Incoloy 825 Allen Screws Specification

Incoloy 825 Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| N08825 | – | 2.4858 | Nife30cr21mo3 | – | Ncf 825 |
Incoloy 825 Allen screws are externally threaded fasteners typically driven into a tapped hole or self-tapped material. TorqBolt manufactures Incoloy 825 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".
Incoloy 825 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.
Incoloy 825 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 Incoloy 825 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.
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.