Cold Finish Tube BK , GBK , BKW , BKS , NBK Cold Drawn Seamless Tube , Black Phosphate
Specifications
GB 3639 DIN 2391 EN 10305 BS6323
cold finish tube BK, GBK, BKW, BKS, NBK cold drawn seamless tube
Production range: OD from 3.75mm to 70mm; wall thickness up to 10mm
Steel grades:
|
Standard Tubes |
||
|
Standards |
TDR Standards |
Steel Grades |
|
DIN |
1629 |
ST 37 / 44 / 52 |
|
EN |
10305-1 |
E215/235/355/255 |
|
GB |
3639 |
10#, 20#, 16Mn, 45# |
|
ASTM |
A 519 |
1010 |
|
ASTM |
A179-A450 |
A450 |
|
ASTM |
A822-A450 |
A450 |
|
BS |
BS 6323 |
CFS3 |
|
NFA |
49310 |
TU 37 b |
Delivery conditions:
Precision tubes are delivered in following conditions
BK (+C) Cold finished/hard (cold finished as drawn).
No heat treatment after last cold forming process.
BKW (+LC) Cold finished/soft (lightly cold worked).
After last heat treatment there is a light finishing pass (cold drawing).
BKS (+SR) Cold finished/stress relieve annealed.
After the final cold forming process the tubes are stress relieve annealed.
GBK (+A) Annealed.
After the final cold forming process the tubes are annealed in a controlled atmosphere.
NBK (+N) Normalized.
After the final cold forming process the tubes are annealed above the upper transformation point in a controlled atmosphere.
Tests: 100% eddy current test, chemical and mechanical inspection, size checking and others
Certificates: according to EN 10204 3.1
SURFACE TREATMENTS
1. Bare Tube (No coating): Bright and smooth
A. Silver galvanized
B. Yellow galvanized
