CFS NBK Cold Drawn Seamless Hydraulic Tube 

1.the steel billets is from Baosteel, Xingcheng Special Steel or Huaisteel, we do 100% visual inspection and chemical inspection randomly, then bars were cut into short pcs as per requirement of final tube length requirement to do hot piercing

2. Specification of  DIN EN10305-4 E355 NBK Cold Drawn Seamless Tube

2.1 Dimensions

Tubes shall be ordered:

2.1.1. by outside diameter and inside diameter

2.1.2. by outside diameter and wall thickness

2.2.2. Tolerances by agreement

2.2.3. Dimensions and tolerances according to standard ASTM A450

2.3 Steel grades

Steel is produced in electric arc furnace and is fullykilled. 

2.4 Delivery conditions and heat treatment

BK (+C) Cold finished/hard (cold finished as drawn). No heattreatment after the last cold forming process

BKW (+LC) Cold finished/soft (lightly cold worked). After the lastheat treatment there is a light finishing pass (cold drawing).

BKS (+SR) Cold finished/stress relieve annealed. After the finalcold forming process the tubes are stress relieve annealed.

GBK (+A) Annealed. After the final cold forming process the tubesare annealed in a controlled atmosphere.

NBK (+N) Normalized. After the final cold forming process thetubes are annealed above the upper transformation point in a controlledatmosphere

2.5 Surface condition

Tube surface corresponds to the standards and depends on themethod of tube manufacturing and method of heat treatment. Value of roughnessRa <0.8 µm.

2.6 Tube ends

The tubes are delivered with plain ends without burrs at the endsof the tube.

Upon request ends could be plugged with plastic caps

3.Testing of  DIN EN10305-4 E355 NBK Cold Drawn Seamless Tube

Testing is performed in accordance with corresponding standards orby agreement

• flattening test , drift expanding test, flaringtest, bending test

• mechanical properties test 

• NDT for detection of transverse imperfections and wallimperfections

4. Packing and Protective coating

4.1 Tubes are supplied either uncoated or with the manufacturersstandard mill coating at the option of the customer (subject of agreementbetween customer and manufacturer).

4.2 Packaging of  DIN EN10305-4 E355 NBK Cold Drawn SeamlessTube

Tubes are packed in round or hexagonal bundles with weightmax.2000 kg. Other possibilities by agreement.

4.2 Packaging of  DIN EN10305-4 E355 NBK Cold Drawn SeamlessTube

Tubes are packed in round or hexagonal bundles with weightmax.2000 kg. Other possibilities by agreement.

5. Mill Test Certificate

Types of inspection documents according to EN 10204 3.1.BInspection certificate (inspector representing the manufacturer)

6. Quality System(ISO9001&TS16949)

Hi,this is Chrisina,thanks very much for your interest in ourproducts,If you want such steel tubes and pipes,or the standard is not listedabove,pls do not hesitate to contact me at once.pls tell me,it's my honor toservice you!

Christina Skype: christina.haibinjx

Tel:+8618056100777