ASME SA387 Grade 11 Class 2 Steel Plate Specification

ASME SA387 Grade 11 Class 2 (SA387 Gr 11 Cl 2) is a quenched-and-tempered (Q&T) 1.25Cr-0.5Mo low-alloy steel plate specified by ASME SA-387/SA-387M (and ASTM A387/A387M) for high-temperature pressure vessels, heat exchangers, and petrochemical equipment. This specification defines the material's chemical composition, mechanical properties, heat treatment, and quality requirements-critical for ensuring safety and performance in elevated-temperature service (up to 593°C/1100°F).

As a leading supplier of industrial steel plates and tube shell heat exchangers, GNEE provides SA387 Gr 11 Cl 2 plates fully certified to ASME Section II and optimized for high-temperature, high-pressure applications.

GNEE supplies SA387 Gr 11 Cl 2 plates in custom sizes to match specific tube shell heat exchanger designs, with thicknesses up to 200mm for heavy-duty pressure vessel applications.

SA387 Gr 11 Class 2 must meet the following chemical limits per ASME SA-387/SA-387M:

SA387 Gr 11 Class 2 must achieve the following properties after quenching and tempering:

ASME SA387 Grade 11 Class 2 steel plates are widely used for:

Pressure vessel shells and heads

Shell & tube heat exchangers

Reactors and separators

Boilers and steam drums

Refinery and petrochemical process equipment

Hydrogenation units

These applications demand reliable mechanical strength under continuous high-temperature operation.

SA387 Gr 11 Class 2 must be furnished in the quenched and tempered (Q&T) condition-this differentiates it from Class 1 (normalized + tempered) and ensures higher strength and creep resistance:

• Quenching: Heat to 870–900°C (1600–1650°F), hold for sufficient time to ensure uniform heating, then quench in water or oil to achieve full martensitic transformation.
• Tempering: Reheat to 620–650°C (1150–1200°F), hold for 1–2 hours per 25mm thickness, then air-cool to relieve residual stresses and improve toughness.

SA387 Grade 11 Class 2 is commonly considered equivalent to:

ASTM A387 Grade 11 Class 2

EN 10028-2 13CrMo4-5 (1.7335)

DIN 13CrMo4-5

GB 713 12Cr1MoVR

JIS G3118 SCMV2

Material substitution should always be approved by the project engineer and governing code authority.

Understanding the ASME SA387 Grade 11 Class 2 steel plate specification is essential for safe and compliant pressure vessel design.
Let GNEE Steel be your reliable partner for high-quality Cr-Mo pressure vessel steel.

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What is SA 387 GR 11 specification?

Key Properties:
Composition: ASME SA387 Grade 11 typically contains about 1% chromium and 0.5% molybdenum. This composition provides good strength and resistance to oxidation at high temperatures. Mechanical Properties: Yield Strength: Minimum of 205 MPa (30,000 psi)

What is the P number of SA 387 GR 11?

The ASME SA-387/ ASTM A387 Gr. 11 steel has the nominal composition of 1.25Cr-0.5Mo-Si with UNS designation number of K11789 and P number of 4.

What is the temperature range for SA387 Grade 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.