T. Senthilvelan

Evaluation of Machining Parameters of Hot Turning of Stainless Steel (Type 316) by Applying ANN and RSM

Stainless steel (Type 316) workpiece was heated by the mixture of Liquid Petroleum Gas (LPG) and oxygen gas, and it was machined in a lathe under different cutting conditions to study the hot machining characteristics. The orthogonal turning operations were carried out on stainless steel (Type 316) using tungsten carbide (WC) cutting tool insert. During machining the cutting speed (Vc), feed rate (fs), depth of cut (a p ), and temperature of the workpiece were varied in the range of 200°C, 400°C, and 600°C. Turning experiments were designed based on the statistical three-level full factorial experimental design techniques. An artificial neural network (ANN) and response surface model (RSM) have been developed, which can predict the surface roughness of the machined workpiece. The experimental results concur well with the results obtained from the predictive models.

Modelling of process parameters on the working of P/M copper preforms

Abstract Powder metallurgy (P/M) manufacturing route has wide industrial applications due to a host of techno-economic advantages. However, defects free and superior products can be obtained only if the process parameters are carefully controlled during forming. Moreover, in metal forming processes conducting trial experiments is costlier and time consuming as well. Hence modelling technique provides effective control in scaling down costs. Mathematical models were developed for P/M working process, using regression analysis and analysis of variance (ANOVA) in order to study the main and interaction effects of process parameters, viz., strain rate, preform density and temperature. The adequacies of the developed models were verified by calculating correlation coefficient. These models can be effectively used to predict the strength coefficient ( K ) and strain-hardening exponent ( n ) and subsequently to estimate the flow stress of P/M copper preforms.

OPTIMISATION OF SHOCK ABSORBER PROCESS PARAMETERS USING FAILURE MODE AND EFFECT ANALYSIS AND GENETIC ALGORITHM

The various process parameters affecting the quality characteristics of the shock absorber during the process were identified using the Ishikawa diagram and by failure mode and effect analysis. The identified process parameters are welding process parameters (squeeze, heat control, wheel speed, and air pressure), damper sealing process parameters (load, hydraulic pressure, air pressure, and fixture height), washing process parameters (total alkalinity, temperature, pH value of rinsing water, and timing), and painting process parameters (flowability, coating thickness, pointage, and temperature). In this paper, the process parameters, namely, painting and washing process parameters, are optimized by Taguchi method. Though the defects are reasonably minimized by Taguchi method, in order to achieve zero defects during the processes, genetic algorithm technique is applied on the optimized parameters obtained by Taguchi method.

Fabrication and Characterization of SiC, Al2O3 and B4C Reinforced Al-Zn-Mg-Cu Alloy (AA 7075) Metal Matrix Composites: A Study

The paper presents the results of experimental investigation on the characterization and analysis of mechanical properties of composites formed. Three aluminum metal matrix composites reinforced with 10 wt% of B4C, SiC and Al2O3 particles were processed. The stir casting method followed by hot rolling was used for fabrications of aluminium 7075 metal matrix composites, being one of the cost effective industrial methods. Experimental results show nearly a uniform distribution and good dispersion of reinforced particles within aluminium matrix. Both tensile strength and hardness are enhanced by incorporation of reinforcement particles into the matrix. Scanning electron microscope (SEM) analysis was done to study the good dispersion of particles and surface characteristics.

Modeling and Optimization of EDM of Al 7075/10wt% Al2O3 Metal Matrix Composites by Response Surface Method

The newly engineered metal matrix composite (MMC) of aluminium 7075 reinforced with 10 wt% of Al2O3 particles were prepared by stir casting method. Electrical discharge machining (EDM) was employed to machine MMC with copper electrode. The experiment plan adopts face centered central composite design of response surface methodology. Analysis of variance was applied to investigate the influence of process parameters and their interactions viz., pulse current, gap voltage, pulse on time and pulse off time on material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (SR). The objective was to identify the significant process parameters that affect the output characteristics. Further a mathematical model has been formulated by applying response surface method in order to estimate the machining characteristics such as MRR, EWR and SR.

Tooling Design and Compaction Analysis on P/M Copper Bushes

The successful production of P/M (powder metallurgy) components depends to a large extent on the tooling used for powder compaction. While designing the tool, the complexities arise from the interaction of the parameters such as powder characteristics, expected green density, the size and geometry of the product, and to whom the properties of the tool materials during compaction should be addressed. Floating type of compaction tooling set (die, punches, and core rod) was designed and fabricated. Pure electrolytic copper powder was compacted in the above-mentioned tool to obtain P/M copper bushes. Compaction pressure–density relationship and their influence on green strength are analyzed.

Testing and Quality Standards for Powder Metallurgy Products

This article enumerates the quality control methods of powder metallurgy process and testing of finished components. The standards followed in various countries and widely used in industries are compiled in this article. The information furnished here will be helpful for research workers, particularly in academic institutions that have no access to international standards.

Analysis of Hot Working Characteristics of Aluminium Based Composites Using Response Surface Methodology

During deformation process, it is essential to control the formability parameters viz., stress, strain, temperature, aspect ratio, volume fraction etc., to obtain sound and defect free products. Moreover, in deformation process in general, upsetting in particular, conducting too many trail experiments results in increased experimental time and cost. Hence modeling of process parameter attracts attention of researchers. The objective of modeling the process parameters is to determine which variables are most influential during metal forming operations. In the present investigation, by connecting the influential process parameters during metal forming in general upsetting in particular, a mathematical model have been developed using Design of Experiments (D.O.E) which could be applied to estimate the flow stress. Aluminium MMCs with silicon carbide (SiCp) and aluminium oxide (Al2O3) as reinforcement have been chosen in this current study as it has significant advantage over conventional materials.

On the Mechanical Properties of Hybrid Aluminium 7075 Matrix Composite Material Reinforced with SiC and TiC Produced by Powder Metallurgy Method

Metal matrix composites are widely used in components of various components of industrial equipment because of their superior material properties like high stiffness to weight ratio and high impact strength and fracture toughness while compared to the conventional material. Due to the concepts of high strength to low weight ratio, Al 7075 was extensively applied in aircraft engine and wings. Even if Al 7075 has higher hardness, higher strength, excellent wear resistance, and high-temperature corrosion protection, it is in need of further enhancement of properties for increasing its applicability. This paper presents the mechanical behavior of aluminium 7075 reinforced with Silicon Carbide (SiC) and Titanium Carbide (TiC) through powder metallurgy route. These specimens were produced by powder metallurgy method. The hybrid composite was made by Al 7075 alloy as the matrix with Silicon Carbide and Titanium Carbide as reinforcement. Silicon Carbide and Titanium Carbide are mixed in different weight ratio based on the design matrix formulated through a statistical tool, namely, Response Surface Methodology (RSM). Enhanced mechanical properties have been obtained with 90% of Al 7075, 4% of TiC, and 8% of SiC composition in the composite. Coefficient of friction appears to be more which has been determined by ring compression test.

Wear Behaviour of Polyurethane Coated Aerospace Aluminium Alloy (7075)

This paper envisages to predict the life of an aircraft coating using high strength precipitation hardening 7000 series aluminum alloys, such as 7075 which is used extensively in aerospace industry. Aerospace aluminum alloy 7075 has been researched upon especially for aircraft materials. The intention of protective coating is to save the aerospace aluminium alloy 7075 metal surface from weatherability and, at the same time, to obtain the required degree of cosmetic finish for the object. One was epoxy polyamide as primer layer and other was the polyurethane as top-coat layer of coating through conventional spray type on aluminum alloy 7075 substrates. Epoxy polyamide is useful binders for aircraft primers. Top-coats have also been prepared, but polyurethane is still the choice for aircraft coating. This coating system is typically comprised, of a primer layer and a topcoat layer. The ability of the polyurethane coating is to prevent corrosion, weatherability depends on its anti-corrosive pigments and its adhesion to the substrate. All these factors are widely variable with the geographic location and season such as temperature, wind, oxygen and atmospheric pollutants. The effect of structural and process variable on wear resistance of polyurethane coating was analyzed to determine the maximum wear rate using DOE software optimum samples were prepare according to best level of each factor and its morphology was examined by scanning electron microscope (SEM).