What is the difference between A537 Class 1 and Class 2?

Difference between A537 Class 1 and Class 2:

Material Grade:

Both A537 Class 1 and Class 2 are grades of pressure vessel steel specified under ASTM A537/A537M Standard.

Composition:

The chemical composition requirements for both classes may be similar, with slight variations to meet specific mechanical properties. Typical elements include carbon, manganese, silicon, phosphorus, and sulfur.

Heat Treatment:

A537 Class 1 and Class 2 are typically supplied in the normalized condition, which involves heating the material to a specific temperature range followed by air cooling to achieve desired properties.

Mechanical Properties:

A537 Class 1:

Tensile Strength: 485-620 MPa (70-90 ksi)

Yield Strength: 345 MPa (50 ksi) minimum

Elongation: 22% min. in 200 mm | 25% min. in 50 mm

A537 Class 2:

Generally has higher tensile strength and yield strength compared to Class 1.

Specific mechanical properties for Class 2 would be detailed in the ASTM standard to meet the intended application requirements.

Applications:

A537 Class 1:

Typically used for welded pressure vessels where improved notch toughness is crucial, operating at moderate and lower temperatures.

A537 Class 2:

Often selected for applications requiring higher strength and impact resistance compared to Class 1.

Suitable for pressure vessel applications where elevated strength properties are necessary without compromising toughness.

Impact Testing:

Both Class 1 and Class 2 materials are subjected to Charpy V-notch impact testing at specified temperatures to evaluate their fracture toughness characteristics.

Weldability:

Both classes exhibit good weldability characteristics, allowing for ease of fabrication and welding during the manufacturing process of pressure vessels.

Certification:

Both materials are certified to meet the requirements of ASTM A537/A537M specifications and may be subject to additional testing and quality control measures as per industry standards.

Availability:

A537 Class 1 and Class 2 are available from steel suppliers and manufacturers who adhere to ASTM specifications and provide material certifications.

Consulting the specific ASTM A537/A537M standard and collaborating with material suppliers or manufacturers can provide detailed information on the differences between A537 Class 1 and Class 2, ensuring appropriate selection based on application-specific requirements for pressure vessel construction.