PIPES & TUBES -
SAW
This process is used for
pipes from 24" to 36" i.e 610mm to 914mm OD. Flat plate is
first pressed into U and later O shape. The O shape is placed in an
automatic welder and backed up on the inside by a water cooled
copper shoe. Two electrodes in close proximity and used. The
electrodes are not in actual contact with the pipe. The current
passes from on electrode through a granular flux and across the gap
in the pipe to the second electrode. The high temperature of the arc
heats the edges of the plate, a welding rod placed just over the
seam is thereby melted and metal is deposited in the groove. After
the outside weld has been made, the pipe is conveyed to an inside
welder where a similar operation is carried on, except that no
backup shoe is need.
