DIN 2391 ST35 steel pipes offer a reliable combination of strength, toughness, and weldability, making them suitable for a wide range of industrial applications. Under standard conditions, ST35 delivers a minimum tensile strength of 480 MPa and a yield strength of 315 MPa, giving it the durability needed for systems exposed to continuous wear and mechanical stress.
These pipes are available in multiple shapes—including the commonly used DIN 2391 ST35 round pipe as well as square and other customized profiles. Shape selection often depends on the project needs: for example, square pipes are preferred in structural installations for their enhanced load-bearing stability.
The DIN 2391 ST35 welded pipe is especially suitable for applications requiring frequent or intensive welding. This grade can be welded easily, with or without filler materials, while maintaining structural integrity.
Thanks to its balanced chemical composition—primarily carbon, silicon, manganese, phosphorus, and sulfur—ST35 steel demonstrates excellent wear resistance, toughness, and performance under demanding conditions. As a result, it is widely used across petroleum, oil and gas, chemical processing, food processing, and power generation industries.
ST35 Steel Grade Pipe Wall Thickness
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Outer diameter and wall Thickness
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Execution
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Size Range
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OD Tolerance
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Wall tolerance
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Hot-rolled Tube
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OD – 80 mmOD > 80 mmWall < 12 mmWall - 12 mm
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± 0.4 mm± 0.5 % of OD
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± 0.7 mm± (5 % x wallthickness + 0.1 mm
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Hot-rolled peeled tube
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All sizesWall < 12 mmWall - 12 mm
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+ 0.25/- 0 mm
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± 0.8 mm± (5 % x wall thickness+ 0.2 mm)
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Cold Worked tubecold-rolled or cold-drawn
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OD < 40 mmOD 40 - 80 mmOD > 80 Wall Thickness< 6 mm Wall Thickness6 - 8 mm Wall Thickness > 8
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+ 0.30/- 0 mm*+ 0.35/- 0 mm*+ 0.40/- 0 mm*
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± 0.30 mm± 0.35 mm± 0.40 mm
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DIN 2391 ST35 Welded Pipe Tolerance
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Component length (mm)
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OD 30-100 mm
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OD 100-254 mm
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10-100
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+ 1.0/- 0
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+ 2.0/- 0
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100-600
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+ 2.0/- 0
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+ 3.0/- 0
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600-1200
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+ 3.0/- 0
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+ 4.0/- 0
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1200-5000
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+ 5.0/- 0
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+ 6.0/- 0
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DIN 2391 ST35 Carbon Steel Welded Pipe Equivalent Material Grade
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OD Tolerance
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4-30mm
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31-40mm
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41-50mm
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51-60mm
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61-70mm
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71-80mm
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81-90mm
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91-100mm
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±0.08mm
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±0.15mm
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±0.20mm
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±0.25mm
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±0.30mm
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±0.30mm
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±0.40mm
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±0.45mm
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WT Tolerance
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±10%
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DIN 2391 Grade ST35 pipe Chemical Resistance Guide
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Standard
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Grade
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C
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Si
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Mn
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P max
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S max
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DIN2391
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St35
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≤0.17
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≤0.35
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≥0.4
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0.025
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0.025
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DIN 2391 ST35 Welded Pipe Mechanical Behaviour
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Cold drawn(Mandatory)
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Cold drawn(Soft)
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Cold Drawn and Stress Release
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Anneal
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Normalizing
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BK1）
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BKW1）
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(BKS)
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(GBK)1）
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(NBK)1）
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Grade
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Tensile
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Elongation
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Tensile
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Elongation
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Tensile
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Yield point
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Elongation
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Tensile
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Elongation
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Tensile
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Yield point
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Elongation
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N/mm2
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%
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N/mm2
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%
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N/mm2
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N/mm2
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%
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N/mm2
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%
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N/mm2
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N/mm2
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%
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St35
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480
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6
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420
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10
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420
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315
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14
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315
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35
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340~470
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235
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25
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