EN10025-6 S500Q SSAW Pipe
EN10025-6 S500Q SSAW Pipe | High Strength Quenched & Tempered Steel for Spiral Welded Pipes
Explore EN10025-6 S500Q, a high strength quenched and tempered structural steel ideal for SSAW pipes. Detailed chemical composition, mechanical properties, thermal data, equivalent standards, and application insights.
Hot rolling, quenching and tempering, cutting, welding, cold forming, machining
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EN10025-6 S500Q SSAW Pipe Introduction
EN10025-6 S500Q is a high yield strength quenched and tempered weldable fine grain structural steel. With a minimum yield strength of 500 MPa, it offers excellent toughness, good weldability, and resistance to brittle fracture, making it suitable for demanding structural applications. The 'Q' designation indicates quenching and tempering, providing a uniform microstructure and balanced mechanical properties. S500Q is commonly used for spiral submerged arc welded (SSAW) pipes, offshore structures, heavy-duty machinery, and pressure vessels. It complies with the European standard EN 10025-6:2004 (or later), ensuring consistent quality and traceability. The steel is delivered in the quenched and tempered condition and can be supplied in plate or coil form for pipe manufacturing.
EN10025-6 S500Q SSAW Pipe Chemical Composition according to EN 10025-6 for S500Q
The following table presents the maximum allowable contents of alloying and residual elements for S500Q steel. The steel is microalloyed with niobium, vanadium, titanium, and/or boron to achieve fine grain structure and high strength after quenching and tempering. Carbon equivalent (CEV) is typically limited to ≤0.47 for thicknesses up to 50 mm to ensure good weldability.
| Element | Standard Value (max %) | Remark |
|---|---|---|
| C | 0.20 | Maximum |
| Si | 0.80 | Maximum |
| Mn | 1.70 | Maximum |
| P | 0.025 | Maximum |
| S | 0.015 | Maximum |
| N | 0.015 | Maximum |
| B | 0.005 | Maximum |
| Cr | 1.50 | Maximum |
| Cu | 0.50 | Maximum |
| Mo | 0.70 | Maximum |
| Nb | 0.06 | Maximum |
| Ni | 2.0 | Maximum |
| Ti | 0.05 | Maximum |
| V | 0.12 | Maximum |
| Zr | 0.15 | Maximum |
EN10025-6 S500Q SSAW Pipe Thermal and Electrical Physical Properties – S500Q
Typical physical properties at room temperature unless otherwise stated. These values are not part of the standard requirements but are representative for quenched and tempered low-alloy structural steels.
| Property | Standard Required Value (Typical) | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | 20 °C |
| Young's modulus (E) | 210 | GPa | 20 °C |
| Shear modulus (G) | 81 | GPa | 20 °C |
| Poisson's ratio (ν) | 0.3 | – | 20 °C |
| Thermal expansion coefficient (α) | 11.1 | 10⁻⁶/K | 20 - 100 °C |
| Thermal expansion coefficient (α) | 11.9 | 10⁻⁶/K | 20 - 200 °C |
| Thermal expansion coefficient (α) | 12.5 | 10⁻⁶/K | 20 - 300 °C |
| Thermal conductivity (λ) | 42 | W/(m·K) | 20 °C |
| Thermal conductivity (λ) | 40 | W/(m·K) | 100 °C |
| Specific heat capacity (c) | 460 | J/(kg·K) | 20 °C |
| Electrical resistivity (ρe) | 0.20 - 0.25 | 10⁻⁶ Ω·m | 20 °C |
EN10025-6 S500Q SSAW Pipe Mechanical Properties – S500Q according to EN 10025-6
Mechanical properties are determined in the longitudinal direction on quenched and tempered specimens. The yield strength (ReH), tensile strength (Rm), elongation (A), and impact energy (KV) are specified for various thickness ranges. Bend test requirement is a mandrel diameter of 4t (where t is the specimen thickness). Impact test is conducted at -20 °C (default for 'Q' quality).
| Property | Standard Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength (ReH) | ≥500 | MPa | Thickness ≤50 mm, longitudinal |
| Yield strength (ReH) | ≥480 | MPa | 50 mm < thickness ≤100 mm |
| Yield strength (ReH) | ≥440 | MPa | 100 mm < thickness ≤150 mm |
| Tensile strength (Rm) | 590 - 770 | MPa | Thickness ≤50 mm |
| Tensile strength (Rm) | 590 - 770 | MPa | 50 mm < thickness ≤100 mm |
| Tensile strength (Rm) | 540 - 720 | MPa | 100 mm < thickness ≤150 mm |
| Elongation (A) | ≥17 | % | Thickness ≤50 mm, longitudinal, gauge length 5.65√S0 |
| Elongation (A) | ≥17 | % | 50 mm < thickness ≤100 mm |
| Elongation (A) | ≥17 | % | 100 mm < thickness ≤150 mm |
| Bend test (mandrel diameter) | 4t | – | All thicknesses, 180° bend |
| Impact energy (KV, longitudinal) | ≥27 | J | At -20 °C, single value |
| Impact energy (KV, longitudinal) | ≥40 | J | At -20 °C, average of three |
EN10025-6 S500Q SSAW Pipe Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-6:2004 | S500Q | Original standard, quenched & tempered |
| Germany | DIN EN 10025-6 | S500Q | Adopted EN standard |
| France | NF EN 10025-6 | S500Q | Adopted EN standard |
| United Kingdom | BS EN 10025-6 | S500Q | Adopted EN standard |
| Italy | UNI EN 10025-6 | S500Q | Adopted EN standard |
| Spain | UNE EN 10025-6 | S500Q | Adopted EN standard |
| International | ISO 4950-2:1995 | E500 | Similar concept but not identical; verify grade |
EN10025-6 S500Q SSAW Pipe Application Introduction
S500Q is specifically suited for SSAW (spiral submerged arc welded) pipes used in the transmission of oil, gas, water, and slurries, as well as for structural pilings and offshore applications. Its high yield strength allows thinner wall designs, reducing weight and cost. The quenched and tempered condition provides excellent toughness at low temperatures, making it reliable for Arctic and subsea projects.
Product Applications: SSAW (spiral submerged arc welded) pipes, Longitudinal welded pipes, Pressure vessels and storage tanks, Offshore platforms and jackets, Structural hollow sections, Piling pipes
Processed into products: Pipe body for SSAW line pipe, Pipe fittings (tees, bends, reducers), Pressure vessel shell courses, Offshore flare booms and conductor casings, Bridge girders and trusses, Tower sections for wind turbines, Hydraulic cylinder bodies
Application industries: Oil & gas (transmission pipelines), Water treatment and distribution, Offshore and subsea engineering, Civil and structural engineering (bridges, high-rise buildings), Heavy machinery and equipment manufacturing, Renewable energy (wind turbine towers, hydropower penstocks)
EN10025-6 S500Q SSAW Pipe Similar / Comparable Alternative Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-6 | S500M | Thermomechanically rolled; similar yield, different production route and toughness |
| Europe | EN 10025-6 | S550Q | Higher yield strength (≥550 MPa), slightly different chemistry |
| Europe | EN 10149-2 | S500MC | Hot-rolled high yield steel for cold forming, lower CEV, limited thickness |
| USA | ASTM A913/A913M | Grade 65 [450] | High-strength low-alloy structural steel; yield 450 MPa, not direct replacement |
| USA | ASTM A514/A514M | Grade H, etc. | Quenched & tempered; yield ≥690 MPa, higher strength, may need design adjustment |
| Japan | JIS G 3128 | SHY685 | High yield strength plate for welded structures; 685 MPa class |
Notes:
For SSAW pipe manufacturing from S500Q plates or coils, special attention must be paid to welding consumables and preheating requirements due to the alloy content and CEV. Carbon equivalent (CEV) should be controlled within 0.47 (for t ≤50 mm) to avoid cold cracking. Post-weld heat treatment (PWHT) is usually not required for thicknesses up to 50 mm, but should be assessed based on service conditions. The steel is fully killed and fine-grained (Al treated). Testing and certification per EN 10204 Type 3.1 or 3.2 is typical.
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