SA517 Grade B is a high-strength, quenched and tempered alloy steel plate primarily used for pressure vessels and boilers. It offers excellent toughness and weldability, suitable for harsh environments with high pressure and temperature, complying with ASME standards.
Chemical Requirements
*Elements represented in percentage
| Elements | Grade B % |
|---|---|
| Carbon | |
| Heat analysis | 0.15-0.21 |
| Product analysis | 0.13-0.23 |
| Manganese | |
| Heat analysis | 0.70-1.00 |
| Product analysis | 0.64-1.10 |
| Phosphorus, max | 0.025 |
| Sulfur, max | 0.025 |
| Silicon | |
| Heat analysis | 0.15-0.35 |
| Product analysis | 0.13-0.37 |
| Nickel | |
| Heat analysis | – |
| Product analysis | – |
| Chromium | |
| Heat analysis | 0.40-0.65 |
| Product analysis | 0.36-0.69 |
| Molybdenum | |
| Heat analysis | 0.15-0.25 |
Tensile Requirements
| 2.50 in. [65 mm] and Under | Over 2.50 to 6 in. [65 to 150 mm] | |
|---|---|---|
| Tensile strength | 115-135 [795-930] | 105-135 [725-930] |
| Yield strength, min, ksi [MPa] | 100 [690] | 90 [620] |
| Elongation in 2 in. [50 mm], min, % | 16 | 14 |
| Reduction of area, min, %: | ||
| Rectangular specimens | 35 | – |
| Round specimens | 45 | 45 |
Applications and Features
Primary Applications: SA517 Grade B is mainly used for unfired pressure vessels, boilers, storage tanks, and heat exchangers where high strength and toughness are required.
Weldability: It is weldable, but welding must be performed in accordance with applicable welding codes. Low hydrogen practices are highly recommended to avoid issues like reheat cracking, which this grade may be susceptible to during post-weld heat treatment.
Corrosion Resistance: It has moderate corrosion resistance; galvanizing or coatings can enhance its performance in harsh chemical conditions.
Equivalents: It is considered equivalent to the US T-1 steel material and ASTM A514 Grade B structural steel, although their final intended applications differ (A517 for pressure vessels, A514 for structural use like bridges).
Processing of SA517 Grade B
Cutting & Shearing: Adopt plasma cutting, flame cutting or high-precision shearing for blanking; preheat the plate to 100–150℃ before cutting thick plates (≥50mm) to prevent cold cracking, and remove oxide scale and cutting burrs post-processing for a smooth edge finish.
Forming: Conduct cold forming or hot forming based on plate thickness and structural requirements; hot forming is recommended for complex shapes with thick plates, with a forming temperature range of 850–1100℃, and avoid rapid cooling after forming to prevent internal stress accumulation.
Welding: Use low-hydrogen welding processes (GMAW, SMAW, SAW) to minimize hydrogen-induced cracking; preheat the base metal to 150–250℃ before welding, maintain interpass temperature ≤300℃, and perform post-weld heat treatment (PWHT) immediately after welding.
Post-Weld Heat Treatment (PWHT): Carry out stress relief annealing at 620–680℃, hold the temperature for 1–2 hours per 25mm plate thickness, then cool slowly at a rate ≤50℃/hour to room temperature, eliminating welding residual stress and improving toughness.
Machining: Perform precision machining (turning, milling, drilling) after heat treatment to ensure dimensional accuracy; use high-hardness cutting tools and control cutting speed/feed rate to avoid work hardening and surface damage of the material.
Final Heat Treatment Touch-Up: For components with severe deformation during processing, conduct a secondary tempering at 580–650℃ to restore mechanical properties, ensuring consistency with the original quenched and tempered state of SA517 Grade B.
Surface Treatment & Inspection: Remove surface rust, oil and impurities via shot blasting or pickling; conduct non-destructive testing (UT, MT, RT) on welding seams and key structural parts to verify no internal defects, meeting industrial pressure equipment quality standards.
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Can SA517 Grade B be used in low-temperature environments?
Yes, it exhibits good low-temperature toughness. It can be used in environments as low as -20°C (-4°F) without significant brittle fracture risk, making it suitable for some cold-region applications.
What is the difference between SA517 Grade B and SA517 Grade F?
The main difference lies in chemical composition and strength. SA517 Grade F has higher chromium and molybdenum content, resulting in higher tensile strength (min. 793 MPa) compared to Grade B (min. 690 MPa), suitable for more severe conditions.
What surface conditions are required for SA517 Grade B plates?
Plates should have a clean surface free of scale, rust, oil, grease, and other contaminants. Common surface finishes include hot-rolled, pickled and oiled, or shot-blasted to ensure good weldability and coating adhesion.
What is the elongation requirement of SA517 Grade B?
It requires a minimum elongation of 16% in 50 mm (2 inches) according to ASME SA-517. This elongation ensures the material has sufficient ductility to withstand deformation without cracking.
How to inspect the quality of SA517 Grade B plates?
Common quality inspections include chemical composition analysis (via spectroscopy), mechanical property testing (tensile, impact, hardness tests), ultrasonic testing (UT) for internal defects, and visual inspection for surface flaws.
What is the typical thickness range of SA517 Grade B plates?
The standard thickness range is 6 mm to 200 mm (0.24 inches to 7.87 inches). Thicker plates may be available on request, but they require stricter heat treatment and quality control to ensure uniform properties.
Can SA517 Grade B be cold-formed?
It can be cold-formed, but due to its high strength, it requires higher forming forces. Preheating may be needed for complex shapes or thick plates to avoid cracking and reduce springback.
What post-weld heat treatment (PWHT) is recommended for SA517 Grade B?
PWHT is usually recommended at 595-650°C (1103-1172°F) for 1-2 hours per inch of thickness. This reduces welding residual stress, improves toughness, and restores material properties near the weld zone.
Is SA517 Grade B resistant to corrosion?
It has moderate corrosion resistance in atmospheric and mild aqueous environments. For harsh corrosive conditions (e.g., acidic or salty environments), additional coatings (e.g., paint, galvanizing) or corrosion-resistant alloys are needed.
What is the modulus of elasticity of SA517 Grade B?
The modulus of elasticity is approximately 200 GPa (29,000 ksi) at room temperature. This value represents the material's stiffness, indicating how much it deforms under elastic load.