Manufacturing of Square Bar from Aluminium Scraps through Friction Stir-Back Extrusion Process

Abstract

Friction Extrusion Process Was Invented By The Welding Institute (Cambridge, Uk) In The Early 1990?�?S. This Process Relies On The Relative Motion Between Plunger And Rotary Sample Charged Chamber To Produce Frictional Heating To Plasticize And Extrude The Aluminium Scraps Directly Into Useable Product In One Step. The Aim Of This Thesis Is To Manufacture Aluminium Square Bar On Conventional Lathe Machine From Aluminium Wire Scraps Through The Novelty Of Friction-Stir Back Extrusion (Fsbe) Process And Study The Viability Of The Process To Produce The Square Bar. The Important Tasks Involved In This Work Are As Follows: The Components (Chamber And Plunger) Used For Experimental Work Was Designed And Manufactured, The Thermo-Mechanical Progression Of Fsbe Process Was Experimentally Studied On Adapted Conventional Lathe Machine Found In Astu Machine Shop. The Relation Between Controlled Parameter (Like Rotational Speed And Consolidation Time) And Response Parameter (Like Extrusion Time, Extrusion Rate, Grain Structure And Hardness) Were Analysed. Preliminary Results Show That, Increasing Or Decreasing Rotational Speeds Results In Defects. Cold Crack And Twisting Defect Were Shown On Square Bar Fabricated Using Low Rotational Speed And Hot Crack Defects Were Observed On Surface Of The Bars Produced By Higher Rotational Speed. The Manufactured Square Bars Were Tested Using Optical Microscope And Vickers Hardness Tester. Microstructural Studies Reveal That Initial Grains Of Aluminium Wire Undergo Significant Refinement And Results In Equiaxed As Well As Recrystallized Grains In The Square Bar Fabricated Through Fsbe Method. The Hardness Tests Show Almost Even Distribution Of Hardness In The Specimen; But Hardness Was Lower Than Parent Aluminium; In Comparison, Uneven Distribution Of Hardness Was Seen In Parent Aluminium. In Addition To Experimental Investigation, Finite Element Analysis Of Temperature Distribution And Extrusion Force Was Discussed With Respect To Experimental Result Using Deform-3d Software.