Hastelloy C-2000 Acorn Nuts Specification

Hastelloy C-2000 Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| – | – | – | – | – | – |
Hastelloy C 2000 Acorn nuts are internally threaded fasteners that mate with bolts and studs to form clamped joints. TorqBolt manufactures Hastelloy C 2000 Acorn 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, Hastelloy C 2000 Acorn 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.
Hastelloy C 2000 Acorn 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 Hastelloy C 2000 Acorn 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.
Hastelloy is the trade designation for a family of nickel-chromium-molybdenum (and nickel-molybdenum) alloys formulated for severe wet-corrosion service: hydrochloric acid, sulfuric acid, chloride pitting, crevice corrosion, and sour wells.
Hastelloy C-276 (UNS N10276) is the workhorse: ~16% Cr, 16% Mo, 4% W gives unmatched resistance to oxidizing + reducing chloride media, the only nickel alloy resistant to wet chlorine + hypochlorite. Hastelloy C-22 (N06022) is upgraded with higher Cr for better oxidizing-acid performance. Hastelloy C-2000 (N06200) adds Cu for superior performance across the full pH range. Hastelloy B-3 (N10675) is Ni-Mo for hot HCl service. Hastelloy G-35 (N06035) targets phosphoric-acid plants.
Hastelloy fasteners ship per ASTM B574 / B575 (rod/bar/plate), with EN 10204 3.1 / 3.2 certification including PMI and intergranular-corrosion testing per ASTM G28. The ASTM A193 grade B14 + B7M designations cover Hastelloy bolting for ASME pressure-vessel use. NACE MR0175 / ISO 15156 sour-service compliance is standard. Welding requires matching filler metal (Ernicrmo-4 for C-276) with no post-weld solution anneal.