galet de guidage

CONT: ... pipes are manufactured in a continuous process on the pipe mill. Raw material, consisting of stainless steel purchased in the form of coils, is fed into the pipe mill and formed to round by five break down rolls and three fin pass rolls prior to welding. The pipe is then plasma welded.
CONT: The mills normally make use of three types of rolls to progressively form the flat steel section into the round form prior to welding. The three types are: break down or forming rolls, the idler vertical closing rolls and fin pass rolls. ... Breakdown rolls provide the initial shaping of the strip towards the round form. ... The fin pass rolls provide perfect guidance into the welding section and in addition coin the strip edges to provide the precise circumference.