ASTM A515 Grade 70 (A515GR70) Pressure Vessel & Boiler Steel Plate
ASTM A515 Grade 70 (A515GR70) Pressure Vessel & Boiler Steel Plate
Comprehensive material data for ASTM A515 Grade 70 pressure vessel and boiler steel plate: chemical composition, mechanical properties, physical properties, international equivalents, and application guide.
Hot rolling, normalizing (if specified), welding, forming, cutting, machining
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ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Introduction
ASTM A515 Grade 70 is a carbon-silicon steel plate intended for intermediate- and higher-temperature service in pressure vessels and boilers. Key features: moderate strength and good weldability at elevated temperatures. It is supplied in the as-rolled or normalized condition. The material is produced to a fine grain practice and is silicon-killed for improved toughness.
- Tensile strength range: 70–90 ksi (485–620 MPa)
- Minimum yield strength: 38 ksi (260 MPa)
- Excellent performance in boilers, fireboxes, and vessels up to 750°F (400°C)
ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Chemical Composition
Chemical composition limits according to ASTM A515/A515M for Grade 70. Requirements vary with plate thickness. Elements: Carbon and manganese ranges ensure strength and elevated temperature properties. Silicon (0.15–0.40%) is added for deoxidation. Phosphorus and sulfur are kept low to prevent embrittlement and hot cracking.
- For thickness ≤ 1 in. (25 mm): C max 0.31%, Mn max 0.90%
- For thickness > 1 in. (25 mm): C max 0.33–0.35% depending on exact thickness, Mn 0.85–1.20%
| Element | Value (wt%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.31 (t ≤1 in.); 0.31–0.35 (t >1 in.) | Thickness dependent: ≤1 in.: max 0.31; >1 to 2 in.: max 0.33; >2 to 4 in.: max 0.35; >4 in.: max 0.37 (see ASTM A515) |
| Manganese (Mn) | ≤0.90 (t ≤1 in.); 0.85–1.20 (t >1 in.) | Heat analysis; product analysis tolerances apply |
| Silicon (Si) | 0.15–0.40 | All thicknesses |
| Phosphorus (P) | ≤0.025 | Or ≤0.035 for older editions (0.025 typical current) |
| Sulfur (S) | ≤0.025 | Same as above |
| Copper (Cu) | ≤0.35 (if specified) | Residual element |
| Nickel (Ni) | ≤0.25 | Residual |
| Chromium (Cr) | ≤0.25 | Residual |
| Molybdenum (Mo) | ≤0.08 | Residual |
| Vanadium (V) | ≤0.02 | Residual |
ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Thermal and Electrical Physical Properties
Typical physical properties for carbon steel grades similar to ASTM A515 Grade 70. These values are indicative and may vary slightly depending on exact composition and heat treatment.
- Density: 7.85 g/cm³
- Elastic modulus ~200 GPa
- Thermal expansion coefficient ~12.2 µm/m·°C (20–100°C)
Use these values for engineering calculations; for critical applications, verify with mill test reports.
| Property | Typical Value | Unit | Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | Ambient temperature |
| Elastic Modulus (E) | 200 | GPa | Room temperature |
| Shear Modulus (G) | 80 | GPa | Room temperature |
| Poisson's Ratio (ν) | 0.30 | - | |
| Thermal Expansion Coefficient (α) | 12.2 | µm/m·°C | 20–100°C |
| Thermal Expansion Coefficient (α) | 13.1 | µm/m·°C | 20–200°C |
| Thermal Expansion Coefficient (α) | 13.9 | µm/m·°C | 20–400°C |
| Thermal Conductivity (λ) | 51.9 | W/m·K | At 20°C |
| Thermal Conductivity (λ) | 49.4 | W/m·K | At 100°C |
| Thermal Conductivity (λ) | 44.0 | W/m·K | At 300°C |
| Thermal Conductivity (λ) | 38.5 | W/m·K | At 500°C |
| Specific Heat Capacity (cp) | 480 | J/kg·K | Room temperature |
| Electrical Resistivity (ρ_e) | 0.20 | µΩ·m | Ambient |
ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Mechanical Properties
Mechanical properties for ASTM A515 Grade 70 plates in the as-rolled or normalized condition. Room temperature tensile testing required. Tensile strength: 70–90 ksi (485–620 MPa). Yield strength: minimum 38 ksi (260 MPa). Elongation depends on thickness; bend test mandatory.
- Plates up to 2 in. thickness: min 21% elongation
- Thicker plates: min 17% elongation
Charpy impact testing is not required by default but may be specified by supplementary requirements.
| Property | Required Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Tensile Strength (Rm) | 485–620 | MPa | Room temperature, for all thicknesses |
| Tensile Strength (Rm) | 70–90 | ksi | |
| Yield Strength (ReH) | ≥260 | MPa | 0.2% offset method |
| Yield Strength (ReH) | ≥38 | ksi | |
| Elongation (A) | ≥21 (t ≤2 in./50 mm); ≥17 (t >2 in.) | % | Gauge length 2 in. (50 mm) |
| Bend Test (Bend Diameter) | 180° bend, d=1½t (t ≤1 in.); d=2t (t >1 in.) | - | No cracking; bend axis transverse to rolling direction |
ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Fully Equivalent Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A515/A515M | Grade 70 (A515GR70) | Original specification, identical material |
| International | ISO 9328-2:2018 | P295GH | Close match in mechanical properties but lower max carbon (≤0.20) and different Mn range; often considered functionally equivalent |
| European | EN 10028-2:2017 | P295GH (1.0481) | Similar elevated temperature properties; verify welding and design data |
| China | GB/T 713-2014 | Q295R (formerly 16Mng) | Approximate match; Q295R has C ≤0.20, Mn 0.80–1.50; check requirements |
| Japan | JIS G3103:2015 | SB410 | Similar in strength but lower carbon; SB410 has tensile 410–550 MPa, not identical |
ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Application Introduction
ASTM A515 Grade 70 is widely used in the fabrication of boilers, pressure vessels, and heat exchangers operating at moderate to high temperatures (up to ~750°F / 400°C). Its good weldability and formability make it suitable for both shop and field construction. Typical applications include:
Product Applications: Firebox boilers, Steam drum shells, Storage spheres and bullets, Tube sheets for heat exchangers, Reactor pressure vessels, Distillation column shells
Processed into products: Cylindrical shells and formed heads (elliptical, torispherical), Manhole covers and flanges, Nozzle reinforcements, Support skirts and saddles, Baffles and tube supports, Welded pipe sections for high-temperature service, Structural parts in boiler framing
Application industries: Oil & gas (refinery vessels, separators), Power generation (boiler drums, steam drums, waterwalls), Chemical processing (reactors, storage tanks, columns), Petrochemical (heat exchangers, pressure vessels), Food and pharmaceutical (sterilizers, autoclaves), Water treatment (pressure filters, hydro-pneumatic tanks)
ASTM A515 Grade 70 Pressure Vessel & Boiler Steel Plate Similar / Alternative Materials with Close Properties
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A516/A516M | Grade 70 | Lower carbon (≤0.30), better notch toughness, for moderate and lower temperatures |
| USA | ASME SA-515/SA-515M | Grade 70 (identical to ASTM A515) | Same material under ASME Boiler & Pressure Vessel Code |
| European | EN 10028-3 | P355N | Higher strength normalized fine grain steel; may replace if design allows |
| China | GB/T 713-2014 | Q345R | Higher strength (tensile 490–620 MPa), suitable for higher pressure vessels |
| Germany (historical) | DIN 17155 | HII | Old standard; tensile 350–480 MPa, lower strength; use with caution |
Notes:
When ordering ASTM A515 Grade 70, specify thickness, width, length, and desired supplementary requirements (e.g., Charpy V-notch testing, ultrasonic examination, normalizing).
- For welded pressure vessels, post-weld heat treatment may be required per ASME code depending on thickness.
- This grade is typically not intended for sour service (H₂S) due to limited hardness control; use ASTM A516 with HIC testing if needed.
- Check the latest ASTM A515/A515M edition for any updates to chemistry or mechanical limits.
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