ASTM A387 Gr.11 Plate Specifications

ASTM A387 / ASME SA-387 Grade 11 plates are supplied in hot-rolled, normalised and tempered condition. The table below covers key specification details for procurement.

Parameter Details
Standard ASTM A387 / ASME SA-387
Form Hot Rolled Plate
Thickness 5 mm – 150 mm (0.20 in – 5.90 in)
Width Up to 4,500 mm (177 in)
Length Up to 18,000 mm (708 in)
Surface Finish Hot Rolled, Descaled
Heat Treatment Normalised and Tempered / Annealed
Testing UT per ASTM A435/A577/A578 available on request

Available Sizes of ASTM A387 Grade 11 Plates

Standard sizes of ASTM A387 Gr.11 plates are available. You can request CNC, plasma, or profile-cut custom sizes.

Dimension Range
Thickness 5 mm – 150 mm (0.20 in – 5.90 in)
Width 500 mm – 4,500 mm (20 in – 177 in)
Length 3,000 mm – 18,000 mm (118 in – 708 in)

For plates outside these ranges or specific cut-to-size requirements, contact our sales team with your project drawings.

ASTM A387 Gr.11 Plates Price

The starting price in India is approximately ₹105/kg, which equates to USD $0.80–$1.20 per kg on a global scale. Thickness, class, and testing requirements drive ASTM A387 Grade 11 alloy steel plate prices. The final costs are contingent upon market conditions, ultrasonic testing, and thermal treatment. The total quote we provide is also influenced by the specific class (1 or 2) and the quantity of your order.

Chemical Composition of ASTM A387 Grade 11 Plates

The table below lists the full heat analysis composition per the ASTM A387 standard. ASTM A387 / ASME SA-387 Grade 11 plates contain 1.00–1.50% chromium and 0.45–0.65% molybdenum, with carbon limited to 0.05–0.17%.

This 1.25Cr-0.5Mo composition gives the alloy its resistance to high-temperature oxidation and hydrogen attack. Low carbon content also supports weldability, which is critical for pressure vessel fabrication.

Carbon C
0.05 – 0.17%
Manganese Mn
0.40 – 0.65%
Phosphorus P
Max 0.035%
Sulphur S
Max 0.035%
Silicon Si
0.50 – 0.80%
Chromium Cr
1.00 – 1.50%
Molybdenum Mo
0.45 – 0.65%

Mechanical Properties of ASTM A387 Gr.11 Plates

To assist you in determining the best pressure rating and strength for your project, the mechanical performance of Class 1 and Class 2 plates is presented.

Class 1 plates are ideal for moderate design pressures, offering reliable ductility. Class 2 plates provide significantly higher tensile and yield strengths through normalisation and tempering, delivering the superior creep resistance required for prolonged, high-load, elevated-temperature service.

Class 1 Value

415–585
MPa
Tensile Strength
240
MPa
Yield Strength (min)
22
%
Elongation in 50 mm (min)
19
%
Elongation in 200 mm (min)

Class 2 Value

515–690
MPa
Tensile Strength
310
MPa
Yield Strength (min)
22
%
Elongation in 50 mm (min)
18
%
Elongation in 200 mm (min)
Property Class 1 Value Class 2 Value
Tensile Strength 415 – 585 MPa 515 – 690 MPa
Yield Strength (min) 240 MPa 310 MPa
Elongation in 50 mm (min) 22% 22%
Elongation in 200 mm (min) 19% 18%
Heat Treatment Standard Normalized & Tempered
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Equivalent Grades for ASTM A387 Grade 11 Plates

Equivalent grades with similar Cr-Mo composition include the following table, which helps buyers cross-reference specifications across different standards systems.

Standard Designation
UNS K11789
EN 10028-2 13CrMo4-5
DIN W.Nr. 1.7335
JIS G4109 SCMV 2
BS 621 B
GB 713 15CrMoG

ASTM A387 Gr.11 Plates Industrial Applications

ASTM A387 Grade 11 chrome moly plates support oil refining, power generation, and chemical processing. They deliver vital elevated-temperature strength, creep resistance, and oxidation resistance. These industries trust our high-performance plates to maintain structural integrity during the most demanding and volatile thermal operations.

Oil Refining & Petrochemical

Refineries use 1.25Cr-0.5Mo plates for reactor vessels and hydroprocessing units. The plates support catalytic cracking equipment and high-temperature pipe headers during heavy daily operations.

Power Generation

Thermal plants rely on ASTM A387 Gr.11 plates for boilers. They stay strong under high pressure and extreme heat.

Chemical Processing

Chemical plants use A387 Grade 11 for distillation and storage. It prevents cracking and oxidation during long-term chemical reactions.

ASTM A387 Gr.11 vs SA 516 Gr 70

SA 516 Gr 70 is a carbon steel plate for moderate-temperature pressure vessels. ASTM A387 Gr.11 is a chromium-molybdenum alloy steel plate for elevated-temperature service above 400°C (752°F). The table below summarises the key differences.

Parameter SA 516 Gr 70 ASTM A387 Gr.11 (Class 2)
Type Carbon Steel Cr-Mo Alloy Steel (1.25Cr-0.5Mo)
Tensile Strength 485 – 620 MPa 515 – 690 MPa
Max Service Temp ~400°C (750°F) ~550°C (1,022°F)
Creep Resistance Limited above 400°C Strong up to 550°C
Cost (relative) Lower Higher (alloy surcharge)

When the service environment contains hydrogen or sulphur compounds or when the design temperature exceeds 400°C, select ASTM A387 Gr.11. SA 516 Gr 70 is the more cost-effective alternative for vessels that operate below this threshold.

Shipping & Packaging

Main export packaging setup Heavy-duty wooden boxes Packing
Export Packaging Standard

We strictly follow seaworthy export handling standards to protect ASTM A387 Gr.11 Plates from transit damage, moisture ingress, and surface contamination during long-distance dispatch.

  • Heavy-duty wooden boxes with moisture barrier lining
  • HDPE stretch film wrapping on all bundles
  • Plastic end caps on threaded and plain-end plate
  • Silica gel desiccants to minimize moisture exposure
  • ISPM-15 fumigated wooden packaging for export
shipping preparation Plate Bundle Edge Protection
Shipping packaging Container End-Cap Protection
Shipping stock Wrapped Export-Ready Bundles

We Export Worldwide

Sachiya Steel International supplies alloy steel products to major industrial markets across North America, Europe, the Middle East, Asia and Africa with export-ready documentation and logistics support.

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Frequently Asked Questions:

What is the difference between ASTM A387 Gr.11 Class 1 and Class 2 Plates? +
For moderate service, Class 1 provides a 415–585 MPa tensile range and 240 MPa yield. However, vessels under intense stress and heat require Class 2. It offers a stronger 515–690 MPa range and 310 MPa yield. If your design code demands higher allowable stress values, specify Class 2. This ensures your project maintains its critical structural integrity.
What is the difference between SA 516 Gr 70 and SA 387 Gr 11 Plates? +
Pressure vessels up to 400°C use SA 516 Gr 70 carbon steel plate. SA 387 Gr 11 is a 1.25Cr-0.5Mo chromium-molybdenum alloy steel plate for high-temperature duty above 400°C with excellent creep and oxidation resistance.
What is SA 387 Gr 11 Cl 2 equivalent material? +
SA 387 Gr 11 (ASTM A387 Gr.11) is equivalent to EN 10028-2 grade 13CrMo4-5, DIN W.Nr. 1.7335, JIS G4109 SCMV 2, and BS 621 B. All share the same 1.25Cr-0.5Mo base chemistry.
What sizes are available for ASTM A387 Gr.11 Plates? +
ASTM A387 Gr.11 plates come in a variety of sizes. For example, their thicknesses can range from 5 mm to 150 mm, their widths can range from 500 mm to 4,500 mm, and their lengths can range from 3,000 mm to 18,000 mm. If you ask, we can make plates in whatever size you choose.
Are ASTM A387 Grade 11 Plates weldable? +
Yes. Relieve residual stresses with 620–680°C post-weld heat treatment per ASME code. A387 Gr.11 plates handle fusion welding well using low-alloy electrodes like AWS A5.5 (SMAW), A5.23 (SAW), A5.28 (GSAW), or A5.29 (FCAW). This ensures every joint meets high-temperature safety standards.
Is ASTM A387 Gr.11 Plate suitable for hydrogen service? +
Cr-Mo makes A387 Gr.11 plates moderately hydrogen-resistant. For severe hydrogen service at high temperatures and pressures, Grade 22 (2.25Cr-1Mo) or Grade 91 may be better. Nelson curve requirements for the temperature-pressure combination should guide selection.
What is the price of ASTM A387 Grade 11 Plates? +
Indicative pricing in India starts at ₹105/kg, while in the USA it costs between USD 0.88 and USD 2.50 per kg. The final price is contingent upon the current market conditions, thermal treatment, quantity, class, and thickness. Please reach out to us for a current quote.
What heat treatment is required for A387 Gr.11 Plates? +
A387 Gr.11 plates are supplied normalised and tempered with a minimum tempering temperature of 620°C (1,150°F). Annealing is also permitted. Post-weld heat treatment at 620–680°C is required per ASME code for all welded fabrications.
Is post-weld heat treatment (PWHT) required for A387 Gr.11? +
ASME Section VIII often requires post-weld heat treatment (PWHT) depending on thickness and service conditions. This reduces residual welding stresses and restores heat-affected zone toughness, preserving the 1.25Cr-0.5Mo matrix.

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