Alloy W Flat Washers Specification

ALLOY W Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| – | – | – | – | – | – |
Alloy W Flat washers distribute clamp load over a wider bearing area, prevent surface damage, and accommodate bolt-hole oversize. TorqBolt manufactures Alloy W Flat 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.
Alloy W Flat 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.
Alloy W Flat 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.
TorqBolt produces Alloy W Flat 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.
High-nickel superalloys beyond the Inconel + Hastelloy family include specialty grades engineered for unique service envelopes — ultra-high-temperature furnace components, oxidation-resistant structural alloys, and corrosion alloys where C-276 reaches its limits.
Alloy 230 (UNS N06230) is a Ni-Cr-W-Mo solid-solution alloy combining the high-temperature strength of Inconel 625 with superior oxidation resistance to 1150°C — the standard for gas-turbine combustor cans and reformer tubes. Alloy 330 (N08330) is a Fe-Ni-Cr alloy for cyclic-temperature furnace fixtures. Alloy 333 (N06333) extends the envelope with higher Mo+W. Alloy 602 CA (N06025) achieves the highest oxidation resistance of any wrought Ni-base alloy at 1200°C+ via Al + reactive-element additions. Alloy W (N10004) is a Ni-Mo-Fe-Cr alloy for sulfuric and reducing-acid service.
These specialty alloys ship per ASTM B435 / B574 / B575 with EN 10204 3.1 / 3.2 certification including chemistry, mechanicals at room + elevated test temperatures, hardness, and oxidation / corrosion testing per the application's requirement. Welding requires matched-composition filler with strict control of dilution.