Experimental Investigation of Aluminum Alloy and Polymer Joints Made by Friction Stir Welding Process

Abstract

Friction Stir Welding (Fsw) Is A Solid-State Welding Process Innovated And Patented By Wayne Thomas In 1991, At London; The Welding Institute (Twi), Used To Join Metals As Well As Non-Metals In Form Of Butt And Lap Weld Joints. The Fundamental Concept Of This Joining Process Is Done By Non-Consumable Rotating Tool Consists Of Shoulder And Pin By Fixing The Base Materials On The Bed Of Convectional Milling Machine With A Fixture And Backing Plates. The Work pieces Were Joined Together By Heat, Material Movement, And Forging Action. Fsw Process Has A Wide Industrial Application Like Automobile, Aerospace, Marine And Fabrication Industries. This Thesis Was Aimed To Join Aluminum Alloy With High Density Polyethylene (Hdpe) Having Of Different Thermal Properties And Thickness Of 3mm Each By The Process Of Fsw. Fsw Process Parameters Such As Rotational Spindle Speed, Welding Speed Were Variables And By Keeping Tilt Angle, Depth Of Penetration And Pin Offset As Constant. To Join The Materials Different Fsw Process Parameters Were Selected Depends On The Previous Researchers Works. The Parameters Selected Were Welding Speed Of (850, 1000 And 1250) Rpm, Tool Speed (40, 50 63) And By Taking 2.50Tilt Angle And 1mm Off Set Distance From The Center To Aluminum Side. Fsw Tool Were Designed And Fabricated As Shoulder Diameter 16mm, Pin Probe Diameter 2.5mm And Probe Length Or Plunge Depth Of2.8 Mm. All The Joints Were Butt Joints. From The Result The Reduction Of Pin Length Is 0.3 Mm (Reduced From 2.8 Mm To 2.5 Mm Length) And The Diameter Of The Pin/Probe Increased By 0.5 Mm (Increased From 3.5 Mm To 4.0 Mm) Is Observed. The Joint Formed By Process Parameter Rotational Speed Of 1250rpm Has Highly Grain Size Of Aluminum And Polymer Mixture And The Cause For That Was Higher Speed Of Rotation. The Most Higher Hardness Joints Were Created With Higher Parameter Values Of 1250rpm And 40mm/Min Which Is 83.4 Hardness Value. And From The Tensile Experiment The Highest Tensile Strength Joint Was Get 1.96 Mpa Which Is 8.5% Of The Polymer Parent Material Which Is By 1250 Rpm And 50 Mm/Min. From The Study Rotational Speed Has Great Effect On Weld Joint More Than That Of Welding Speed.