2. Stretching

2.1 Tubes

The drawing blank is made up of: a hot-spun tube on a needle or in an extrusion-fed process, a rolled tube or a welded rolled tube.

Initial surface preparation is adapted to the nature of the blank.

There are two types of drawing:

• continuous drawing, which consists in drawing coiled tubes in coils; these are small-diameter tubes, generally less than 25 mm, in soft alloys from the 1,000, 3,000 and 6,000 series; each coil can comprise up to 2,000 meters of blank tube;

• discontinuous drawing of tube blanks up to 10 meters in length and of various diameters (14 mm to over 300 mm).