NIMONIC 75 Rings manufactured at TorqBolt are corrosion resistant,high temperature resistant with ultimate tensile strength.
Dimensional standards as per DIN 471,DIN 472,DIN 5417,DIN 983,AS 568,BS 1806,ISO 3601,DIN 3771 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. NIMONIC 75 Rings are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.
Nimonic 75 Is A Nickel Chromium Alloy With Additions Of Carbon And Titanium. Also Known As Alloy 75 This Alloy Is Resistant To Oxidation At Elevated Temperatures With A Medium Strength. Nimonic Alloy 75a Can Be Provided In Solution Annealed And Precipitation Hardened Condition.
Nimonic 75 rings are seamless rolled or open-die forged components used as pressure-vessel flanges, valve bodies, hub-mount blanks, and shaft-end retention rings. TorqBolt supplies Nimonic 75 rings per ASTM A182 (forged flange standard), ASTM A266/A668 (carbon ring), and EN 10222 (pressure-purpose forging), in OD sizes from 50 mm up to 3000 mm.
Forging Process
Rings are produced via either seamless ring rolling (radial-axial mill, for OD > 200 mm) or open-die hammer forging (for short-run / oversize parts). Reduction ratio ≥ 4:1 from billet to final ring is enforced for grain-flow continuity. Heat treatment is per the alloy spec — solution-anneal + quench + age for precipitation-hardening alloys; quench & temper for low-alloy steels.
Dimensional Tolerance
Nimonic 75 rings are supplied to ASTM A788 dimensional tolerances by default: OD ±1.5 mm or ±1% (whichever is larger), ID ±1.5 mm, height ±0.8 mm. Tighter tolerances (machined finish, ±0.1 mm) available for direct-mount applications. Out-of-roundness controlled to 1.5 mm; concentricity 0.2 mm/100 mm.
Mechanical Testing
Each ring lot ships with full mechanical certification: tensile (ASTM E8), Charpy impact (ASTM E23) at the application's MDMT, hardness traverse, and grain size per ASTM E112. For Nimonic 75 ring stock destined for hydrogen / sour service, additional HIC testing (NACE TM0284) and SSC testing (NACE TM0177) per the customer's spec.
Surface & Inspection
Nimonic 75 rings ship rough-machined or finish-machined per drawing. Standard NDT: 100 % UT (ASTM A388 reference) and surface MT/PT to ASTM E709 / E165. Radiography on request. Each ring is hard-stamped with heat number, lot, and certification reference for traceability through the dispatch chain.
Nimonic — Nickel-Chromium Wrought Superalloys
Nimonic is a family of wrought nickel-chromium superalloys originally developed for jet-engine turbine blade and bolting service, where steady-state operating temperatures exceed 700°C under high cyclic stress. Composition centers on ~50-75% Ni, 15-22% Cr, 0-20% Co with Ti+Al additions for γ' precipitation hardening. Nimonic alloys retain creep strength well beyond the limits of conventional Fe-Ni-Cr superalloys.
Nimonic 75 (UNS N06075) is the simplest grade: solid-solution Ni-Cr without precipitation hardening, used for furnace fixtures and mild-temperature bolting to 760°C. Nimonic 80A (N07080) adds Ti+Al for age-hardening — tensile ~1100 MPa, the workhorse of steam-turbine and exhaust-valve bolting per ASTM B637 / AMS 5662. Nimonic 90 (N07090) adds 16-20% Co for service to 920°C with stress-rupture life suitable for gas-turbine combustor bolts.
Nimonic fasteners ship per ASTM B637 / B564 with EN 10204 3.1 / 3.2 certs covering chemistry, hardness (HRC 30-42), tensile at room + elevated temperature, and stress-rupture acceptance per the heat-treat condition. NACE MR0175 sour-service compliance available in solution-annealed condition.
