- EN / Grade
- 1.4959
- Other designations / UNS
- Incoloy 800HT / Alloy 800HT
UNS N08811 - Family
- Nickel-iron
The documentation distinction between H and HT
Although 800HT chemistry falls within the 800H family limits, not every 800H heat meets 800HT requirements. Dual certification must therefore be supported by records demonstrating compliance with both sets of conditions. Two UNS numbers appearing together in a cross-reference table do not make them automatically interchangeable.
The role of grain and annealing
Chemical analysis alone does not describe high-temperature behaviour. Controlled grain and the appropriate annealing condition are also part of delivery. Subsequent hot forming or welding should be assessed for their effect on the final condition. Strength requirements must be related to the actual exposure time and loading pattern.
Product-specific acceptance requirements
ASTM B407 for seamless pipe and tube and ASTM B409 for flat products are example product specifications; confirm N08811 coverage in the applicable revision. Provide diameter or thickness, length, delivery condition, grain and testing requirements. The 800HT name alone does not define an identical delivery scope across all product forms.
Typical application areas
High-temperature process tubes, heater hardware and continuously operated thermal equipment.
Product and cutting options
Share the section and dimensions you require for this grade. Availability is assessed for each request; the catalogue does not represent live stock.
What to specify in your enquiry
- Grade designation and applicable material standard
- Section, finished dimensions and machining allowance
- Quantity, delivery condition and certificate requirements
Frequently asked questions
Can I request 1.4959 in cut lengths?+
Share your required section, dimensions and quantity. Our team will assess suitable supply and cutting options for the specific grade.
Are the listed grade designations interchangeable?+
Designation systems can overlap, but they do not make every specification identical. Use the exact standard and certificate requirements defined by your project.