Cupronickel 70-30 Washers manufactured at TorqBolt are seawater resistant,crevice resistant,stress corrosion crack resistant & hydrogen embrittlement resistant.
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 classified as copper based nickels. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. Cupronickel 70-30 Washers are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
Copper Nickel 70-30 Is A High Content Resistant To Corrosion At Elevated High Temperatures Due To Presence Of Nickel Oxide At High Temperature. 70-30 Is Extremely Used In Offshore Industries.
Cupronickel 70 30 washers distribute clamp load over a wider bearing area, prevent surface damage, and accommodate bolt-hole oversize. TorqBolt manufactures Cupronickel 70 30 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
Cupronickel 70 30 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
Cupronickel 70 30 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 Cupronickel 70 30 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.
Copper-Nickel & Cupronickel Alloys
Copper-nickel (cupronickel) alloys combine copper's bio-fouling resistance with nickel's strength and corrosion enhancement. The two production grades dominate marine + desalination service where titanium is too costly: 90/10 Cu-Ni (~90% Cu, 10% Ni) and 70/30 Cu-Ni. Cu-Ni alloys are the only commercial materials inherently resistant to marine bio-fouling, eliminating the need for antifouling coatings on heat-exchanger tubes and ship hulls.
C70600 (90/10 Cu-Ni) is the high-volume marine alloy: yield ~105 MPa, used for desalination tubing, condenser tubes, hull cladding, and offshore piping fasteners. C71500 (70/30 Cu-Ni) increases nickel for higher strength (~160 MPa yield) and better seawater erosion-corrosion at higher flow velocities — the choice for naval condensers and high-pressure desalination. C71640 (70/30 + Fe + Mn) extends service to even higher flow rates.
Cu-Ni fasteners ship per ASTM B151 (rod/bar) and B171 (plate/forging) with EN 10204 3.1 / 3.2 certificates. Welding uses ERCuNi or ENiCu-7 filler with low-heat-input technique to avoid hot cracking. NACE MR0175 sour-service application is limited; ammoniacal stress-corrosion can occur if exposed to NH₃ in service.
