BK (+C) Cold finished/hard (cold finished as drawn). No heat treatment after the last cold forming process
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
2.5 Surface condition
Tube surface corresponds to the standards and depends on the method of tube manufacturing and method of heat treatment. Value of roughness Ra <0.8 µm.
2.6 Tube ends
The tubes are delivered with plain ends without burrs at the ends of the tube.
Upon request ends could be plugged with plastic caps
3.Testing ofSt35 NBK material Precision Cold Drawn Seamless Tube
Testing is performed in accordance with corresponding standards or by agreement
• flattening test , drift expanding test, flaring test, bending test
• mechanical properties test
• NDT for detection of transverse imperfections and wall imperfections
4. Packing and Protective coating
4.1 Tubes are supplied either uncoated or with the manufacturers standard mill coating at the option of the customer (subject of agreement between customer and manufacturer).
St35 NBK material Precision Cold Drawn Seamless Tube
Hi,this is Chrisina,thanks very much for your interest in our products,If you want such steel tubes and pipes,or the standard is not listed above,pls do not hesitate to contact me at once.pls tell me,it's my honor to service you!
Christina Skype: christina.haibinjx
Tel:+8618056100777
