DIN 17100 St44-2 SSAW Pipe
St44-2 DIN 17100 SSAW Pipe: Chemical, Mechanical & Physical Properties, Equivalents
Complete material data for St44-2 steel SSAW pipes according to DIN 17100, including chemical composition, mechanical properties, thermal & electrical properties, international equivalents, similar materials and application guidance.
Hot Rolling, Welding (Spiral Submerged Arc Welding), Forming, Cutting
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DIN 17100 St44-2 SSAW Pipe Introduction
St44-2 is a general structural steel grade originally specified in DIN 17100, commonly used for the production of spiral submerged arc welded (SSAW) pipes. This steel offers moderate strength, good weldability and reliable formability, making it suitable for a wide range of structural and fluid transmission applications.
- Minimum yield strength of 235 MPa for thicknesses up to 16 mm.
- Tensile strength range of 410–540 MPa.
- Good elongation properties ensuring ductile behavior in service.
- Supplied in hot-rolled condition, often as coils for pipe manufacturing.
The designation has been superseded by EN 10025-2 S275JR, but St44-2 remains recognized in many global projects. SSAW pipes produced from this grade are widely applied in water, oil and gas transmission, piling, structural frameworks and general construction.
DIN 17100 St44-2 SSAW Pipe Chemical Composition
The chemical composition of St44-2 according to DIN 17100 is designed to ensure good weldability and structural integrity. Maximum limits are specified for carbon, manganese, silicon, phosphorus, sulfur and nitrogen. These elements control strength, ductility and toughness. SSAW pipe production from hot-rolled strips maintains these limits.
| Element | Standard Value (max %) | Remarks |
|---|---|---|
| Carbon (C) | 0.21 | Maximum for heat analysis; typical range 0.15–0.21 |
| Manganese (Mn) | 1.60 | Contributes to strength and hardenability |
| Silicon (Si) | 0.55 | Deoxidizer; upper limit for fine grain practice |
| Phosphorus (P) | 0.045 | Maximum allowable to avoid brittleness |
| Sulfur (S) | 0.045 | Maximum for good weldability |
| Nitrogen (N) | 0.009 | For products not containing nitrogen-binding elements |
DIN 17100 St44-2 SSAW Pipe Thermal & Electrical Physical Properties
Physical properties are characteristic of low-carbon structural steels and apply to St44-2 base material. Density, elastic moduli, thermal expansion, thermal conductivity, specific heat capacity and electrical resistivity are given for room temperature unless otherwise specified.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Modulus of Elasticity (E) | 210 | GPa | At 20 °C |
| Shear Modulus (G) | 81 | GPa | At 20 °C |
| Poisson's Ratio (ν) | 0.3 | — | At 20 °C |
| Thermal Expansion Coefficient (α) | 11.7 × 10⁻⁶ | K⁻¹ | Between 20 °C and 100 °C |
| Thermal Conductivity (λ) | 53 | W/(m·K) | At 20 °C |
| Specific Heat Capacity | 460 | J/(kg·K) | At 20 °C |
| Electrical Resistivity (ρ_e) | 0.20 × 10⁻⁶ | Ω·m | At 20 °C |
DIN 17100 St44-2 SSAW Pipe Mechanical Properties
Mechanical properties of St44-2 for thicknesses ≤ 16 mm are presented below. For SSAW pipes, the properties of the base material (strip) are relevant before welding. Yield strength, tensile strength, elongation and bend test are defined. Impact energy is not mandatory for St44-2 but may be specified by agreement.
| Property | Specified Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 235 | MPa | Thickness ≤ 16 mm; transverse direction |
| Tensile Strength (Rm) | 410 – 540 | MPa | Thickness ≤ 16 mm; transverse direction |
| Elongation (A) | ≥ 22 | % | Gauge length 5.65√So; transverse, thickness ≤ 16 mm |
| Elongation (A) | ≥ 24 | % | Gauge length 5.65√So; longitudinal, thickness ≤ 16 mm |
| Bend Test | Bend angle 180°; mandrel diameter 1.5t | — | Thickness ≤ 16 mm; no cracks |
DIN 17100 St44-2 SSAW Pipe Fully Equivalent Material Standards and Substitutable Grades
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-2:2004 | S275JR (1.0044) | Direct successor to St44-2; identical chemical and mechanical requirements for t ≤ 16 mm |
| International | ISO 630-2:2011 | Fe430B | Corresponds to St44-2; structural quality steel (formerly Fe430B in ISO 630:1995) |
| China | GB/T 700-2006 | Q235B | Comparable carbon structural steel; yield ≥ 235 MPa, tensile 370–500 MPa |
| Japan | JIS G3101:2015 | SS400 | General structural rolled steel; tensile strength 400–510 MPa, yield ≥ 245 MPa (t ≤ 16 mm) |
| USA | ASTM A36/A36M-19 | A36 | Carbon structural steel; tensile 400–550 MPa, yield ≥ 250 MPa (t ≤ 200 mm) |
DIN 17100 St44-2 SSAW Pipe Application Introduction
St44-2 SSAW pipes are produced from hot-rolled coils by spiral submerged arc welding, offering cost-effective large-diameter pipes with good structural integrity. The steel's moderate strength and excellent weldability make it ideal for:
- Low-pressure fluid transmission systems
- Structural frameworks and piling
- General fabrication and construction equipment
Product Applications: Spiral Submerged Arc Welded (SSAW) pipes, Large-diameter pipelines for water and slurry transportation, Structural hollow sections and pipe piles, Energy sector casing and conductor pipes, Bridge and highway sign structures
Processed into products: Welded pipe elbows, tees and reducers, Flanges and gaskets matched with SSAW pipes, Pipe spools for modular piping systems, Structural supports and stubs for industrial facilities
Application industries: Oil & Gas (offshore and onshore pipelines, flowlines), Water Supply and Sewage (mains, penstocks, distribution pipes), Construction & Infrastructure (building columns, bridge supports, foundation piles), Marine & Dredging (marine riser pipes, dredge pipes, offshore structural members), Mechanical Engineering (structural elements of machinery, conveyor frames)
DIN 17100 St44-2 SSAW Pipe Materials with Similar Performance
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-2:2004 | S235JR (1.0038) | Lower strength (yield ≥ 235 MPa, tensile 360–510 MPa) but similar weldability for less demanding structures |
| Europe | EN 10025-2:2004 | S355JR (1.0045) | Higher strength (yield ≥ 355 MPa) for weight saving in structural applications |
| China | GB/T 700-2006 | Q345B | Higher yield ~345 MPa, often used as an upgrade for structural pipes |
| Russia | GOST 380-2005 | St3sp | General structural steel; tensile 380–490 MPa, frequently used in pipes |
Notes:
St44-2 according to DIN 17100 has been officially replaced by EN 10025-2 S275JR, but many legacy projects still reference the old designation. SSAW pipes in St44-2 are typically supplied with a mill test certificate (EN 10204 3.1). For services requiring notch toughness, a supplementary impact energy requirement (e.g., 27 J at 20 °C) may be agreed upon. Welding procedures should be qualified according to EN ISO 15614 or equivalent standards using matching filler metals such as E7018 or ER70S-6. Hot-dip galvanizing or coating systems are recommended for corrosion protection in buried or exposed environments.
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