‌DIN 2391 Precision Seamless Steel Tube

St35, ST45, ST52, NBK / GBK / CW / SR

1. ‌Basic Specifications‌

• ‌Standard‌: DIN 2391 (German Industrial Standard for cold-drawn precision seamless steel tubes)‌1.
• ‌Material‌: Carbon steel (e.g., ST52 grade)‌8, suitable for mechanical and hydraulic applications‌6.
• ‌Surface Treatment‌: Options include phosphating (anti-corrosion treatment)‌4 and honed/bright surfaces (improved smoothness)‌

2. ‌Manufacturing Process‌

• ‌Cold Drawing‌: Precision cold-drawn process ensures dimensional accuracy and mechanical strength‌
• ‌Honing‌: Post-processing to achieve ultra-smooth internal surfaces for hydraulic systems‌

3. ‌Dimensions & Tolerances‌

• ‌Outer Diameter (OD)‌: 6-168mm
• ‌Wall Thickness‌: Tolerance within ±8% of specified thickness
• ‌Length‌: 5.8M / 6M / 11.8M , random length 5-5.8M

4. ‌Mechanical Properties‌

• High-pressure resistance and excellent load-bearing capacity‌
• Optimized for applications requiring tight tolerances and structural integrity‌

5. ‌Key Features‌

• ‌High Precision‌: Tight dimensional tolerances for seamless integration in complex assemblies‌
• ‌Surface Quality‌: Bright or honed surfaces reduce friction and enhance cleanliness in hydraulic/pneumatic systems‌
• ‌Durability‌: Enhanced strength from cold-working processes‌

6. ‌Applications‌

• ‌Hydraulic/Pneumatic Systems‌: Cylinder tubing and pipelines‌
• ‌Automotive‌: Precision components requiring high dimensional stability‌
• ‌Heavy Machinery‌: Structural parts in mechanical engineering‌

• Mechanical properties at room temperature

  Steel Grade

  Minimum values for the delivery condition

  Steel Name

  Steel Number

  BK

  BKW

  BKS

  GBK

  NBK

  Rm

  A %

  Rm

  A %

  Rm

  ReH

  A %

  Rm

  A %

  Rm

  ReH

  A %

  Mpa

  Mpa

  Mpa

  Mpa

  Mpa

  Mpa

  Mpa

  St 35

  1.0308

  480

  6

  420

  10

  420

  315

  14

  315

  25

  340 to 470

  235

  25

• Standard	Grade		Chemical Components (%)
  	Symbol	Material No.	C	Si	Mn	P	S
  DIN2391	St 35	1.0308	≤0.17	≤0.35	≥0.40	≤0.025	≤0.025

Keywords: DIN2391, Precision seamless steel tube, steel tube, seamless steel tube