ALUMINUM AUTOMOTIVE BODY CONSTRUCTION.pptx

This PPT discusses about use of aluminum in automotive industry.

1. ALUMINUM AUTOMOTIVE BODY CONSTRUCTION Submitted by Name: Vivek Pandey University Roll No.: 139109432

2. REQUIREMENTS OF THE MATERIALS IN AUTOMOTIVE DESIGN Light weight Economic effectiveness Safety Recycling

3. LIGHT WEIGHT As there is a high emphasis on greenhouse gas reductions, reduction of emission and improving fuel efficiency this criterion is most important one for an automotive company. Lightweight materials can improve fuel efficiency more than other factors. Experiments reveal that 10 percent of weight reduction can lead to 6 to 8 percent improvement in fuel usage. Weight reduction can be obtained by r eplacing materials of high specific weight with lower density materials without reducing rigidity and durability. For example replacement of steel with aluminum.

4. The aluminum alloys offer strength-to-weight ratio improvements over mild steel on the order of 3:1 Even given strength and stiffness between aluminum and steel, weight reductions of 40 to 60% can still be realized.

5. ECONOMIC EFFECTIVENESS One of the most important consumer driven factors in automotive industry is the cost. Cost includes three components: actual cost of raw materials manufacturing value added the cost to design and test Aluminum alloys are certainly more costly than steel and cast irons. Since cost may be higher, decisions to select light metals must be justified on the basis of improved functionality.

6. SAFETY Aluminum can absorb twice as much crash energy as steel . Aluminum components can be designed to fold predictably during a crash, allowing the vehicle to absorb much of the crash energy before it gets to the passenger compartment. Aluminum sheets offer corrosion benefits over even galvanized steels . This is of considerable advantage when addressing increased reliability requirements on newer generations of vehicles .

7. RECYCLING The process involves simply re-melting the metal. Far less expensive and energy-intensive than recycling steel. The recycling of aluminium generally produces significant cost savings over the production of new aluminium, even when the cost of , collection separation recycling , are taken into account.

8. MAJOR WELDING TECHNOLOGIES USED IN AUTOMOTIVE INDUSTRY RESISTANCE SPOT WELDING RESISTANCE PROJECTION WELDING CONDUCTIVE HEAT RESISTANCE WELDING MECHANICAL FASTENING FRICTION WELDING ULTRASONIC WELDING

9. RESISTANCE SPOT WELDING Resistance spot welding ( RSW) is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current. Work-pieces are held together under pressure exerted by electrodes. The sheets are in the 0.5 to 3 mm (0.020 to 0.118 in) thickness range . The process uses copper alloy electrodes to concentrate welding current into a small " spot“.

10. RESISTANCE SPOT WELDING

11. RESISTANCE PROJECTION WELDING Projection welding is a modification of spot welding. The weld is localized by means of raised sections, or projections, on one or both of the work pieces.

12. CONDUCTIVE HEAT RESISTANCE WELDING The process essentially is resistance welding of an aluminum stack-up with one or more cover sheets employed. T he cover sheets are made from steel. T he high resistivity of the steel provides the necessary heat generation for the process The steel cover sheets are of relatively high thermal stability and actually act to constrain the melting aluminum which occurs during the process

13. Schematic representation of the conductive heat resistance welding (CHRW) process

14. MECHANICAL FASTENING Mechanical fastening covers a broad range of approaches, including screwing, folding, clamping, riveting. Mechanical fastening offers the opportunity to assemble aluminum sheet structures without the thermal effects associated with welding.

15. FRICTION WELDING Friction welding is a form of solid state welding where the heat is obtained from the mechanically induced sliding motion between the parts to be welded. The weld parts are held together under pressure. T he frictional heat is generated by rotating one part against the other.

16. ULTRASONIC WELDING

17. ULTRASONIC WELDING Ultrasonic metal welding is a technology that employs translational motion between opposing sheet work pieces to generate the necessary heat and deformation for bonding. The process functions at frequencies on the order of 20 kHz with displacements on the order of 100s of microns. The vibratory action is developed by electrical excitation of a piezoelectric element, which is then amplified through a booster arrangement . B oth melting and solid-state deformation takes place in this process

18. ULTRASONIC WELDING Ultrasonic spot welding is done at constant power. W eld strengths increase with higher levels of power, time (total energy), and force. Both the material cost and the body in- white manufacturing cost of aluminum are higher than that of steel. In order to achieve expanded use of aluminum in automotive body construction, lower-cost joining methods are important. Ultrasonic metal welding is one such potential welding method.

19. PROCESS ROBUSTNESS TO FOUR KEY MANUFACTURING VARIABLES WELD ORIENTATION ALUMINUM SHEET ROLLING DIRECTION RESIDUAL STAMPING LUBRICANT LEVEL MATERIAL AGE

20. WELD ORIENTATION Weld strength is not effected by weld orientation in ultrasonic welding

21. ALUMINUM SHEET ROLLING DIRECTION If the rolling lines of sheets were aligned, weld shear strengths could be 25% higher than if they were perpendicular to one another.

22. RESIDUAL LUBRICANT LEVEL T he surface condition of aluminum workpieces can affect their ultrasonic weldability . The presence of lubricant on the surface of aluminum sheet influences weld formation Precleaning of aluminum workpieces could significantly increase bond strength. MATERIAL AGE Material age do not impact ultrasonic weldabilty.

23. REFERENCES 1. E.T.Hetrick , Baer.J.R . Et al. ―Ultrasonic metal welding process robustness in aluminum automotive body construction applications, welding journal AWS (2009) 149s-158s 2. J.E. Gould ―Joining aluminum sheet in the automotive industry – a 30 year history‖ welding journal AWS (January 2012)23s-34s   3. D.grewell , Benator.A , ‖ welding of plastics: fundamentals and new developments‖ (2007) 43-60