ASTM A387 Grade 11 Class 2 alloy steel plate is a chromium-molybdenum (Cr-Mo) pressure vessel steel designed for high-temperature and high-pressure service.
ASTM A387 Grade 11 Class 2 alloy steel plate
With a nominal 1.25% chromium and 0.50% molybdenum, this grade offers excellent creep strength, oxidation resistance, and corrosion resistance, making it ideal for boilers, reactors, and pressure vessels in demanding environments.
As a professional steel manufacturer and exporter, Gnee Steel supplies ASTM A387 Gr 11 Cl.2 plates with stable quality, full certification, and fast global delivery.
Why Choose ASTM A387 Gr 11 Class 2 Steel Plate?
Compared with Class 1, Class 2 provides higher tensile and yield strength, achieved through stricter heat treatment requirements.
Key advantages include:
- Excellent performance at elevated temperatures
- Strong resistance to oxidation and corrosion
- High tensile and yield strength
- Good weldability and fabrication performance
- Long service life under heavy loads
- Suitable for post-weld heat treatment (PWHT)
ASTM A387 Grade 11 Class 2 Applications
ASTM A387 Gr 11 Cl.2 plates are widely used in:
- Pressure vessels and boilers
- Heat exchangers and reactors
- Petrochemical and refinery equipment
- Power generation plants
- Oil & gas processing units
- High-temperature industrial installations
ASTM A387 Gr 11 Cl.2 Plate Specifications
Standard: ASTM A387 / ASME SA387
Grade: Grade 11 Class 2
Steel Type: Chromium Molybdenum Alloy Steel
Available Size Range (Gnee Steel):
Thickness: 8 – 100 mm (up to 400 mm on request)
Width: 1000 – 4500 mm
Length: 3000 – 18000 mm
Delivery Condition (Optional):
As Rolled
Normalized
Normalized + Tempered
Quenched & Tempered
Simulated PWHT
Vacuum Degassing
HIC / Impact Test (if required)
Chemical Composition of ASTM A387 Grade 11 Class 2 (%)
| Element | Content |
|---|---|
| C | 0.04 – 0.17 |
| Mn | 0.35 – 0.73 |
| Si | 0.44 – 0.86 |
| P | ≤ 0.035 |
| S | ≤ 0.035 |
| Cr | 0.94 – 1.56 |
| Mo | 0.40 – 0.70 |
Mechanical Properties of ASTM A387 Gr 11 Cl.2
| Property | Value |
|---|---|
| Tensile Strength | 75–90 ksi / 485–620 MPa |
| Yield Strength | ≥ 45 ksi / ≥ 310 MPa |
| Elongation (200 mm) | ≥ 18% |
| Elongation (50 mm) | ≥ 22% |
ASTM A387 Grade 11 Class 2 Equivalent Grades
| Standard | Grade |
|---|---|
| ASTM / ASME | A387 / SA387 Gr 11 Cl.2 |
| UNS | K11789 |
Gnee Steel is a competitive manufacturer and global supplier of ASTM A387 Grade 11 Class 2 pressure vessel steel plates, with:
Monthly capacity up to 10,000 tons
Strict quality control & mill test certificates (EN 10204 3.1 / 3.2)
Stable chemical composition & mechanical properties
Fast delivery and export-standard packaging
Contact Gnee Steel today for pricing, technical support, or customized ASTM A387 Gr 11 Class 2 steel plate solutions.
Contact now to get ASTM A387 Quote
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.