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Castle Metals supplier a wide range of Alloy 800 sheet and plate from their facility in the UK, with various added value processing including water jet, laser, plasma and hi definition plasma, Castle are able to profile to any shape or size to meet customers specific requirements. All material kept by Castle Metals is certified to the highest industry standards used in some of the most demanding environments in the world.
Alloy 800H (UNS N08810) is an austenitic high-strength solid-solution Ni-Fe-Cr alloy with controlled levels of carbon, aluminium, titanium, silicon and manganese and controlled content of (Al+Ti).
The analysis is similar to that of alloy 800, but a special solution treatment (with grain sizes ≥ 90μm/ASTM No.4) gives signiﬁcantly increased creep-rupture strength above 600°C (1110°F).
For services below 600°C (1110°F) the use of soft annealed alloy 800 is suggested.
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Alloy 800H and alloy 800HT are austenitic, solid solution alloys containing small amounts of precipitated titanium nitride and carbide, carbonitrides and chromium carbide.
During long-term exposure of alloy 800H to temperatures below 700°C (1290°F) γ’-phase may be formed which lowers the ductility.
Alloy 800HT precipitates γ’-phase combined with a loss of ductility.
The high nickel and chromium contents of alloy 800H and alloy 800HT ensure excellent resistance to oxidation. The alloys are also very resistant to carburisation, nitriding and oxidising sulphur-bearing atmospheres. The protective oxide ﬁlm which is formed is adherent in both static and cyclic conditions of heating and cooling, and resistance to carburisation is enhanced when a thin ﬁlm of oxide is ﬁrst formed on the alloy. Resistance to hydrogen is excellent and alloy 800H and alloy 800HT are standard materials used in the production of hydrogen in steam/hydrocarbon reforming processes.
The following properties are applicable to the solution-treated condition and the indicated size ranges. Material outside these size ranges is subject to special enquiry. The values are valid for longitudinal and transverse specimens.
Sheet and strip up to 3mm 1/8″
Sheet and plate up to 50mm 2″
Tube up to 200mm dia 8″ dia
Rod and bar , forgings up to 250mm 10″
170… according to VdTÜV no.412 and 434 and converted (N/mm2 x 0.145=ksi) 141… values determined by graphs/diagrams <> informative only minimum short-time mechanical properties of alloy 800H at room and elevated temperatures according to VdTÜV data sheets 412 and 434.
Please Note: The ﬁgures quoted are intended for guidance only. For further information, please refer to the standards listed or contact our sales or QA department.
Due to high strength during long periods of service and resistance to carburisation and nitriding, alloy 800H and 800HT have found many applications in steam/hydrocarbon reforming, for components such as: pigtails, headers/collectors/manifolds, transfer piping, catalyst tubes (in low-pressure processes) and quench-system piping.
Typical applications include: