M. Uthayakumar

Machinability of Nickel-Based Superalloy by Abrasive Water Jet Machining

This paper deals with the machinability of nickel-based superalloys using abrasive water jet machining process. The machining studies were carried out with three different parameters such as water jet pressure, traverse speed of jet nozzle, and standoff distance at three different levels. The performances of the process parameters are evaluated by measuring difference in kerf width, kerf wall inclination, and material removal rate (MRR). Further, the surface morphology and material removal mechanisms are analyzed through scanning electron microscope (SEM) images. It is found that water jet pressure is the most influencing factor related to surface morphology and surface quality.

Electrical Discharge Machining of Al(6351)–SiC–B4C Hybrid Composite

Metal matrix composites are found to have many applications in the materials and structural engineering field. In this work, an investigation is carried out to find the influence of process parameters such as pulse current (I), pulse on time (T on), pulse duty factor (τ), and voltage (V) on the machining of Al(6351)—5 wt% silicon carbide (SiC)—5 wt% boron carbide (B4C) hybrid composite through electrical discharge machining. The individual parameters were analyzed with an objective to minimize electrode wear ratio (EWR), surface roughness (SR), and power consumption (PC). The experimental result shows that the output responses were greatly influenced by pulse current, with a contribution of 33.08% to EWR, 76.65% to SR, and 48.08% to PC. The surface characteristics were also examined through scanning electron microscope and the presence of craters and recast layers was observed.

Machining behavior of AA6351–SiC–B4C hybrid composites fabricated by stir casting method

ABSTRACT This study presents an effective approach to assess the machinability of 6351 aluminum alloy matrix, reinforced with 5 wt.% silicon carbide (SiC) and (0, 5, and 10 wt.%) boron carbide (B4C) particles. The turning tests are carried out with a polycrystalline diamond (PCD) tool to identify the effect of the B4C particles addition to the composite, with an objective to improve the material removal rate (MRR) and to reduce the surface roughness (Ra) and power consumption (P). The significant level of each factor, which contributes to affect the output response, is found through analysis of variance (ANOVA). The results show that the inclusion of B4C particles in the hybrid composite significantly affects the machinability, with a contribution to the surface roughness by 7.87% and P by 6.36%. The increase in MRR affects the quality of the material, irrespective of the composites.

Effect of Abrasive Grain Size of the AWJM Performance on AA(6351)-SiC-B4C Hybrid Composite

In this work, Abrasive Water Jet Machining (AWJM) on aluminum based hybrid composite with Silicon Carbide (SiC) and Boron Carbide (B4C) reinforcement particles are investigated. Two different abrasive grain sizes of 80 mesh and 120 mesh are selected to carry out the experiments. The cutting parameters namely pressure, standoff distance (SOD) and traverse speed are assessed in terms of the kerf angle, Material Removal Rate (MRR) and Surface Roughness (Ra). The result shows that the coarse abrasive particle has a favorable effect on the MRR, while the fine grained abrasive particle produced minimum kerf angle and good surface finish.

Electrical discharge machining of Al (6351)-5% SiC-10% B 4 C hybrid composite: a grey relational approach

The goal of the present experimental work is to optimize the electrical discharge machining (EDM) parameters of aluminum alloy (Al 6351) matrix reinforced with 5 wt.% silicon carbide (SiC) and 10 wt.% boron carbide (B4C) particles fabricated through the stir casting route. Multiresponse optimization was carried out through grey relational analysis (GRA) with an objective to minimize the machining characteristics, namely electrode wear ratio (EWR), surface roughness (SR) and power consumption (PC). The optimal combination of input parameters is identified, which shows the significant enhancement in process characteristics. Contributions of each machining parameter to the responses are calculated using analysis of variance (ANOVA). The result shows that the pulse current contributes more (83.94%) to affecting the combined output responses.

Influence of Cutting Force on Bimetallic Piston Machining by a Cubic Boron Nitride (CBN) Tool

Bimetallic pistons are most widely used in diesel engine vehicles for weight reduction and enhanced performance with long life. Aluminum alloy is reinforced with cast iron insert to realize the bimetallic pistons. The bonding between aluminum and cast iron is achieved through a patented process named the Al-Fin process. To ensure better bonding, the insert is dipped in the molten aluminum bath, this dipping time playing a vital role. The present study focuses on varying the dipping time from 90 s to 5 min to find the optimum dipping time. Achieving the near net shape of the bimetallic pistons without damaging the bonding between the aluminum and cast iron is the major challenge. This investigation also obtains optimal cutting parameters in turning off such pistons with cubic boron nitride as a single tool to machine the metal. The bond integrity after machining is primarily related to the magnitude of the cutting forces. Taguchi design of experiment analysis was conducted on the inserts which are subjected to various dipping time. The optimal cutting parameters for minimized cutting forces were identified. The extent of deboning and the surface finish were measured after machining to ensure the minimum cutting force condition to satisfy the requirements.

Influence of Process Parameters on Cu–Fly Ash Composite by Powder Metallurgy Technique

In this study influence of compaction pressure, sintering temperature, and sintering time on mechanical and wear behavior of the fly ash reinforced copper-based composites are analyzed. The composites were prepared by powder metallurgy (P/M) technique with copper as matrix, 5 and 10 wt% of fly ash as reinforcement. The green compacts were prepared at three different pressures such as 350, 400, and 450 MPa. The prepared green composites were sintered at 700, 800, and 900 °C for the time period of 30, 60, and 90 min, respectively. From the results it is observed that when the process parameter increases the density, hardness, compression strength, and wear resistance increases.

Parametric Optimization of AWJM in AA6351-SiC-B4C Hybrid Composite Using Grey Relational Analysis

In the present study, the aluminum based hybrid composite with Silicon Carbide (SiC) and Boron Carbide (B4C) particles are prepared through the stir casting process and subjected to Abrasive Water Jet Machining (AWJM). The pressure, standoff distance and traverse speed are considered as the input process parameters and the output response such as Kerf angle, Material Removal Rate (MRR) and Surface Roughness (Ra) are measured and optimized using Grey Relational Analysis (GRA). The Analysis of Variance (ANOVA) and the F-test are performed to understand the contribution and the significant level of importance of each input parameter over the output response. The experimental result shows that the traverse speed and the standoff distance contributed more on affecting the performance, with a contribution of 62.14% and 18.43% respectively.

Performance of surface-textured end-mill insert on AISI 1045 steel

ABSTRACT Recently, the surface texturing of tool/work pieces to improve performance has been investigated in the manufacturing industry. Grinding is employed to produce quality products with improved dimensional accuracy. The combination of grinding and end milling is a suitable method for surface texturing. The present study explains the effect of a textured-pattern end-milling tool on AISI 1045 steel. The effects of the pitch and depth of the pattern are investigated in detail, as are the effects of the input parameters on the cutting force and tool wear. The experimental results show that tool wear is reduced by 53% with surface texturing. Moreover, the surface-textured pattern helps to reduce the cutting force. The tool material wastage which can pose economy threats, can be drastically reduced by increasing the tool life using surface texturing.

Three dimensional numerical investigation of forced convection heat transfer from offset square cylinders placed in a confined channel

Flow over two isothermal offset square cylinders in a confined channel is simulated for different Reynolds number to reveal the forced convection heat transfer from the heated square cylinders to the ambient fluid. The distance between the cylinder in normal direction as well as transverse direction are fixed as two-dimensional and the blockage ratio is fixed as 0.167. Heat transfer from the cylinders to the ambient fluid as well as conducted within solid wall through conjugate interface boundary investigated in connection with Reynolds number are reported for both steady and periodic flow. Simulation is carried out for Reynolds number varies from 10 to 1,000 for the fluid as air. The isotherm, streamline contours are reported for various Reynolds number. The stagnation zone results higher Nusselt number than remaining walls and rear wall results lowest Nusselt number. Asymmetry vortices are reported at higher Reynolds number. The downstream cylinder results higher Nusselt number than the upstream cylinder.