ASTM A387 Grade 11 Class 2
ASTM A387 grade 11 class 2 is ASTM A387 grade 11 steel in the normalized and tempered condition.
ASTM A387 Grade 11 Class 2 is a high-quality chromium-molybdenum (Cr-Mo) alloy steel plate specifically designed for use in weldable pressure vessels, boilers, and heat exchangers. This grade is optimized for elevated temperature service, where maintaining structural integrity and resisting oxidation are critical requirements.
ASTM A387 Grade 11 Class 2 is a chromium-molybdenum alloy steel plate for high-temperature pressure vessels, offering higher strength than Class 1 due to enhanced heat treatment, featuring ~1% Cr and ~0.5% Mo, and requiring Charpy impact testing, ideal for oil/gas, petrochemicals, and power generation.
Key Characteristics:
Type: Alloy Steel Plate
Grade 11: Contains approximately 1.00-1.50% Chromium (Cr) and 0.45-0.65% Molybdenum (Mo).
Class 2: Indicates a higher strength level (Yield: 45 ksi, Tensile: 75-100 ksi) with mandatory impact testing, making it suitable for more demanding, high-stress, elevated-temperature applications compared to Class 1.
Impact Test: Required (e.g., at -52°C for some suppliers).
Applications:
Pressure vessels, boilers, heat exchangers.
Oil & Gas processing, petrochemical plants.
Power generation equipment.
In Summary: ASTM A387 Gr 11 Cl 2 is a robust, weldable chrome-moly steel for critical components in high-heat environments where superior strength and thermal stability are essential.
Equivalents
| BS | EN | ASTM/ASME | DIN |
| 621 B | ––– | A387-11-2 | ––– |
Specifications for ASTM A387 Grade 11 Alloy Steel Plates
Chromium & Molybdenum content (according to the ASME specification)
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
| A387 Grade 11 | 1.25% | 0.50% |
Tensile Requirements for ASTM A387 Grade 11 Alloy Steel Plates Class 1 Plates
| Designation: | Requirement: | Grade 11 |
| A387 Grade 11 | Tensile strength, ksi [MPa] | 75 to 100 [515 to 690] |
| Yield strength, min, ksi [MPa]/(0.2% offset) | 43 [310] | |
| Elongation in 8 in. [200mm], min % | 18 | |
| Elongation in 2 in. [50mm], min, % | 22 | |
| Reduction of area, min % | ––– |
ASTM A387 GR 11 CLASS 2 Chemical Composition
| Grade | C | Mn | P | S | Si | Cr | Mo |
| A387 Gr.11 | 0.05-0.17 | 0.40-0.65 | 0.035 | 0.035 | 0.50-0.80 | 1.00-1.50 | 0.45-0.65 |
1 What is ASTM A387 Grade 11 Class 2 equivalent to?
ASTM A387 Grade 11 Class 2 is equivalent to ASME SA387 Grade 11 Class 2, the same material under ASME (American Society of Mechanical Engineers) rules, and is also similar to European standards like EN 10028 13CMoSi5-5, offering excellent corrosion resistance for pressure vessels and boilers at high temperatures with 1.25% Chromium and 0.50% Molybdenum.
2What is the difference between ASTM A387 Grade 11 Class 2 and ASME SA387 Grade 11 Class 2?
There is no difference in specification; ASTM A387 Grade 11 Class 2 and ASME SA387 Grade 11 Class 2 refer to the exact same chromium-molybdenum alloy steel plate for pressure vessels, with the "SA" prefix simply indicating ASME adoption of the ASTM standard, essentially making them interchangeable and covered by identical chemical and mechanical property requirements (like 75-100 ksi tensile strength for Class 2) for elevated-temperature service
3What is theASTM A387 Grade 11 Class 2 material properties?
ASTM A387 Grade 11 Class 2 is a chromium-molybdenum alloy steel for elevated temperature pressure vessels, featuring 1.0-1.5% Chromium and 0.45-0.65% Molybdenum for high-temp strength and oxidation resistance, with specific mechanical properties like 75-100 ksi tensile strength and a 43 ksi minimum yield strength, ideal for demanding applications in oil, gas, and chemical processing.
4What are the primary advantages of ASTM A387 Grade 11 Class 2?
ASTM A387 Grade 11 Class 2's main advantages are its excellent high-temperature strength, oxidation resistance, and corrosion resistance, thanks to its chromium-molybdenum (Cr-Mo) alloy, making it ideal for pressure vessels and boilers in hot, aggressive conditions like oil & gas and chemical processing, offering better mechanical strength than Class 1.
5What are common testing requirements for ASTM A387 Grade 11 Class 2?
ASTM A387 Grade 11 Class 2 requires essential mechanical tests like tensile strength (75-100 ksi), yield strength (min 43 ksi), and elongation (min 22% in 2"), plus chemical checks (Cr 1-1.5%, Mo 0.45-0.60%) and must meet heat treatment requirements, with additional testing like impact, hardness, or radiographic tests often done for pressure vessel use to ensure quality and performance at high temperatures.
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