R. Velu ¹, Moses Raja Cecil ²

Affiliations
1 Mechanical Department, Dr.M.G.R. University, E.V.R.Salai, Chennai-600095, IN
2 Design and Development Division, Integral Coach Factory, Chennai-600038, IN

Abstract

Interfacial friction plays a vital role in cold forming and forging. Since this shear force, if uncontrolled, would lead to many defects and problems, it is essential to measure this entity and to overcome it. Using spike and disc forming test, this interfacial friction is measured. A circular billet is extruded to form a spike on one side and upset to form a disc on the other. Aluminium alloy 6063 is used as the material. Simulation is carried out for various combinations of height/ diameter of the billet and for different spike diameters. The ratio of the height of the spike to the disc diameter is a measure of the friction force. This ratio is plotted to form calibration curves. Using these curves, the friction present during the cold forming process is quantified.

Keywords

Aluminium, Friction Measurement, Interface Friction, Spike Extrusion, Calibration Curves, Lubricants

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K. Logesh ¹, V. K. Bupesh Raja ², R. Velu ³

Affiliations
1 Department of Mechanical Engineering, Sathyabama University, Chennai-600119, Tamil Nadu, IN
2 Department of Automobile Engineering, Sathyabama University, Chennai-600119, Tamil Nadu, IN
3 Department of Mechanical Engineering, Vel Tech University, Chennai-600062, Tamil Nadu, IN

Abstract

Fiber Metal Laminates are now-a-days a dominant material for applications such as automobile body panels, aircrafts cabins and railway wagons, because of reasons such as superior mechanical properties such as high strength and less weight. Hand Lay-up technique was used to fabricate four fiber metals laminates comprising of aluminium alloy 5052-H32 as the skin material and E-glass fiber as the core. The formability behavior of the laminate was found using Erichsen cupping test using an indigenously developed test setup. The Erichsen cupping index on the specimen varied from 5.95 to 7.28 respectively. The test specimens were investigated through microscope and macroscopic approach. Macroscopic examination revealed that the laminate was ductile in nature, which was backed by the aluminium skin. The defect created on the specimen during the test was smaller than the diameter of the ball used during the test. Microscopic examination through Scanning Electron Microscope revealed that the laminates had microscopic defects such as fiber pullout and surface cracks in the skin materials. The fibers were subjected to brittle failure while the skin material sustained ductile fractures. The Erichsen cupping index value depended upon the factors such as complexity of composite sheet forming operations, simple mechanical property measurements made from the tension test area of tested value. Ductile fracture was observed in the specimen due to the influence of progressive loading through Erichsen cupping test. There was non-uniform distribution of reinforcement in material, Microstructure revealed fiber cracks which were oriented in line to the crack growth on the skin material. Hence, it can be concluded that the proposed material can be safely applied for automotive, aeronautical and locomotive body panels or as a skin material.

Keywords

Erichsen Cupping Index, Erichsen Cupping Test, Fiber Metal Laminate, Formability Behavior

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N. Dilip Raja ¹, R. Velu ², S.T. Selvamani ¹

Affiliations
1 Department of Mechanical Engineering, Vel Tech Multi Tech Dr. Rangarajan Dr. Sakunthala Engineering College, Avadi, Chennai – 600062, Tamil Nadu, IN
2 Department of Mechanical Engineering, Vel Tech Multi Tech Dr. Rangarajan Dr. Sakunthala Engineering College, Avadi, Chennai – 600062, Tamil Nadu

Abstract

Friction Stir Welding is a versatile metal joining process, which has been adopted to join composite materials. Many research activities have been conducted on this metal joining processes which lead to the process being used in diverse field of applications. AA6061 plates of 6mm thick each were joined through butt welding configuration by Friction Stir Welding process using a CNC milling machine and a non consumable tool with square pin profile. Six joints were made using the combination of three tool rotation speed 350 rpm, 550 rpm and 900 rpm and three weld traverse speed 55 mm/min, 100 mm/min, 110 mm/min. The prepared joints were tested in order to analyze its microhardness, tensile strength, temperature distribution, force and microstructure along the joint. It was identified that for a given tool rotation speed, the microhardness increased proportionally with respect to the weld speed and depth along the joint. However it was noticed that for different tool rotation the maximum of the microhardness was obtained for 350 rpm. Measurement of tensile strength revealed that the strength was maximum when the weld speed and tool rotation speed was maximum. The tensile strength measurement indicated that the strength was directly proportional to the weld speed and tool rotation speed. Temperature measured during welding revealed that the temperature was maximum along the weld center, while same decreased away from the weld center. This was because of the dissipative effect of AA6061. Microstructure of the prepared joint revealed that the due to the influence of the tool, the grain structure reformed. There were finer grains at place traversed by the tool and coarse grains at place away from the tool. The joints thus fabricated can be used for applications which require reliable and defect free joints such as automobile frames and aeronautical structures.

Keywords

AA6061, Friction Stir Welding, Microhardness, Microstructure, Temperature distribution

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