GB/T 1591 Q460D High Strength Low Alloy Steel Material for SSAW Pipe
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe - Properties & Applications
Explore the chemical, mechanical and physical properties of Q460D steel under GB/T 1591 standard. Find international equivalents, similar grades, and typical applications for spiral submerged arc welded (SSAW) pipes and structural engineering.
Hot rolling, cold forming, welding, bending, cutting, normalization, TMCP
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Introduction
Q460D is a high-strength low-alloy structural steel specified in GB/T 1591-2018. It offers a minimum yield strength of 460 MPa, good weldability, and excellent low‑temperature toughness (impact tested at -20°C). The D variant ensures fine‑grain practice and is typically supplied in normalized or thermo‑mechanically controlled rolled (TMCP) condition. Widely used for heavy‑duty structures, the grade is particularly suitable for the manufacture of spiral submerged arc welded (SSAW) pipes employed in oil & gas transportation, water mains, piling, and structural columns. Its balanced alloy design with micro‑alloying elements (Nb, V, Ti) delivers superior strength without compromising ductility or formability.
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Chemical Composition
Chemical composition of Q460D according to GB/T 1591-2018. Values are maximum unless a range is indicated. The steel is micro‑alloyed with elements such as Nb, V, Ti, Al to refine grain size and improve strength and toughness. The sum of Nb+V+Ti is typically controlled for optimal properties.
| Element | Standard Value (wt%) | Remarks |
|---|---|---|
| C | ≤0.18 | |
| Si | ≤0.60 | |
| Mn | ≤1.80 | |
| P | ≤0.030 | |
| S | ≤0.025 | |
| Nb | ≤0.11 | At least one of Nb, V, Ti shall be present; grain refiner |
| V | ≤0.12 | At least one of Nb, V, Ti shall be present |
| Ti | ≤0.20 | At least one of Nb, V, Ti shall be present |
| Cr | ≤0.30 | |
| Ni | ≤0.30 | |
| Cu | ≤0.40 | |
| Mo | ≤0.20 | |
| N | ≤0.015 | |
| Alt (total Al) | ≥0.015 | Optional but often used for deoxidation and grain refinement |
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Thermal and Electrical Physical Properties
Typical physical properties for Q460D low‑alloy steel at room temperature and ambient pressure. Values are representative for this class of steel; slight variations may occur depending on exact composition and heat treatment condition.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20°C |
| Modulus of Elasticity (E) | 190 – 210 (≈205) | GPa | 20°C |
| Shear Modulus (G) | ≈80 | GPa | 20°C |
| Poisson's Ratio (ν) | 0.3 | - | 20°C |
| Thermal Expansion Coefficient (α) | 11.5 – 12.5 (≈12.0) | 10⁻⁶/K | 20–100°C |
| Thermal Conductivity (λ) | 45 – 52 (≈50) | W/(m·K) | 20°C |
| Specific Heat Capacity (cp) | 450 – 480 (≈460) | J/(kg·K) | 20°C |
| Electrical Resistivity (ρe) | 0.20 – 0.30 (≈0.25) | µΩ·m | 20°C |
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Mechanical Properties
Mechanical properties of Q460D as per GB/T 1591-2018. Values vary with product thickness. For SSAW pipe applications, the steel usually falls within the thickness range of 6–40 mm. The impact energy is measured on Charpy V‑notch specimens at -20°C.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥460 | MPa | t ≤ 16 mm |
| Yield Strength (ReH) | ≥450 | MPa | 16 < t ≤ 40 mm |
| Yield Strength (ReH) | ≥430 | MPa | 40 < t ≤ 63 mm |
| Yield Strength (ReH) | ≥410 | MPa | 63 < t ≤ 100 mm |
| Tensile Strength (Rm) | 540 – 720 | MPa | t ≤ 100 mm |
| Elongation (A) | ≥17 | % | t ≤ 16 mm, gauge length L0 = 5.65√S0 |
| Elongation (A) | ≥16 | % | 16 < t ≤ 40 mm |
| Elongation (A) | ≥15 | % | 40 < t ≤ 63 mm |
| Elongation (A) | ≥14 | % | 63 < t ≤ 100 mm |
| Charpy Impact Energy (KV2) | ≥47 | J | -20°C; t ≤ 40 mm, longitudinal specimens |
| Charpy Impact Energy (KV2) | ≥47 | J | -20°C; 40 < t ≤ 100 mm, longitudinal specimens |
| Bend Test (180°) | d = 3a | - | t ≤ 16 mm, width ≥ 20 mm |
| Bend Test (180°) | d = 4a | - | 16 < t ≤ 40 mm |
| Bend Test (180°) | d = 5a | - | 40 < t ≤ 100 mm |
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Completely Equivalent Material Standards and Substitutable Grades
| Country/Region | Standard | Grade | Notes |
|---|---|---|---|
| China | GB/T 1591-2018 | Q460D | Original specification, normalized or TMCP |
| Europe | EN 10025-3:2019 | S460N | Normalized, impact at -20°C, equivalent strength and toughness |
| International | ISO 630-2:2011 | Fe 460D | Grain refined steel, similar chemical and mechanical properties |
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Application Introduction
Q460D steel is tailored for heavy‑duty structural applications requiring high strength, good weldability, and reliable toughness at sub‑zero temperatures. Its main use in SSAW pipes covers oil & gas transportation, water supply lines, and foundation piling. The material can be welded using all common arc welding processes, and its fine‑grained structure allows thickness reductions compared to lower strength grades, saving weight.
Product Applications: SSAW spiral welded pipes, LSAW longitudinal pipes, Steel plate and coil for structural fabrication, Bridge and building frames, Crane beams and heavy equipment
Processed into products: Pipe bodies and pipe sections, Flanges, fittings, elbows, Piling and foundation tubes, Steel structural columns and girders, Weld neck flanges and connectors
Application industries: Oil & Gas (transmission pipelines), Water supply and sewage systems, Civil engineering and construction, Offshore and marine structures, Machinery manufacturing
GB/T 1591 Q460D High Strength Low Alloy Steel for SSAW Pipe Similar / Alternative Material Recommendations
| Country/Region | Standard | Grade | Notes |
|---|---|---|---|
| Europe | EN 10025-6 | S460Q | Quenched and tempered, higher strength but different delivery condition |
| USA | ASTM A572/A572M | Grade 65 [450] | Yield strength 450 MPa, slightly lower than Q460D, not specifically low‑temp tested |
| Japan | JIS G 3106 | SM 570 | Yield ~450 MPa, tensile 570–720, suitable for welded structures but not identical properties |
Notes:
Q460D is not intended for subsequent heat treatment (except stress relieving) by the purchaser. For SSAW pipe manufacturing, the base material often undergoes hot‑rolling and normalizing (or TMCP) to achieve the required properties. Welding consumables should be selected to match or slightly over‑match the strength level. Pre‑heating and post‑weld heat treatment are generally not required for thicknesses up to 40 mm, but may be recommended for thicker sections.
- Share
