SA 515 Grade 70 (ASME SA-515 Gr. 70) is a high-strength carbon steel plate standard for pressure vessels and boilers used in intermediate to high-temperature service, known for its excellent weldability, strength, and formability, commonly supplied normalized for improved mechanical properties and used in demanding applications like heat exchangers and power generation.
Chemical Requirements
| Elements Composition % | SA 515 Gr 70 (Grade 485) |
|---|---|
| Carbon, max | |
| 1 in. (25 mm) and under | 0.31 |
| Over 1 to 2 in. (25 to 50 mm), incl | 0.33 |
| Over 2 to 4 in. (50 to 100 mm), incl | 0.35 |
| Over 4 to 8 in. (100 to 200 mm), incl | 0.35 |
| Over 8 in. (200 mm) | 0.35 |
| Manganese, max | |
| Heat analysis | 1.20 |
| Product analysis | 1.30 |
| Phosphorus, max | 0.035 |
| Sulfur, max | 0.04 |
| Silicon | |
| Heat analysis | 0.15-0.40 |
| Product analysis | 0.13-0.45 |
Tensile Requirements
| SA 515 Gr 70 (Grade 485) |
|
|---|---|
| Tensile strength, ksi (MP) | 70-90(485-620) |
| Yield strength, min. ksi (MP) | 38(260) |
| Elongation in 8 in. (200 mm), min, % | 17 |
| Elongation in 2 in. (50 mm), min, % | 21 |
Applications
Power Generation Industry: It is a core material for thermal power plants, mainly used to manufacture boiler drums, header shells and high-pressure heaters. These components work under 300-400℃ and 9-12MPa, and the material's high-temperature strength and oxidation resistance ensure stable operation. It is also applied in auxiliary systems of nuclear power plants, such as deaerator water tanks, reducing costs while meeting performance requirements.
Petrochemical Industry: Widely used in medium-pressure reaction vessels and heat exchangers. It is suitable for hydrogenation refining reactors (300-380℃, 4-8MPa) and catalytic cracking regenerators, with good resistance to mild hydrogen sulfide corrosion. It is also used to make shells of shell-and-tube heat exchangers, featuring excellent weldability with stainless steel tubes.
Environmental Protection and Industrial Boiler Fields: Applied in garbage incinerator secondary combustion chambers (resistant to flue gas corrosion below 450℃) and biomass power plant high-temperature combustion chamber guards. In papermaking and textile industries, it is used to fabricate pressure-bearing shells of special boilers.
Other Industries: Utilized in offshore oil drilling equipment, chemical storage tanks, pharmaceutical equipment and mining machinery. It is also suitable for manufacturing condensers, gas processing equipment and hot rollers due to its wear resistance and high-temperature stability.
Application Conditions
Temperature and Pressure Limits: Operates stably at temperatures up to 450℃ and pressures up to 500 bar. It is not applicable for working conditions above 400℃ for long periods; high-temperature alloy steels should be used instead.
Material Performance Requirements: Tensile strength ranges from 485-620MPa, yield strength ≥260MPa, elongation ≥17% (200mm gauge length). It must pass Charpy impact tests to ensure low-temperature toughness and avoid brittleness.
Heat Treatment and Delivery Conditions: Plates with thickness >50mm must be normalized to refine grain structure. Thinner plates (≤50mm) can be supplied in rolled, normalized or stress-relieved annealing state, as required.
Welding and Testing Requirements: Low carbon equivalent (≤0.42) ensures good weldability, reducing hydrogen cracking risks. Welded parts must pass ultrasonic or radiography tests. Chemical composition must meet standards (C: 0.30-0.35%, Mn: 1.00-1.50%, P/S ≤0.035%).
Medium and Environmental Conditions: Suitable for non-strong corrosive media. Avoid long-term contact with strong acids/bases. Strictly control impurity content in materials to prevent performance degradation in harsh environments.
Related Standards
ASTM A515:
The American Society for Testing and Materials standard, identical to ASME SA-515.
ASME SA-516 Gr 70:
A similar specification, though A515 is generally for higher temperatures than SA-516.
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What is SA515 Grade 70?
SA515 Grade 70 is a carbon steel plate specification for pressure vessels, formulated by ASME. It has good tensile strength (485-655 MPa) and weldability, widely used in moderate-temperature pressure vessel applications like boilers and storage tanks.
What are the main chemical compositions of SA515 Grade 70?
Its main chemical compositions include C (max 0.31%), Mn (0.85-1.20%), P (max 0.035%), S (max 0.035%), Si (0.15-0.40%), and Fe as the base metal, ensuring good mechanical properties and processability.
What is the minimum tensile strength of SA515 Grade 70?
The minimum tensile strength of SA515 Grade 70 is 485 megapascals (MPa), which meets the ASME standard requirements for pressure vessel carbon steel. This strength ensures it can withstand moderate pressure and temperature conditions safely.
What is the yield strength range of SA515 Grade 70?
SA515 Grade 70 has a yield strength range of 260-485 MPa. The specific value may vary slightly with production processes, but it must comply with ASME SA515 standards to guarantee structural stability in pressure vessel operations.
In which temperature range is SA515 Grade 70 commonly used?
SA515 Grade 70 is typically used in the temperature range of -29°C to 482°C (-20°F to 900°F). It maintains good toughness and strength within this range, suitable for low to moderate temperature pressure vessel services.
What are the common applications of SA515 Grade 70?
Common applications include boiler drums, steam headers, storage tanks for oil and gas, chemical reactors, and pressure vessels in power generation, petrochemical, and refining industries, due to its reliable pressure-bearing capacity.
Which standard governs SA515 Grade 70?
SA515 Grade 70 is governed by the ASME Boiler and Pressure Vessel Code (BPVC), specifically Section II, Part A, Specification SA515. This standard defines its chemical composition, mechanical properties, and manufacturing requirements.
Is SA515 Grade 70 weldable?
Yes, SA515 Grade 70 has excellent weldability. It can be welded using common methods like SMAW (Shielded Metal Arc Welding), GMAW (Gas Metal Arc Welding), and GTAW (Gas Tungsten Arc Welding) without preheating in most cases.
Does SA515 Grade 70 require preheating before welding?
Preheating is not always necessary but depends on plate thickness and ambient temperature. For plates thicker than 25 mm or in cold environments, preheating to 60-150°C is recommended to prevent weld cracks and improve toughness.
What is the maximum thickness of SA515 Grade 70 plates?
The maximum thickness of SA515 Grade 70 plates typically ranges up to 200 mm, but it can be customized for specific projects. Thicker plates may require additional heat treatment to ensure uniform mechanical properties.