ASTM A517 Grade B is a high-strength alloy steel plate supplied in the quenched and tempered condition and used for fusion-welded pressure vessels, boilers, and heavily loaded structural assemblies. The grade provides a minimum yield strength of 690 MPa with dependable toughness, supporting reduced wall thickness and weight savings in pressure-containing components. It is commonly used in high-pressure vessels, penstocks, hydraulic equipment, and heavy machinery where a high strength-to-weight ratio is the governing design requirement.

Chemical Composition

A517 Grade B is produced with controlled carbon at 0.15–0.21%, combined with 0.70–1.00% manganese and 0.40–0.65% chromium for strength and hardenability. Molybdenum at 0.15–0.25% improves temper resistance, while boron at 0.0005–0.005% raises hardenability so that thick sections harden uniformly through the full thickness. Vanadium at 0.03–0.08% and titanium at 0.01–0.04% refine the grain structure and stabilise strength after tempering. Phosphorus and sulfur are held at low levels to protect toughness and weld quality.

Mechanical Properties

A517 Grade B provides a minimum yield strength of 690 MPa and a tensile strength range of 795–930 MPa for plate thickness up to 65 mm. Elongation is 16% minimum in 50 mm gauge length, with a reduction of area of 35% minimum on rectangular specimens. For plate from 65 to 150 mm, the required yield strength is 620 MPa minimum with a tensile range of 725–930 MPa and elongation of 14% minimum. The Cr-Mo-B alloy system combined with quenching and tempering delivers this strength with sufficient ductility for forming and welding.

Available Size Range

Thickness: 3–150 mm Width: 1220–4200 mm Length: 5000–18000 mm

Stock & Processing Services

Cutting • Beveling • Welding preparation • Heat treatment • Custom fabrication for pressure vessels

Applications

• High-pressure reactors and separators

• Penstocks and hydraulic equipment

• Boiler and pressure vessel shells

• Heavy machinery and lifting structures

• Mining and excavation equipment

• High-strength welded assemblies