1. KWK STEEL CO.,LTD
ISO9001:2008
Tel: +86-576-88805030 Fax: +86-576-88809380
E-mail: sales@kwksteel.com
www.kwksteel.com
Address: E801, Xintai Square, Taizhou, Zhejiang, China 318000
KWK STEEL FEATURED PRODUCT
DIN Seamless Precision Steel Tube
Size:
O.D.: 6.0-650.0mm W.T.: 1.0-65.0mm Length: Max.12000mm
Description:
DIN Seamless precision steel tube, cold
drawn and cold rolled seamless. And we've
been featured involved in this kind of product.
We exported large quantity to many
countries.
Customized technical specification for the
providing of seamless precision tubes.
This kind of tube concern seamless steel cold
drawn tubes suitable for the telescopic,
piston rods, hydraulic-oleo dynamic cylinder manufacturing and fix their dimensions,
tolerances, chemical composition, mechanical properties and delivery technical
conditions.
As well, we supply our customers extra
requirements stricter than standard like
Tolerance, Eccentricity, Straightness,
Ovality, etc.

2. KWK STEEL CO.,LTD
ISO9001:2008
Tel: +86-576-88805030 Fax: +86-576-88809380
E-mail: sales@kwksteel.com
www.kwksteel.com
Address: E801, Xintai Square, Taizhou, Zhejiang, China 318000
KWK STEEL FEATURED PRODUCT
Precision Steel Tube DIN2391
Application:
Cold drawn or cold rolled
precision seamless steel tubes
for hydraulic pressure and
pneumatic services.
For Auto. use, machinery use,
oil cylinder tube, motorcycle
shock reducer use, auto shock
reducer inner cylinder, etc.
Size:
O.D.: 6.0-650.0mm W.T.: 1.0-65mm Length: Max.12000mm
Steel Grade and Chemical Composition(%)
Standard Grade C≤ Si≤ Mn P≤ S≤
DIN2391
St35 0.18 0.35 ≥0.40 0.025 0.025
St45 0.22 0.10-0.35 ≥0.40 0.025 0.025
St52 0.22 0.55 ≤1.60 0.025 0.025

3. KWK STEEL CO.,LTD
ISO9001:2008
Tel: +86-576-88805030 Fax: +86-576-88809380
E-mail: sales@kwksteel.com
www.kwksteel.com
Address: E801, Xintai Square, Taizhou, Zhejiang, China 318000
Final Supply Condition
Symbol Designation Description
BK Cold finished(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 allows a certain degree of cold
forming(e.g. 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.
GBK Annealed
The last cold forming process is followed by
annealing in a controlled atmosphere.
NBK Normalized
The last forming process is followed by annealing
above the upper transformation point in a controlled
atmosphere.
Mechanical Properties
Rm:Tensile Strength(Mpa) ReH:Yield Point(Mpa) A%:Elongation Mpa=N/mm2
Standard Grade
BK BKW BKS GBK NBK
Rm≥A%≥Rm≥A%≥Rm≥ReH≥A%≥Rm≥ A%≥ Rm≥ ReH≥ A%≥
DIN2391
St35 480 6 420 10 420 315 14 315 25 340-470 235 25
St45 580 5 520 8 520 375 12 390 21 440-570 235 21
St52 640 4 580 7 580 420 10 490 22 490-630 355 22

4. KWK STEEL CO.,LTD
ISO9001:2008
Tel: +86-576-88805030 Fax: +86-576-88809380
E-mail: sales@kwksteel.com
www.kwksteel.com
Address: E801, Xintai Square, Taizhou, Zhejiang, China 318000
KWK STEEL FEATURED PRODUCT
Precision Steel Tube EN10305
Cold drawn or cold rolled precision seamless steel tubes for hydraulic pressure and
pneumatic services.
For Auto. use, machinery use, oil cylinder tube, motorcycle shock reducer use, auto
shock reducer inner cylinder, etc.
Size:
O.D.: 6.0-650.0mm W.T.: 1.0-65mm Length: Max.12000mm
Application:
Steel tubes for precision
applications.
Steel Grade and Chemical Composition(%)
Standard Grade C≤ Si≤ Mn≤ P≤ S≤ Al
EN10305
E215 0.10 0.05 0.70 0.025 0.025 ≥0.025
E235 0.17 0.35 1.20 0.025 0.025 /
E355 0.22 0.55 1.60 0.025 0.025 /

5. KWK STEEL CO.,LTD
ISO9001:2008
Tel: +86-576-88805030 Fax: +86-576-88809380
E-mail: sales@kwksteel.com
www.kwksteel.com
Address: E801, Xintai Square, Taizhou, Zhejiang, China 318000
Final Supply Condition
Symbol Designation Description
+C Cold drawn(hard) No heat treatment after the final cold drawing process.
+LC Cold drawn(soft)
After the final heat treatment there is a suitable
drawing pass.
+SR
Cold drawn and
stress-relleved
After the final cold drawing process there is a stress
relief heat treatment in a controlled atmosphere.
+A Annealed
After the final cold drawing process the tubes are
annealed in a controlled atmosphere.
+N Normalized
After the final cold drawing operation the tubes are
normalized in a controlled atmosphere.
Mechanical Properties
Rm:Tensile Strength(Mpa) ReH:Yield Point(Mpa) A%:Elongation Mpa=N/mm2
Grade
Minimum values for the delivery condition(Exclude +N Rm)
+C +LC +SR +A +N
Rm≥ A%≥ Rm≥ A%≥ Rm≥ ReH≥ A%≥ Rm≥ A%≥ Rm ReH≥ A%≥
E215 430 8 380 12 380 280 16 280 30 290-430 215 30
E235 480 6 420 10 420 350 16 315 25 340-480 235 25
E355 640 4 580 7 580 450 10 450 22 490-630 355 22