What is the allowable stress for A283 Grade C?
SA 283 Grade C Product Introduction
SA 283 Grade C is a carbon steel plate specification from the ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code, Section II, Part A. It is a general-purpose, low to intermediate tensile strength steel primarily used for structural and moderate pressure applications.
Its closest and most widely accepted equivalents are in the ASTM A283 specification and international standards.
The allowable stress for SA-283 Grade C is not a single universal number-it is determined by the governing design code and the temperature of the application.For its most common use in ASME Boiler and Pressure Vessel Code (BPVC) Section VIII, Division 1 pressure vessels, here are the key values.
ASME Section VIII, Div. 1 Allowable Stress Values
The values are found in ASME Section II, Part D, Table 1A. Below are the most relevant ones for plate.
At Room Temperature (up to 650°F / 343°C):
For Plate ≤ 1/2 in. (12.7 mm) thick:
13.0 ksi (89.6 MPa) - This is the most commonly cited value.
For Plate > 1/2 in. to 4 in. thick:
13.0 ksi (89.6 MPa) - *Note: For A283 Grade C, the value does not decrease with thickness like some higher-strength steels.*
At Elevated Temperature:
The allowable stress decreases with temperature. A few key points:
700°F (371°C): 12.9 ksi (88.9 MPa)
750°F (399°C): 9.2 ksi (63.4 MPa)
800°F (427°C): 5.5 ksi (37.9 MPa)
Maximum Temperature: The use of SA-283 Grade C is typically limited to 850°F (454°C) per the ASME stress tables, but practical design often limits it to lower temperatures due to strength loss.
How These Values Are Derived
Per ASME rules, the allowable stress (S) at room temperature is the lowest of the following, based on the material's specified minimum properties:
1/4 of the specified minimum tensile strength (55 ksi / 4 = 13.75 ksi)
2/3 of the specified minimum yield strength (30 ksi * 2/3 = 20.0 ksi)
The controlling factor is the tensile strength, resulting in 13.0 ksi (which is slightly conservative from the calculated 13.75 ksi, accounting for rounding and standardizing within the table).
Summary Table (ASME VIII-1)
| Temperature | Allowable Stress (S) for Plate |
|---|---|
| ≤ 650°F | 13.0 ksi (89.6 MPa) |
| 700°F | 12.9 ksi (88.9 MPa) |
| 750°F | 9.2 ksi (63.4 MPa) |
| 800°F | 5.5 ksi (37.9 MPa) |
| 850°F | ~3.3 ksi (22.8 MPa) |
Final and Most Important Advice: Always verify the allowable stress from the latest edition of the applicable ASME Code (Section II, Part D) that is mandated for your project. Never rely on a value from an old textbook or memory. For critical applications, the use of SA-283 Grade C should be carefully evaluated against better-suited materials like SA-516.
What is SA 283 Grade C equivalent to?
ASME SA 283 Gr C equivalent material in EN standard is S235JR steel. S235JR steel has good plasticity, toughness and weldability, certain strength and good cold bending properties.
What is ASTM A283 grade C?
ASTM A283 Grade C is a specification for low and intermediate tensile strength carbon steel plates of structual quality for general applications. ASTM A283 Grade C has a specified minimum yield strengths of 30 ksi.
What is the difference between A283 C and A36 C?
A36 has a lower carbon content compared to A283 Grade C, making it easier to weld and more ductile. Mechanical Properties: A283 Grade C: higher strength and higher yield point compared to A36, making it suitable for high-strength applications.
What is the allowable stress for A283 Grade C?
Most carbon grades, including the Sa 283 Gr C, have a maximum allowed stress of 13,750psi.
What is the difference between SA 283 C and SA 36?
Alloy Composition
These differences suggest that A36 might be preferred for applications requiring higher strength and better fatigue resistance, while SA283 Grade C could be suitable for applications where the slightly lower strength properties are acceptable and potentially more cost-effective.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
