ASTM A387/A387M · Cr-Mo Alloy Plate for Pressure Service

ASTM A387 Plate Standard

The ASTM A387 Plate Standard decision must be matched to the standard scope, grade, dimensions, service conditions, testing, and verifiable documents.

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Price on request · confirmed against the standard edition, grade, class and the mill certificate

Standard scope, grades, classes & dimensions

What ASTM A387 covers, and what the order must fix

Specify with enough detail to make acceptance unambiguous: the standard and edition, the grade, the class and heat-treatment condition, plate thickness, width and length, any supplementary requirement, surface and edge condition and document expectations. The standard sets the scope; the grade, class and heat treatment are decisions fixed on the order.

ASTM A387/A387M — scope, grade & class basis

Input	Typical basis (verify)	Buyer implication	Evidence / RFQ field
Designation	ASTM A387/A387M — chromium-molybdenum alloy steel plate for pressure vessels and elevated-temperature service, read together with the standard edition named on the order	Names the exact standard and edition; chemistry, mechanical and test minimums follow from it	Exact designation + standard edition
Grade	A387 is published in a range of Cr-Mo grades distinguished by their nominal chromium and molybdenum content — the grade is chosen against the design temperature, the process environment and the applicable design code	The grade is a purchasing decision tied to the service: a plate ordered as "A387" without a grade is not a complete specification	Exact grade (e.g. Grade 22)
Class	The standard publishes classes that differ primarily in the heat-treatment condition applied to the plate — the class is a separate field from the grade	Two plates of the same grade but different class are not interchangeable on the order; the class fixes how the material is supplied	Exact class (as ordered)
Heat treatment	Heat treatment is central to this standard and is specified through the class — the condition as supplied must be stated on the certificate for the plate shipped	Sets the mechanical values the plate is accepted against and is verified on the mill certificate, never inferred from the grade alone	Heat-treatment condition + class
Product form	Alloy steel plate for pressure-retaining and elevated-temperature service	Fixes applicability to the plate form and its thickness range	Product form: plate
Supplementary requirements	Any supplementary requirement, restriction or project addendum named in the RFQ	Governing extras are explicit on the order, never assumed from the designation	Supplementary requirement set

Grade and class are separate fields — the grade fixes the chemistry, the class fixes the heat-treatment condition, and both must be named on the order.

Plate size / unit-weight basis

Dimension / tolerance	Typical basis (verify)	Buyer implication	Evidence / RFQ field
Thickness	Plate range per the edition (declare exact; mechanical values are thickness-dependent)	Sets mass, tolerance, mechanical response and availability for the plate	Nominal thickness + unit
Width / Length	Per declared blank or customer size	Determines cut plan, nesting, packing and the piece count	Width × Length or plate standard size
Tolerance basis	Thickness / flatness tolerance per the declared standard or the referenced dimensional specification	Confirms the plate meets the fit-up intent for pressure-equipment fabrication	Tolerance basis + edition
Unit weight	From declared density × volume — verify against MTC	Confirms mass for transport and the quotation basis	Quantity in plates and tonnes

Units, tolerance and mass basis must be stated and verified with the mill / gauge record — computed from density, never assumed.

A387 — mechanical & service temperature basis

Property	Typical basis (verify)	Buyer implication	Evidence / RFQ field
Tensile strength	A387: a tensile band per grade and class — verify per edition for the grade and heat-treatment condition ordered	Confirms the strength envelope the design code works to	Grade + class + test record
Yield strength	A387: a minimum yield requirement per grade and class, falling with thickness — verify per edition	Confirms the design allowable for the elevated-temperature service	Grade + class + thickness + test requirement
Elongation	A387: elongation minimum per the declared grade, class and thickness	Confirms ductility for the forming and fabrication route	Grade + class + thickness + elongation record
Elevated-temperature properties	The standard supports the elevated-temperature service the grade is selected for; the design values actually used come from the applicable design code, not from the standard's room-temperature minimums alone	Design at temperature is a code calculation — the plate is ordered against the grade and heat treatment the calculation assumes	Design code + design temperature + grade/class

Mechanical values depend on grade, class and thickness — carry each into the RFQ for verification against the mill certificate.

ASTM A387 Plate Standard procurement scene showing plate inspection — Plate edge, surface and identification marks prepared for inspection

Related standards & resources

ASTM A516 pressure vessel plate ASTM A36 carbon structural plate ASTM A131 shipbuilding plate ASTM A572 high-strength plate All steel plate standards

Quality, testing & documentation

What gets verified on an A387 plate

Verification follows the purchase specification. Ask for the documents and test records the project requires, and match material identification to the ordered grade, class and condition. Certificates, approvals, origin statements and special tests must be confirmed for the actual supply — they are not assumed from this page.

Chemistry and mechanical results are held against the ordered A387 grade and class — not assumed from the standard number or from a familiar Cr-Mo grade figure.
The heat-treatment condition and class are stated on the mill certificate and verified against the order, because the mechanical results are read against that condition rather than inferred from the grade.
Dimensional, flatness, surface and edge checks, any NDT or supplementary test, and third-party inspection where specified are requested explicitly — never an unsupported certificate.

ASTM A387 Plate Standard procurement scene showing fabrication planning — Cut layout, welding notes and shipment tagging prepared for hand-off

Document & inspection matrix

Product evidence

Mill Test Certificate — chemistry and mechanical results against the ordered A387 grade and class
Heat-treatment condition and class stated on the certificate for the plate shipped
Heat / lot traceability to the shipped consignment

Inspection records

Dimensional, surface or edge inspection per the agreed route
Mechanical (tensile / yield / elongation) test record
NDT or supplementary test records where the order requires them

Destination documents

Commercial invoice and packing list
Origin / transport documents per the Incoterm
Customs declaration inputs for the destination

Specification Gate

ASTM A387 plate specification gate

Compare the details that actually change a purchase: the standard and edition, grade, class and heat-treatment condition, thickness and dimensions, service duty, fabrication route, inspection documents, quantity and destination. Missing inputs are flagged before an RFQ is prepared so an apparently similar option is not treated as equivalent.

RFQ summary

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Add missing fields

Exact standard / designation *

Grade *

Class *

Heat-treatment condition

Product form *

Thickness *

Width

Length

Quantity *

Application / service

Design temperature basis

Inspection / testing

Welding / fabrication / processing

MTC / certificate / document set

Destination *

Incoterm

Required date

Notes

Fit summary

Insufficient evidence. Still open: Designation / standard, Grade, Class, Product form, Thickness, Quantity, Destination. These stay visibly unresolved rather than being assumed.

No A387 grade is named. The grade is selected against the design temperature and the process environment, so the grade must be set before the chemistry and mechanical requirement can be checked — "A387" on its own is not a complete specification.
No class is named. The class fixes the heat-treatment condition the plate is supplied in, and the mechanical results are read against it — two plates of the same grade in different classes are not interchangeable on the order.
Thickness is not yet stated. Mechanical values are thickness-dependent, so the thickness band is needed before the mechanical requirement can be checked.

Comparison routes are offered once the grade and class are set — the page will point to the closer standard or grade rather than assuming equivalence.

How this gate works

Compliance is scored from the controlling source (ASTM A387/A387M), the grade, the class and the heat-treatment condition it fixes, the thickness dependencies and the supplementary requirements you supply — not from the standard number alone. Result is Fit for technical review, Comparison needed, or Insufficient evidence. Price on request; availability, lead time and any inspection or document add-ons are confirmed with your quotation, never invented upfront.

Your RFQ summary is sent to the commercial coordinator; a quote follows on your details.

Fit, alternatives & selection logic

Narrowing the A387 specification

Start with the service requirement, then narrow by material family, governing specification, grade or class, heat-treatment condition and dimensional range. A candidate is suitable only when those order details align with the project requirement — related grades are comparison paths, not automatic substitutes.

Type and material

A387 is a chromium-molybdenum alloy plate for pressure-retaining and elevated-temperature service. Confirm the grade, the class and the design temperature against the applicable design code before the plate basis is fixed.

Grade and class

The grade is selected against the design temperature and process environment; the class fixes the heat-treatment condition the plate is supplied in. Both are separate fields on the RFQ — a plate ordered without a class is not a complete specification.

Dimensions and tolerances

Thickness, width, length and the tolerance basis fix the plate, its unit weight and the mechanical values it is accepted against. Keep the unit system coherent and cite the edition.

Heat treatment and fabrication

Heat treatment is central to this standard and is fixed by the class. Because the material is fabricated into pressure equipment, welding procedure, heat-treatment controls and NDT requirements sit on the order and are confirmed against the project — never assumed from the designation.

ASTM A387 Grade 22 plate

The most commonly specified Cr-Mo grade for elevated-temperature pressure service — use this route to check the grade-specific specification and purchasing inputs.

Compare ASTM A387 Grade 22 plate

ASTM A516 pressure vessel plate

The carbon steel pressure-vessel standard — where the service is at ambient or moderate temperature and the Cr-Mo grades are not required.

Compare ASTM A516 pressure vessel plate

ASTM A387 Plate Standard procurement scene showing specification review — Marked plate documentation, calipers and a dimension sketch narrow the specification before the RFQ is sent

Chemistry

What defines an ASTM A387 plate

Composition is a purchasing input, not a slogan. The chromium-molybdenum balance that gives the grade its elevated-temperature behaviour is stated against the ordered grade and class and verified against the mill certificate — never assumed from the grade number alone.

Chromium-molybdenum composition

A387 grades are distinguished by their nominal chromium and molybdenum content, which is what gives the material its elevated-temperature strength and its resistance to hydrogen attack in process service. The exact composition for the ordered grade is verified against the mill certificate, and any supplementary restriction the project adds is applied on top of the standard — never assumed from the grade number alone.

RFQ field: the chemistry requirement is written into the MTC / certificate request and verified against the plate actually shipped.

Why it changes the purchase

Because the grade is chosen against a design temperature and the class fixes the heat-treatment condition, the grade, class, heat treatment and design temperature are separate RFQ fields rather than one specification. Mechanical values are read against the heat-treated condition the class specifies, so a change of class changes what the plate is accepted against even when the grade number is unchanged.

RFQ field: the chemistry requirement is written into the MTC / certificate request and verified against the plate actually shipped.

Equivalents

Comparing ASTM A387 on evidence, not a similar figure

A related alternative is comparable only when the governing requirements have been compared and verified. No absolute product-superiority claim is made — each difference is a decision the buyer, the design authority and the coordinator reconcile to the pressure service.

Comparable pressure-vessel plate standard

Another pressure-vessel plate standard is comparable only when its chemistry, grade, heat-treatment condition, thickness dependency, mechanical and elevated-temperature properties and any project requirement match the intended service. Every difference is verified against the mill certificate and the governing design code.

Buyer implication: place this into the RFQ as an explicit comparison basis before any substitution is accepted.

When substitution must be verified

Do not present a different standard or grade — including an ASTM A516 carbon plate or an EN 10028 grade — as equivalent to an A387 grade from a similar strength figure alone. The chromium and molybdenum content, the heat-treatment condition and the temperature capability differ, and the substitution must be confirmed by the design authority before it is accepted.

Buyer implication: place this into the RFQ as an explicit comparison basis before any substitution is accepted.

Related standard routes

Follow a related link only when it answers a real specification decision — a neighbouring page is not evidence that two standards are interchangeable.

ASTM A516 pressure vessel plate

The carbon pressure-vessel standard — where the design temperature does not call for the Cr-Mo grades.

Compare ASTM A516 pressure vessel plate

ASTM steel grades

Compare the ASTM designations across product forms, holding the standard and grade basis consistent across the specification.

Compare ASTM steel grades

MTC requirements

Mill Test Certificate & document evidence for A387 plate

The MTC ties the chemistry and mechanical results to the plate actually shipped, with the heat-treatment condition and class stated and heat / lot traceability recorded. Every document is requested against the ordered grade and class — never an unsupported certificate.

Mill Test Certificate traceability

The MTC ties the chemistry and mechanical results to the plate actually shipped, with the heat-treatment condition and class stated and heat / lot traceability recorded. For an A387 plate it is requested against the ordered grade and class, together with any supplementary or NDT record the project requires — never an unsupported certificate.

RFQ field: state the MTC, the ordered grade and class, the heat-treatment condition, heat / lot traceability, the chemistry and mechanical results, and any NDT or supplementary test requirement in the RFQ so the document set matches the plate shipped.

Inspection & document set

Dimensional, flatness, surface, edge, mechanical-test, NDT and any third-party inspection are requested explicitly, alongside the commercial, origin and transport documents for the destination. Every document is quotation-dependent and stated before acceptance.

Advantages

How the A387 decision gets safer

A well-qualified enquiry reduces rework at three points: material selection, document review and fabrication hand-off. The practical gain is not a generic promise of superiority — it is a clearer comparison between compliant offers, earlier visibility of missing requirements and a more complete RFQ for technical review.

Risk

Unnamed grade or class on the order

The RFQ forces a named A387 grade and class before any value is shown, matching the design temperature and the governing design code.

An ASTM A387 plate whose grade, class and heat-treatment condition are unconditional, auditable ordering inputs.

Risk

Heat treatment assumed from the grade

The class — which fixes the heat-treatment condition — is a separate, explicit RFQ field, verified on the certificate rather than inferred.

A plate whose acceptance basis is stated and evidenced rather than assumed.

Risk

Chemistry and mechanical values unchecked

Chemistry, mechanical-test and traceability needs are explicit RFQ fields, requested against the ordered grade and class before quotation.

An MTC and test-record set that matches the plate actually shipped.

Risk

Quotation gaps or hidden assumptions

Application, processing, destination, Incoterm and date are separate explicit fields, never buried in a price.

A quotation that states delivery and import expectations rather than hiding them.

Risk

Unsupported stock or lead-time claims

Every stock, price, origin or delivery claim is either verified or left to the RFQ to confirm against the mill and destination process.

No surprise when availability and lead time are confirmed.

Journey

From an A387 requirement to a documented consignment

Seven checkpoints carry the enquiry from a requirement to a confirmed, documented delivery — each with the responsible owner and the input the RFQ expects. At each step, unresolved requirements stay open rather than being replaced by assumptions.

Requirement
Buyer / design
In: Design temperature, process environment, design code, A387 grade, class, product form, thickness, width, length, quantity and any supplementary requirement.
Out: A387 grade and class basis stated; route and material identified.
No grade or class named — "A387" alone.
Next: Name the grade and class.
Destination & importer
Buyer + commercial
In: Destination, port or delivery location, importer/consignee details.
Out: Destination and clearance owner explicit.
Importer not confirmed.
Next: Add importer/consignee inputs.
Documents & Incoterm
Buyer + commercial
In: Invoice/origin/transport-document needs, Incoterm + named place.
Out: Document set and delivery terms stated.
Customs assumptions unstated.
Next: Confirm document checklist.
Quotation
Commercial
In: Quantity, Incoterm, destination, date.
Out: Availability and pricing on request.
Unknown lead time.
Next: Receive confirmed offer.
Inspection & documents
Technical / QA
In: Chemistry, mechanical, heat-treatment condition, dimensional and any NDT or supplementary checks.
Out: Grade, class, heat treatment and mass reconciled to the mill ticket and test record.
Missing class statement, heat-treatment record or test report.
Next: Approve document set.
Packing & shipping
Supplier / forwarder
In: Strapping, marking, Incoterm, port.
Out: Coordinated to the destination.
Document delay.
Next: Track to delivery location.
Delivery & follow-up
Commercial
In: Site handover, closed-out docs.
Out: Handed to site with documents.
Open claims.
Next: Close out.

FAQ

ASTM A387 plate questions

Straight answers to the questions procurement and QA teams ask most. Each answer depends on the project specification and the actual order conditions.

Which standard, edition, grade and class should be stated on an RFQ for ASTM A387 plate?

State the designation ASTM A387/A387M with the edition named on the order, the grade (chosen against the design temperature and process environment), the class, the product form and the thickness band, together with any supplementary requirement the project adds. Grade and class are separate decisions: the grade fixes the chromium-molybdenum chemistry, while the class fixes the heat-treatment condition the plate is supplied in. Both must be named for the quotation and mill certificate to be matched against the plate actually shipped.

Why does heat treatment matter so much on this standard?

Heat treatment is central to A387 and is specified through the class, so it determines the condition the mechanical results are read against. A change of class changes the acceptance basis even when the grade number is unchanged, which is why the class and heat-treatment condition are stated separately on the order and shown on the mill certificate. Post-weld heat treatment of the finished equipment is a separate fabrication requirement governed by the design code.

Which dimensions and tolerances govern acceptance?

Confirm nominal thickness, width, length and quantity in plates and tonnes, plus the thickness and flatness tolerance basis and one coherent unit system. Mechanical values under the standard are thickness-dependent, so the exact thickness band and its tolerance are carried together and reconciled to the mill certificate. State the surface and edge condition and any cut-to-size or edge preparation before quotation.

Which inspection documents should be requested?

Request the Mill Test Certificate with the chemistry and mechanical results against the ordered grade and class, a statement of the heat-treatment condition, heat and lot traceability, and the mechanical test record. Add the dimensional and gauge record, any NDT or supplementary test the project requires, third-party inspection where specified, and the commercial, origin and transport documents for the destination. Everything is stated explicitly — never inferred from the designation.

Can a related standard or grade be substituted, and what destination details are needed for a firm offer?

A related standard or grade is comparable only when its chemistry, grade, heat-treatment condition, thickness dependency, mechanical and elevated-temperature properties and any project requirement match the intended service; ASTM A516 carbon plate and EN 10028 grades are not automatically equivalent to an A387 grade. Substitution must be confirmed by the design authority and verified against the mill certificate. For the commercial offer, the destination country, delivery location or port, Incoterm and named place, packing requirements and the required delivery date all change the quotation and document set.

Qualified RFQ

Request a qualified ASTM A387 plate quote

Provide the standard, grade and class or the service requirement, thickness, width, length, quantity, destination, required documents and any cutting, testing or inspection scope. If a requirement is still undecided, state it explicitly so the technical review can identify what must be resolved before a commercial offer is finalised.

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Price on request · availability and lead time confirmed with your quotation

Applications

ASTM A387 plate, mapped to service duty

Application fit depends on what the plate will do in service and how it will be fabricated. Use these paths only where the duty matches — the same nominal plate description can require different toughness, weldability, corrosion, wear or documentation controls.

Boilers & elevated-temperature service

Boiler and heat-exchanger service: reconcile the grade, class, heat-treatment condition and design temperature to the governing design code before the plate basis is fixed.

Explore Boilers & elevated-temperature service

Storage tanks

Tank and containment work at temperature: check whether the service requires the Cr-Mo alloy grades or whether a carbon pressure-vessel plate is the correct basis.

Explore Storage tanks

Fabrication

Where the duty is structural rather than pressure-retaining or elevated-temperature, a structural standard is likely to be the correct basis instead.

Explore Fabrication

GCC markets

GCC procurement for ASTM A387 plate

For GCC procurement, keep the technical specification unchanged while checking the destination-specific import path, consignee requirements and shipment documents. Customs, conformity and duty treatment must be confirmed for the actual shipment.

United Arab Emirates

Destination and import documentation.

Carry the A387 grade, class, heat-treatment condition and destination emirate into the RFQ so the quotation and document set match the UAE requirement for the declared elevated-temperature plate.

United Arab Emirates

Saudi Arabia

Project specification and import documentation.

Confirm the A387 grade, class, heat treatment, dimensions, quantity and delivery window so the plate estimate and logistics stay aligned to the order and the governing project specification.

Saudi Arabia

Qatar

Specification and delivery inputs.

State the A387 grade and class, heat-treatment condition, plate thickness, width, length, quantity, documents and delivery base so the Qatar quotation is fixed on a verified basis.

Qatar

Oman

Port-oriented supply for process projects.

Oman projects are typically supplied through port destinations, harmonising the A387 plate specification with the project's fabrication and inspection requirements.

Oman

Kuwait

Refinery and process procurement hand-off.

Link plate selection and any cutting or forming to the fabrication, welding and inspection needs, with shipment agreed against the destination and delivery window.

Kuwait

Bahrain

Industrial supply and re-export coordination.

Coordinate material, heat-treatment and testing documentation to the delivery requirement so the A387 plate and its document set stay aligned.

Bahrain

Logistics & Incoterm

Commercial comparison after the technical basis is aligned

Quote requests should identify quantity, plate dimensions, destination, required delivery term, inspection/document package and any processing scope. Price, stock and lead time must be confirmed for the live enquiry rather than inferred from a catalogue page.

Packing

Plates stacked, strapped and marked by size, grade, class, heat and lot, matched to the declared route and destination. Confirm packing in the RFQ.

Delivery route

Name the destination, port or delivery location. Delivery terms are matched to the route and stated on the quotation.

Incoterm & named place

State the Incoterm and named place so packing, transport and document obligations are explicit and auditable for the A387 plate import.

References

Related pages and technical resources

Verify a closer standard, material, application or technical guide before requesting a quote, keeping the pressure-vessel material basis consistent across the specification.

ASTM steel grades

Compare the ASTM designations across product forms, holding the standard and grade basis consistent across the specification.

Explore ASTM steel grades

Cutting & processing

Review how cutting, edge preparation and processing scope change the order, the packing and the inspection requirements.

Explore Cutting & processing

Thickness tolerance

Review how the thickness and flatness tolerance basis changes acceptance for pressure-equipment fabrication.

Explore Thickness tolerance

Related steel plate pages

Parent and cluster paths that keep the plate specification intact while you compare the product forms.

Steel plate hub All steel plate grades All steel plate materials All steel plate standards All steel plate types

Expert insight

Reading the ASTM A387 scope before you order

The safest purchasing sequence for an ASTM A387 plate is to identify the governing service requirement first, then lock the material specification and edition, grade or class, heat-treatment condition, dimensions, testing and documents. That sequence avoids comparing offers that share a familiar name but differ in acceptance basis or fabrication risk.

What the standard governs

ASTM A387/A387M covers chromium-molybdenum alloy steel plate for pressure vessels and elevated-temperature service, published in a range of grades distinguished by their nominal chromium and molybdenum content. The grade is chosen against the design temperature and the process environment, while the class specifies the heat-treatment condition the plate is supplied in — so the grade and the class are two separate decisions, not one. Because the mechanical results are read against the heat-treated condition the class fixes, a change of class changes the acceptance basis even when the grade number is unchanged.

As a steel trading house we do not guarantee that a listed standard applies to every case — the edition, grade, class, heat treatment and any supplementary requirement are reconciled to the pressure service and the governing design code before an order, and the working frame is the published ASTM A387/A387M reference.

Expert perspective on A387 procurement

Name the grade and the class. The grade fixes the Cr-Mo chemistry and the class fixes the heat treatment — \"A387\" without either is not a complete specification.
Start from the design temperature. The grade is selected against the design temperature and the process environment, so the design code and design condition belong on the RFQ before the material basis is fixed.
Bring the chemistry, mechanical and heat-treatment evidence. Hold the mill ticket, class and heat-treatment statement, heat / lot traceability and the mechanical record against the plate actually shipped.
Plan fabrication and NDT up front. Welding procedure, post-weld heat treatment and inspection requirements are decisions stated on the order and confirmed against the design code, not assumptions.

Working frame: ASTM International — A387/A387M · Information date 2026-10-06 · Price on request.