Ferralium Socket Cap Screws Specification

Ferralium Socket Cap Screws Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD | Forging |
|---|---|---|---|---|---|---|
| S32950 | – | 1.4507 | X2CrNiMoCuN25-6-3 | – | – | Sa 182 F61 |
Ferralium Socket Cap screws are externally threaded fasteners typically driven into a tapped hole or self-tapped material. TorqBolt manufactures Ferralium Socket Cap 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".
Ferralium Socket Cap 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.
Ferralium Socket Cap 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 Ferralium Socket Cap 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.
Duplex stainless steels have a roughly 50/50 ferrite-austenite microstructure, doubling the yield strength of austenitic 304/316 grades while improving chloride pitting + stress-corrosion resistance. Duplex is the modern default for offshore platform fasteners, desalination plants, and sour-gas piping where austenitics fail to chloride SCC and martensitics fail to hydrogen embrittlement.
Duplex 2205 (UNS S32205 / S31803) is the standard grade with PREN ~35, suitable for chloride-bearing service to ~250°C. Super Duplex 2507 (S32750) and Zeron 100 (S32760) push PREN to 41-42 with higher Cr+Mo+N, qualifying for the most aggressive seawater + sour-well environments. SA-182 F51 / F53 / F55 / F60 are the ASME forged-flange equivalents.
Phase balance is critical: ferrite content must stay within 35-65% in weld + HAZ to maintain corrosion + impact properties (ASTM A923 testing). Solution anneal at 1040-1100°C followed by water quench locks the duplex microstructure. Fasteners ship per ASTM A276 / A479 with EN 10204 3.1 / 3.2 certs including ferrite count and Charpy impact at -46°C. NACE MR0175 / ISO 15156 sour-service certification is standard.