Carbon steel

Carbon steel sits beside the stainless range for the parts of a project that need strength and weldability rather than corrosion resistance: base frames, skids, tank shells, supports and machined components.

The plate stock follows the grades that Saudi fabricators specify most. A36, S275JR and S355JR cover structural work, A516 grade 70 and P265GH cover pressure equipment, and EN8 round bar covers shafts, pins and machined parts.

What the carbon steel range covers

• Hot-rolled plate in structural grades.
• Pressure-vessel plate for tank shells, dished ends and nozzles.
• EN8 bright and black round bar for machine shops.
• Cut, rolled and bevelled pieces ready for the welding bay.

Choosing the grade

S275JR is the general-purpose plate for frames and platforms, and S355JR steps up where a lighter section must carry the same load. A36 is the equivalent on projects drawn to American practice, and the grade equivalent tool maps one system onto the other.

A516 grade 70 and P265GH are made and tested for the stresses inside a vessel, so they are the plate to specify for storage tanks and pressure vessels. The article on carbon versus stainless for Gulf structures covers when to switch material altogether.

Black bar or bright bar

EN8 is a medium-carbon steel for shafts, studs, keys and pins. Black bar is hot-rolled with a scaled surface, the economical choice when the part is fully machined. Bright bar is cold-drawn or peeled to a closer size and cleaner surface, which saves a pass when only the ends are worked.

Processing before delivery

Plate rarely leaves as a full sheet. Robotic plasma cutting handles thick profiles and weld preparations, waterjet cutting avoids a heat-affected zone on parts that will be machined, plate rolling forms shells and cones, and bevelling prepares edges for full-penetration welds.

For a fabricated assembly rather than cut plate, the steel structures page describes what the engineering division builds. Send drawings through the quotation form and the plate, the cutting and the fabrication are quoted together.

Common questions

Can plate be cut to shape before delivery?

Yes. Profiles, holes and bevels are cut from the drawing or DXF file you send, by plasma for thick plate and waterjet where the edge must stay cold. Nested parts arrive ready for the welding bay.

Is EN8 the same as mild steel?

No. Mild steel grades such as S275JR are low-carbon plate meant for welding into structures. EN8 carries more carbon, which gives it higher strength and lets it be hardened for shafts and pins, but makes it less suited to welding. Choose EN8 for machined parts and a structural grade for fabricated frames.

Which grade do I need for a tank or vessel?

Pressure equipment is drawn to a pressure code, and that code lists acceptable plate grades. A516 grade 70 is the usual choice on American designs and P265GH on European ones. Send the design pressure, temperature and code reference with the enquiry so the plate matches the design.

How do I estimate the weight before I order?

Use the sheet and plate weight calculator for flat pieces and the metal weight calculator for bar. Both return a theoretical figure from the grade density; delivered weight varies within the mill thickness allowance, as the note on theoretical versus actual weight explains.