The up-to-date forming and welding equipment of the pipe welding unit (ТЭСА 42-168, ТЭСА 140-426) allows us to manufacture pipe up to 426 mm in outside diameter and up to 14 mm in wall thickness. The welding modes are set and controlled using the automatic system. The special devices allow the system remove the outside and inside flash efficiently. The in-line rolls changeover operation is automated and that helps minimize the changeover time.
Before the hot-rolled steel goes to the welding stand, the following technological operations are performed:
- Stacking and inspection of coils in accordance with the normative technical documentation and accompanying certificates (1);
- Slitting the coils into narrower ones of required width (strips) at the slitting machine (2);
- Stacking of coils (strips) after slitting (3);
- Coil feeding into the pipe welding mill (4);
- Straightening of strips (5);
- Strip ends cropping (6);
- Butt-welding of the strip ends (7);
- Accumulating of the strip at the spiral accumulator (8) with the subsequent forming the strip into the pipe using rolls.
Immediately after welding (9), 100% ultrasonic inspection of the weld joint (10) and annealing of the weld and the weld area (11) are conducted in order to get the uniform structure of the weld seam metal, stress relief and the uniformity of mechanical properties of base metal and weld joint.
After annealing, pipe cooling in air (with the subsequent emulsion cooling) (12) and in-line pipe sizing (13) by diameter are performed.
Then, a continuous pipe (14) is cut into lengths from 6 to 12 m in accordance with the purchase order requirements, the inside washing (15), straightening (16), and chamfering on both ends are carried out (17).
The finishing line equipment is designed to be used for finishing, testing and inspection of pipe coming from the mill line (including geometrical parameters) (18)). In addition, the line is equipped with the hydro tester (19), as well as NDT inspection systems (ultrasonic and magnetic) capable of detecting longitudinal and transverse imperfections through the entire pipe length on outside and inside surfaces (20). The operation of the in-line machines is fully-automated.
The quality inspection of products is performed at all production stages. The chemical composition analysis and mechanical testing, metallographic analysis of products are conducted in the Central Factory Laboratory.
Pipe can be protected using the protection coating as required by the customer (21).
Pipe goes through acceptance inspection, length measuring and weighing of each pipe, automatic banding in hexagonal bundles (22). The tied bundles go to the final products warehouse or to the divisions: Heat Treatment Line or Threading Line for the subsequent finishing (23).