ASTM A516 Gr 70 vs A36: Key Differences Explained

As a leading manufacturer and exporter of pressure vessel and boiler steel plates, Gangsteel provides high-quality ASTM A516 GR 70 and other steel grades for industries such as oil and gas, petrochemical, and power generation.

When selecting materials for structural or pressure vessel applications, understanding the differences between ASTM A516 GR 70 and ASTM A36 is critical for engineers and fabricators. This article compares their chemical composition, mechanical properties, and applications to guide informed material selection.

Chemical Composition Comparison

The chemical composition of ASTM A516 GR 70 and ASTM A36 significantly impacts their performance. ASTM A516 GR 70 is a carbon steel designed for pressure vessels, while A36 is a structural steel for general applications. The table below outlines their chemical compositions:

Key Differences:

• Carbon: Both have similar carbon content, but ASTM A516 GR 70 is tightly controlled for weldability in pressure vessel applications.
• Manganese: A516 GR 70’s higher manganese range (0.85–1.20%) enhances toughness, while A36’s manganese varies by plate thickness.
• Phosphorus and Sulfur: A516 GR 70 has stricter limits, improving notch toughness for low-temperature service.
• Aluminum: A516 GR 70 is fully killed, ensuring better uniformity and toughness compared to A36, which may not be fully killed.

Gangsteel ensures ASTM A516 GR 70 meets ASME SA516 GR 70 standards, with rigorous testing for chemical consistency.

Mechanical Properties Comparison

The mechanical properties of ASTM A516 GR 70 and A36 determine their suitability for specific applications. A516 GR 70 is optimized for pressure vessels, while A36 is used for structural components. The table below compares their key mechanical properties:

Key Differences:

• Tensile Strength: ASTM A516 GR 70 offers higher tensile strength (485–620 MPa) than A36 (400–550 MPa), making it better for high-pressure applications.
• Yield Strength: A516 GR 70’s higher yield strength (260 MPa vs. 250 MPa) ensures greater structural integrity under pressure.
• Impact Toughness: A516 GR 70 is tested for low-temperature performance (-46°C), while A36 is not typically evaluated for impact toughness, limiting its use in cryogenic conditions.
• Ductility: A36 has slightly higher elongation, suitable for structural forming, but A516 GR 70’s ductility is sufficient for pressure vessel fabrication.

Applications

• ASTM A516 GR 70: Designed for pressure vessels and boilers, it excels in:
  • Oil and gas processing (e.g., LNG storage tanks).
  • Petrochemical reactors requiring high strength and low-temperature toughness.
  • Power generation boilers, meeting ASME SA516 GR 70 standards.
• ASTM A36: Used for general structural applications, such as:
  • Buildings, bridges, and infrastructure.
  • Non-pressure components like base plates and structural beams.
  • Applications where low cost and moderate strength are priorities.

A516 GR 70’s superior strength and toughness make it unsuitable for general structural use where A36’s cost-effectiveness is preferred. Conversely, A36 lacks the toughness and certification for pressure vessel applications.

Weldability

• ASTM A516 GR 70: Fully killed and often normalized, it offers excellent weldability using SMAW, GTAW, and SAW processes. Its low carbon and sulfur content minimize weld imperfections, ideal for pressure vessel fabrication.
• ASTM A36: Weldable with standard processes, but its higher sulfur content and non-killed nature may require additional precautions to avoid porosity or cracking.

Gangsteel’s ASTM A516 GR 70 plates are supplied in normalized conditions to enhance weldability and toughness.

Comparison with Other A516 Grades

For context, ASTM A516 GR 70 can be compared to other grades in the A516 family:

For equivalent standards, such as EN P355GH, refer to Gangsteel’s ASME SA516 GR 70 Equivalent Grade guide.

Why Choose Gangsteel?

Gangsteel specializes in ASTM A516 GR 70 and ASME SA516 GR 70 plates, offering:

• Certified Quality: Plates undergo ultrasonic testing, Charpy impact tests, and chemical analysis to meet ASTM/ASME standards.
• Customization: Available in hot-rolled, normalized, or clad forms for specific project needs.
• Global Supply: Competitive pricing and reliable delivery worldwide.
• Technical Support: Expert guidance on selecting ASTM A516 GR 70 versus ASTM A516 GR 65, ASTM A516 GR 60, or ASTM A516 GR 55.

Gangsteel Solution

ASTM A516 GR 70 outperforms ASTM A36 in tensile strength, low-temperature toughness, and pressure vessel applications, while A36 is better suited for general structural uses. Gangsteel’s ASME SA516 GR 70 plates are engineered for reliability, meeting stringent standards for demanding industries. For more on equivalent grades, explore our ASME SA516 GR 70 Equivalent Grade guide.