Incoloy 800ht Nylon Lock Nuts Specification

Incoloy 800HT Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| N08811 | – | 1.4959 | X8nicralti32-21 | – | – |
Incoloy 800ht Nylon Lock nuts are internally threaded fasteners that mate with bolts and studs to form clamped joints. TorqBolt manufactures Incoloy 800ht Nylon Lock nuts per ASME B18.2.2, ISO 4032/4033/4034, DIN 934/EN 24032, and DIN 6915 (heavy hex), in sizes M6–M100 and 1/4"–4".
For vibration-loaded joints, Incoloy 800ht Nylon Lock nuts are available as nyloc (polymer insert), all-metal prevailing-torque (DIN 980, distorted-thread style), flange-serrated (DIN 6923, integral washer face with anti-back-off teeth), and castle / slotted (DIN 935, cotter-pin retention). Each locking style trades reusability against prevailing-torque retention.
Incoloy 800ht Nylon Lock nut threads are gauged per ASME B1.1 / ISO 965 to Class 2B / 6H by default; high-strength variants use 3B / 4H6H. Proof-load testing per ASTM F606 verifies the nut can develop the bolt's full strength without thread strip; hardness range is controlled to prevent stress-corrosion susceptibility (HV 250–353 typical for high-grade nuts). Each lot is EN 10204 3.1 / 3.2 certified.
TorqBolt also produces Incoloy 800ht Nylon Lock nuts in weld-nut, T-nut, square-nut, knurled thumb-nut, and rivet-nut patterns. NACE MR0175 / ISO 15156 sour-service certification available; NORSOK M-650 qualified mills supplying high-temperature service grades.
Incoloy is the family of nickel-iron-chromium alloys positioned between stainless steels (low Ni) and Inconel superalloys (low Fe). Incoloy combines the high-temperature strength of nickel alloys with cost savings from iron substitution — the working-class superalloy.
Incoloy 800 (UNS N08800) and the modified Incoloy 800H / 800HT grades (controlled C, Al+Ti chemistry) are the most widely specified for heat-treating fixtures, ethylene-cracking furnace tubes, and steam-superheater bolting up to 1100°C. Incoloy 825 (N08825) adds Mo + Cu to deliver outstanding resistance to sulfuric, phosphoric, and reducing acids — the default for mineral-acid service and pickling-line fasteners. Incoloy 925 (N09925) is age-hardenable for high-strength sour-service applications, qualified to NACE MR0175.
Incoloy fasteners are supplied per ASTM B408 (rod/bar) and ASTM B564 (forged), with EN 10204 3.1 / 3.2 certification covering chemistry, mechanicals, intergranular corrosion (ASTM G28), and grain size. Welding uses matching filler (ENiCrMo-3 type for 800/825); post-weld solution-anneal at ~980°C restores corrosion resistance in heavy sections.