Roll Bending

Roll Bending  Production Process


3 Roll-Banding Process


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In Roll Bending plant a method of pipe production is used that can produce pipes with outside diameter from 20” to 64” and thickness from 6.4 mm to 31.8mm. In this process an individual nominal 12 meter plate is formed to an individual nominal 12 meter longitudinal seam submerged arc welded pipe. The main process for forming open seam pipes from the plates in this plan is “Roll Bending”. And the welding technique is submerging arc weld (SAW).


This process is consisting of 3 main steps and parts:

Pipe Forming Operation:
Pipe forming is done with a pre-stressed top roll in a 3-Roll hydraulic bending machine. After 2 or 3 passes a plate is bent into the shape of an open seam pipe. The remaining longitudinal flat ends plate sides are formed to proper pipe curvature by the post bending machine, which works by an innovative roll/die process.

Joining and welding operation:
The slot pipe is continuous tack welded with a single arc by gas metal arc process over the entire length. Tab plates are welded on pipe ends for avoiding of start and stop weld defects located on the pipe.
After that, all of the pipes are guided to two welding lines for inside and outside welding process.
All of the pipes are welded with a single pass in the inside and outside respectively.

Final pipe sizing operation:
In this step inside and outside diameter of the pipes according to the customer specifications are increased by the expansion machine and the parts of the pipes that do not have proper curvature are improved and also in this step out of roundness (oval form) of the pipe are rounded. Then Pipe ends are chamfered according to the customer requirements by end chamfering machine, and tested with different NDT methods in the line. All the pipes after passing the testing stations are transferred to the coating plant or final destination at the option of the purchaser.
Roll Bending Factory