MP 35N Lock washers manufactured at TorqBolt are corrosion resistant,high temperature resistant with ultimate tensile strength.
Dimensional standards as per DIN 6797,DIN 6931 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. MP 35N Lock washers are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
Mp 35n Lock washers distribute clamp load over a wider bearing area, prevent surface damage, and accommodate bolt-hole oversize. TorqBolt manufactures Mp 35n Lock 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
Mp 35n Lock 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
Mp 35n Lock 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 Mp 35n Lock 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.
MP35N — Ni-Co-Cr-Mo Multiphase Alloy
MP35N (UNS R30035) is a multiphase nickel-cobalt-chromium-molybdenum alloy combining ultra-high tensile strength with outstanding corrosion resistance — positioned where Inconel 718 lacks sufficient corrosion resistance and Hastelloy C-276 lacks sufficient strength. The cold-work + age-hardening response yields tensile strength >2000 MPa with excellent fatigue and stress-corrosion performance.
The MP35N microstructure is a two-phase mix of fcc + hcp regions; specific cold-work reduction (40-50%) followed by ageing at 540-650°C transforms the matrix to deliver the alloy's signature combination of strength + corrosion resistance. Composition centers on ~35% Ni, 35% Co, 20% Cr, 10% Mo.
MP35N is the dominant material for sour-well wireline + casing bolting, downhole completion equipment, surgical implants requiring biocompatibility + fatigue strength, and high-pressure aerospace fasteners. The alloy is fully qualified to NACE MR0175 / ISO 15156 across the standard hardness range (up to ~52 HRC), making it one of the few materials capable of meeting both extreme-strength and sour-service criteria simultaneously.
MP35N fasteners are supplied per ASTM F562 / AMS 5844 / 5845 with EN 10204 3.2 third-party-witnessed certification including chemistry, mechanicals, hardness, fatigue, and stress-corrosion testing. Welding is generally avoided; mechanical joints with matching MP35N hardware are preferred.
