A517 Grade B is a high-strength quenched and tempered alloy steel plate specified under ASTM A517, primarily used in the fabrication of welded structures that require excellent toughness and high yield strength at relatively low temperatures. It is commonly applied in pressure vessels, storage tanks, and heavy machinery components where reliability under demanding loading conditions is essential. The material typically exhibits a minimum yield strength of around 690 MPa and good weldability when proper preheating and interpass temperature control are implemented during fabrication.
A517 Grade B pressure vessel steel chemical composition %
| Grade | C | Mn | P max | S max | Si | Ni | Cr | Mo | B | V | Ti | Z max | Cu max | Co max |
| A517 Grade B | 0.15-0.21 | 0.70-1.00 | 0.025 | 0.025 | 0.15-0.35 | - | 0.40-0.65 | 0.15-0.25 | 0.0005-0.005 | 0.03-0.08 | 0.01-0.04 | - | - | - |
A517 Grade B pressure vessel steel Mechanical properties
| Grade | Thickness (mm) | Yield strength ReH MPa min | Tensile strength Rm MPa | Elongation A% min | |
| 200mm | 50mm | ||||
| A517 Grade B | t≤25 | 690 | 795-930 | - | 16 |
| 25﹤t | 620 | 725-930 | - | 14 | |
Core Processing Methods
Heat Treatment: The standard delivery condition is quenched and tempered.
Quenching: Steel is heated to a minimum of 1650°F [900°C] and rapidly cooled in water or oil to form a strong martensitic structure.
Tempering: Reheated to at least 1150°F [620°C] to reduce internal stress and improve toughness and ductility.
Welding: Considered "fair" to "well weldable" if strict controls are maintained.
Consumables: Low-hydrogen electrodes (e.g., E-100/11018M) are recommended to prevent hydrogen-induced cracking.
Preheating: Maintaining a minimum preheat temperature (e.g., ~200°F) is critical to prevent cracking.
Post-Processing: Susceptible to reheat cracking in the heat-affected zone (HAZ) during stress relieving or post-weld heat treatment (PWHT).
Forming: Exhibits good cold forming characteristics despite its high strength, though formability is lower compared to drawing steels.
Primary Pressure Vessel Applications
Boilers & Tanks: Specifically intended for fusion-welded boilers and unfired pressure vessels.
Energy Storage: Ideal for liquid gas storage tanks and transportation due to its high strength-to-weight ratio and stability at varying temperatures.
Oil & Gas: Used in the construction of heat exchangers and large-scale storage tanks for oil and gas projects.
Industrial & Structural Applications
While A514 is the standard for structural use, A517 Grade B is often applied in demanding industrial settings where pressure resistance is paramount:
Heavy Machinery: Found in crane booms, excavator components, and mining equipment.
Offshore Engineering: Used for subsea structural applications and jack-up offshore platform piles.
Construction & Transportation: Utilized in projects requiring high-performance structural steel that must also meet pressure vessel quality (PVQ) standards.
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What is A517 Grade B?
A517 Grade B is a high-strength, quenched and tempered alloy steel plate, mainly used for pressure vessels and structural components that require excellent toughness and weldability, suitable for low-temperature and harsh working environments.
What are the main chemical components of A517 Grade B?
Its key chemical components include carbon (C), manganese (Mn), silicon (Si), chromium (Cr), molybdenum (Mo) and nickel (Ni), which jointly ensure the steel's high strength and excellent mechanical properties.
What is the minimum tensile strength of A517 Grade B?
The minimum tensile strength of A517 Grade B is 690 MPa (100 ksi), a high value that enables it to bear heavy loads stably in industrial applications such as pressure vessel manufacturing.
What is the minimum yield strength of A517 Grade B?
A517 Grade B has a minimum yield strength of 515 MPa (74.7 ksi), which reflects its strong ability to resist plastic deformation under external forces and ensures structural stability in service.
What heat treatment process is A517 Grade B subjected to?
A517 Grade B undergoes quenching and tempering (Q&T) heat treatment: quenching enhances its hardness and strength, while tempering improves toughness and reduces brittleness to balance mechanical properties.
What is the typical application of A517 Grade B?
It is widely applied in manufacturing pressure vessels, boilers, offshore platforms and heavy machinery components, especially suitable for low-temperature and high-pressure working conditions.
Is A517 Grade B weldable?
Yes, A517 Grade B has good weldability. To avoid weld cracks and ensure the integrity of welded joints, proper preheating and post-weld heat treatment are recommended during welding.
What is the maximum thickness of A517 Grade B plates usually supplied?
The maximum thickness of A517 Grade B plates typically supplied is around 200 mm, and it can be customized according to specific project requirements and the manufacturer's production capabilities.
What standard does A517 Grade B comply with?
A517 Grade B complies with the ASTM A517 standard, which specifies technical requirements for high-strength carbon and alloy steel plates used in pressure vessels and structural applications.
What is the impact toughness of A517 Grade B?
A517 Grade B has excellent impact toughness, especially at low temperatures. It usually meets the Charpy V-notch impact test requirements at -20°C (-4°F) or even lower temperatures.