DIN2391 St35.0 St37.0 St44.0 St45St52.0 BKW BKS GBK NBK Seamless Precision Cold Drawn Steel Tubes

Standard: DIN2391 Seamless Cold Drawn/Rolling Steel Tubes

Applications: for Auto industry / for machinery use / Oil Cylinder Tube / Motorcycle shock absorber

     
Auto shock absorber inner cylinder / Telescopic Cylinders            

                            
Size range: O.D.:6-350mm     W.T.:1-50mm      L:max12000mm     

Materials:

The tubes are manufactured from electric steel or basic oxygen stel, the melting and casting processes being at the discretion of the manufacturer.

The steel is cast as killed steel             

Apperance:

Tubes have a smooth internal and external surface with the cold working process

Tube ends:

Square cut, no burrs                   

Steel Grade and Chemical Compositions:

Note: Special steel grade is also available, according to customer request.
 

Final Supply Condition:

BK - Cold finish (hard)      

Tubes do not undergo heat treatment following the final cold forming and, thus

have a rather high resistance to deformation

BKW - Cold finished(soft)  

The final heat treatment is followed by cold drawing involving limited deformation.

Appropriate further processing allow a certain degree of cold forming (bending, 

expanding)

BKS - Cold finished and stress-relieved

Heat treatment is applied following the last cold forming process. Subject to appropriate processing conditions, the increase in the residual stresses involved enables both forming and machining to a certain degree.

GKB - Annealed

The last cold forming process is followed by annealing in a controlled atmosphere.

NBK - Normalized

The last cold forming process is followed by annealing above the upper transformation point in a controlled atmosphere.

Testing:

1. dimensional chec

2. surface inspection

3. tensile test as DIN EN10002 Part 1

4. flattening test, as DIN EN10233

5. drift expanding test as DIN EN10234

DIN2391-1 standard does not cover the following standard:

-seamless circular unalloyed steel tubes subject to special requirements ( DIN1629)

-high performance seamless circular unalloyed steel tubes (DIN1630)

-seamless circular steel tubes for structural steel work (DIN17121)

-seamless circular fine grain steel tubes for structural steelwork  (DIN17124)

-seamless circular tubes made from steel with low-temperature toughness (DIN17173)

-seamless tubes made from steel with elevated temperature properties (DIN17175)

-seamless circular fine grain steel tubes subject to special requirements (DIN17179)

-seamless circular austenitic stainless steel tubes subject to special requirements (DIN17458)

-steel pipes for conveying combustible liquids and gases (DIN17171)