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The
service demanded of tube expanders is severe, therefore,
these precision tools require a reasonable amount of care. For long, trouble-free, and economical service,
the following is suggested:
- Remove all rust, mill scale and other foreign matter from
the
inside and outside of the tube. Foreign matter on the inside
of
the tube will become imbedded in the tube wall and may cause
flaking or galling of the rolls and mandrel. Mill scale or
grit left
on the outer wall of the tube can cause damage to the tube
seat and prevent formation of a pressure-tight joint. Cleaning
tube ends is best accomplished with a wire brush or a tube
end polisher.
- Before using, the expander should
be washed in a commercial solvent to remove anti-rust, dirt, grease and
other foreign matter. Inspect the expander to make sure the rolls
and mandrels are free and in good condition.
- Before using, an
expander should be properly lubricated with
a pressure resistant lubricant such as Wilson
Expander Lube. This water soluble lubricant was developed
specifically for tube rolling and may be mixed with water
to the desired consistency. For small diameter and light Gauge
tubes, immerse the expander in Wilson Expander Lube or a light bodied
oil* such as SAE 10 or 20. For large diameter and heavy Gauge
tubes, swab or brush the expander with Wilson Expander Lube
or a mixture of SAE 40* and graphite.
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- Expanders should be
rotated at a speed proportionate to the tube size, Gauge and the length of the tube seat. Tube metal must also be taken into consideration. The proper speed will provide safe cold working of the tube metal without crystallization or flaking. It will also ensure maximum expander life without undue roll or mandrel breakdown. The ideal speed will keep to a minimum mandrel slippage and heating of the mandrels and rolls.
- After rolling each tube, clean and cool the expander in
a
solvent or light oil*, then properly lubricate the expander.
It is a good practice to use two expanders, if possible,
so one can be cooling while the other is being used.
- Inspect the rolls and the mandrel after rolling each
tube.
Replace a chipped roll or mandrel immediately! A small
chip in a roll can damage the entire set of rolls and the
mandrel if not replaced at once.
- When the job is completed,
the expander should be cleaned
thoroughly with a commercial solvent or light oil*, and
it should be stored in a manner which will avoid the possibility
of the parts rusting.
*CAUTION: The presence of oil in the space between the
tube and the tube seat can prevent the formation of a leak-tight
joint. Do not allow excess lubrication to run down the face
of the sheet, so that it can seep into unrolled joints.
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