ASTM A588 vs A606 Type 4: Plate or Sheet for Your RFQ?
Start with the specified product form, not the word “Corten”. A588 structural plate and A606 Type 4 sheet or strip are separate purchasing routes. A similar weathered appearance does not make a quotation for one an acceptable replacement for the other. Before comparing prices, check what the drawing requires and what the supplier is actually offering.
This guide addresses specification selection and offer comparison. For drainage, adjacent finishes and the service environment, use our separate weathering-steel RFQ checklist. Final material selection and any substitution remain subject to the responsible designer’s approval.
What should the enquiry identify first?
| Question | A588 plate enquiry | A606 Type 4 enquiry |
|---|---|---|
| Material identity | State A588/A588M and the required grade, such as Grade A or Grade B. | State A606/A606M Type 4 and the required rolling condition. |
| Product to quote | Identify plate and the finished dimensions or cutting schedule. | Identify sheet, strip, coil or cut lengths; do not rely on a commercial “plate” label alone. |
| Fabrication information | Identify connection plates, holes, edge preparation and drawing revisions where relevant. | Identify forming requirements, finished panel dimensions or receiving-equipment constraints. |
| Acceptance basis | Ordered edition, grade, dimensions and required inspection records. | Ordered edition, type, product form, condition and required inspection records. |
Do not compare a strength number without its conditions
Producer tables are useful references, but their thickness range, specimen basis and notes belong with the numbers. SSAB’s A588 Grade A plate information uses transverse tensile testing, while its A606 Type 4 coil information uses longitudinal testing. A copied strength row without that context is not a complete acceptance specification.
Read the SSAB A588 Grade A reference and SSAB A606 Type 4 reference with their qualifications. These producer references are not confirmation of ASC inventory, a particular mill source or certification of material offered for your order.
Why “A606 plate” needs a follow-up question
A buyer may use “plate” to describe a cut flat piece. A606, however, identifies a sheet-and-strip specification. Ask whether the offer is cut-to-length sheet from coil, strip or another stated product form, and make sure the dimensions and acceptance requirements match the drawing. Do not silently change an A588 plate line item into A606 cut sheet because both can be supplied as flat pieces.
For an actual enquiry, compare our A588 Grade A and Grade B plate information with our A606 Type 4 sheet and strip information. Keep the material designation on each line of a mixed order rather than describing the entire package as weathering steel.
A practical way to compare two offers
- Match the drawing revision. Check that both suppliers have priced the same parts and quantities.
- Match material and form. Record the specification, edition, grade or type, and rolling or delivery condition.
- Match dimensional scope. Compare thickness, width, length, tolerances, cut edges and any processing included. For coils, agree the receiving and handling requirements.
- Match documentation. Confirm which material test records and additional inspections are included. Request any proposed deviation explicitly before acceptance.
- Separate supply from design. Clarify who is responsible for fabrication, connections, protective treatment and installation. A material quotation is not approval of a finished assembly.
Questions buyers often ask
Can A606 Type 4 replace A588?
Not by default. Treat an alternative as a documented substitution request. Compare product form, ordered requirements and the design basis, and obtain the responsible designer’s acceptance before changing the order.
Does matching patina prove matching material?
No. Appearance is not material identification. Use the agreed grade designation and traceable records, not surface colour, when checking what was supplied.
Should every enquiry specify the same thickness range?
No. State the actual drawing dimensions and ask for the available combination. A producer’s published range or a standard’s scope is not a promise that every grade and size is stocked by the supplier.
Send a specification-led flat-steel enquiry
Send Amardeep Steel Centre LLP the material designation, product form, dimensions, quantity, drawing revision, required documents and delivery destination. We can then discuss the supply requirement without treating A588 and A606 Type 4 as interchangeable names. Explore our weathering plate, sheet and coil range or contact our team.