Taguchi L9 orthogonal approach for maximizing the ultimate tensile strength by using MiniTab software . Radiography test was performed to know the soundness of the welds. Tensile specimens are fabricated as per ASTM E8 standard for tensile testing. Microstructural observations of the weld are performed. Correlations have been obtained to know the effect of welding speed, welding current and shielding gas flow rate on tensile strength and an optimum level of parameter is obtained at welding current of 145 Ampere, welding speed of 115 mm/min and shielding gas flow rate of 5 Litre/min.

Abstract: Vertical machining center (VMC) five-axis is advanced metal cutting process which used tomachine advanced materials for creating parts for industries like die, automotive, aerospace, machinerydesign, etc. Input parameters selection very important in VMC-five axis to obtain better surface finishon milled part and enhanced machining economics. In the present work, experimental analysis has beenplanned to study the significances of milling parameters on quality response, surface roughness (Ra) ofD3 steel. The experiments have been planned on D3 steel in VMC five axis as per Box-Behnken designof response surface methodology (RSM). Modeling and optimization have been done by hybrid RSMand Jaya optimization algorithm. The factor effects on Ra has been studied by analysis of signal-tonoise ratio. The concluding remarks has been drawn from the study

Abstract: Sheet metal forming forms in numerous industries like vehicle depend on the yielding of the sheet metals when strained. Yielding is portrayed by plastic flow of the materials when strained. The yield point if there should be an occurrence of uniaxial tension can be effectively decided from the pressure strain diagram, yet if there should arise an occurrence of multi axial Stresses it gets complicated. A connection between the principal stresses is required determining the conditions under which plastic flow occurs. This intricacy is tended to by the anisotropic yield capacities. Likewise, the tests used to acquire yield loci might be costly and time taking in such case these yield capacities end up being exceptionally viable. The yield criteria additionally help in deciding planar distribution of yield stresses and anisotropic coefficients, which gives a decent gauge of these mechanical parameters without having to through the pain of trial assurance. This project aims at using Hill 1948 criterion to obtain the Yield surface Diagrams for SS304 in annealed and original state and subsequently obtain the planar distribution of the uniaxial yield stress and anisotropic coefficient. Also, the performance evaluation of both the distributions will be done using accuracy index.

Abstract: Inconel-718 is a nickel based super alloy (difficult-to-cut material) used in aerospace industry. Analysis of machining performances viz. Over Cut (OC) & Surface Roughness (SR) for Inconel-718 through rotary Cu-pin tool electrode have been carried out. Peak current (I_p), pulse-on time (T_on), tool rotation (N_t) & hole depth (h) were used as input factors in Electrical Discharge Drilling (EDD) of Inconel-718 work-piece. Effect of input parameters on performance characteristics like OC & SR were found by Taguchi’s L₉ (3⁴) orthogonal array. It is reveals that I_p & h are most affecting factors that affects OC & SR. The Scanning Electron Microscope image was used to measure diameter of hole on work-piece after machining.

Abstract: In this paper, some preliminary experimental investigations have been reported for analysing the machining performance characteristics viz. Material Removal Rate (MRR) & Tool Wear Rate (TWR). Electrical Discharge Machining (EDM) of Inconel-718 alloy via helical threaded cryogenically treated rotary copper tool electrode is conducted. Impact of machining factors viz. peak current (I_p), pulse-on time (T_on), tool rotation (N_t) & hole depth (h) were investigated using Taguchi’s L₉ (3⁴) Orthogonal Array (OA). Optimum arrangements of factors for greatest MRR & least TWR were found in current study. Results predicts that I_p & N_t are two most affecting machining factors that affects MRR. Whereas I_p & T_on are two most affecting machining factors that affects TWR.

Abstract: Newly developed D2 steel is widely used for various advanced engineering applications. Machining of D2 steel to obtain desired quality responses has immense importance for the effective utilization of these materials for advanced industrial applications like aerospace, marine, automobile, etc. Wire electrical discharge machining (WEDM) is used to machine difficult to machine materials and to produce sophisticated features with better dimensional accuracy. Obtaining the fine surface roughness in WEDM has highly depends on correct selection of process parameters. In the present work, experimental investigation was planned to study the effects of WEDM input parameters on surface roughness (R_a) of D2 steel. Experimental runs were conducted by using L₁₆ orthogonal array of Taguchi method. The analysis of variance was employed to determine the influences of process parameters on R_a. Response surface methodology (RSM) and cuckoo search optimization (CSO) algorithm had been used to model and optimize the surface roughness. From the study, it was found that R_a value had improved as compared to initial experimental runs.

Abstract: The effect of milling time on consolidation of Al5083-5wt. % nanoyttrium oxide powders which are milled from 0-35 hours using planetary ball mill. nanocrystalline structure was observed after 10hours of milling. X-ray diffraction results reveals the formation of 57nm and 31nm for 20hr and 35hr of milling with increase in lattice strain. Circular and Elliptical morphology of milled powders were confirmed through SEM with decrease in particle size. The 90^o die channel angle ECAP die was used to consolidate 20hr and 35hr milled powder aided with and without back pressure. The optical micrographs reveal the formation of fine grains. The35hr milled powder shows the maximum densification of 96% and 20hr milled powder shows maximum hardness of 82HRB was observed in 20hr milled powder. Both are consolidated for two passes in route-A and sintered at 430°C for one hour.

Abstract: To determine the maximum velocity of a rotating hollow shaft it is mandatory to understand the effects of material & geometrical properties variations. In this paper, mechanical behavior & maximum rotational speed of a hollow FGM shaft in elastic zone is investigated. The analysis is based on small deformation in plane-strain state. Young's modulus, density & yield stress are assumed to vary as a power-law function of radial coordinate. Introducing dimensionless parameters, the equilibrium equation has been analytically solved. For the case of equal exponent parameters, numerical results compared the effect of density & yield stress variation on displacement, strain & stress elements. The results are compared with a homogeneous shaft & a variable material properties case. It shows material properties’ variation may have a considerable effect on the stress & strain components & radial displacement & causes yielding onset from the inner radius of the shaft.

Abstract: In this research work, an efficient optimization technique, grey relational analysis (GRA) has been used to for optimization of wire electrical discharge machining process of Titanium (grade 2) by considering multiple output parameters. This technique combines Taguchi’s orthogonal array with grey relational analysis for the design of the experiment. The central focus of this research is to achieve improved Kerf width, surface roughness and cutting speed. GRA method is implemented to decide the best input parameter that optimizes the output parameters. This study has been conducted by applying Taguchi’s L9 orthogonal array. Each experiment has been conducted in altered conditions of input variables. For the optimization of multiple criteria, GRA is suggested as a suitable technique for the optimization of complex interrelationships between multi-performance characteristics. By analysis of variance (ANOVA) it is found that the percentage of contribution of peak current on overall performance is maximum i.e.73.1%.