| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| N08367 | – | – | – | – | – |
Al 6xn U bolts are externally threaded fasteners with an integral head, manufactured per ASME B18.2.1, ISO 4014/4017, and DIN 933/931. TorqBolt produces Al 6xn U bolts in metric (M6–M100) and imperial (1/4"–4") diameters with custom lengths from 10 mm up to 3000 mm.
Al 6xn U bolts are supplied with full or partial threading. Full-thread (UNC, UNF, ISO metric coarse/fine) for tension-only joints; partial-thread shank for shear loads where the unthreaded grip carries the load. Thread fits per ASME B1.1 (Class 2A) or ISO 965 (6g) by default; tighter Class 3A / 4h6h fits available on request. Engagement length follows the 1.5×D rule for tapped holes; 1.0×D minimum on through-bolting.
Al 6xn U bolts achieve characteristic tensile strength, yield, and elongation per the source-material spec, with proof-load testing and hardness verification per ASTM F606 / ISO 898-1. Torque-tension calibration is published per ASME PCC-1 for critical joints. Each lot ships with EN 10204 3.1 (or 3.2 on request) certificates listing chemistry, mechanicals, hardness, and dimensional inspection.
TorqBolt can produce Al 6xn U bolts to drawing, with non-standard heads, drilled-shank variants, double-end, captive, or matched-set configurations. Coatings include zinc, PTFE, Xylan, hot-dip galvanized, and electroless nickel. NACE MR0175 / ISO 15156 sour-service certification on request.
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.