SA 387-11-1 Steel Plate

SA 387 Gr 11 CL 1 is a low-alloy chromium-molybdenum (Cr-Mo) steel plate that complies with the ASME SA-387 standard, specifically designed for high-temperature and high-pressure service environments. It is typically processed by normalizing and tempering or quenching and tempering heat treatments, which refine its microstructure, enhance high-temperature strength, toughness, creep resistance, and weldability, while reducing internal stress. With moderate corrosion resistance, especially against hydrogen attack, this steel grade is widely recognized as a reliable material for critical equipment in harsh industrial processes.

SPECIFICATION

Grade ASME SA 387 GR.11 CL.1 Alloy Steel Plate

Width：1000mm-4500mm

Thickness ：5mm-150mm

Length ：3000mm-18000mm
Impact tested ：52° C
 

Chemical Requirements for ASME SA387 Grade 11 Alloy Steel Plates

Heat Treatment Processes

The heat treatment of SA 387 Gr 11 CL 1 mainly adopts two standard processes to optimize its mechanical properties, ensuring it meets the requirements of high-temperature and high-pressure service. Both processes are in line with the ASME SA-387 standard and are designed to refine the microstructure, reduce internal stress, and enhance key performances such as high-temperature strength, toughness, and creep resistance.

Normalizing + Tempering:

First, heat the steel plate to a temperature above the critical range (typically 890-920°C), hold it at this temperature for a sufficient time to achieve uniform austenitization, then cool it in air. This step refines the grain size and homogenizes the microstructure. Subsequent tempering involves reheating the normalized plate to a lower temperature (around 600-700°C), holding for a specified duration, and cooling to further relieve internal stress and improve toughness.

Quenching + Tempering:

Heat the steel plate to the appropriate austenitizing temperature, then cool it rapidly using oil or water to form a hard martensitic structure, which significantly improves the material's hardness and strength. After quenching, tempering is essential-reheat the plate to a moderate temperature, hold to eliminate brittleness from quenching, and adjust the structure to obtain the desired balance of strength, toughness, and ductility for industrial applications.

Applications

Boilers and Pressure Vessels: Used in fabricating pressure vessels, boiler components, and reactor shells for oil refineries, chemical plants, and power generation facilities, adapting to elevated pressure and temperature conditions.

Petrochemical Processing Equipment: Applied in manufacturing process units, reboilers, and condensers that handle corrosive fluids and high-temperature process streams.

High-Temperature Piping Systems: Utilized for producing piping, flanges, and pipe fittings in systems conveying hot oil, gas, or steam, ensuring leak-tight connections and structural integrity.

Heat Exchangers: Suitable for making plates, tubes, and other components of shell-and-tube heat exchangers, leveraging its excellent heat transfer performance and thermal fatigue resistance.

Power Generation Equipment: Employed in high-temperature ducting, steam headers, and auxiliary components of thermal power plants and waste incineration facilities.

Heavy-Duty Industrial Valves: Used to manufacture valve bodies, bonnets, and trim parts for critical control and isolation valves in high-temperature, high-pressure pipelines.

Pipe Supports and Clamps: Fabricated into heavy-duty pipe clamps and supports for high-temperature piping systems, resisting creep and maintaining pipe alignment under sustained thermal loads.

Oil and Gas Infrastructure: Applied in onshore and offshore oil/gas processing equipment, including wellheads, separators, and transport pipelines for high-temperature hydrocarbons.

Contact now

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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.

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 inspection methods are required for SA387 GR 11 CLASS 1 after heat treatment?

It requires mechanical property testing (tensile, impact), microstructure inspection, and non-destructive testing (ultrasonic, radiographic) to meet ASME standards.

 Is SA387 GR 11 CLASS 1 suitable for manufacturing high-temperature piping flanges?

Yes, it can withstand thermal cycling and mechanical stress, ensuring leak-tight connections in high-temperature and high-pressure piping systems.

What precautions should be taken when welding SA387 GR 11 CLASS 1?

 Preheating before welding and post-weld heat treatment are necessary to prevent weld cracks and maintain the material's mechanical properties.