Random lengths
approx. 6 m
Customer-made length as required
Manufacturing finishes
Cold drawn, hard, BK
Cold drawn, soft, BKW
Cold rolled, BKM
Leak testing
Annealing
GBK
After the last cold forming the tubes are annealed under exclusion of oxygen. Rust preventing agents and drawing grease may leave behind remains on this annealing method and cause discoloration. This can be avoided to a great extent by NBK annealing.
NBK
Tubes are annealed above the upper transformation-point under exclusion of oxygen. (Thin walled tubes with a relation of diametre/wall thickness bigger than 40:1 are annealed GBK only.)
Grades of steel used
Hot rolled strip
- Construction steels
- Quality steel with defined strengths
- Steel with special cold-forming properties
- Micro-alloyed steels
- Specifically anneal-stable cold-formable steel
- Special, high-strength cold-formable steel
- Heat-temperad steels
Cold-rolled strip
- Quality steel with special cold-forming properties
- Micro-alloyed steels
Galvanised steel grades
Fin cutting
On request, we can remove the internal weld seam on cold-rolled tubes.