Modelling Of The Friction Welding Process Between Mild Steel And Alumina
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Date
2011-06
Authors
Seli, Hazman
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The heat transfer, mass diffusion and thermo-mechanical mechanisms in friction
welding (FW) are not fully understood. In friction welding of two dissimilar
materials, two rods are welded together by holding one of them still rotated while the
other under the influence of an axial load which creates frictional heat in the
interface. This thesis reports a study of the thermal, thermo-mechanical and mass
diffusive behaviors of friction welded alumina–mild steel rods with the use of
aluminum alloy sheet as interlayer. A series of temperature measurement and energy
dispersive X-Ray (EDX) line scan analysis for Al element concentration were carried
out near and across the interfaces region and were combined with thermal, diffusion
and 3D FEM thermo-mechanical models to acquire material parameters. This work
demonstrated the significant change in time-temperature history profiles in alumina
rod and the Al element content across the interfaces of alumina-aluminum alloy and
steel- aluminum alloy. The bond was obtained through interfacial interlocking and
narrow intermetallic phase formation. The finite difference (FD) thermal and
diffusion profiles predictions were compared to actual thermocouple and EDX
analysis data respectively from welds conducted under identical conditions and were
shown to be in fair agreement. A preliminary simulation was made to predict the
deformation, stress, strain and temperature distribution during the joining operation
using a fully coupled thermo-mechanical FE model. The aluminum alloy metal
being rubbed was simulated using a phenomenological Johnson–Cook viscoplasticity
material model, which suited for materials subjected to large strains, high strain rates
and high temperatures. The highest stress, strain and deformation are found to be
within the heat affected of the weld close to the periphery rubbing surface region and
correspond to the highest temperature profiles observed.
Description
Keywords
Friction welded alumina–mild steel rods , use of aluminum alloy sheet as interlayer