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ASTM A387 Grade 11 Class 1(A387GR11CL1) Boiler And Pressure Vessel Steel Plate

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ASTM A387 Grade 11 Class 1 (A387GR11CL1) is a chromium-molybdenum alloy steel plate with good high-temperature strength and resistance to hydrogen corrosion. It is commonly used in the manufacturing of welded boilers and pressure vessel components, such as reactors, towers, boiler drums, etc.

Standard :
ASTM A387/A387M
Grade :
A387 Grade 11 Class 1 (A387GR11CL1)
Thickness :
6.0-300.0 mm
Width :
1500-4050 mm
Length :
3000-15000 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

ASTM A387 Grade 11 Class 1 is a chromium-molybdenum alloy steel plate specifically designed for high-temperature and high-pressure environments. It offers good high-temperature strength, resistance to hydrogen corrosion, weldability, and workability. It is primarily used in the manufacturing of welded boilers, pressure vessels, and other industrial equipment operating under high-temperature and high-pressure conditions.

Grade	A387 Grade 11 Class 1 (A387GR11CL1)
Standard	ASTM A387/A387M: Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum
Delivery Conditions	Annealing (A)
Weldability	The weldability is good, but strict preheating, controlled interpass temperature, and post-weld heat treatment (PWHT) procedures are required to prevent cold cracking.
Machinability	Machining operations such as cutting, bending, and stamping can be performed. Stress relief annealing is required after cold forming.
Quality Control	100% ultrasonic testing (UT) is performed in accordance with ASTM A578 to ensure the absence of internal laminations or cracks. Magnetic particle testing (MT) and/or penetrant testing (PT) are used for surface flaw inspection.

Key Features and Advantages

1. Excellent High-Temperature Performance: Maintains good strength and creep resistance at temperatures as high as 595°C (1100°F).

2. Hydrogen Attack Resistance: The addition of chromium and molybdenum enables it to resist the erosion of steel by hydrogen atoms in high-temperature and high-pressure hydrogen environments (such as hydrotreating units in refineries), preventing hydrogen-induced cracking and hydrogen blistering.

3. Good Weldability: Due to its lower carbon equivalent, A387 Gr.11 offers better weldability than higher-grade chromium-molybdenum steels (e.g., Gr.22). However, strict welding procedures, including preheating and post-weld heat treatment, must still be followed.

4. Sufficient Toughness and Ductility: The annealed condition provides good formability and processing capabilities.

Chemical Composition

Grade	A387 Grade 11 Class 1 (A387GR11CL1)
Element	C	Si	Mn	P	S	Cr	Mo
Content (max, %)	0.04 - 0.17	0.35 - 0.73	0.30 - 0.60	0.025	0.025	0.94 - 1.56	0.40 - 0.70

Mechanical Properties

Grade	A387 Grade 11 Class 1 (A387GR11CL1)
Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]	Hardness (HBW) [max]
240	415 - 585	18	201

Applications

ASTM A387 Grade 11 Class 1 (A387GR11CL1) steel plate is specifically used for manufacturing equipment that operates in high-temperature, high-pressure, and corrosive environments.

1. Petrochemical Industry: Hydrogenation reactors, synthesis towers, heat exchangers, separators, etc., capable of withstanding high temperatures, high pressures, and corrosive media (such as hydrogen, hydrogen sulfide).

2. Power Industry: Power station boiler drums, high-temperature pipelines, suitable for supercritical units with steam parameters up to 540°C.

3. Nuclear Energy Sector: Nuclear reactor pressure vessels and auxiliary equipment, meeting stringent safety requirements.

4. Other Applications: Liquefied petroleum gas storage tanks, high-pressure pipelines for hydropower stations, industrial furnace components, etc.

Other Information

Comparison: Class 1 vs. Class 2

Grade	Delivery Conditions	Features
ASTM A387 Grade 11 Class 1	Annealing (A)	It has lower strength but better plasticity and toughness.
ASTM A387 Grade 11 Class 2	Normalizing & Tempering (N&T)	It offers higher strength and superior high-temperature performance.

Why Choose ASTM A387 Grade 11 Class 1(A387GR11CL1) Boiler And Pressure Vessel Steel Plate for Oil & Gas Projects?

✔ High-Temperature Service: Up to 595°C (1100°F)

✔ Hydrogen Resistance: Prevents embrittlement in H₂-rich environments

✔ Sour Service Capability: NACE MR0175 compliant option available

✔ Optimized Weldability: Low cracking risk with proper PWHT

FAQ

Q1:

What custom processing services do you offer for LR Grade AH36 shipbuilding steel plates?

We provide one-stop value-added processing services, including precision cutting, bending, drilling, beveling, surface derusting, shot blasting, anti-corrosion treatment, and heat treatment, to meet all custom manufacturing and installation requirements for high-standard offshore engineering projects.

Q2:

Does your LR Grade AH36 shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade AH36 shipbuilding steel plates fully support third-party inspections by internationally recognized organizations such as SGS and BV. They come with complete official LR certification and original factory test certificates, ensuring comprehensive quality traceability.

Q3:

What is the application of LR Grade AH36 shipbuilding plate?

LR Grade AH36 shipbuilding steel plate is a high-strength hull structural steel certified by Lloyd’s Register (LR). It is primarily used in ultra-large ocean-going vessels, deep-sea offshore platforms, heavy-duty offshore engineering facilities, and high-load-bearing ship structures, and serves as a core load-bearing material for high-grade offshore engineering projects.

Q4:

Is LR Grade AH36 marine steel plate compatible with other classification society standards?

Yes. This product fully complies with the relevant marine steel standards of major classification societies such as CCS, ABS, BV, and DNV. We can provide dual or multiple classification society joint certifications based on customer requirements to meet marine engineering acceptance standards in different countries or regions.

Q5:

What is the main difference between LR Grade AH32 and LR Grade AH36 shipbuilding steel plates?

Both are high-strength hull structural steels certified by Lloyd’s Register (LR). The key difference lies in their yield strength grades: LR AH32 has a minimum yield strength of 315 MPa, while LR AH36 has a minimum yield strength of 355 MPa.

Therefore, LR AH32 is suitable for conventional-tonnage vessels and general offshore engineering projects, offering better cost-effectiveness; LR AH36, on the other hand, is intended for applications requiring higher strength, such as ultra-large vessels and high-load-bearing offshore structures.

Q6:

Does your LR Grade AH32 shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade AH32 shipbuilding steel plates support inspections by internationally recognized third-party organizations such as SGS, BV, and DNV. They come with complete official LR certification and original mill test certificates, ensuring full quality traceability.

Q7:

What processing services can you provide for LR Grade AH32 shipbuilding steel plates?

We offer one-stop value-added processing services, including precision cutting, bending, drilling, beveling, surface derusting, shot blasting, anti-corrosion treatment, and heat treatment, to meet all custom manufacturing and installation requirements for offshore engineering projects.

Q8:

Does LR Grade AH32 shipbuilding steel plate require special welding procedures?

LR Grade AH32 shipbuilding steel plate offers excellent overall weldability, stable material properties, and a low carbon equivalent. It is suitable for all conventional shipbuilding welding processes and does not require complex preheating or special protective measures.

Standard marine welding operating procedures ensure consistent weld quality, effectively reduce construction difficulties, and improve project efficiency.

Q9:

What is the application of LR Grade AH32 shipbuilding steel plate?

LR Grade AH32 shipbuilding steel plate is primarily used in the construction of commercial vessels, conventional offshore platforms, coastal marine infrastructure, and the maintenance of marine equipment. It is suitable for various marine engineering applications that require high strength and stable overall structural performance.

Q10:

What is the weldability of LR Grade E shipbuilding steel plates?

The weldability is good, and the carbon equivalent (CEV) is typically controlled at ≤ 0.40% (depending on the specific thickness).

For thicknesses of 40 mm or less, preheating is generally not required at ambient temperatures (≥0°C), but low-hydrogen electrodes must be used.

For plates thicker than 40 mm or highly constrained joints, preheating to 50°C–100°C is recommended to reduce the cooling rate and prevent cold cracks.

Important Note: Welding consumables approved by the classification society and compatible with LR Grade E must be used.

Q11:

What is the main difference between LR Grade D and Grade E marine steel?

The basic strength parameters of the two grades are the same; the key difference lies in low-temperature impact resistance and application scenarios.

LR Grade D must pass an impact test at -20°C and is suitable for conventional cold-water regions; LR Grade E must pass an impact test at -40°C and offers superior low-temperature toughness and resistance to brittle fracture, making it suitable for polar and extremely cold marine environments.

Q12:

What is the application of LR Grade E shipbuilding steel plates?

LR Grade E shipbuilding steel plate is a high-performance, ordinary-strength marine structural steel plate with exceptional impact toughness at ultra-low temperatures of -40°C. It is primarily used in polar icebreakers, polar research vessels, ultra-cold ocean-going vessels, extremely cold offshore structures, and high-end marine infrastructure requiring resistance to brittleness at extremely low temperatures. It serves as an upgraded replacement for LR Grade D shipbuilding steel plate in polar and extremely cold marine environments.

Q13:

What are the delivery conditions for LR Grade D shipbuilding steel plates?

The standard delivery conditions for LR Grade D shipbuilding steel plates are as follows:

1) Hot-rolled (HR): Suitable for thin plates with a thickness of ≤12 mm; this is the standard supply condition.

2) Thermomechanically Controlled Process (TMCP): The primary delivery condition for medium- and thick plates; grain refinement ensures compliance with impact toughness requirements at -20°C without the need for additional heat treatment.

3) Normalized (N): Suitable for thick plates with a thickness of ≥50 mm; used for critical components with stringent low-temperature toughness requirements.

All delivery conditions must pass LR third-party inspection prior to shipment.

Q14:

What processing services do you offer for LR Grade D marine steel plates?

Q15:

Does your LR Grade D shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade D shipbuilding steel plates are fully compatible with inspections by internationally recognized third-party organizations such as SGS, BV, and DNV. They come with complete official LR certification and original factory test reports, ensuring comprehensive quality traceability.