254-SMO Washers manufactured at TorqBolt are corrosion resistant,high temperature resistant with ultimate tensile strength.
Dimensional standards as per DIN 125,ISO 7089,ISO 7090,ISO 7092,DIN 433,DIN 7349,DIN 9021,ISO 7093, are provided.
The raw material of these fasteners is further classified as Super Nickel Alloys. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. 254-SMO Washers are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
254-smo Is A High Moly Alloy Austenitic Stainless Steel With Additions Of Nickel And Copper.254smo Has Good Resistance To Pitting’s And Crevice Corrosion.
254 Smo washers distribute clamp load over a wider bearing area, prevent surface damage, and accommodate bolt-hole oversize. TorqBolt manufactures 254 Smo washers per ASME B18.21.1 / B18.22.1, DIN 125 / 126 / 127 / 9021, and ISO 7089 / 7090 / 7093 / 7094, in metric (M3–M100) and imperial (#4–4") sizes.
Plain Washer Dimensions
254 Smo plain washers are characterized by three critical dimensions: ID (clearance over bolt diameter), OD (load distribution area), and thickness (compressive stiffness). Standard tolerances are h13 on OD and H13 on ID per ISO 286-2; flatness 0.05 mm/100 mm and parallelism 0.05 mm/100 mm verified per lot. Edge break / chamfer per drawing.
Form Variants
Form A (regular) — DIN 125-A / ISO 7089, the default plain washer
Form B (large OD) — DIN 9021 / ISO 7093, for soft mating surfaces
Form C (heavy) — DIN 7349 / ISO 7094, for slotted holes / structural use
Spring (split) — DIN 127 / ASME B18.21.1, helical anti-vibration
Conical / Belleville (DIN 6796 / 2093) — preload maintenance
Hardness & Surface
254 Smo washers are hardness-controlled to balance load-distribution stiffness against surface damage to mating parts. Typical Vickers HV ranges: plain 140–180 HV; spring 380–440 HV; Belleville 460–540 HV. Surface finish Ra 1.6 µm or better; on critical sealing applications, Ra 0.8 µm available.
Special Patterns
TorqBolt produces 254 Smo washers in square (DIN 436), fender (oversized OD), tab / lock-tang (DIN 462 / 463), and spherical seat washer + cup combinations. EN 10204 3.1 / 3.2 material certificates standard; NACE MR0175 / ISO 15156 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.
