Hastelloy C276 Allen Screws Specification

Hastelloy C276 Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| N10276 | – | 2.4819 | – | – | Qa C276 |
Hastelloy C276 Allen screws are externally threaded fasteners typically driven into a tapped hole or self-tapped material. TorqBolt manufactures Hastelloy C276 Allen screws per ASME B18.3 (socket products), ASME B18.6.3 (machine screws), DIN 912 / 7991 / 6912, and ISO 4762 / 10642, in metric M3–M48 and imperial 0–1/2".
Hastelloy C276 Allen screws are available in cap (cylindrical), button (low-profile dome), countersunk / flat (82° or 90°), pan, fillister, truss, and shoulder configurations. Countersunk per DIN 7991 with 90° head angle is standard for metric; 82° per ASME B18.6.3 for imperial.
Hastelloy C276 Allen screws use full-thread or partial-thread (length-under-head) configurations. Machine screws are typically full-thread; cap screws use partial thread for grip control. Threading per ASME B1.1 (UNC/UNF) or ISO 965 (metric coarse/fine), Class 2A or 6g default. Length-under-head is measured from the bearing surface for hex/cap, from the largest face for countersunk. Custom lengths quoted to drawing.
TorqBolt produces Hastelloy C276 Allen set screws (cup-point, cone-point, dog-point, flat-point, hex-socket DIN 913/914/915/916), shoulder screws (precision-ground shoulder for pivot applications), and self-tapping screws (Type AB, Type 25). All certified per EN 10204 3.1 / 3.2 with optional NACE MR0175 sour-service compliance.
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.