ASME SA387 Grade 11 Class 2 is a chromium-molybdenum alloy steel specifically developed for pressure vessel applications operating at elevated temperatures.
This material is widely used across multiple industries and has proven particularly effective in the oil, gas, and petrochemical sectors, where liquids and gases are frequently processed and stored under high-temperature and high-pressure conditions.
The relatively higher chromium content enhances the steel's resistance to oxidation and corrosion, making SA387 Grade 11 Class 2 a reliable choice for sour gas and corrosive service environments.
ASME SA387 Gr.11 CL.2 BQ Steel Plate Specification :
Grade : ASME SA 387 Grade 11 CL.2 Alloy Steel Plates
Width : 1000mm-4500mm
Thickness : 5mm-150mm
Length : 3000mm -18000mm
Impact tested : -52° C
Process : Hot-Rolled (HR)
SA 387 Gr.11 Plate Price per kg
| Min (Price in INR) | Max (Price in INR) |
|---|---|
| 120 | 180 |
SA 387 Gr 11 Cl 2 Equivalent Material
| COUNTRY | USA | EUROPEAN | GERMANY | ENGLAND | FRANCE | RUSSIA |
| STANDARDS | ASME | EN 10028 | DIN | BS | AFNOR 36206 | GOST |
| Grade 11 | SA387 | 13CrMoSi5-5 | - | 621B | - | - |
SA 387 Gr 11 Chemical Composition
| Grade | C | Mn | P | S | Si | Cr | Mo | V |
| SA 387 Gr.11 | 0.05 - 0.17 | 0.40 - 0.65 | 0.025 | 0.025 | 0.50 - 0.80 | 1.00 - 1.50 | 0.45 - 0.65 | - |
ASME SA387 Gr 11 CL.2 Alloy Steel Plates Mechanical Properties
| Class | Tensile (MPa) | Yield (MPa) | Elong. (50mm) | Elong. (200mm) | Reduc'n of Area* |
| Class 1 | 415 - 585 | 240 min | 22% min | 19% min | - |
| Class 2 | 515 - 690 | 310 min | 22% min | 18% min | - |
applications
1. Oil, Gas, and Petrochemical Industries
This steel is widely utilized for equipment processing hazardous or high-temperature media.
Pressure Vessels & Separators: Used in fabricating large vessels that store liquids and gases under high pressure.
Hydrotreating & Hydrogenation Reactors: Specifically chosen for its resistance to oxidation and hydrogen-induced issues.
Fractionation Columns: Thermal stability makes it ideal for continuous refining unit operation.
Sour Gas Service: Elevated chromium content provides essential resistance to corrosion in environments containing hydrogen sulfide (𝐻2𝑆).
2. Power Generation
Its strength at elevated temperatures is leveraged in thermal and nuclear power plants.
Boiler Drums & Headers: Essential for components subjected to prolonged thermal and mechanical stress.
Steam Piping Systems: Used for high-temperature ducting and piping that carries steam to turbines.
Steam Turbines: Applied in turbine components requiring high creep resistance.
3. Heat Transfer Equipment
SA387 Grade 11 Class 2 is a preferred material for thermal exchange equipment.
Heat Exchangers: Used in shell-and-tube designs that must withstand continuous thermal cycling.
Furnace Components: Employed in parts of industrial furnaces where high-heat tolerance is required.
4. Specialized Fittings and Components
Beyond large plates, this grade is processed into critical auxiliary hardware:
Flanges and Valves: For secure connections in high-pressure pipelines.
Pipe Clamps and Fittings: To support high-temperature piping systems.
processing
1. Melting and Refining
Killed Steel Practice: The steel must be fully killed and produced using grain-refining practices.
Impurity Control: Modern production utilizes Vacuum Degassing (VD) and Ladle Refining to strictly limit trace elements like Phosphorus (P), Tin (Sn), Antimony (Sb), and Arsenic (As). This is crucial to minimize the J-Factor or X-Bar value, reducing the risk of temper embrittlement during long-term high-temperature service.
2. Heat Treatment (Defining Class 2)
The "Class 2" designation signifies higher strength levels compared to Class 1, achieved through specific cooling rates:
Normalizing and Tempering (N+T): The plates are heated to an austenitizing range (approx. 900°C–950°C) and air-cooled, followed by high-temperature tempering.
Quenching and Tempering (Q+T): For heavy thicknesses, liquid quenching or accelerated cooling is often employed to ensure a uniform bainitic microstructure throughout the cross-section.
Tempering Temperature: A minimum tempering temperature of 620°C (1150°F) is mandatory to stabilize the mechanical properties and relieve internal stresses.
3. Cutting and Forming
Preheated Cutting: Thermal cutting (Plasma or Flame) usually requires preheating the plate to 100°C–150°C for thicker sections to prevent edge cracking.
Hot Forming: If the material is hot-formed (typically above 900°C), it must undergo a full re-normalization and tempering cycle to restore its mechanical integrity.
4. Welding Procedures
Preheat & Interpass Temperature: Continuous preheating between 150°C and 250°C is required during the entire welding process to avoid cold cracking (hydrogen-induced cracking).
Low-Hydrogen Consumables: Only low-hydrogen electrodes (e.g., E8018-B2) or specialized flux-cored wires are used.
Post-Weld Heat Treatment (PWHT): This is a critical final step. The welded assembly is heated to 620°C–700°C to reduce weld hardness, improve toughness, and eliminate residual stresses.
5. Quality Control and Testing
Ultrasonic Testing (UT): 100% volumetric inspection to ensure the absence of internal laminations or defects.
Simulated PWHT (SPWHT): Test coupons are subjected to simulated heat cycles (often representing multiple repair cycles) to verify that the material will still meet minimum strength and toughness requirements after years of service and maintenance.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
Can SA387 Grade 11 Class 2 be repaired after damage?
Yes, welding repair is feasible. Follow proper preheating and post-weld heat treatment procedures to restore performance.
Does SA387 Grade 11 Class 2 require certification?
Yes, it usually requires MTC (Material Test Certificate) to confirm chemical composition, mechanical properties, and heat treatment compliance.
Is SA387 Grade 11 Class 2 compliant with ASME standards?
Yes, it meets ASME Boiler and Pressure Vessel Code Section II, making it acceptable for use in ASME-certified equipment.
What is the equivalent material of SA387 Grade 11 Class 2 in EN standards?
Its approximate EN equivalent is 13CrMo4-5, with similar chemical composition and mechanical properties for pressure vessel applications.
How to avoid machining defects in SA387 Grade 11 Class 2?
Maintain stable cutting speeds, use sharp tools, and avoid excessive heat. Proper heat treatment before machining also minimizes defects.
Can SA387 Grade 11 Class 2 be formed by bending?
Yes, it can be bent cold or hot. Hot bending at 925-1040°C improves formability and reduces the risk of cracking during the process.
What is the maximum bending radius for SA387 Grade 11 Class 2?
The minimum bending radius depends on thickness, usually 3-5 times the material thickness for cold bending, smaller for hot bending.
How to ensure the surface quality of SA387 Grade 11 Class 2 during fabrication?
Clean surfaces before processing, avoid scratches, and use proper welding techniques. Post-fabrication grinding can also improve surface smoothness.
What factors affect the service life of SA387 Grade 11 Class 2?
Temperature, pressure, corrosive media, and maintenance frequency. Proper operation within design limits extends service life.
How to test the integrity of SA387 Grade 11 Class 2 components?
Use NDT methods like ultrasonic testing, radiography, and magnetic particle testing to detect cracks, defects, and material degradation.