Highly effective, ASTM A387 Grade 11 Class 2 is used in a variety of industries.
ASTM A387 A387 Grade 11 Class 2 Chrome Moly (Chromium Molybdenum) steel is alloyed with 1.25% Cr and 0.50% Mo. These special alloys together give the steel enhanced mechanical properties (tensile & yield) at high working temperatures, along with excellent corrosion and oxidation resistance.
ASTM A387 Grade 11 Class 2 is a chrome-moly alloy steel plate standard for elevated temperature service, featuring higher strength (75-100 ksi tensile) than Class 1, with 1.00-1.50% Chromium and 0.45-0.65% Molybdenum, used for pressure vessels in oil & gas, petrochemicals, and power plants. Its 'Class 2' designation signifies improved mechanical properties through specific heat treatment, making it suitable for high-stress, high-temperature applications.
Key Properties:
Composition: ASTM A387 Grade 11 Class 2 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)
Tensile Strength: Minimum of 415 MPa (60,000 psi)
Class 2: This classification indicates that the material has undergone additional heat treatment, enhancing its properties compared to Class 1, which may not have the same level of treatment. Class 2 is intended for applications requiring greater performance under higher stress and temperature conditions.
Applications:
ASTM A387 Grade 11 Class 2 is commonly used in:
-Pressure vessels in the oil and gas industry
-Boilers
-Heat exchangers
-Pipelines and other equipment operating at elevated temperatures
The higher content of chromium will provide excellent corrosion and oxidation resistance, so the material could be used for sour services, and to storage oil, gas, liquid for different industries.
Chromium & Molybdenum content (according to the ASTM specification):
| Designation | Nominal Chromium Content (%) | Nominal Molybdenum Content (%) |
|---|---|---|
| ASTM A387 Grade 11 Class 2 | 1.25% | 0.50% |
Tensile Requirements for Class 2 Plates
| Designation | Requirement | Grade 22 |
|---|---|---|
| ASTM A387 Grade 11 Class 2 | Tensile strength, ksi [MPA] | 75 to 100 [515 to 690] |
| Yield strength, min, ksi [MPa]/(0.2% offset) | 43 [310] | |
| Elongation in 8 in. [200 mm], min % | 18 | |
| Elongation in 2 in. [50 mm], min, % | 22 | |
| Reduction of area, min % |
Chemical Requirements
| C | Mn | P | S | Si | Cr | Mo | V |
|---|---|---|---|---|---|---|---|
| 0.05 – 0.17 | 0.40 – 0.65 | 0.025 | 0.025 | 0.05 – 0.80 | 1.00 – 1.50 | 0.45 – 0.65 | – |
1What is ASTM A387 Grade 11 Class 2 equivalent to?
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.
2What temperature is ASTM A387 Grade 11 Class 2?
ASTM A387 Grade 11 Class 2 is a chromium-molybdenum alloy steel for high-temperature pressure vessels, suitable for service in the 350°C to 480°C (660°F - 900°F) range, with specific maximum use temperatures depending on the ASME Code. It offers higher strength than Class 1 due to stricter heat treatment (normalized and tempered at a minimum 620°C/1150°F) and is used in reactors and heat exchangers.
3 What is the difference between ASTM A387 Grade 11 Class 2 and ASME SA387 Grade 11 Class 2
There is no difference in material properties, chemistry, or mechanical requirements between ASTM A387 Grade 11 Class 2 and ASME SA387 Grade 11 Class 2 because the ASME standard (SA387) incorporates the ASTM standard (A387) as its equivalent, meaning they specify the same chromium-molybdenum alloy steel for high-temperature pressure vessels, with Class 2 indicating higher tensile strength than Class 1. The 'A' in ASTM signifies 'American Society for Testing and Materials', while 'SA' in ASME signifies 'Soci(ety) of Mechanical Engineers' adopted standard, covering identical specifications.
4What is the hardness of ASTM A387 Grade 11 Class 2?
ASTM A387 Grade 11 Class 2 is typically supplied in a normalized and tempered condition, with its hardness specified through tensile strength, generally requiring a minimum tensile strength of 75-100 ksi (515-690 MPa) and minimum yield strength of 43 ksi (310 MPa), with Brinell hardness typically around 250 HBW, reflecting its higher strength compared to Class 1 due to stricter heat treatment.
5What temperature is ASTM A387 Grade 11 Class 2?
ASTM A387 Grade 11 Class 2 is a Cr-Mo alloy steel plate for high-temperature pressure vessels, designed for service in the medium-temperature range of approximately 350°C to 480°C (660°F to 900°F), offering excellent strength and creep resistance at elevated temperatures, with a minimum tempering temperature of 620°C (1150°F) during manufacturing for its higher strength.
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