Forming of dished
ends is achieved in one of three ways:
- Completely spun - Ends formed using this technique are spun
over a tool, which has both the spherical and the knuckle radii.
This allows the end to be formed entirely on one spinning machine.
- Press and Flanging - A contract specific spherical radius
is formed using specialist hydraulic Boldrini presses. Following
this the required knuckle radius is spun using Boldrini flanging
units.
- Spin and flanging - Unlike pressing, the spherical radius
is formed by spinning the plate blank against a fixed forming
tool. Forming of the knuckle radius is made in the same way
as pressed ends.
Procedure of Dished-End Manufacturing
Pre Manufacturing Process :
- Firstly the material is being procured of the quality specified
by the client.
- Heat Mark numbers mentioned on the material are verified
and co-related with the numbers mentioned in the Manufacturer’s
Test Certificate(MTC).
- The material is checked to verify that it is free from all
visual and surface defects.
- The dimension of the material are co-related with the dimension
mentioned in the MTC.
- The test piece of the material is been sent to recognised
Laboratory for physical and chemical testing in accordance with
the material specification.
- If all the above mentioned points are found fulfilled in
accordance then the material is taken into manufacturing process.
Manufacuting Process :
- Firstly the blank diameter requirement is been assessed in
accordance with the specification given by the client/ code.
- The circle is been cut as per requirement.
- Welding of the circle is been done, if the diameter of the
circle is bigger than the width of the plate.
- Radiography Test of the Weld-Seam is performed, if required
by the customer.
- Pressing process is started of the circle for making the
Crown portion of the Dished-End.
- After making the Crown portion the piece is loaded on the
Spinning Machine for making the Knuckle portion and the Straight
Flange. Now the manufacturing process is completed.
Post-Manufacturing Process :
- The complete Dished-End is checked for surface defects, to
ensure that no cracks or fiction marks are developed on the
Dished-End.
- The final dimensions of the Dished-End are taken in accordance
with the specified dimensions of the customer.
- Dye Penetrant testing of Knuckle portion and Edges of the
Dished-End is done to check any occurance of pin-holes or minute
cracks on the surface.
- After all these activities the Dished-End if offered for
inspection to the customer for Final Inspection.
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