SA387 Grade 11 Class 1 is a chromium-molybdenum (Cr-Mo) alloy steel plate for high-temperature pressure vessels and boilers, offering excellent high-temperature strength, oxidation, and corrosion resistance, especially in sour gas (H2S) environments, due to its ~1.25% Cr and ~0.5% Mo content, with specific tensile properties like 75-100 ksi tensile strength.
Equivalents
| BS | EN | ASTM/ASME | DIN |
| 621 B | ––– | SA387-11-1 | ––– |
Specifications for ASME SA387 Grade 11 Alloy Steel Plates
Chromium & Molybdenum content (according to the ASME specification)
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
| SA387 Grade 11 | 1.25% | 0.50% |
Tensile Requirements for ASME SA387 Grade 11 Alloy Steel Plates Class 1 Plates
| Designation: | Requirement: | Grade 11 |
| SA387 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 ASME SA387 Grade 11 Alloy Steel Plates
| Element | Chemical Composition (%) | |
| SA387 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 |
Applications
Oil & Gas Industry: Used for equipment in oil refineries, gas processing plants, and storage tanks handling hot liquids and gases.
Petrochemical Facilities: Ideal for heat exchangers and pressure vessels in chemical processing where high temperatures are common.
Power Generation: Utilized in boilers and other thermal equipment requiring long-term structural integrity at elevated temperatures.
Sour Service Environments: Its chromium content offers excellent resistance to corrosion and hydrogen attack, making it suitable for "sour" (hydrogen sulfide-containing) gas applications.
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1.What temperature is SA 387 GR 11?
In the lower end of the temperature range SA 387 Gr 11 (1150 °F min tempering temperature) , and SA 387 Gr 22 (1250 °F min tempering temperature) are used. These grades can be specified in either class 1 or 2 and can also be provided in the Normalized & Tempered or Quenched and Tempered.
2.What is the temperature range of SA387 GRADE 11 class1 ?
SA387 Grade 11 Class 1 steel is designed for elevated temperatures, with typical service temperatures ranging from low-temperature toughness (often impact tested to -52°C or lower) up to potentially several hundred degrees Celsius, but its key high-temperature application range is limited by allowable stresses, with common use up to around 375°C (700°F) for pressure vessel design, though it offers resistance to oxidation at higher temperatures. It's used in power plants, refineries, and chemical plants for high-temperature service, requiring specific heat treatments like normalizing and tempering.