1.4958/1.4959
- N08810/N08811
- Alloy 800H/HT
Alloys 800H (UNS N08810) and 800HT (UNS N08811) are dual-certifiable Nickel-Iron-Chromium materials that resist oxidation, carburization and other high temperature corrosion. The chemical composition of the two alloys are identical to Alloy 800 (UNS N08800), with the exception of the higher level of carbon present in both grades (0.05 – 0.10%) in alloy 800H, and (0.06 – 0.10%) in alloy 800HT. Alloy 800HT also has an addition of up 1.0 % aluminum and titanium. Application : Chemical and Petrochemical Processing — process equipment for the production of ethylene, ethylene dichloride, acetic anhydride, ketene, nitric acid and oxy-alcohol, power generation, thermal processing fixtures.
Mechanical Properties
| Tensile strength: | 531 | N/mm² |
| Yield strength 0,2% : | 200 | ≥ N/mm² |
| Elongation: | 52 | ≥ % |
| Hardness HB30: | 127 | ≤ HB |
Chemical Composition
Carbon
C
0,5-0,1% max
Silicon
Si
0,75% max
Magnese
Mn
1,50% max
Phosphorus
P
0,045% max
Sulphur
S
0,015% max
Chromium
Cr
19-23% max
Nickel
Ni
30-35% max
Aluminum
Al
see below *1
Titanium
Ti
see below *2
*1 : 0.15 min. – 0.60 max. (800H) / 0.25 min. – 0.60 max (800HT)
*2 : 0.15 min. – 0.60 max.(800H) / 0.25 min. – 0.60 max.(800HT)
Heat Treatment
1149°C mini
The alloys have corrosion resistance that is comparable to 304 when used in nitric and organic acid service. The alloys should not be used in sulfuric acid service. They are subject to chromium carbide precipitation if in service for prolonged exposure in the 1000 – 1400°F(538 – 760°C) temperature range.
Since Alloys 800H and 800AT were developed primarily for high-temperature strength, corrosive environments to which these grades are exposed normally involve high temperature reactions such as oxidationand carburization.
Alloys 800H and 800AT are easily welded and processed by standard
shop fabrication practices.
Marking
All material will be marked as follow:
- Manufacturer’s name
- Material grade
- Size
- Heat Number
Certification
Material will be delivered with certificate EN 10204 3.1
