ASTM A387 Grade 11 is a chromium-molybdenum alloy steel specifically designed for high-temperature pressure vessel applications.
Below are five key reasons to choose ASTM A387 Grade 11 steel for your high-temperature projects:
High-Temperature Strength

Yield Strength (ReH): ≥ 205 MPa (30,000 psi)
Tensile Strength (Rm): 415–585 MPa (60,000–85,000 psi)
Benefits:
Maintains structural integrity at elevated temperatures (up to 595°C or 1100°F).
Ideal for boilers, heat exchangers, and reactors operating under high thermal stress.
Excellent Creep Resistance
Creep Strength: High resistance to deformation under prolonged stress at high temperatures.
Benefits:
Extends the service life of pressure vessels in high-temperature environments.
Reduces the risk of failure due to creep-induced cracking.
Superior Weldability

Preheating: 150–200°C (300–400°F) for thicknesses ≥ 25 mm.
Welding Methods: Use low-hydrogen electrodes (e.g., AWS E8018-B2).
Benefits:
Minimizes the risk of weld cracking and hydrogen-induced cracking (HIC).
Simplifies fabrication and repair processes.
Corrosion and Oxidation Resistance
Chromium Content: 1.00–1.50%
Molybdenum Content: 0.45–0.65%
Benefits:
Resists oxidation and scaling at high temperatures.
Suitable for environments with moderate sulfur and hydrogen exposure.
Compliance with Industry Standards

Standards: ASTM A387/A387M, ASME Section VIII.
Certifications: EN 10204 3.1/3.2 mill certificates available.
Benefits:
Ensures compliance with global pressure vessel codes.
Facilitates international trade and project approvals.
Applications
Power Generation: Boilers, superheaters, and steam drums.
Oil & Gas: Reactors, separators, and heat exchangers.
Chemical Processing: Pressure vessels for high-temperature chemical reactions.
Case Study: ASTM A387 Grade 11 in Power Plant Boilers

Challenge: Reduce boiler weight while maintaining high-temperature performance.
Solution: Use ASTM A387 Grade 11 steel for boiler drums and headers.
Result: 20% weight reduction, enabling higher efficiency and lower fuel consumption.
If you want to learn more about GNEE's products, you can send an email to alloy@gneesteelgroup.com. We are more than happy to assist you.
FAQ
Q: What is A387 Grade 11 material?
A: The ASTM A387 specification is the Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum intended primarily for use in welded boilers and pressure vessels designed for elevated temperature service.
Q: What is SA 387 GR 11 Cl 1 equivalent material?
A: Sa 387 Gr 11 Equivalent Material
With similar chromium, molybdenum, and chemical content the, Sa 387 Gr 11 Cl 1 Equivalent Material of the BS 621B exhibits identical properties.
Q: What temperature is SA 387 GR 11?
A: 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.
Q: What is the difference between SA 387 GR 11 cl1 and cl2?
A: The difference between SA 387 Grade 11 Class 1 and Class 2 Plate lies in their mechanical properties. However, they both have the same chemical composition. The tensile strength and yield strength of class 2 material is higher than that of class 1, whereas the elongation for class 1 is higher compared to class 2.
Q: What is SA 387 Grade 11 material?
A: Composition: ASME SA387 Grade 11 typically contains about 1% chromium and 0.5% molybdenum. This composition provides good strength and resistance to oxidation at high temperatures. Mechanical Properties: Yield Strength: Minimum of 205 MPa (30,000 psi)
Q: What is the difference between SA 387 Grade 11 CL 1 and Class 2?
A: The Chemical Composition remains the same in both Class 1 and Class 2 (Cl1 and Cl2) but the only Difference is in the Mechanical Properties which is mentioned in below Table.
Q: What is SA 387 Grade 11 Class 2 equivalent to?
A: Sa 387 Gr 11 Equivalent Material is the ASME SA387 in the US markets with the European Union having modules in 13CrMoSi5-5 grade. The Sa 387 Gr 11 Cl 2 Equivalent Material is the SA387-11-2 of the ASME and ASTM standard.
Q: What temperature is SA 387 GR 11?
A: 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.
Q: What is the chemical composition of ASTM A387 Grade 11 Class 2?
A: ASTM A387 GR 11 CL 2 Plates is designed with the composition of chemicals such as carbon, silicon, phosphorous, chromium, sulfur, molybdenum, and manganese. Alloy ASTM A387 is made with specifications such as different standards, finishing, hardness, form, width, and thickness.
Q: What is the difference between SA 516 GR 70 and SA 387 GR 11?
A: Compared to carbon steel plates, SA 387 Gr 11 plates offer superior corrosion and oxidation resistance while maintaining good tensile and yield strength. Compared to SA 516 Gr 70 plates, SA 387 Gr 11 plates have better resistance to oxidation and corrosion, making them a better choice for high-temperature environments.
| Grades Of Pressure Vessel Plates Supplied By GNEE | |||||
| ASTM | ASTM A202/A202M | ASTM A202 Grade A | ASTM A202 Grade B | ||
| ASTM A203/A203M | ASTM A203 Grade A | ASTM A203 Grade B | ASTM A203 Grade D | ASTM A203 Grade E | |
| ASTM A203 Grade F | |||||
| ASTM A204/A204M | ASTM A204 Grade A | ASTM A204 Grade B | ASTM A204 Grade C | ||
| ASTM A285/A285M | ASTM A285 Grade A | ASTM A285 Grade B | ASTM A285 Grade C | ||
| ASTM A299/A299M | ASTM A299 Grade A | ASTM A299 Grade B | |||
| ASTM A302/A302M | ASTM A302 Grade A | ASTM A302 Grade B | ASTM A302 Grade C | ASTM A302 Grade D | |
| ASTM A387/A387M | ASTM A387 Grade 5 Class1 | ASTM A387 Grade 5 Class2 | ASTM A387 Grade 11 Class1 | ASTM A387 Grade 11 Class2 | |
| ASTM A387 Grade 12 Class1 | ASTM A387 Grade 12 Class2 | ASTM A387 Grade 22 Class1 | ASTM A387 Grade 22 Class2 | ||
| ASTM A515/A515M | ASTM A515 Grade 60 | ASTM A515 Grade 65 | ASTM A515 Grade 70 | ||
| ASTM A516/A516M | ASTM A516 Grade 55 | ASTM A516 Grade 60 | ASTM A516 Grade 65 | ASTM A516 Grade 70 | |
| ASTM A517/A517M | ASTM A517 Grade A | ASTM A517 Grade B | ASTM A517 Grade E | ASTM A517 Grade F | |
| ASTM A517 Grade P | ASTM A517 Grade J | ||||
| ASTM A533/A533M | ASTM A533 Grade A Class1 | ASTM A533 Grade B Class1 | ASTM A533 Grade C Class1 | ASTM A533 Grade D Class1 | |
| ASTM A533 Grade A Class2 | ASTM A533 Grade B Class2 | ASTM A533 Grade C Class2 | ASTM A533 Grade D Class2 | ||
| ASTM A533 Grade A Class3 | ASTM A533 Grade B Class3 | ASTM A533 Grade C Class3 | ASTM A533 Grade D Class3 | ||
| ASTM A537/A537M | ASTM A537 Class1 | ASTM A537 Class2 | ASTM A537 Class3 | ||
| ASTM A612/A612M | ASTM A612 | ||||
| ASTM A662/A662M | ASTM A662 Grade A | ASTM A662 Grade B | ASTM A662 Grade C | ||
| EN | EN10028-2 | EN10028-2 P235GH | EN10028-2 P265GH | EN10028-2 P295GH | EN10028-2 P355GH |
| EN10028-2 16MO3 | |||||
| EN10028-3 | EN10028-3 P275N | EN10028-3 P275NH | EN10028-3 P275NL1 | EN10028-3 P275NL2 | |
| EN10028-3 P355N | EN10028-3 P355NH | EN10028-3 P355NL1 | EN10028-3 P355NL2 | ||
| EN10028-3 P460N | EN10028-3 P460NH | EN10028-3 P460NL1 | EN10028-3 P460NL2 | ||
| EN10028-5 | EN10028-5 P355M | EN10028-5 P355ML1 | EN10028-5 P355ML2 | EN10028-5 P420M | |
| EN10028-5 P420ML1 | EN10028-5 P420ML2 | EN10028-5 P460M | EN10028-5 P460ML1 | ||
| EN10028-5 P460ML2 | |||||
| EN10028-6 | EN10028-6 P355Q | EN10028-6 P460Q | EN10028-6 P500Q | EN10028-6 P690Q | |
| EN10028-6 P355QH | EN10028-6 P460QH | EN10028-6 P500QH | EN10028-6 P690QH | ||
| EN10028-6 P355QL1 | EN10028-6 P460QL1 | EN10028-6 P500QL1 | EN10028-6 P690QL1 | ||
| EN10028-6 P355QL2 | EN10028-6 P460QL2 | EN10028-6 P500QL2 | EN10028-6 P690QL2 | ||
| JIS | JIS G3115 | JIS G3115 SPV235 | JIS G3115 SPV315 | JIS G3115 SPV355 | JIS G3115 SPV410 |
| JIS G3115 SPV450 | JIS G3115 SPV490 | ||||
| JIS G3103 | JIS G3103 SB410 | JIS G3103 SB450 | JIS G3103 SB480 | JIS G3103 SB450M | |
| JIS G3103 SB480M | |||||
| GB | GB713 | GB713 Q245R | GB713 Q345R | GB713 Q370R | GB713 12Cr1MoVR |
| GB713 12Cr2Mo1R | GB713 13MnNiMoR | GB713 14Cr1MoR | GB713 15CrMoR | ||
| GB713 18MnMoNbR | |||||
| GB3531 | GB3531 09MnNiDR | GB3531 15MnNiDR | GB3531 16MnDR | ||
| DIN | DIN 17155 | DIN 17155 HI | DIN 17155 HII | DIN 17155 10CrMo910 | DIN 17155 13CrMo44 |
| DIN 17155 15Mo3 | DIN 17155 17Mn4 | DIN 17155 19Mn6 | |||



