Specifications

Chemical composition and mechanical properties

Alloy 800HT also requires Al + Ti 0.85–1.20%. Alloys 800H and 800HT have grain size and heat-treatment requirements for elevated-temperature service, as given in the standards.

Values common to ASTM B407, B409 and B408 (alloy 800 family), B423, B424 and B425 (alloy 825) and B564 forgings; check the standard for the product form and size.

Background and equivalents are on the Incoloy page.

Choosing the alloy

Incoloy 800 bars are used for components in moderate high-temperature and corrosive service, including heat-exchanger parts, valve trim and fasteners up to about 600 °C. Incoloy 800H and 800HT bars are used for parts that must keep their creep strength above that temperature – furnace hangers, supports and fixtures, reformer and cracker components, and flanges and fittings machined from bar for 800H piping. Incoloy 825 bars are used for parts exposed to sulphuric and phosphoric acids, chlorides and sour fluids: pump shafts and valve stems in acid plants, fasteners and fittings for 825 piping, and oil and gas wellhead and downhole components.

How we manufacture Incoloy bars

We manufacture Incoloy round bars from certified billets by hot rolling or forging, followed by annealing or solution annealing. Bright bars are peeled, turned or centreless ground for a close tolerance and smooth surface. For 800H and 800HT, the solution anneal sets the coarse grain size needed for creep strength, and the grain size is reported on the certificate. Every bar is marked with alloy and heat number, and ultrasonic testing is carried out on request for bars that will be machined into pressure parts.

Machining Incoloy bars

Incoloy alloys are tough and work-harden during machining. Use rigid machines and tooling, sharp carbide tools with positive rake, moderate speeds, steady feeds that cut below the work-hardened layer, and plenty of coolant. Avoid dwelling or rubbing, which hardens the surface and makes the next cut harder. Bars in the annealed condition machine more predictably than cold-worked bars of the same alloy.

Corrosion and temperature limits

Incoloy 800 family alloys resist oxidation and carburisation at high temperature, but in strongly reducing sulphur-bearing atmospheres they may suffer sulphidation, and higher-chromium alloys may be preferred. Incoloy 825 is designed for aqueous corrosion rather than high temperature, and is normally used below about 540 °C. For sour service, 825 can be supplied to NACE MR0175 / ISO 15156 on request. Please state the service conditions with the enquiry so the alloy can be confirmed.

Ordering Incoloy round bars

Please give the alloy and specification, shape and size, tolerance, condition, surface, length, quantity and any ultrasonic testing or inspection requirement. Bars are bundled or boxed, with bright bars wrapped, and each piece is traceable to its mill test certificate.

Applications and related products

Incoloy round bars are used for flanges, fittings and valve parts machined from bar, fasteners, shafts and stems, furnace fixtures, reformer and cracker components, and oil and gas wellhead parts. Matching products include Incoloy pipes and tubes, Incoloy sheets and plates, Incoloy flanges, Incoloy pipe fittings and Incoloy fasteners. Other bar materials are on the round bars, rods and wires page.