RESEARCH PAPER 1- Paper on Dissimilar Materials by Friction Stir Welding Process

By  Vuppula Prasanna1 , Shilpa2 Associate Professor1 , Assistant Professor2

Abstract: Recently many reports on Friction Stir Welding (FSW) of various dissimilar systems such as Aluminium to Copper and Aluminium to Brass been reported. FSW of Aluminium, Copper and Brass has captured important attention from manufacturing industries, such as Shipbuilding, Automotive, Railway and Aircraft production. Brass materials are widely used as engineering materials in industry because of their high electrical and thermal conductivity, high strength, and high corrosion resistance . Copper and its alloys are widely used in industrial applications due to their excellent electrical & thermal conductivities, good strength, corrosion & fatigue resistance. The aim of present study was analogy of the microstructures and mechanical properties of friction stir welded joint of Aluminium to Copper and Aluminium to Brass plates in 4mm thickness.

Paper on Dissimilar Materials by Friction Stir Welding Process

·         Vertical milling machine of 7Kw is used to join the dissimilar plates

·         The plate size of Al6061 and pure copper are having 100mm length, 70mm width and 4mm thickness.

·         Work H13 tool is used. The tool is having tapered shoulder and pin.

·         The Vickers micro hardness was measured by using HARDWOOD HWMMT-X7 micro hardness tester.

·         Shoulder diameter(SD) -25mm

·          Pin diameter(PD)- 6mm

·          Pin length (PL) 3.6mm

·         Rotation Speed Rpm-Exp1- 710 ,900,1120  Exp2- 710,900,1120

·         Transverse speed -10-60 mm/min

·         Material Dissimilar Thickness 4mm Length 100mm

·         Width 70mm

·         Rotational Speed 710,900 and 1120 rpm

·          Feed 15-30 mm/min

·         For 710 rpm   Ultimate Tensile strength 37.69 N/mm²    Yield Strength 29.808 N/mm² % Elongation 0.42%

·         For 900 rpm Ultimate Tensile strength- 55.89 N/mm²    Yield Strength- 40.5 N/mm²

·         For 1120 rpm  Ultimate Tensile strength -108.56 N/mm²    Yield Strength -89.9 N/mm² % Elongation- 0.98%

JOINING OF ALUMINIUM TO COPPER BY FRICTION STIR WELDING-Dhaval S. Chaudhari

·         Summary

·         The study has been aimed towards extracting mechanical properties and microstructures of friction stir welded joint of 6082 aluminium alloy and pure copper plates in 3 mm thickness. Zinc, Tin, Silicon Carbide have been used as filler materials. Welds were produced using High molybdenum high speed steel, with a cylindrical pin tool having 3 mm and 14 mm diameter of pin and shoulder respectively. Optical microscopy was used to study the microstructures and grain size in TMAZ, HAZ and NZ were analyzed.

·         Vickers hardness was used to study the hardness of the weld and tensile test were done to analyse the weakest portion of weld joints.

·         In conclusion, Microharness in NZ of Al/Al with Rare earth filler metal powder was lower than base metal. Tensile strength of Al/Cu

·with SiC and Al/Al with Zinc were good compares to others and all the welds  were defect free.

·         Parameters:

·         Material: Aluminium and copper

·         plate size: 150 mm length, 100 mm width and 3 mm thickness

·          rotation speed: 1000 rpm

·         feed rate: 28 mm/min.

·         Tool material: high molybdenum high speed steel 

·         Shape of tool: concave shoulder.

·         tool dimensions: shoulder diameter=14 mm with 2.7 mm pin length and 3 mm pin diameter.

·         tool pin: cylindrical.

 Weld-ability and mechanical properties of dissimilar aluminium–copper lap joints made by friction stir welding T. Saeida, A. Abdollah-zadehb, B. Sazgarib

       Summary

·         The rolled plates of 1060 aluminum alloy and commercially pure copper were used as the top and bottom plates of the lap joints.The experimental results of friction stir welding of 1060 aluminum alloy and commercially pure copper revealed that a dark area was formed in the aluminum close to the Al/Cu interface. In this area the intermetallic compounds of Al4Cu9 and Al2Cu, and some micro-cracks were detected. The frequency of such micro-cracks decreased with increasing welding speed. . This can be related to both introduction of copper in small quantities and less intensive mixing condition at high welding speeds. Some of the copper fragments contain the layer structure while the others consist of fine grains of copper rich structure. On the other hand, at higher welding speeds of 118 and 190 mm/min, the cavity defects were formed inside the joints as a result of insufficient heat input. Decreasing the welding speed of a tool due to higher amount of micro-cracks reduced the tolerable shear load.

·         Furthermore, lower welding speed caused more vertical transport, while a higher welding speed caused less vertical transport on the retreating side.The results of tensile shear test revealed that the maximum tensile shear strength of joint was obtained at welding speed of 95 mm/min. At this welding speed, no cavity defects, and few micro-cracks were observed in the weld.

·         Parameters:

·         The rolled plates of 1060 aluminum alloy and commercially pure copper were

·         used as the top and bottom plates of the lap joints. Table 1 indicates chemical com-

·         position and thicknesses of these two materials.

·         Plate dimensions: 20 mm length and 10 mm

·         rotating tool material: quenched and tempered steel.

·         Tool dimensions: It has a 15 mm diameter shoulder and a left-hand threaded pin (-5 mm × 6.5 mm).

·         pin rotating speed: 1180 rpm

·         welding speed: 30, 60, 95, 118, 190, 300, and 375 mm/min.

 

2. APPLICATION OF RESISTANCE OF WELDING

Resistance seam welding can be used to make gas- or fluid-tight joints in a variety of sheet metal fabrications. Steel fuel tanks for motor vehicles are a prime example. It is also used in making tin cans, steel drums and domestic radiators.

The process lends itself particularly to welding seams which are straight or have a regular curvature: abrupt changes in the weld line in any plane should be avoided. Welding is not possible into internal corners or where other features of a component obstruct access for the wheel electrodes.

Access to both sides of the joint is necessary, and a lap joint configuration is generally required. Components comprising two half shells may be welded, for example petrol tanks or domestic radiators. Alternatively, sheet can be rolled into tubular form and the longitudinal seam welded, as in tin cans or steel drums.

§  Resistance welding is widely used in automotive industries.

§  Projection welding is widely used in production of nut and bolt.

§  Seam welding is used to produce leak prove joint required in small tanks, boilers etc.

§  Flash welding is used to welding pipes and tubes.

1. SPОT:
Resistance spоt welding SPОT: Resistance spоt welding is made by passing current, fоr a timed interval, thrоugh the wоrkpieces frоm electrоdes which apply the welding fоrce.

2. SEAM:
Seam welding SEAM: Seam welding cоnsists оf making a series оf оverlapping spоt welds by using оne оr twо rоtating wheel electrоdes withоut оpening the electrоdes between spоts.

3. CRОSS WIRE:
In practice, it usually cоnsists оf welding a number parallel wire at right angles tо оne оr mоre wires оr rоds.

4. UPSET:
Is a resistance welding prоcess which prоduces cоalescence simultaneоusly оver the entire area оf abutting surfaces оr prоgressively alоng a jоint.

5. RESISTANCE BRAZING:

Resistance brazing is a methоd оf lоw-temperature brazing by the applicatiоn оf heat and fоrce tо the parts tо be jоined using heat generated by the current in either the parts themselves, in the dies hоlding the parts оr the electrоdes making cоntact with the area tо be brazed, оr bоth.