The difference between Class 1 and Class 2 SA-387

SA-387 alloy steel plates are widely used in pressure vessels, boilers, heat exchangers, and reactors operating at elevated temperatures.

As a professional pressure vessel steel plate supplier, GNEE Steel often receives a key technical question from EPC contractors and equipment manufacturers:

What is the difference between Class 1 and Class 2 SA-387?

The main difference between SA387 Class 1 and Class 2 steel plates lies in their mechanical properties, specifically tensile and yield strength, with Class 2 offering higher strength (and sometimes lower elongation) due to potentially different heat treatments or processing, while chemical composition remains nearly identical across grades like Grade 11 or 22, making Class 2 suitable for higher-stress, higher-temperature applications.

This article provides a clear, practical explanation from a pressure vessel and alloy steel expert perspective, helping buyers select the correct SA-387 class for their applications while meeting ASME code requirements.

The primary difference between Class 1 and Class 2 SA-387 lies in:

✅ Heat treatment condition
✅ Mechanical strength requirements
✅ Design pressure and temperature capability

Key Definition:

Class 1 → Supplied in the As-Rolled or Normalized condition

Class 2 → Supplied in the Normalized and Tempered (N+T) condition

This difference significantly affects strength, toughness, and allowable stress values under ASME design codes.

🔹 SA-387 Class 1

As-rolled or normalized

Lower tensile and yield strength

Simpler production process

Suitable for moderate pressure and temperature

🔹 SA-387 Class 2

Normalized + tempered

Improved grain structure

Higher yield and tensile strength

Better toughness and creep resistance

Preferred for critical pressure vessel service

Selecting between SA-387 Class 1 and Class 2 depends on your equipment's operating conditions and performance requirements:

When to Use SA-387 Class 1:

Moderate temperature (≤593°C) and pressure applications.

General-purpose heat exchangers, low-stress vessels, and piping systems.

Cost-sensitive projects where high alloy content is not necessary.

 

When to Use SA-387 Class 2:

High-temperature (up to 649°C) and high-pressure critical equipment.

Heavy-duty tube shell heat exchangers, petrochemical reactors, and steam generators.

Environments prone to corrosion or creep, such as sour gas processing plants.

At GNEE, we supply ASTM A387-certified Class 1 and Class 2 steel plates tailored to the needs of industrial equipment manufacturers-especially for tube shell heat exchangers, which are our core product line.

Our SA-387 plates offer:

• Strict compliance with ASTM A387/A387M standards, ensuring consistent alloy composition and mechanical properties.
• Customizable thicknesses (6mm–200mm) and widths to fit your equipment design.
• Quality control through non-destructive testing (NDT), including ultrasonic inspection, to eliminate defects.

Seamless integration with GNEE's tube shell heat exchangers, providing a one-stop solution for your industrial project.

Whether you need SA-387 Class 1 for general-purpose heat exchangers or Class 2 for high-temperature critical equipment, GNEE's team of experts can help you select the right grade and provide technical support to ensure optimal performance.

Choosing the correct SA-387 Class 1 or Class 2 is critical to the safety and efficiency of your pressure vessel project.

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What is SA 387 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.

What is SA 387 material?

The ASME SA387 standard covers the supply of weldable chrome molybdenum alloy steel plates for pressure vessels used in elevated temperature service. The added molybdenum and chromium provides excellent corrosion resistance and high temperature resistance respectively.

What is SA 387 equivalent to?

What is SA 387 equivalent material? The Equivalent materials of Sa 387 Gr 12 are BS 620B, UNS K11757, A387 / SA 387, DIN 13 CRMO 44, and EN 3 CRMO 45.

What temperature is SA 387 GR 11?

In the lower end of the temperature range SA 387 Gr 11 (1150 °F min tempering temperature) , and SA 387 Gr 22 (1250 °F min tempering temperature) are used. These grades can be specified in either class 1 or 2 and can also be provided in the Normalized & Tempered or Quenched and Tempered.

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.