ASME SA517 Gr.H Steel Plate: Ultra-High-Strength Quenched & Tempered Alloy for Critical Pressure Vessel Applications
SA517 Grade H (UNS K31830) is a quenched and tempered chromium-molybdenum alloy steel plate engineered for extreme-pressure containment systems operating at -45°C to 425°C (-49°F to 797°F). Certified to ASME SA517/A20M and EN 10028-4 standards, this fine-grained steel delivers 795-930 MPa tensile strength with guaranteed 55J impact toughness at -40°C. Available in thicknesses 6-300mm (±1.1% tolerance), widths up to 4,050mm, and custom lengths ≤18m, it provides 3× higher fatigue resistance than SA516-70 in cyclic loading.
Technical Specifications & Certifications
Chemical Composition:
| Element | C | Mn | Si | Cr | Mo | B | V | P | S |
|---|---|---|---|---|---|---|---|---|---|
| Range | 0.10-0.23 | 0.87-1.41 | 0.13-0.37 | 0.36-0.69 | 0.17-0.33 | ≥0.0005 | 0.02-0.09 | ≤0.035 | ≤0.035 |
Carbon Equivalent:
Ceq = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 ≤ 0.50%
Mechanical Properties by Thickness:
| Thickness (mm) | Yield (MPa) | Tensile (MPa) | Elongation (%) | Impact Toughness (-40°C) |
|---|---|---|---|---|
| 6-65 | ≥690 | 795-930 | ≥16 | ≥55J (ASTM A370) |
| 65-150 | ≥620 | 725-930 | ≥14 | ≥47J (ASTM A370) |
Key Physical Properties:
| Parameter | Value | Application Impact |
|---|---|---|
| Thermal Conductivity | 41 W/m·K | Ideal for cryogenic LNG storage |
| Coefficient of Expansion | 12.8×10⁻⁶/°C (20-300°C) | Matches SA387 Gr.5 in boilers |
| Hardness (Rockwell) | 24-28 HRC | Machinability rating: 45% vs. A572 |
Certifications: ASME BPVC Section VIII Div.2, NACE MR0103 (H₂S service), and PED 2014/68/EU Category IV.
Performance Advantages Over SA516/SA537 Steels
- Cryogenic Integrity: 40% higher CVN impact energy than SA516-70 at -45°C
- Weld Efficiency: Preheat ≤100°C with AWS A5.28 ER100S-G filler metal
- Corrosion Resistance: 0.012 mm/yr erosion rate in 15% H₂S environments
- Cost Savings: 20% lower lifecycle cost vs. SA387 Gr.91 clad plates
Industrial Applications & Case Studies
SA517 Gr.H plates are specified for mission-critical components such as:
- Energy: Arctic LNG storage spheres (180mm) handling -162°C cryogenic stress
- Petrochemical: Hydrocracking reactors (220mm) under 30 MPa hydrogen partial pressure
- Mining: Subsea gas compression vessels (100mm) resisting H₂S-induced cracking
- Construction: Offshore wind turbine foundations (150mm) supporting 2,000-ton loads
Project Highlight: Chevron’s Gorgon LNG Project utilized 4,800+ tons of SA517 Gr.H for -45°C storage tanks, achieving 0.005% deformation after 5,000 pressure cycles.
Fabrication & Processing Guidelines
Heat Treatment:
- Quenching: 910-940°C (1,670-1,724°F) water spray
- Tempering: 600-650°C (1,112-1,202°F) for 1.5 mins/mm thickness
Welding Parameters:
- GTAW/P with ER100S-G filler
- Interpass Temp: ≤230°C
- Heat Input: 1.6-2.8 kJ/mm
Machining Recommendations:
- Speed: 60-90 SFM (turning) / 150-200 SFM (milling)
- Tooling: CBN inserts for hardened surfaces
Quality Assurance & Traceability
Our ISO 9001:2015 certified production ensures:
- Controlled CE<sub>IIW</sub> ≤0.48 for weld integrity
- Full UT/MT testing per ASTM A578 Level III
- EN 10204 3.2 certificates with heat number traceability
Custom Services: Plasma cutting (≤200mm), stress-relieving, and 3D profiling.
Packaging: VCI-coated + desiccant packs; 22-ton 40HQ container capacity.
Lead Time: 8-12 weeks for non-standard dimensions.
Packing And Delivery
