ASTM A387 Grade 11 Class 1 steel plate is a chromium-molybdenum alloy steel specifically developed for pressure vessel and boiler applications operating under high temperature and pressure.
As a professional steel plate manufacturer and exporter, GNEE supplies ASTM A387 Gr11 Cl1 plates in Normalized and Tempered (N+T) condition to ensure consistent mechanical performance and long-term service reliability.
ASTM A387 Grade 11 Class 1 steel plate
Within the first 100 words, it is important to clearly state that GNEE is a manufacturer-oriented supplier, not a temporary trader. We work with stable mills, strict quality control systems, and experienced technical teams to support global energy, petrochemical, and refinery projects.
Typical tensile strength of A387 Grade 11 Class 1 steel ranges from 415 to 580 MPa, making it suitable for demanding load-bearing environments.
A387 Grade 11 Class 1 Steel Properties and Performance Advantages
The outstanding performance of A387 Grade 11 Class 1 steel plate is mainly attributed to its chromium-molybdenum alloy composition. The relatively high chromium content provides excellent oxidation resistance and corrosion resistance, which is especially critical for sour gas and high-temperature service conditions.
Key performance advantages include:
- High tensile strength and structural stability
- Excellent weldability and fabrication performance
- Good dimensional accuracy and surface finish
- Resistance to pitting corrosion and crevice corrosion
- Strong resistance to stress corrosion cracking
- Long service life under heavy loads and thermal cycles
These features make ASTM A387 Grade 11 Class 1 steel plates widely used across global industries where safety, durability, and performance consistency are essential.
Chemical Composition of ASTM A387 Grade 11 Class 1 Steel Plate
The chemical composition of A387 Grade 11 Class 1 steel is strictly controlled to balance strength, toughness, and corrosion resistance.
Chemical Composition Table (%)
| Grade | C | Mn | Si | P max | S max |
|---|---|---|---|---|---|
| ASTM A387 Grade 11 Class 1 | 0.04–0.17 | 0.35–0.73 | 0.44–0.86 | 0.035 | 0.035 |
This optimized composition ensures stable performance during welding, forming, and long-term operation.
Mechanical Properties of ASTM A387 Grade 11 Class 1 Steel Plate
ASTM A387 Gr11 Cl1 steel plates are designed to maintain mechanical stability under pressure and elevated temperatures.
Mechanical Property Table
| Property | Requirement |
|---|---|
| Tensile Strength | 415–580 MPa |
| Yield Strength (min) | 240 MPa |
| Elongation (50 mm) | ≥22% |
These mechanical properties help prevent deformation and fracture during long-term service.
ASTM A387 Grade 11 Class 1 Steel Plate Specifications & Sizes
GNEE supplies A387 Grade 11 Class 1 steel plates in various dimensions to meet different fabrication and engineering requirements.
Specification details:
Standard: ASTM A387
Grade: A387 Grade 11 Class 1 / A387 GR11 CL1
Thickness range: 3.0 mm – 150 mm
Shapes: Plates, sheets, coils
Finish: Hot Rolled (HR), Cold Rolled (CR)
Applications of ASTM A387 Grade 11 Class 1 Steel Plate
Thanks to its excellent heat resistance and corrosion resistance, ASTM A387 Grade 11 Class 1 steel plate is widely used in:
Boilers and boiler drums
Pressure vessels and reactors
Heat exchangers and condensers
Oil & gas storage tanks
Sour gas and petrochemical equipment
These applications demand materials that can withstand harsh operating environments over extended service periods.
Inspection and Quality Control for A387 Grade 11 Class 1 Plates
To ensure consistent quality, A387 Grade 11 Class 1 steel plates undergo strict inspection throughout production and delivery. Certified third-party inspection agencies are involved at specified stages to verify compliance with project requirements.
Inspection options include:
Ultrasonic Testing (UT)
Charpy V-Notch Impact Test
Third-party inspection (SGS, BV, Lloyd's)
Each inspection report confirms that raw materials, production processes, and finished plates meet ASTM standards, giving buyers confidence in product reliability and delivery timelines.
Equivalent Grades of ASTM A387 Grade 11 Class 1 Steel Plate
ASTM A387 Grade 11 Class 1 steel plate is commonly considered equivalent to:
BS: 622-515B
EN: 10CrMo9-10
DIN: 10CrMo9-10
This equivalency allows the material to be used in international projects without compatibility concerns.
As an experienced manufacturer and exporter, GNEE supplies ASTM A387 Grade 11 Class 1 steel plate with stable chemistry, reliable mechanical properties, and strict quality control. Our products are trusted by customers in more than 45 countries, supporting pressure vessel and boiler projects worldwide.
Contact us for the latest ASTM A387 Grade 11 Class 1 steel plate price list, technical data sheet, and delivery schedule.
Contact us for latest ASTM A387 Grade 11 Class 1 steel plate price list
What is ASTM A387 material?
ASTM A387 GR. 91 CL. 2 Alloy Steel Plates manufactured at the world's finest steel mills, this molybdenum-chrome based alloy has excellent resistance to greater working temperatures, making it the right selection for various applications like in gas, oil, chemical, and power generation.
What is ASTM A387 Grade 11 equivalent to?
ASTM A387 grade 11 equivalent steel is ASME SA387 grade 11. ASTM A387 grade 11 covers A387 grade 11 class 1 and A387 grade 11 class 2, which are equivalent to ASME SA387 grade 11 class 1 and SA387 grade 11 class 2 respectively.
What is the difference between ASTM A182 and A387?
A387 is Plate material. A182 is Forging material. You can refer relevant ASTM Book of standards.
What is ASTM A387?
The ASTM A387 specification is the Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum plates used in the application of welded boilers and pressure vessels subjected to elevated temperatures. The two grades SSAB produces are available as Class 1 and/or Class 2.