ASME SA 387 Grade 12 Class 1 is a standard specification for chromium-molybdenum alloy steel plates primarily used in the fabrication of weldable boilers and pressure vessels designed for elevated temperature service.
SPECIFICATION
Grade ASME SA 387 GR.12 CL.1/2 Alloy Steel Plate
Width 1000mm-4500mm
Thickness 5mm-150mm
Length 3000mm-18000mm
Mechanical properties for SA387 Grade 12 CL 2 pressure vessel steel plate:
|
Yield strength (Mpa) |
Tensile strength (Mpa) |
Elongation ≥,% 200mm |
|
275 |
450-585 |
19 |
Chemical composition of Heat analysis for SA387 Grade 12 CL 2 Alloy plate (Max %):
|
C |
Si |
Mn |
P |
S |
Cr |
Mo |
|
0.05/0.15 |
0.50 |
0.30/0.60 |
0.035 |
0.035 |
2.00/2.50 |
0.90/1.10 |
processing
Heat Treatment Cycles
The material must be thermally treated to achieve its mechanical properties.
Initial Treatment: Typically normalized and tempered. Some specifications allow for annealing or accelerated cooling (quenching) from the austenitizing temperature if followed by tempering.
Minimum Tempering Temperature: Must be at least 1150°F (620°C) for Grade 12.
Post-Weld Heat Treatment (PWHT): Essential to relieve residual stresses and prevent hydrogen cracking. The recommended temperature range for Grade 12 is typically 1200°F to 1300°F (650°C to 700°C).
Fabrication & Welding
SA 387 Grade 12 is a weldable alloy, but it requires careful preparation:
Preheating: Necessary for plates thicker than 10mm to prevent cold cracking. Typical preheat temperatures range from 300°F to 400°F (150°C to 200°C).
Filler Materials: Compatible consumables include E8018-B2 for SMAW or ER80S-B2 for TIG/MIG welding.
Edge Preparation: Precise beveling (e.g., 60° V-groove) is required to ensure full penetration. Edges are often prepared using flame or plasma cutting followed by grinding to remove contamination.
Forming and Cutting
Cutting: Common methods include plasma, laser, or oxy-fuel cutting. For thicker plates, waterjet cutting is preferred to avoid a heat-affected zone (HAZ) during the sizing process.
Cold/Hot Forming: The material can be cold formed, but intermediate stress relief or full re-heat treatment is often required if the fiber elongation exceeds specific limits set by ASME codes.
Core Industrial Applications
This alloy is preferred for environments requiring both heat and corrosion resistance:
Oil and Gas Industry: Used extensively for sour service applications where resistance to hydrogen-induced cracking and corrosive media is essential. It is a standard choice for refinery equipment, gas processing units, and separators.
Petrochemical Processing: Employed in the fabrication of chemical reactors, high-temperature storage tanks, and pipelines that handle aggressive chemicals at elevated pressures.
Power Generation: Used for critical components in thermal power plants, including boiler drums, steam pipelines, and turbine components that must withstand constant thermal stress.
Heat Transfer Equipment: Frequently specified for heat exchangers due to its ability to maintain structural integrity during efficient heat transfer processes in extreme conditions.
Specific Components
Beyond large vessels, the material is also used for smaller high-stress components:
Piping Systems: High-temperature ducting and pressurized steam lines.
Hardware: Flanges, pipe clamps, and specialized fittings for high-pressure systems.
Storage: Large metallic tanks and oxygen cylinders designed for high-pressure gas containment.
Service Environment Suitability
Temperature Range: Effective in systems operating between 316°C (600°F) and approximately 593°C (1100°F).
Resistance: Offers specialized protection against chloride cracking, crevice corrosion, and oxidation.
If you have project requirements for ASME SA 387 Grade 12 Class 1, we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:beam@gneesteelgroup.com.
What is ASME SA 387 Grade 12 Class 1?
It is a low-alloy Cr-Mo steel plate for pressure vessels, designed for high temperatures with good creep resistance and weldability, widely applied in petrochemical fields.
What is the main chemical composition of SA 387 Grade 12 Class 1?
Key components: C (0.15-0.20%), Cr (0.80-1.20%), Mo (0.45-0.60%), Mn (0.40-0.70%), Si (0.15-0.35%), with trace P and S restricted.
What is the minimum tensile strength of SA 387 Grade 12 Class 1?
Its minimum tensile strength is 415 MPa (60,000 psi), minimum yield strength 205 MPa (30,000 psi), ensuring structural stability under working loads.
What temperature range is SA 387 Grade 12 Class 1 suitable for?
It works well from -29°C (-20°F) to 593°C (1100°F), resisting thermal fatigue and retaining mechanical properties in high-temperature settings.
What are the common applications of SA 387 Grade 12 Class 1?
It is used in pressure vessels, boilers, heat exchangers and piping in petrochemical, refinery and power generation industries for high-temperature fluid handling.
Is SA 387 Grade 12 Class 1 weldable?
Yes, it has excellent weldability. Preheating (150-200°C) and post-weld heat treatment are recommended to prevent cracking and enhance toughness.
What post-weld heat treatment (PWHT) is required for SA 387 Grade 12 Class 1?
Typical PWHT: hold at 620-675°C (1150-1250°F) for enough time, then slow cool to relieve residual stress and improve ductility.
What is the maximum thickness available for SA 387 Grade 12 Class 1 plates?
The common maximum thickness is 200 mm (7.87 inches), and it can be customized for specific projects with strict manufacturing control.
What standard governs the production of SA 387 Grade 12 Class 1?
It is governed by ASME BPVC Section II, Part A, which specifies material requirements, testing standards and certification procedures.
What is the hardness range of SA 387 Grade 12 Class 1 after heat treatment?
After PWHT, its Brinell hardness (HB) ranges 170-220, balancing strength and toughness for pressure-containing applications.