What is SA387 Grade 12 Class 1?
SA387 Grade 12 Class 1 Chromium-Molybdenum (Cr-Mo) alloy steel plate, standardized by ASME/ASTM, designed for weldable pressure vessels and boilers operating at elevated temperatures, offering good strength, toughness, and improved corrosion resistance due to its chromium content, suitable for demanding oil & gas, petrochemical, and power generation applications.
Equivalents of SA387 Grade 12 Class 1
| BS | EN | ASTM/ASME | DIN |
| 620 B | 13 CRMO 45 | SA387-12-1 | 13 CRMO 44 |
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 1 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 |
What is SA387 Grade 12 Class 1?
SA387 Grade 12 Class 1 is a chromium-molybdenum alloy steel plate specification, part of the ASME Boiler and Pressure Vessel Code, designed for service in welded pressure vessels operating at moderate to high temperatures.
What is the chemical composition of SA387 Gr 12 Cl 1?
Its typical composition includes Chromium (0.80-1.25%) and Molybdenum (0.44-0.65%), along with controlled amounts of Carbon, Manganese, Silicon, Phosphorus, and Sulfur.
What are the mechanical properties of SA387 Grade 12 Class 1?
Key mechanical properties include a minimum tensile strength of 415 MPa (60 ksi) and a minimum yield strength of 220 MPa (32 ksi), with elongation requirements that vary by plate thickness.
Is SA387 Grade 12 Class 1 equivalent to ASTM A387 Gr12?
Essentially, yes. SA387 is the ASME designation, which is generally identical to the ASTM A387 Gr12 specification. The "SA" prefix indicates its adoption by ASME for code construction.
What is the difference between Class 1 and Class 2 for SA387 Grade 12?
The main difference is the mandatory heat treatment for Class 2. SA387 Grade 12 Class 2 must be supplied in the normalized and tempered condition, while Class 1 can be supplied as-rolled, annealed, or normalized and tempered.
What is the temperature limit for SA387 Grade 12 steel?
It is suitable for service temperatures up to approximately 800°F (427°C), making it a common choice for hydrogen service and other elevated temperature applications in refineries.
How do you weld SA387 Grade 12 Class 1 plate?
Welding requires proper procedures, including preheating (typically 250-400°F / 121-204°C) and post-weld heat treatment (PWHT) for most applications. Common filler metals include E8016-B2 or ER80S-B2.
Where is SA387 Grade 12 Class 1 typically used?
It is widely used in the fabrication of pressure vessels, reactors, and heat exchangers for the oil & gas, petrochemical, and power generation industries.
Is SA387 Grade 12 Class 1 a creep strength enhanced ferritic (CSEF) steel?
No, it is not. SA387 Gr12 is a traditional 1Cr-0.5Mo alloy. CSEF steels like Grades 91, 92, and 122 have different compositions and significantly higher temperature strength.
What is the hardness of SA387 Grade 12 Class 1?
Hardness is not explicitly specified in the standard, but it is controlled by the chemistry and mechanical properties. In service, hardness is often limited to a maximum (e.g., 200 HB Brinell) to resist hydrogen-induced cracking (HIC) or sulfide stress cracking (SSC).
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
