SM520C Steel for SSAW Pipes
SM520C Steel for SSAW Pipes - High-Strength Weldable Structural Steel to JIS G3106
Comprehensive technical data for SM520C steel under JIS G3106, widely used for spiral submerged-arc welded (SSAW) pipes in structures. Covers chemistry, mechanical and physical properties, international equivalents, and application guidance.
Hot rolling, cold forming, gas/metal-arc welding, submerged-arc welding, machining, shearing
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
SM520C Steel for SSAW Pipes Introduction
SM520C is a high-strength, weldable structural steel grade specified in JIS G3106 – Rolled steels for welded structure. It offers minimum yield strengths of 295–365 MPa depending on thickness, with tensile strength between 520 and 640 MPa. The 'C' suffix indicates guaranteed Charpy-V impact energy of at least 47 J at 0 °C, ensuring reliable toughness for low-temperature service. This steel is primarily supplied as hot-rolled plates, sheets, and sections, and is a preferred base material for manufacturing SSAW (spiral submerged-arc welded) pipes used in oil & gas transportation, structural piling, and heavy civil engineering. Its balanced composition and clean microalloying provide excellent weldability, formability, and resistance to brittle fracture.
SM520C Steel for SSAW Pipes Chemical Composition
Heat analysis limits according to JIS G3106:2015 for SM520C. Ceq or Pcm may be reported on request for weldability assessment. Maximum carbon content depends on product thickness. Elements not listed may be present as residuals or optional microalloying additions (Nb, V, Ti) to achieve strength and toughness.
| Element | Value (%) | Remarks |
|---|---|---|
| C | ≤0.20 | For thickness ≤40 mm |
| C | ≤0.22 | For thickness >40 mm |
| Si | ≤0.55 | |
| Mn | ≤1.60 | May be increased by agreement |
| P | ≤0.035 | |
| S | ≤0.035 |
SM520C Steel for SSAW Pipes Thermal and Electrical Physical Properties
Typical reference data for hot-rolled low-alloy structural steel similar to SM520C at ambient temperature and over a temperature range. Actual values may vary slightly with exact composition and heat treatment. Density, Young's modulus, and Poisson's ratio are commonly used in structural design.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Modulus of Elasticity (E) | 205 | GPa | At 20 °C |
| Shear Modulus (G) | 80 | GPa | At 20 °C |
| Poisson's Ratio (ν) | 0.30 | - | At 20 °C |
| Thermal Expansion (α) | 11.1 | 10<sup>-6</sup>/K | 20–100 °C |
| Thermal Expansion (α) | 12.3 | 10<sup>-6</sup>/K | 20–300 °C |
| Thermal Expansion (α) | 13.5 | 10<sup>-6</sup>/K | 20–500 °C |
| Thermal Conductivity (λ) | 51 | W/(m·K) | At 20 °C |
| Specific Heat Capacity | 486 | J/(kg·K) | At 20 °C |
| Electrical Resistivity (ρ<sub>e</sub>) | 0.15 | Ω·mm²/m | At 20 °C |
SM520C Steel for SSAW Pipes Mechanical Properties
Minimum requirements per JIS G3106. Tensile test pieces are taken in the transverse direction for plates and strips. Yield strength is upper yield (ReH) or 0.2% proof strength. Impact energy tested on Charpy V-notch specimens at 0 °C, longitudinal direction, average of three tests ≥47 J (single min. 33 J). Bend test: no cracks on outside surface after 180° bending.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥365 | N/mm² | Thickness ≤16 mm |
| Yield Strength (ReH) | ≥355 | N/mm² | Thickness >16 to ≤40 mm |
| Yield Strength (ReH) | ≥335 | N/mm² | Thickness >40 to ≤75 mm |
| Yield Strength (ReH) | ≥325 | N/mm² | Thickness >75 to ≤100 mm |
| Yield Strength (ReH) | ≥305 | N/mm² | Thickness >100 to ≤160 mm |
| Yield Strength (ReH) | ≥295 | N/mm² | Thickness >160 to ≤200 mm |
| Tensile Strength (Rm) | 520–640 | N/mm² | All thicknesses |
| Elongation (A) | ≥15 | % | Thickness ≤5 mm (No.5 test piece) |
| Elongation (A) | ≥17 | % | Thickness >5 to ≤16 mm (No.1A test piece) |
| Elongation (A) | ≥21 | % | Thickness >16 to ≤50 mm (No.1A test piece) |
| Elongation (A) | ≥23 | % | Thickness >40 mm (No.10 test piece) |
| Bend Test (mandrel dia.) | 1.5×t | Thickness ≤16 mm, 180° bend | |
| Bend Test (mandrel dia.) | 2.0×t | Thickness >16 to ≤100 mm, 180° bend | |
| Bend Test (mandrel dia.) | 2.5×t | Thickness >100 mm, 180° bend | |
| Impact Energy (KV) | ≥47 (avg.) | J | 0 °C, V-notch, longitudinal |
SM520C Steel for SSAW Pipes Exact Equivalent Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM520C | Reference material; tensile strength 520–640 MPa, impact 0°C |
| Europe | EN 10025-3 | S460N / S460NL | Yield ≥460 MPa (≤16 mm), TS 540–720; -20°C impact for NL; close but higher strength and different chemistry |
| USA | ASTM A572 / A709 | Grade 60 (415) / Grade 65 (450) | Yield 415 or 450 MPa min, TS 520 min (Gr.60) or 550 min (Gr.65); non-equivalent toughness requirements |
| China | GB/T 1591 | Q460D | Yield ≥460 MPa (≤16 mm), TS 550–720; -20°C impact; exceeds SM520C strength slightly |
SM520C Steel for SSAW Pipes Application Introduction
SM520C steel combines high strength with excellent weldability and sufficient toughness at 0°C, making it ideal for heavy welded structures. When formed into SSAW pipes, it serves both pressure-retaining and structural functions. The following industries and products demonstrate its versatility:
Product Applications: SSAW (spiral submerged-arc welded) steel pipes for long-distance pipelines and structural piling, LSAW (longitudinal submerged-arc welded) pipes and ERW pipes using SM520C plate, Welded box columns, built-up beams, and bridge girders, Wind turbine towers and tubular structures, Pressure vessels and storage tanks
Processed into products: Pipeline segments (oil, gas, slurry, water), Pipe piles and foundation casings, Bridge arch ribs and truss members, Crane runway beams and heavy-duty brackets, Ship hull stiffeners and offshore jacket members, Hydroelectric penstock sections
Application industries: Oil and gas transmission (onshore/offshore pipelines), Civil engineering and construction (high-rise buildings, bridges, stadiums), Marine and shipbuilding (offshore platforms, jack-up legs, structural sections), Water treatment and hydropower (penstocks, large-diameter water mains), Mining and heavy machinery (conveyor structures, crane booms, excavator components)
SM520C Steel for SSAW Pipes Near / Similar Substitution Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490C | Lower strength (TS 490–610 MPa, YS ≥325–365), same impact class; suitable when strength can be reduced |
| Japan | JIS G3106 | SM570 | Higher strength (TS 570–720 MPa), no guaranteed impact; overqualification |
| Europe | EN 10025-2/3 | S420N/NL | Yield ≥420 MPa (≤16 mm), TS 520–680; direct strength overlap in thicker sections |
| ISO | ISO 630-2 | S460N | Similar to EN S460N, with normalized delivery |
Notes:
When SM520C steel is used for SSAW pipes, the pipe manufacturing standard (e.g., API 5L PSL2 – equivalent proprietary grades, or JIS G3444 – with agreement) specifies additional inspection and testing. Typical pipe properties derive from the base steel; however, the welding process (double submerged-arc) introduces a heat-affected zone (HAZ) that should be evaluated for toughness and hardness. Supplementary impact testing at low temperatures (e.g., -20°C) or through-thickness tensile testing (Z-quality) may be ordered for critical applications. Processing requires compliance with welding procedure specifications (WPS) and post-weld heat treatment where stress relief is mandated by design codes.
- Share
