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The technique of moving the metal rather than removing it has encouraged
the researchers and technologists to go in for the manufacturing process where
the processing cost and the wastage of material are minimized, and improved
mechanical properties are obtained.
The advantages of metal forming are savings in the value added materials
and energy for getting the final shapes. However, bulk deformation of the metal
requires large amount of forces and heavy presses. Therefore, the trend is towards
localizing the deformation to a small region of the workpiece in order to reduce the
forming forces and consequently reduce the size of the machine required to carry out
these processes. In case of metal forming, the stresses are localized to a small area and
the material is made to flow over the mandrel with the help of rollers.
Considerable amount of work is being done on forming and shear spinning
of materials. Most of the work is on the soft materials like lead, aluminum, mild
steel, copper, etc. However, a few researchers have tried the forming process of
hard-to-work materials.
Hayama and Kudo (1979a and 1979b) have studied the process
experimentally and presented an analysis for the determination of the working forces and
energy consumed during deformation considering diametral growth.
Singhal et al. (1987) have studied the shear spinning of long tubes. Their
paper presents the results of experiments conducted on commercially pure titanium,
incoloy 825, inconel 600 and stainless steel AISI-304. It is concluded that the process can
be used on a commercial basis for producing long, small-bore, thin-walled, high
precision tubing in hard-to-work materials, particularly when the volume required
prohibits heavy investments. |
