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ASTM A387 Grade 22 Class 2 (A387GR22CL2) Boiler And Pressure Vessel Steel Plate

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ASTM A387 Grade 22 Class 2 (A387GR22CL2) is a chromium-molybdenum alloy steel plate used in high-temperature and high-pressure environments. It possesses high-temperature strength, creep resistance, and hydrogen attack resistance, making it widely applicable in pressure vessels, reactors, and piping systems in industries such as petrochemicals, power generation, and boilers.

Standard :
ASTM A387/A387M
Grade :
A387 Grade 22 Class 2 (A387GR22CL2)
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 22 Class 2 (A387GR22CL2) chromium-molybdenum steel plate is the preferred material for manufacturing high-temperature and high-pressure equipment due to its strong high-temperature performance, hydrogen corrosion resistance, and weldability.

Grade	A387 Grade 22 Class 2 (A387GR22CL2)
Standard	ASTM A387/A387M: Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum
Delivery Conditions	Normalizing & Tempering (N&T)
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	It can undergo machining such as cutting, drilling, and milling, and supports hot forming (with heating temperature controlled to ≤950°C). Stress relief annealing is required after cold forming.
Quality Control	Ultrasonic Testing (UT) is performed in accordance with SA-578 to ensure the absence of internal laminations and discontinuities.

Key Features and Advantages

Excellent High-Temperature Strength: Maintains high strength at elevated temperatures (typically up to 550-600°C) with minimal susceptibility to creep deformation.

Good Hydrogen Corrosion Resistance: The addition of chromium and molybdenum enables resistance to hydrogen atom erosion in environments such as petroleum refining and coal chemical processing, preventing hydrogen-induced cracking and hydrogen blistering.

Good Toughness and Plasticity: The normalizing and tempering treatment provides a favorable combination of mechanical properties.

Weldability: As a medium-alloy steel, it offers acceptable weldability but requires strict welding procedures, including preheating and post-weld heat treatment, to prevent cold cracking and restore the properties of the heat-affected zone.

Chemical Composition

Grade	A387 Grade 22 Class 2 (A387GR22CL2)
Element	C	Si	Mn	P	S	Cr	Mo
Content (max, %)	0.04 - 0.15	0.50	0.25 - 0.66	0.025	0.025	1.88 - 2.62	0.85 - 1.15

Mechanical Properties

Grade	A387 Grade 22 Class 2 (A387GR22CL2)
Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]	Hardness (HBW) [max]
310	515 - 690	18	201

Applications

ASTM A387 Grade 22 Class 2 (A387GR22CL2) steel plate is primarily used in the manufacturing of pressure equipment operating in high-temperature and/or hydrogen-rich environments, such as:

1. Petrochemical industry: Hydrogenation reactors, reforming units, synthesis towers, and other high-temperature and high-pressure equipment.

2. Power industry: Supercritical boiler drums, high-temperature pipelines, and steam turbine components.

3. Energy sector: Coal chemical industry gasifiers, LNG storage tanks, and nuclear pressure vessels.

4. Special environments: Hydrogen-containing media (e.g., refinery hydrocracking units) and sulfur corrosive environments.

Other Information

Welding Precautions

Welding material selection: Matching chromium-molybdenum welding wire (such as ER80S-B3) or electrodes (such as E8018-B3) to ensure the weld metal composition matches the base material.

Preheating and interpass temperature: Preheat to 150-250°C, with interpass temperature not lower than the preheat temperature to prevent cold cracking.

Post-weld treatment: Mandatory PWHT (690-730°C × 2h) to eliminate the risk of hydrogen-induced cracking and improve joint performance.

Machining Precautions

It can undergo cold working such as cutting, bending, and stamping, but care must be taken to control the amount of deformation to avoid stress concentration.

The hot working temperature is recommended to be controlled between 900-1100°C, avoiding prolonged exposure in the sensitive range of 800-950°C.

FAQ

Q1:

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.

Q2:

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.

Q3:

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.

Q4:

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.

Q5:

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.

Q6:

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.

Q7:

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.

Q8:

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.

Q9:

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.

Q10:

What processing services do you offer for LR Grade D marine 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 extreme-low-temperature offshore engineering projects.

Q11:

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.

Q12:

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

The key difference lies in low-temperature impact resistance. LR Grade B is tested at 0°C and is suitable for temperate and mildly cold waters; LR Grade D is subject to a mandatory -20°C low-temperature impact test, offering greater cold resistance and making it suitable for cold waters and extremely cold marine environments. Both grades have the same basic tensile strength and yield strength.

Q13:

Do you provide official certification for your LR Grade D marine steel plates?

Yes. All of our LR Grade D shipbuilding steel plates hold valid official certification from Lloyd’s Register (LR) and EN 10204 3.2 mill test certificates. These certificates are internationally recognized and fully support global project bidding, high-standard engineering acceptance, and cross-border customs clearance requirements.

Q14:

What is the range of available dimensions for your LR Grade B marine steel plates?

Thickness: 5 mm - 150 mm (thicknesses ≥ 40 mm: require normalizing or TMCP heat treatment)

Width: 1,500 mm - 4,000 mm

Length: 6,000 mm - 18,000 mm

We offer custom flame-cutting or plasma-cutting services based on shipyard drawings, with cutting tolerances meeting LR rules requirements.

Q15:

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

Yes. All of our LR Grade B shipbuilding steel plates are subject to inspection by internationally recognized third-party organizations such as SGS, BV, and DNV, and come with complete official LR certification and original Mill Test Certificate (MTC) to ensure full quality traceability.