Plate stock

What a plate order must establish

Under SSAB's cited Strenx thickness tolerance of −0.6/+0.4 mm at 15.0 ≤ t < 25.0 mm, 20.0 mm nominal can arrive at 19.4 mm. It may already fall below a 20.0 mm finished minimum. For an 18.0 mm target, worst-case thickness leaves 1.4 mm total cleanup, subject to flatness, surface condition and machining movement. SSAB thickness and flatness guarantee

“Plate” is a stock-form description, not an alloy, strength grade or finished-part tolerance. An order needs material specification, grade and condition together with thickness, width, length and applicable dimensional requirements. Do not use one universal sheet/plate thickness boundary across all metals and product standards.

ASTM B209/B209M, for example, covers aluminum and aluminum-alloy flat sheet, coiled sheet and plate in specified alloys and tempers. Its scope treats inch-pound and SI requirements independently and warns against mixing the two systems to establish conformity. A rounded metric conversion of an inch size is therefore not automatically the same ordered product. ASTM B209/B209M-21a scope

A useful material record separates what the metal is, how it was supplied, and what the blank must measure. See Stock forms and dimensions.

Distinguish the production and finishing route

Outokumpu describes quarto plate as individually rolled stainless plate that can be customized and supplied with edge preparation or other prefabrication. Its separate hot-rolled coil/strip/plate offering includes leveled products and multiple surface finishes. Those routes can overlap in commercial thickness ranges; the word “plate” alone does not identify the route or all applicable tolerances. Outokumpu quarto plate, hot-rolled coil, strip and plate

For a machined component, distinguish mill plate, a sawed or profiled blank, and a precision-machined blank. A processor may control only selected faces. TCI's DB-MIC6-1000-06-12, a 1×6×12 inch MIC-6 cast-tooling-plate blank, specifically retains stock thickness while milling width and length to ±0.002 inch. That is a named processed product, not a general tolerance for all cast or rolled plate. TCI four-side precision blank

Dimensions and tolerances are separate fields

SSAB's Strenx plate guarantee illustrates the distinction. For nominal thickness 15.0 ≤ t < 25.0 mm, its published table gives −0.6/+0.4 mm thickness tolerances and 0.6 mm within-plate variation. Its flatness tables separately depend on the exact product and thickness and use a 1 m ruler. These are Strenx product guarantees, not default tolerances for all steel plate. SSAB thickness and flatness guarantees

The British Stainless Steel Association's EN 10029 guidance likewise separates thickness classes from normal/special flatness requirements. It describes flatness measurement with the plate on a flat surface and a 1000 or 2000 mm straightedge, with prescribed measurement exclusions near edges. That measurement is different from simply reading height above a table at one location. Confirm the governing standard edition and full applicable method rather than importing an isolated number. BSSA plate-tolerance guidance

A plate may have nearly constant thickness while being bowed, or acceptable flatness while varying in thickness. Neither requirement alone guarantees two finished faces that meet a machining drawing's parallelism and thickness requirements. Define the required final geometry and inspection condition explicitly.

Bounded machining-allowance example

Allocate the 1.4 mm across the two faces according to the actual flatness, surface condition, cut geometry and machining movement. Within-plate variation is a separate stock requirement.

Select stock using the required usable envelope. A thicker blank may provide cleanup material, but the appropriate thickness and machining sequence remain a process decision. A commercial flatness guarantee on the uncut parent plate does not by itself qualify the final pocketed, welded or heat-treated component.

Availability is a combination, not three independent maxima

Outokumpu's quarto product page lists a broad dimensional envelope but explicitly says that availability depends on grade, the thickness/width combination and maximum piece-weight restrictions. Do not combine a catalogue's maximum thickness, maximum width and maximum length into an assumed orderable plate. Outokumpu dimensional restrictions

Its December 2023 product-and-dimension program tabulates maximum length by grade, width and thickness. The same program states that local stock differs by service center. An available manufacturing size and an immediately stocked size are different sourcing facts. Outokumpu dimension program

Original mass estimate: assume a rectangular 20×1000×2000 mm blank and a declared estimating density of 7850 kg/m³. Volume is 0.020 × 1.000 × 2.000 = 0.040 m³; nominal mass is 314 kg. The density is an example assumption, not a universal plate property. Actual thickness, grade density, surface treatment and cut shape alter mass. Keep theoretical purchasing mass, weighed delivery mass and lifting requirements distinct.

Surface, edges and traceability

Outokumpu's program normally supplies its quarto plates hot rolled, annealed and pickled, identified as 1D (EN) / Finish No. 1 (ASTM), and normally uses plasma-cut or sheared edges. It offers tailored welding edges and cut shapes separately. A surface-finish designation therefore does not imply a precision-machined edge or final weld preparation. Outokumpu delivery and edge preparation

For cut blanks, agree the cutting process, edge allowance, burr acceptance, identification transfer and whether dimensions describe the rough blank or finished part. Preserve heat/lot and condition information when a parent plate becomes several pieces. Add rolling direction, test orientation or internal-quality requirements where the application requires them; they cannot be recovered reliably from a stock-size label alone.

Source editions and release record

The Outokumpu PDF prints 1259EN:8, December 2023; its URL's 2024 modification parameter is not a new technical edition. ASTM lists B209/B209M-21a as active, last updated January 12, 2022. The cited SSAB, Outokumpu live pages, BSSA guidance and TCI product record display no technical revision date.

Before release, align the supplier acknowledgement with the drawing: material and condition, product route, stock and finished dimensions, tolerance methods, surfaces and edges, usable machining allowance, certificate and traceability. Any structural, pressure, wear or corrosion performance requires the relevant material/process qualification beyond the stock form.