What is ASTM A387 GR 22 Class 2?

ASTM A387 GR 22 Class 2 refers to a specific grade of alloy steel plate used for elevated temperature service. It is part of the ASTM A387 specification, which covers chromium-molybdenum alloy steel plates for pressure vessels.

The key characteristics and specifications of ASTM A387 GR 22 Class 2 are as follows:

Chemical Composition (in weight percentage):

Carbon (C): ≤0.05%

Manganese (Mn): 0.30-0.60%

Phosphorus (P): ≤0.045%

Sulfur (S): ≤0.045%

Silicon (Si): 0.50-0.80%

Chromium (Cr): 2.00-2.50%

Molybdenum (Mo): 0.90-1.10%

Vanadium (V): 0.05-0.15%

Nickel (Ni): ≤0.50%

Mechanical Properties:

Tensile Strength: 75-100 ksi (thousands of pounds per square inch) or 515-690 MPa

Yield Strength: 45-85 ksi or 310-585 MPa

Elongation: 18% minimum in 8 inches and 22% minimum in 2 inches

Heat Treatment:

The material typically undergoes normalization and tempering processes to achieve desired mechanical properties.

Applications:

ASTM A387 GR 22 Class 2 is commonly used for applications in the petroleum, chemical, power generation, and other industries where elevated temperature resistance and high strength are required. It is particularly suitable for pressure vessel components operating at elevated temperatures.

Additional Testing and Requirements:

The material may undergo various tests such as tension test, Charpy impact test, ultrasonic examination, and notch toughness testing to ensure compliance with specified standards.

ASTM A387 GR 22 Class 2 is just one specific grade within the ASTM A387 specification, which includes multiple grades differentiated by their chemical composition and mechanical properties. Each grade is designed for specific applications and temperature ranges.