ASTM A572 Grade 50 SSAW Pipe
ASTM A572 Grade 50 SSAW Pipe - High-Strength Low-Alloy Structural Steel Spiral Welded Tube
Detailed material data for ASTM A572 Grade 50 spiral welded steel pipe, including chemical composition, mechanical properties, physical properties, international equivalents, and application guidance.
Spiral submerged arc welding (SSAW), cutting, beveling, coating, bending (for pipe forming), cold working where applicable
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ASTM A572 Grade 50 SSAW Pipe Introduction
ASTM A572 Grade 50 is a high-strength low-alloy (HSLA) structural steel with minimum yield strength of 50 ksi (345 MPa) and good weldability. It is widely used for structural shapes, plates, and welded pipes, including spiral submerged arc welded (SSAW) pipes. The material exhibits excellent strength-to-weight ratio, good notch toughness, and can be supplied in various delivery conditions. Typical applications include piling, structural columns, and heavy-duty mechanical components. SSAW pipes made from this grade combine the advantages of spiral forming with the consistent properties of Grade 50 steel, allowing large-diameter thin-walled pipes for infrastructure and industrial use.
ASTM A572 Grade 50 SSAW Pipe Chemical Composition
Typical ladle analysis of ASTM A572 Grade 50 steel. The standard specifies maximum limits for C, Mn, P, S; Silicon is commonly added for deoxidation. Grain-refining elements such as niobium and vanadium may be present. Values shown are as per ASTM A572/A572M for plates and shapes up to applicable thickness.
| Element | Typical Value (max unless range) | Remarks |
|---|---|---|
| Carbon, C | ≤0.23 | Maximum for all product forms |
| Manganese, Mn | ≤1.35 | For thickness ≤20 mm; may be lowered for heavier sections |
| Phosphorus, P | ≤0.040 | Or as agreed (typical ≤0.035) |
| Sulfur, S | ≤0.050 | Or as agreed (typical ≤0.035) |
| Silicon, Si | 0.15–0.40 | Typical for killed steel; not mandated but commonly present |
| Niobium, Nb | 0.005–0.05* | Optional microalloy; grain refinement |
| Vanadium, V | 0.01–0.15* | Optional microalloy; grain refinement |
| Titanium, Ti | ≤0.05* | May be used for grain refinement; not a standard requirement |
| Copper, Cu | ≤0.20* (if specified) | May be present as residual |
ASTM A572 Grade 50 SSAW Pipe Physical, Thermal and Electrical Properties
Physical constants for carbon-manganese low-alloy steel representative of ASTM A572 Grade 50. Values are approximate and may vary slightly with exact chemistry and heat treatment. Data compiled from ASME B31.3 and common engineering references for similar steel grades.
| Property | Typical Value | Unit | Conditions |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Elastic modulus (E) | 200 | GPa | 20 °C, static test |
| Shear modulus (G) | 80 | GPa | 20 °C, calculated from E and ν |
| Poisson's ratio (ν) | 0.30 | — | Room temperature |
| Thermal expansion coefficient (α) | 11.7 | 10⁻⁶/K | 20–100 °C average |
| Thermal conductivity (λ) | 51.9 | W/(m·K) | 20 °C |
| Specific heat capacity (cp) | 486 | J/(kg·K) | 20 °C |
| Electrical resistivity (ρe) | 0.17 | µΩ·m | 20 °C (i.e., 0.17×10⁻⁶ Ω·m) |
ASTM A572 Grade 50 SSAW Pipe Mechanical Properties
Properties of the base plate/coil used for SSAW pipe, per ASTM A572 Grade 50. Values apply for thickness ≤20 mm; for heavier walls, slight reductions may be permissible. Elongation is reported on 200 mm (8 in.) and 50 mm (2 in.) gauge lengths as per ASTM A370. Welded pipe may exhibit local property variations at the seam; the pipe body generally retains the parent metal properties.
| Property | Minimum / Typical Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Yield Strength (ReH) | 345 | MPa | At 0.2% offset; transverse specimen |
| Tensile Strength (Rm) | 450 | MPa | Minimum |
| Elongation (A) 200 mm | 18 | % | Longitudinal; for thickness ≤20 mm |
| Elongation (A) 50 mm | 21 | % | Longitudinal; for thickness ≤20 mm |
| Bend Test (180°) | 3t (typical) | — | Bend diameter = 3 times specimen thickness; no cracks |
| Hardness | ≤ 190 HBW (typical) | HBW | As-rolled or normalized condition |
ASTM A572 Grade 50 SSAW Pipe Full Equivalents – International Standards with Closely Matching Requirements
| Country/Region | Standard | Grade/Designation | Remarks |
|---|---|---|---|
| USA | ASTM A572/A572M | Grade 50 | Original specification for SSAW pipe base material |
| China | GB/T 1591 | Q345D | Meets similar yield and tensile requirements; fine grain option |
| Europe | EN 10025-2 | S355JR (1.0045) | Yield 355 MPa min; close chemical and mechanical overlap |
| International | ISO 630-2 | S355JR | Harmonized with EN; suitable substitute for structural applications |
| Japan | JIS G3106 | SM490A | Tensile ≥490 MPa, yield ≥325 MPa; often accepted for static structures |
| Russia | GOST 19281 | 17G1S | Low-alloy structural steel; similar strength class |
ASTM A572 Grade 50 SSAW Pipe Application Introduction
ASTM A572 Grade 50 SSAW pipe is ideally suited for demanding structural applications where high strength, good weldability, and cost efficiency are required. Its spiral weld configuration enables economical production of large-diameter pipes with controlled mechanical properties. Typical uses include:
- Foundation piles and marine structures
- Structural columns and braces in high-rise buildings
- Bridge piers and superstructure components
- Transmission poles and wind turbine towers
- Water and slurry transport pipelines
The material can be cut, drilled, welded, and coated using standard fabrication methods. It is often delivered with a protective coating for atmospheric or buried service.
Product Applications: SSAW steel pipe (bare, coated, or lined), Pipe piles with end plates or shoes, Structural tubular sections, Casing pipes for foundation work, Large-diameter penstocks
Processed into products: Pile shoes, connectors, and ring stiffeners, Flanges and bolted clamps attached to pipe ends, Cut-to-length bracing members for modular structures, Welded T-joints and branch connections for manifold systems, Spiral finned pipes (by additional fabrication)
Application industries: Civil Construction and Infrastructure, Oil and Gas (structural only, not sour service), Port and Marine Engineering, Wind Energy (tower foundation piles), Water Transmission and Treatment, Heavy Machinery Manufacturing
ASTM A572 Grade 50 SSAW Pipe Similar or Compatible Substitutes
| Country/Region | Standard | Grade/Designation | Remarks |
|---|---|---|---|
| Europe | EN 10025-2 | S355J0 / S355J2 | Higher impact energy options; otherwise comparable to S355JR |
| China | GB/T 1591 | Q345B / Q345C | Widely available; verify CVN requirements for cold service |
| Japan | JIS G3106 | SM490B | Slightly higher carbon equivalent, good weldability |
| India | IS 2062 | E350 grade / E410 | Narrower strength range, similar applications |
| Brazil | ABNT NBR 5000 | AR 350 COR | Weathering steel variant; atmospheric corrosion resistance added |
Notes:
Additional notes: When supplying SSAW pipes, compliance with supplementary requirements such as Charpy V-notch impact testing (e.g., at -20°C or -40°C) can be specified. For cold service or dynamic loading, normalized or thermomechanically rolled grades (S355J2+N, Q345D) are preferred. Welding consumables must match the strength of Grade 50 (E70XX electrodes or equivalent). For severe corrosion environments, consider weathering steel versions (e.g., ASTM A572 Grade 50 with copper content) or protective coatings. Always verify the latest edition of the material standard and the pipe fabrication specification (e.g., API 5L, ISO 3183) for product-specific requirements.
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