A387 Vs P355GH: Petrochemical Steel Selection Guide

Selecting the right steel plate is critical for the safety, efficiency, and service life of petrochemical pressure vessels and boilers. Two commonly specified materials in global projects are ASTM/ASME A387 chromium-molybdenum alloy steel and EN P355GH pressure vessel steel. While both are designed for pressure applications, they differ significantly in alloy design, temperature capability, and typical service environments.

This guide provides a professional comparison of A387 vs P355GH, helping engineers, EPC contractors, and buyers choose the most suitable steel for petrochemical projects. As a reliable pressure vessel steel supplier, GNEE Steel offers both materials with full certification and international delivery capability.

Chemical Composition Comparison

Typical chemical composition (wt.%):

Mechanical Properties

A387 Cr-Mo Alloy Steel

Tensile Strength: 415 – 690 MPa (grade dependent)

Yield Strength (min): 205 – 310 MPa

Excellent creep resistance at elevated temperatures

P355GH

Tensile Strength: 490 – 630 MPa

Yield Strength (min): 355 MPa

Excellent toughness at moderate temperatures

While P355GH offers higher yield strength at room temperature, A387 maintains mechanical stability at higher operating temperatures, which is essential for petrochemical processing equipment.

High-Temperature and Service Performance

A387 – Designed for Severe Petrochemical Service

Suitable for high-temperature and high-pressure environments

Excellent resistance to creep, oxidation, and hydrogen attack

Ideal for long-term continuous operation

P355GH – Moderate Temperature Pressure Service

Designed for elevated but limited temperature ranges

Good weldability and fabrication performance

Not recommended for severe hydrogen or very high-temperature environments

In petrochemical units where temperature and pressure fluctuate frequently, A387 provides higher safety margins.

Typical Applications

A387 Applications

Petrochemical reactors

Hydrogenation vessels

Refinery pressure vessels

High-temperature heat exchangers

Boilers and steam drums

P355GH Applications

Storage vessels

Steam boilers

Heat exchangers

Pressure tanks under EN standards

The application environment is the key factor when choosing between these two steels.

How to Choose the Right Steel

Choose A387 if:

Operating temperature is high

Equipment is exposed to hydrogen or corrosive media

Long-term reliability is critical

Project follows ASTM / ASME standards

Choose P355GH if:

Operating temperature is moderate

Cost efficiency is a priority

Project follows EN standards

Why Choose GNEE Steel

GNEE Steel supplies both A387 Cr-Mo alloy steel and P355GH pressure vessel steel with:

Full compliance with ASTM, ASME, and EN standards

• Thickness range from 6mm to 150mm
• EN 10204 3.1 / 3.2 certification
• Third-party inspection support (SGS, BV, TUV)
• Technical consultation for material selection

Conclusion

While both A387 and P355GH are widely used in pressure vessel applications, they serve different petrochemical operating conditions. Understanding their differences ensures safer design, longer service life, and optimized project cost.

📩 Contact GNEE Steel today for expert guidance, competitive pricing, and reliable supply of pressure vessel steel plates for your petrochemical projects.

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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 P355 material grade?

P355 grade steel is a high quality structural material with excellent mechanical properties. P355 steel is mild, fine grain structural steel that is often used in pressure vessels and boilers. Its high strength and corrosion resistance make it the ideal choice for use in demanding industrial applications.

What is P355GH material equivalent to?

P355GH pressure vessel steel is an equivalent to ASTM A516 Grade 70 and ASME SA516 Grade 70.

What is the ASTM A387 equivalent to?

Among the ASTM A387 Grade 22 equivalent steel grades, SA387 Grade 22, 10CrMo9-10 is more popular than other equivalents. SA387 Grade 22 steel is under ASME SA387/ SA387M standard. The chemical performance and technical requirements of SA387 Grade 22 steel is almost same with ASTM A387 Grade 22 steel.

What is P235GH pipe equivalent ASTM material?

Equivalent Astm Material is A285 Grade C. What is P235GH Plate ? The P235GH Plate material is a European specified steel, which are mainly used in heat exchangers, boilers, and pressure vessels.

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.