Difference for A387 Gr 11 and ASTM A516 Gr70 steel plate

When selecting steel plates for pressure vessels, boilers, and industrial equipment, material choice directly affects safety, service life, and project cost. Two of the most commonly specified materials are ASTM A387 Grade 11 and ASTM A516 Grade 70 steel plates. Although both are pressure vessel steels, they are designed for very different service conditions.

This article provides a clear and practical comparison of A387 Gr 11 vs A516 Gr 70, helping engineers, EPC contractors, and buyers make the right material decision. As a professional pressure vessel steel supplier, GNEE Steel offers both grades with stable quality and global export experience.

Typical chemical composition (wt.%):

The presence of chromium and molybdenum in A387 Gr 11 is the key reason it performs well in high-temperature and hydrogen-containing environments, where A516 Gr 70 is not recommended.

Both steels meet pressure vessel requirements, but their strength profiles differ.

ASTM A387 Grade 11 (Class 1 / Class 2)

Tensile Strength: 415–585 MPa

Yield Strength (min): 205 MPa

Supplied in normalized & tempered or normalized condition

ASTM A516 Grade 70

Tensile Strength: 485–620 MPa

Yield Strength (min): 260 MPa

Usually supplied in normalized or as-rolled condition

While A516 Gr 70 has higher yield strength at room temperature, A387 Gr 11 maintains strength stability at elevated temperatures, which is critical for boilers and high-temperature pressure vessels.

This is the most important distinction between the two materials.

A387 Grade 11 – High Temperature Service

Suitable for service temperatures up to ~540°C

Excellent creep resistance

Strong resistance to hydrogen attack

Commonly used in:

• Boilers and steam drums
• Refinery reactors
• Heat exchangers
• Petrochemical pressure vessels

A516 Grade 70 – Moderate Temperature Service

Recommended for low to medium temperature pressure vessels

Excellent notch toughness

Widely used in:

• Storage tanks
• LPG vessels
• Air receivers
• Low-temperature pressure vessels

Using A516 Gr 70 in high-temperature environments may result in creep deformation and reduced service life.

Both steel grades are widely used due to their good fabrication performance.

A516 Grade 70 has excellent weldability with minimal preheating, making it ideal for general fabrication.

A387 Grade 11 requires controlled welding procedures, including:

Preheating

Low-hydrogen consumables

Post Weld Heat Treatment (PWHT)

Although fabrication costs are higher for A387 Gr 11, this is justified by its performance in demanding service conditions.

Choose ASTM A387 Grade 11 if your project involves:

High operating temperature

High pressure

Hydrogen or corrosive environments

Long-term continuous operation

Choose ASTM A516 Grade 70 if your project involves:

Moderate temperature and pressure

Cost-sensitive applications

Storage or low-temperature pressure vessels

Although ASTM A387 Grade 11 and ASTM A516 Grade 70 are both pressure vessel steel plates, they serve distinctly different purposes. Understanding their differences in composition, temperature capability, and application is essential for safe and economical material selection.

📩 Contact GNEE Steel today for expert material advice, competitive pricing, and reliable supply for your pressure vessel and boiler steel plate requirements.

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What is the difference between SA 516 GR 70 and SA 387 GR 11?

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

What is the ASTM A387 Grade 11 equivalent to?

ASTM A387 grade 11 equivalent steel is ASME SA387 grade 11. ASTM A387 grade 11 covers A387 grade 11 class 1 and A387 grade 11 class 2, which are equivalent to ASME SA387 grade 11 class 1 and SA387 grade 11 class 2 respectively.

What is the material equivalent to ASTM A516 GR 70?

What is the equivalent material for A516 GR 70? Common equivalents include ASME SA516 GR 70, EN 10028 P355GH, and BS1501 224-490 A & B, suitable for similar pressure vessel applications.

What is the difference between A36 and A516 GR 70?

Elongation: A36 offers slightly better ductility (23% in 50mm), while A516 Gr 70 plate prioritizes strength over flexibility. Impact Resistance: a516 gr 70 impact test results show superior toughness at low temperatures, unlike A36, which is not typically tested for impact in structural applications.

What is the difference between SA 387 Grade 11 CL 1 and Class 2?

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.

GNEE Steel also supplies a variety of boilers and pressure vessel steel plates, such as A204 Grade B,A515 Grade 70,A537 Class 1,SA387 Grade 11 Class 1,P265GH,S537 Class 2,P355Q,P275N,P355N,P690Q,Q345R, etc. If you want to know more about other types of steel plates, you can call the consultation hotline at +8615824687445 or send an email to alloy@gneesteelgroup.com. You are welcome to consult us, and we are very willing to answer your questions.