Both ASTM A387 Grade 11 Class 1 steel plate and ASTM A387 Grade 11 Class 2 steel plate are chromium-molybdenum alloy steel plates designed for pressure vessels, boilers, and high-temperature service applications.
ASTM A387 Grade 11 Class 1 steel plate
While they share the same chemical composition, the main difference lies in their mechanical properties and tensile strength requirements, making each suitable for slightly different engineering conditions.
Chemical Composition of ASTM A387 Grade 11 Class 1 and A387 Grade 11 Class 2 steel plate
The chemical composition of ASTM A387 Grade 11 Class 1 steel plate and ASTM A387 Grade 11 Class 2 steel plate is identical and ensures excellent high-temperature performance and corrosion resistance.
| Element | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Molybdenum |
|---|---|---|---|---|---|---|---|
| Max. % (Heat Analysis) | 0.05–0.17 | 0.40–0.65 | 0.025 | 0.025 | 0.50–0.80 | 1.00–1.50 | 0.45–0.65 |
Mechanical Properties of A387 Grade 11 Class 1 and A387 Grade 11 Class 2 steel plate
The key difference between ASTM A387 Grade 11 Class 1 steel plate and ASTM A387 Grade 11 Class 2 steel plate is the tensile strength and yield strength, while elongation remains comparable.
| Steel Plate | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| ASTM A387 Grade 11 Class 1 | 415–585 | 240 | 19–22 |
| ASTM A387 Grade 11 Class 2 | 515–690 | 310 | 18–22 |
Heat Treatment of A387 Grade 11 Class 1 and A387 Grade 11 Class 2 steel plate
Both ASTM A387 Class 1 and ASTM A387 Class 2 steel plates are supplied in thermally treated conditions to achieve desired mechanical properties:
- Annealing
- Normalizing and tempering
- Accelerated cooling from austenitizing temperature (air blast or liquid quench) followed by tempering
- Minimum tempering temperature: 1150°F (620°C)
These treatments ensure uniform internal microstructure, stable chemical composition, and enhanced creep resistance at elevated temperatures.
Applications of A387 Grade 11 Class 1 and A387 Grade 11 Class 2 steel plate
ASTM A387 Grade 11 steel plates are widely used in industries requiring heat resistance, high strength, and durability, including:
| Industry | Typical Applications |
|---|---|
| Petroleum & Petrochemical | Pressure vessels, reactors, distillation columns |
| Chemical Equipment | Heat exchangers, process vessels |
| Power Generation | Boilers, steam drums |
| General Engineering | Welded high-temperature pressure vessels |
ASTM A387 Class 2 steel plate is preferred where higher pressure and tensile strength are required, while Class 1 steel plate is sufficient for standard temperature and pressure applications.
- Same chemical composition, both chromium-molybdenum alloy steel
- Main difference: ASTM A387 Class 2 steel plate has higher tensile and yield strength than ASTM A387 Class 1 steel plate
- Applications: Both are ideal for pressure vessels, boilers, and high-temperature service, with ASTM A387 Class 2 suitable for more demanding conditions
- Heat treatment: Normalizing, tempering, or accelerated cooling ensures long-term structural reliability
Choosing between ASTM A387 Grade 11 Class 1 steel plate and ASTM A387 Grade 11 Class 2 steel plate depends on the design pressure and operating conditions of the pressure vessel or boiler.
For standard elevated temperature service, ASTM A387 Class 1 steel plate is sufficient, while ASTM A387 Class 2 steel plate is recommended for high-pressure and high-stress applications.
Contact now to get A387 Steel Quote
What is A387 material?
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.
What is a A387 steel equivalent to?
Other designations that are equivalent to AISI A387 grade 22-PVQ alloy steel include the following: ASTM A182 (F22-1) ASTM A199 (T22)
What is A387 grade 22 material?
ASTM A387 Grade 22 (ASME SA387 Grade 22) is Chrom-Moly steel plate used for making boilers and pressure vessles designed for high temperature high pressure serivce, chrome content at 2.00% to 2.50%, and Moly 0.90% to 1.10% for SA387 GRADE 22 material.
What is the chemical composition of ASTM A387 Grade 12?
ASTM A387 GR 12 CL 2 Plates is designed with chemical components such as silicon, chromium, vanadium, molybdenum, sulfur, phosphorus, carbon, and manganese. Alloy Gr 12 has some tensile requirements, such as tensile strength, area reduction, elongation, and yield strength.
What is the difference between ASTM A182 and A387?
Both ASTM A182 grade F11 class 2 and ASTM A387 grade 22 steel are iron alloys. They have a very high 99% of their average alloy composition in common. There are 32 material properties with values for both materials. Properties with values for just one material (1, in this case) are not shown.