SA387 Grade 12 Class 2 is a chromium-molybdenum (chrome-moly) alloy steel plate used in high-temperature applications, particularly for weldable pressure vessels and industrial boilers. It is known for its corrosion and oxidation resistance, making it suitable for sour service in the oil and gas industries. The "Class 2" designation indicates it has higher mechanical properties, specifically higher tensile and yield strength compared to Class 1 material.
Specifications for ASME SA387 Grade 12 Alloy Steel Plates
Chromium & Molybdenum content (according to the ASME specification)
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
| SA387 Grade 12 | 1.00% | 0.50% |
Tensile Requirements for ASME SA387 Grade 12 Alloy Steel Plates Class 2 Plates
| Designation: | Requirement: | Grade 12 |
| SA387 Grade 12 | Tensile strength, ksi [MPA] | 65 to 85 [450 to 585] |
| Yield strength, min, ksi [MPa]/(0.2% offset) | 40 [275] | |
| Elongation in 8 in. [200mm], min % | 19 | |
| Elongation in 2 in. [50mm], min, % | 22 | |
| Reduction of area, min % | ––– |
Chemical Requirements for ASME SA387 Grade 12 Alloy Steel Plates
| Element | Chemical Composition (%) | |
| ASME SA387 Grade 12 | ||
| 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: | 0.15 - 0.40 |
| Product Analysis: | 0.13 - 0.45 | |
| Chromium: | Heat Analysis: | 0.80 - 1.15 |
| Product Analysis: | 0.74 - 1.21 | |
| Molybdenum: | Heat Analysis: | 0.45 - 0.60 |
| Product Analysis: | 0.40 - 0.65 |
