Nimonic Alloys: Grades, Properties & Product Forms

NIMONIC is a registered trademark of Special Metals Corporation. Sagiant Piping Industries is an independent supplier and stockist, not the alloy producer. Nimonic 75 is a solid-solution grade and is not precipitation-hardened; identify the exact grade, UNS, specification edition and condition on enquiry.

Producer/BS HR reference limits; “bal” denotes balance and is not a fixed value; a dash means not separately specified, not zero. The 105 UNS is shown as not verified rather than guessed. These are not full heat analyses — the purchase specification edition and heat/product certificate control acceptance, and specification limits must not be mixed with tighter producer limits.

“Core” grades appear on this page; “Reference” names are documented in producer literature and quoted until chemistry, form, specification and availability are confirmed — a listing is not a stock statement, and even producer index pages can carry metadata errors. Historical names (original 80, 100, OEM-modified conditions) and boundary items such as cobalt-base MP35N are tracked separately and are not merged with the 75–115 turbine grades.

Typical room-temperature values in the fully heat-treated condition, not contractual minima; they lack the product form, size, grain-size and test basis needed for design. Nimonic 75 is annealed (solid-solution), the others are solution-treated and aged. For a turbine-alloy reference, room-temperature tensile data alone is insufficient — elevated-temperature tensile, creep strain vs stress/temperature/time, stress-rupture life and ductility, low-/high-cycle and thermal fatigue, and stress relaxation for bolts/springs are supplied per grade and condition from the ordered specification, with measured data distinguished from extrapolation. Do not derive code allowable stresses from tensile strength.

Aerospace BS HR specifications, AMS specifications, OEM requirements and dimensional standards are separate systems and are not conflated. There is no “ASTM B637-style” compliance — B637 requires the exact UNS, form, treatment and edition, and does not cover tube/plate from a bar/forging standard. Designations are cross-references, not substitution approvals: 90 is N07090/2.4632 and 263 N07263/2.4650 on their verified basis; 75/80A dual Werkstoff references need form/standard caveats; 105 UNS is not verified. Shared names or related national grades do not establish identical chemistry, treatment, creep life or qualification. For aerospace supply, the approved source, melt route, material/process specifications and traceability are recorded as ordered — a generic MTC does not establish OEM approval.

Availability is confirmed per enquiry with stocked / sourced / made-to-order status by grade — the ranges below are indicative and verified against supply records per order.

These grades are supplied primarily as bar, sheet and forgings; scheduled pipe is not a standard offering — pipe/fitting/flange dimensions are by specification or drawing, and a universal NPS schedule table is not implied. Where scheduled pipe is genuinely required, the actual NPS/DN/OD/wall, dimensional standard (B36.10M / B36.19M) and grade-specific mass are confirmed on enquiry, separate from alloy qualification. See the weight calculator for grade-specific mass.

• 75: solid-solution grade for combustor sheet, ducting, rings and lower-stress hot components — it does not deliver the creep strength of the aged grades.
• 80A / 90: age-hardened blades, discs, ring sections, bolts and exhaust valves where creep and fatigue strength are required.
• 105: higher-temperature aged blade/disc material; multistage heat-treatment routes matter.
• 263: combustor and fabricated hot-section sheet/ring assemblies, chosen for weldability and formability with useful aged strength.
• Environment: separate oxidation/scaling, hot corrosion under fuel/ash/salt deposits, sulfidation and thermal cycling — oxidation resistance is not evidence of aqueous acid or seawater resistance, and no generic “NACE approved” or corrosion-proof claim applies.

Every temperature statement depends on grade, microstructure, stress/load, required life, atmosphere and continuous/intermittent/cyclic exposure. Producer development-temperature statements (roughly 815–950°C for the aged grades) are not universal allowable design temperatures; melting point, annealing temperature, oxidation-test temperature and long-term allowable metal temperature are different quantities.