ASTM A285 Grade C Carbon Steel Coil/Plate
ASTM A285/A285M Grade C Carbon Steel Plate for Pressure Vessels (Commonly Mislabeled as Weather-Resistant, Not Intended for Atmospheric Corrosion Resistance)
Detailed material data sheet for ASTM A285/A285M Grade C, a low to intermediate tensile strength carbon steel intended for fusion-welded pressure vessels. Clarifies that this grade is not a weather-resistant (weathering) steel, despite occasional mislabeling.
Fusion welding, forming, bending, shearing, machining (conventional methods), and post-weld heat treatment where required
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ASTM A285 Grade C Carbon Steel Coil/Plate Introduction
ASTM A285/A285M Grade C is a carbon steel specification covering low and intermediate tensile strength plates intended for fusion-welded pressure vessels. This material is normally supplied in the as-rolled condition and is suitable for moderate service temperatures. Important note: Despite some market descriptions referring to it as 'Weather Resistant Steel', ASTM A285 Grade C does not contain the alloying elements (such as copper, chromium, nickel) required for atmospheric corrosion resistance (weathering characteristics). For genuine weather-resistant steel, consult ASTM A588 or A242 standards. The grade offers good formability and weldability, with a minimum yield strength of 205 MPa (30 ksi) and tensile strength between 380–515 MPa (55–75 ksi). It is widely used in the fabrication of storage tanks, boilers, and low-pressure vessels.
ASTM A285 Grade C Carbon Steel Coil/Plate Chemical Composition per ASTM A285/A285M
The chemical requirements are based on heat analysis. ASTM A285 Grade C limits residual elements but does not specify deliberate additions of chromium, nickel, copper, or molybdenum. Note: The lack of these alloying elements confirms that this grade is not a weather-resistant steel. Silicon is usually present as a deoxidizer; the standard gives typical ranges but not mandatory limits.
| Element | Standard Value (max, unless range) | Remarks |
|---|---|---|
| Carbon (C) | 0.28 % | For Grade C, heat analysis |
| Manganese (Mn) | 0.90 % | Heat analysis; may be reduced by agreement |
| Phosphorus (P) | 0.035 % | Max limit |
| Sulfur (S) | 0.035 % | Max limit |
| Silicon (Si) | 0.15–0.40 % (typical) | Not specified in standard; typical for killed carbon steel |
| Copper (Cu) | ≤ 0.20 % (residual) | No minimum; not specified for corrosion resistance |
| Nickel (Ni) | ≤ 0.20 % (residual) | No minimum |
| Chromium (Cr) | ≤ 0.20 % (residual) | No minimum |
| Molybdenum (Mo) | ≤ 0.06 % (residual) | No minimum |
| Vanadium (V) | ≤ 0.02 % (residual) | No minimum |
| Niobium (Nb) | ≤ 0.02 % (residual) | No minimum |
ASTM A285 Grade C Carbon Steel Coil/Plate Thermal and Electrical Physical Properties
Physical properties are not mandated by ASTM A285 standard. The values below are typical for low-carbon steel (approximately 0.20% C) and are provided for engineering guidance only. Actual values may vary with processing condition and temperature.
| Property | Standard Requirement Value (Typical) | Unit | Test Condition / Temperature |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Elastic Modulus (E) | 200 | GPa | At 20 °C |
| Shear Modulus (G) | 80 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.29 | - | At 20 °C, in elastic range |
| Thermal Expansion Coefficient (α) | 11.7 | 10⁻⁶/°C | 0–100 °C (average) |
| Thermal Expansion Coefficient (α) | 12.8 | 10⁻⁶/°C | 0–200 °C |
| Thermal Conductivity (λ) | 51.9 | W/(m·K) | At 20 °C |
| Thermal Conductivity (λ) | 48.0 | W/(m·K) | At 200 °C |
| Specific Heat Capacity (cp) | 486 | J/(kg·K) | At 20 °C |
| Electrical Resistivity (ρ_e) | 0.16 | µΩ·m | At 20 °C |
| Melting Point | ~1425–1510 | °C | Approximate |
ASTM A285 Grade C Carbon Steel Coil/Plate Mechanical Properties per ASTM A285/A285M
Tensile requirements are mandatory for plates. Notch toughness is not a standard requirement but can be agreed upon. Bending tests are normally performed. Values are for plates in as-rolled condition. Note: 'typical' means the guaranteed minimum or range from the standard, not average product data.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 30 | ksi | 0.2% offset, as-rolled |
| Yield Strength (ReH) | ≥ 205 | MPa | 0.2% offset, as-rolled |
| Tensile Strength (Rm) | 55–75 | ksi | Room temperature |
| Tensile Strength (Rm) | 380–515 | MPa | Room temperature |
| Elongation (A) in 8 in. [200 mm] | ≥ 23 | % | Standard rectangular tension test specimen, 8 in. gage length |
| Elongation (A) in 2 in. [50 mm] | ≥ 27 | % | Standard rectangular tension test specimen, 2 in. gage length |
| Bend Test | No cracks; 180° bend | - | Bend diameter = 2.5 × specimen thickness for plates ≤ 1 in. thick; larger diameters for thicker sections |
| Hardness | Not specified | HBW/HRB | Informational; typical range 80–95 HRB |
ASTM A285 Grade C Carbon Steel Coil/Plate Fully Equivalent International Standards and Possible Substitute Grades
| Country/Region | Standard – Grade | Remarks |
|---|---|---|
| Europe | EN 10028-2: P265GH | Closest European equivalent; P265GH has lower carbon (≤0.20) and higher tensile (410-530 MPa) but similar yield and application. May be used as a substitute with re-verification of design. |
| Japan | JIS G3115: SPV235 | Comparable pressure vessel steel with min. tensile 400-510 MPa and yield ≥235 MPa. Slightly higher strength but acceptable in many cases. |
| China | GB/T 713: Q245R | Chinese pressure vessel steel. Mn ≤0.80%, C ≤0.20%, tensile 400-520 MPa, yield ≥245 MPa. Closest chemical/matching grade; often used interchangeably in heat exchangers and storage tanks. |
| India | IS 2002: Grade 2 / IS 2041: R220 | Indian standards for boiler quality steel; similar strength levels. Should be assessed for specific thickness and temperature. |
ASTM A285 Grade C Carbon Steel Coil/Plate Application Introduction
ASTM A285 Grade C is primarily used in welded pressure vessels and boilers where moderate strength and good workability are required. Due to its limited corrosion resistance, protective coatings or linings are often necessary for outdoor exposure. It is not suitable for unpainted weathering applications. The material can be formed into cylindrical shells, heads, and structural supports. Common fabrication includes rolling, bending, punching, and welding. Service temperatures are typically between -20 °C and 350 °C, depending on thickness and code requirements.
Product Applications: Fusion-welded pressure vessels (ASME Section VIII Div.1), Atmospheric and low-pressure storage tanks (API 650), Boiler shells and fireboxes, Heat exchanger shells and channels, Air receivers and compressed air tanks, LPG storage bullets (with design approval)
Processed into products: Cylindrical shell courses, Dished and flanged heads (ellipsoidal, torispherical), Nozzle forgings (when made from plate), Manway rings and reinforcements, Skirt supports and saddle pads, Internal baffle plates
Application industries: Oil & Gas (storage tanks, separators), Chemical Processing (reactors, heat exchangers), Power Generation (boiler drums, steam drums), Food & Beverage (silos, dairy tanks when coated), Water Treatment (pressure filters, tanks), Shipbuilding (small pressure containers)
ASTM A285 Grade C Carbon Steel Coil/Plate Similar / Nearby Alternative Material Recommendations
| Country/Region | Standard – Grade | Remarks |
|---|---|---|
| USA | ASTM A588 / A588M Grade C | This is a high-strength low-alloy weather-resistant steel with guaranteed atmospheric corrosion resistance (Cu, Cr, Ni added). Min. yield 345 MPa (50 ksi), tensile ≥485 MPa (70 ksi). Ideal replacement if weather resistance is required. |
| USA | ASTM A242 Type 1 | Another weathering steel with approx. yield 345 MPa and similar corrosion-resistant properties. Often used for structural applications. |
| USA | ASTM A516 Grade 70 | Pressure vessel carbon steel with higher strength (yield ≥260 MPa, tensile 485-620 MPa) and improved notch toughness. Not weather-resistant, but suitable for moderate/low temperature service where A285-C is insufficient. |
| Europe | EN 10025-5: S355J2W | Weathering structural steel with tensile 470-630 MPa and yield ≥355 MPa. Suitable for outdoor uncoated applications. Can replace A285-C only when increased strength and weather resistance are desired. |
| Europe | EN 10028-2: P355GH | Higher strength boiler steel (yield ≥280 MPa) for elevated temperature service. Non-weathering, but often selected for larger vessels where A285-C thickness limitations are reached. |
Notes:
Important Clarification on Weather-Resistant Label: ASTM A285/A285M Grade C is frequently incorrectly advertised as 'weather resistant steel coil'. This material does not meet the requirements for atmospheric corrosion resistance per ASTM G101 or similar. For genuine weather-resistant applications, use ASTM A588, A242, or equivalent.
- Welding: Preheating is recommended for thicknesses above 25 mm. Common processes: SMAW, SAW, GMAW with matching carbon steel fillers (E7018, ER70S-6).
- Heat Treatment: Post-weld heat treatment (PWHT) is required above certain thicknesses according to ASME code (e.g., PWHT above 32 mm nominal thickness).
- Surface Condition: Unless pickup or deseamed, the mill scale surface offers minimal corrosion protection.
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