SA 387 Gr.11 Cl.1 refers to a specific type of ASME SA-387 Chromium-Molybdenum (Cr-Mo) alloy steel plate, designed for welded pressure vessels and boilers in elevated temperature service, offering good strength, heat resistance, and weldability.
Manufacture & Heat Treatment
The ASME SA-387 Gr.11 plates shall be made by a killed process. Three types of heat treatment may be furnished: (1) annealing; (2) normalizing and tempering; (3) when permitted by the purchaser, quenching and tempering. The tempering temperature shall be no less than 620°C [1150°C]. The "quenching" means accelerated cooling from the austenitizing temperature by air blasting or liquid quenching.
Chemical Composition Requirements
| Element | Heat Analysis |
Product Analysis |
|---|---|---|
| C | 0.05-0.17 | 0.04-0.17 |
| Mn | 0.40-0.65 | 0.35-0.73 |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.025 | ≤0.025 |
| Si | 0.50-0.80 | 0.44-0.86 |
| Cr | 1.00-1.50 | 0.94-1.56 |
| Mo | 0.45-0.65 | 0.40-0.70 |
Tensile Requirements
| ASME SA-387 Grade 11 Class 1 |
|
|---|---|
| Tensile Strength MPa [ksi] |
415-585 [60-85] |
| Yield Strength MPa [ksi], min. |
240 [35] |
| Elongation in 8", min. % |
19 |
| Elongation in 2", min. % |
22 |
| Reduction of area, min. % |
- |
Processing Steps of SA387 GR 11 CLASS 1
Raw Material (Steel Plate): Purchase steel plates complying with SA-387/A387 Grade 11 Class 1 specifications, usually in annealed or normalized condition.
Cutting: Cut the steel plate into the required shape by plasma cutting, laser cutting, shearing or other methods according to design requirements.
Forming:
Hot Forming: Commonly used for manufacturing cylinder sections or conical sections. Heat to recrystallization temperature (e.g., 900-1100°C) for pressure forming, followed by normalization (e.g., 870-950°C) and tempering (e.g., 680-750°C) heat treatments.
Cold Forming: Also applicable for thinner plates, but springback and stress must be considered. Stress relief annealing is usually performed after forming.
Welding: Use matching welding consumables (e.g., ER80S-G or E8018-C1), adopt multi-layer and multi-pass welding, and strictly control interpass temperature to prevent cracks.
Post-Weld Heat Treatment (PWHT): This is a critical step. Heat the welded component as a whole to a specific temperature (e.g., 600-650°C), hold for a certain period, then cool slowly to eliminate welding stress, restore microstructure and improve toughness.
Machining: Grind and finish the weld area and its surroundings to remove slag and burrs.
Non-Destructive Testing (NDT): Perform Magnetic Particle Testing (MT) or Ultrasonic Testing (UT) on welds to inspect internal defects.
Hydrostatic Test/Pneumatic Test: Conduct strength and tightness tests on pressure vessels.
Final Inspection: Including dimensional inspection, marking, and review of Material Test Certificate (MTC), etc.
Key Applications
Oil & Gas: Equipment for processing and storing liquids/gases at high temperatures, including sour service (H2S) environments.
Petrochemical Plants: Reactors, vessels, and piping in high-temperature processes.
Power Generation: Boilers, heat exchangers, and components in thermal power plants.
Chemical Plants: Equipment requiring resistance to high temperatures and corrosion.
Why It's Used
High-Temperature Service: Designed to maintain strength and integrity under sustained heat.
Corrosion Resistance: Chromium content provides superior resistance to oxidation and corrosion, vital for harsh chemical environments.
Creep Resistance: Molybdenum improves resistance to deformation at high temperatures over time.
Weldability: Suitable for fabrication into complex pressure-retaining structures.
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.
What is the critical temperature range for normalizing SA387 GR 11 CLASS 1?
It is typically heated above the critical temperature (around 890-920°C) before air cooling.
Which standard governs the production and inspection of SA387 GR 11 CLASS 1?
It complies with the ASME SA-387 standard, a specification for pressure vessel plates for high-temperature service.
What is the primary application of SA387 GR 11 CLASS 1?
It is mainly used to manufacture components of high-temperature and high-pressure equipment, such as boilers and pressure vessels.
Does SA387 GR 11 CLASS 1 have good corrosion resistance?
It has moderate corrosion resistance, especially resistance to hydrogen attack, suitable for harsh process environments in petrochemical industries.
What cooling medium is usually used for quenching SA387 GR 11 CLASS 1?
Oil or water is commonly used for rapid cooling to form a martensitic structure and improve hardness.
How does SA387 GR 11 CLASS 1 differ from SA387 GR 22 CLASS 1 in terms of alloy content?
GR 11 CLASS 1 has 1.25% Cr and 0.5% Mo, while GR 22 CLASS 1 has 2.25% Cr and 1% Mo, giving GR 22 better high-temperature creep resistance.
What is the difference in heat treatment effects between Normalizing+Tempering and Quenching+Tempering for SA387 GR 11 CLASS 1?
Normalizing+Tempering refines grains more uniformly, while Quenching+Tempering provides higher hardness and strength, suitable for more demanding pressure conditions.
How does SA387 GR 11 CLASS 1 compare to carbon steel plates in high-temperature service?
It has far better high-temperature strength and creep resistance than carbon steel, avoiding deformation or failure under long-term elevated temperatures.
What is the difference between SA387 GR 11 CLASS 1 and SA387 GR 11 CLASS 2?
CLASS 1 has lower carbon content and better weldability, while CLASS 2 has higher carbon content and slightly higher strength but poorer weldability.
How does SA387 GR 11 CLASS 1 perform compared to SA516 GR 70 in pressure vessel applications?
SA516 GR 70 is for low-temperature to medium-temperature service, while SA387 GR 11 CLASS 1 excels in high-temperature scenarios with superior creep resistance.
What is the difference in microstructure between SA387 GR 11 CLASS 1 after quenching and after tempering?
Quenching forms hard martensite, while tempering transforms it into tempered martensite, relieving internal stress and improving toughness.
How does SA387 GR 11 CLASS 1 compare to stainless steel in terms of cost and application scope?
It is more cost-effective than stainless steel, suitable for Cr-Mo compatible high-temperature environments, while stainless steel is preferred for strong corrosion resistance needs.
What is the difference in high-temperature ductility between SA387 GR 11 CLASS 1 and SA387 GR 91?
GR 91 has higher chromium content and better high-temperature ductility, while GR 11 CLASS 1 is more cost-efficient for medium-high temperature applications.
Can SA387 GR 11 CLASS 1 be used to manufacture heat exchanger components?
Yes, its excellent heat transfer characteristics and thermal fatigue resistance make it suitable for heat exchanger plates and tubes.