Materials, grades and standards

Grade pages give composition and mechanical properties: SS 304 sheets and plates, SS 316 sheets and plates, SS 310S plates, ASTM A516 Grade 70 plates and Hastelloy C276 sheets and plates.

Plate, sheet or coil?

For stainless steel flat products, the general requirements standard ASTM A480 classes material less than 4.76 mm (3/16") thick as sheet or strip, and 4.76 mm and thicker as plate. Thinner gauges are covered on our sheets page and continuous rolled product on our coils page. Discs cut from plate are supplied as circles.

Sizes, finishes and supply condition

Plate thickness and size ranges vary by grade and mill. Send the grade, thickness, width, length and quantity, and we will confirm what can be supplied.

Quality and inspection

Plates are produced by hot rolling slabs to thickness at the mill, followed by the heat treatment the grade requires – solution annealing for stainless and nickel alloys, normalising for many pressure-vessel steels. Each plate carries the mill's marking with grade, specification, heat number and dimensions. Before dispatch we check plates against the mill test certificate (MTC) and the order, and third-party inspection can be arranged on request. Plates are packed flat on pallets with protective covering for transport.

Stainless and nickel alloy plates are stored and handled separately from carbon steel, on timber or with protective interleaving, because iron particles picked up from tools, slings or racks can cause rust staining and pitting on the finished surface. The same care is needed in the fabrication shop. For discs and rings produced from plate, see our circles and rings pages; for thinner material, see sheets and coils.

Choosing a plate grade

For carbon steel pressure vessels operating at moderate and lower temperatures, ASTM A516 is the usual specification, with Grade 70 chosen where higher strength allows a thinner shell. For vessels and heat-exchanger parts in high-temperature hydrogen or steam service, chrome-moly plate to ASTM A387 – Grade 11 (1¼Cr-½Mo) or Grade 22 (2¼Cr-1Mo) – is common. Stainless plate is selected for corrosion resistance and cleanliness: 304L for general duties, 316L where chlorides or many acids are present, and 310S for heat resistance. Duplex 2205 offers roughly double the yield strength of 316L with better resistance to chloride stress corrosion cracking, while nickel alloys and titanium are kept for the most aggressive media. For structural work, IS 2062 E250 or E350 and ASTM A36 are standard.

Ordering plates

Please give the grade and specification, thickness, width, length, quantity, any heat treatment or supplementary requirements (impact testing, ultrasonic testing, simulated post-weld heat treatment), the edge condition and the inspection required.

Applications

Plates are used for pressure vessels and columns, heat-exchanger shells and tube sheets, storage tanks, boilers, reactors and agitator vessels in chemical, petrochemical, pharmaceutical, food and fertiliser plants; for marine and offshore structures; and for structural fabrication, machinery and general engineering. Carbon steel A516 Grade 70 is a common choice for pressure vessels, chrome-moly A387 for high-temperature vessels, and stainless or duplex plate where corrosion resistance is needed. Every product form is listed on the products page.

Thick plates are also machined into tube sheets, flange blanks, blind flanges and baffles for heat exchangers and vessels, so the plate grade is often chosen to match the forgings and pipes used elsewhere in the same equipment.

Plates for export are supplied with the mill test certificate, packing list and, where required, third-party inspection reports, packed on pallets suitable for container loading.