ASME SA387 Gr.12 Cl.2 Steel Plate: Chrome-Molybdenum Alloy for High-Temp Pressure Vessels
ASME SA387 Grade 12 Class 2 (UNS K11562) is a quenched & tempered chrome-molybdenum (1% Cr, 0.5% Mo) alloy steel plate designed for pressure vessels operating at 400-550°C (752-1,022°F). Certified to ASME BPVC Section II Part A and NACE MR0175, this normalized steel delivers 450-585 MPa tensile strength with 25J guaranteed impact toughness at -20°C. Available in thicknesses 6-300mm (±1.5% tolerance), widths up to 4,500mm, and lengths ≤16m, it offers 30% better oxidation resistance than SA516-70 in sour gas service.
Technical Specifications & Global Equivalents
Chemical Composition:
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon | 0.05-0.17 | 0.04-0.17 |
| Manganese | 0.40-0.65 | 0.35-0.73 |
| Chromium | 0.80-1.15 | 0.74-1.21 |
| Molybdenum | 0.45-0.60 | 0.40-0.65 |
| Phosphorus | ≤0.035 | ≤0.035 |
| Sulfur | ≤0.035 | ≤0.035 |
Key Global Equivalents:
- DIN 17155: 13CrMo44
- BS 1501: 620-440 B
- EN 10028-2: 13CrMo4-5
- JIS G4109: SCMV2
Mechanical Properties:
| Property | Value | Test Standard |
|---|---|---|
| Tensile Strength (MPa) | 450-585 | ASTM A370 |
| Yield Strength (MPa) | ≥275 | ASTM A370 (0.2% offset) |
| Elongation (50mm) (%) | ≥22 | EN ISO 6892-1 |
| Reduction of Area (%) | ≥45 | ASTM A370 |
Physical Properties:
| Parameter | Value | Application Impact |
|---|---|---|
| Thermal Conductivity | 42 W/m·K | Optimal for refinery cokers (450°C) |
| Thermal Expansion | 11.5×10⁻⁶/°C (20-500°C) | Matches SA387 Gr.11 in reformers |
| Elastic Modulus | 200 GPa | 10% higher rigidity vs. SA285-C |
Performance Advantages Over Standard Grades
- Sour Service Resistance: 0.02 mm/year corrosion rate in H₂S environments (NACE TM0177)
- High-Temp Stability: Retains 80% yield strength at 500°C vs. 55% for SA516-70
- Weld Efficiency: Preheat ≤100°C with AWS A5.23 EM12K filler metal
- Cost Savings: 18% lower lifecycle cost vs. SA387 Gr.11 clad plates
Industrial Applications
SA387 Gr.12 Cl.2 is critical for high-pressure/high-temperature systems including:
- Oil & Gas: Sour gas separators (150mm) at 50 bar/200°C
- Power: Steam drums (200mm) operating at 540°C/15 MPa
- Chemicals: Hydrocracker reactors (180mm) with 20,000+ thermal cycles
- Renewables: Biomass boiler headers (80mm) resisting ash corrosion
Project Case: ExxonMobil’s Singapore refinery utilized 1,200+ tons of SA387 Gr.12 Cl.2 for 480°C hydrocracker vessels, achieving <0.005% deformation after 8-year service.
Fabrication Guidelines
Heat Treatment:
- Normalizing: 900-960°C (1,652-1,760°F) + air cooling
- Stress Relieving: 595-650°C (1,103-1,202°F) for 2 mins/mm
Welding Parameters:
- SAW with F12P8-EH12CrMo flux/wire combo
- Interpass Temp: ≤175°C
- Heat Input: 1.3-2.1 kJ/mm
Machining Tips:
- Speed: 60-90 SFM (turning) / 160-200 SFM (milling)
- Tooling: PCBN inserts for hardened surfaces
Quality Assurance
- 100% UT per ASTM A578 Level III
- Charpy tests at -20°C (ASTM E23)
- PMI verification via OES
Custom Services: Plasma cutting (≤150mm), edge prep, and PWHT.
Packaging: VCI + desiccant; 22-ton 40HQ container capacity.
Lead Time: 8-12 weeks for mill orders.
Packing And Delivery
