Materials, grades and standards

Grade pages: SS 304 round bars, SS 316 round bars, Inconel 625 round bars, Monel 400 round bars and titanium Grade 5 round bars.

ASTM A276 or A479?

Both standards cover stainless steel bars. ASTM A276 is for general use, such as machined parts and shafts. ASTM A479 is for bars used in boilers and other pressure vessels and carries additional testing and property requirements for that service – which is why pressure-retaining parts machined from bar are usually ordered to A479. Bars are often certified to both standards.

Shapes, conditions and finishes

Hexagonal bars are machined into nuts, fittings, plugs and bushings, where the flats save a turning operation; square bars are used for keys, machine parts and forged components. Very large diameters are normally produced as forged bars, which are rough turned or peeled before supply. Bars are bundled and tagged with the grade, size and heat number so each piece can be traced to its test certificate.

Wires and rods

We also supply stainless steel wires to ASTM A580 and Inconel wires for springs, mesh, fasteners, heating elements and fabrication. Wire is supplied in coils or straightened and cut lengths, in annealed or hard-drawn condition, with the diameter and finish stated on the order.

Manufacturing and inspection

Bars are hot rolled or forged from billets, heat treated as the specification requires, and then finished to size by peeling, turning, cold drawing or centreless grinding. Bright bars are straightened and their ends cut square. Each bar or bundle is marked with grade, heat number and size and checked against the order for diameter, straightness and length. Bars are supplied with mill test certificates (MTC); ultrasonic testing and third-party inspection can be arranged on request, and material can be supplied to NACE MR0175 / ISO 15156 on request.

Choosing a bar grade and tolerance

For shafts and machined parts in general corrosive service, 304L and 316L are the usual stainless choices; 303 is chosen where heavy machining matters more than corrosion resistance. Martensitic grades such as 410 and 420 can be hardened for wear, and 17-4PH combines high strength with good corrosion resistance. Duplex and super duplex bars are used for pump shafts and fasteners in seawater, while alloy steels such as 4140 or EN24 are heat treated for high-strength mechanical parts. Nickel alloy and titanium bars are kept for severe chemical, marine or high-temperature duties.

Bright bars are normally ordered to an ISO 286 tolerance such as h9 or h11, while black bars follow the hot-rolled or forged tolerance of the material standard. For machined parts, state the finished size you need so the bar size, condition and machining allowance can be matched.

Ordering bars

Please give the grade and standard, shape, diameter or across-flats size, tolerance, condition (black or bright, heat treatment), length, quantity, and any ultrasonic testing, NACE MR0175 / ISO 15156 or third-party inspection requirement.

Applications

Round bars are used for pump and valve shafts and stems, fasteners and stud bolts, forged and machined fittings, flange blanks, rings, marine propeller shafts, heat-exchanger parts and general machining in oil and gas, chemical, power, marine, food and pharmaceutical industries. All product forms are listed on the products page.

In flanged piping, bar of the same grade as the flange is often used to machine small-bore forged fittings, plugs and bushings, so pipes, fittings and bolting can all be supplied in one consistent material with matching certificates.

For export orders, bars are bundled, tagged and packed in wooden cases or on pallets, with the mill test certificate and packing list sent with the shipment documents.