Bulging Test of Aluminium at room temperature

Abstract

During Compression Testing, a solid specimen (Hexagonal in Cross-Section) is compressed
axially between the punch and the bottom plates. As a result of this, the work piece material
undergoes deformation which basically is Bulging at its centre position. This test can further be
carried out at different temperatures to record the nature of compression for different ranges of
temperatures.
In Compression or Upsetting, the presence of frictional constraints between the dies and the
work piece directly affects the plastic deformation of the work piece. The friction at the faces of
contact retards the plastic flow of metals around the surface and in its vicinity. A conical wedge
of a relatively undeformed metal is formed directly below it while the rest of the cylindrical
metal suffers high strain hardening and subsequently bulges out. However, in practice, the use of
lubricants greatly reduces the degree of bulging to a great extent. Hence it is necessary to apply a
correction factor for the purpose of bulging design of die.
For a ductile material like Aluminium used here lateral distortion takes place and due to
restraining influence of friction of the load faces, the cross section becomes greater at the centre,
the test piece taking up a barrel shape. Hence this is also termed as Barreling.
In this particular experimentation the behavior of Aluminium specimen under different loading
conditions and at room temperature is recorded and the data thus generated is utilized in
predicting the behavior of Aluminium and other metals under cold loading conditions.