ASTM A387 Grade 11 Class 2 is a chromium-molybdenum alloy steel plate specified by ASTM A387/A387M, designed for high-temperature, high-pressure pressure-bearing equipment, with excellent resistance to hydrogen corrosion, sulfide stress cracking and creep deformation.
Equivalents
| BS | EN | ASTM/ASME | DIN |
| 621 B | ––– | A387-11-2 | ––– |
Specifications for ASTM A387 Grade 11 Alloy Steel Plates
| 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 2 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 % | ––– |
Chemical Requirements for ASTM A387 Grade 11 Alloy Steel Plates
| Element | Chemical Composition (%) | |
| A387 Grade 11 | ||
| Carbon: | Heat Analysis: | 0.05 - 0.17 |
| Product Analysis: | 0.04 - 0.17 | |
| Manganese: | Heat Analysis: | 0.40 - 0.65 |
| Product Analysis: | 0.35 - 0.73 | |
| Phosphorus: | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Sulphur (max): | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Silicon: | Heat Analysis: | 0.50 - 0.80 |
| Product Analysis: | 0.44 - 0.86 | |
| Chromium: | Heat Analysis: | 1.00 - 1.50 |
| Product Analysis: | 0.94 - 1.56 | |
| Molybdenum: | Heat Analysis: | 0.45 - 0.65 |
| Product Analysis: | 0.45 - 0.70 |
Key Applications
Oil & Gas Industry: Refineries, petrochemical plants, sour gas services, and high-temperature piping that resists hydrogen sulfide corrosion, high pressure, and cyclic thermal stress in harsh, long-term operating environments.
Power Generation: Boiler drums, headers, and high-temperature steam piping in thermal and combined-cycle power plants, ensuring structural stability under extreme pressure and heat loads.
Chemical Processing: Equipment in facilities handling hot, corrosive liquids and gases, adapting to continuous high-temperature reaction conditions and aggressive chemical media.
Heat Exchangers & Boilers: Critical components requiring reliable resistance to heat and corrosion, suitable for heavy-duty thermal transfer systems across multiple industrial sectors.
Request a professional quotation for ASTM A387 Grade 11 Class 2 from GNEE Steel.
How do A387 Grade 11 CL 1 and CL 2 differ?
CL 2 undergoes quenching-tempering (or equivalent) heat treatment, with higher tensile strength (515-690 MPa) and yield strength (≥310 MPa); CL 1 is normalized, focusing on stability for conventional high-temperature scenarios.
What are the key mechanical properties of A387 Grade 11 CL 2?
Tensile strength: 515-690 MPa; Minimum yield strength: 310 MPa; Minimum elongation (50mm): 22%; Hardness: 163-235 HB; Impact energy (at -20°C): ≥60 J.
What heat treatment is required for A387 Grade 11 CL 2?
It is supplied after normalizing + tempering (or normalizing + rapid cooling + tempering), with a minimum tempering temperature of 620°C, to enhance its mechanical strength and toughness.