ALLOY 20 Allen Screws manufactured at TorqBolt are corrosion resistant,high temperature resistant with ultimate tensile strength.
Dimensional standards as per ANSI B18.3 ,B18.3.1M.DIN 912,DIN 6912,DIN 7984,ANSI B18.3,ISO 4762,UNI 5931,BS 2470,BS 4298 are provided.
The raw material of these fasteners is renowned as registered trademarks like Carpenter® 20, 20CB-3®. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. ALLOY 20 Allen Screws are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
Alloy 20 Allen Screws — Specifications & Dimensions
Alloy 20 Allen screws are externally threaded fasteners typically driven into a tapped hole or self-tapped material. TorqBolt manufactures Alloy 20 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".
Drive Types
Hex socket (Allen) — ASME B18.3 / DIN 912, primary for high-torque industrial use
Alloy 20 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.
Thread & Length
Alloy 20 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.
Specialty Screws
TorqBolt produces Alloy 20 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.
Super-austenitic stainless steels are high-molybdenum (Mo ≥ 6%), high-nitrogen austenitic alloys positioned above the 316L envelope but below nickel-alloy cost. They deliver chloride-pitting resistance approaching duplex grades while retaining the formability and weldability of austenitic structure — ideal for seawater + flue-gas-desulfurization service.
254 SMO (UNS S31254) is the benchmark with PREN ~43, formulated for the most aggressive chloride + sulfuric acid service. 904L (N08904) is the original 4.5% Mo super-austenitic, widely specified for sulfuric-acid plants. Alloy 20 (N08020) is a Cu-bearing variant optimized specifically for hot sulfuric acid (50-80%) where standard austenitics fail rapidly. AL-6XN (N08367) and 654 SMO (S32654) extend service to higher pitting resistance with 6.5%+ Mo.
Super-austenitic fasteners are supplied per ASTM A276 / A479 with EN 10204 3.1 / 3.2 certification including pitting-resistance testing per ASTM G48 Method A at the temperature appropriate for the alloy. Welding requires Ni-base filler (alloy 625 / C-276) to avoid molybdenum segregation in the weld pool that would create preferential corrosion sites. NACE MR0175 sour-service certification is standard.
