Nickel Alloy Nimonic 75-SR (Stress relieved)
Heat-treated state
UNS N06075 · EN 2.4951, NiCr20Ti · BS HR1
Applied to formed or welded assemblies to remove residual stress and stabilise carbides without fully recrystallising the structure.
Values for the SR condition
Other Nimonic 75 tempers and conditions
Nimonic 75 is listed in 6 conditions; see the grade overview at Nimonic 75.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed / softened | Standard stocked condition for sheet, plate, bar and tube; maximum ductility and formability with stable grain-boundary carbides. | 300 | 750 | 40 | 180 HB | — |
Hot rolled | Choose for thicker bar, forging stock and heavy plate where mill-scale surface and slightly coarser grain are acceptable. | 330 | 780 | 37 | 195 HB | 1.6 % IACS |
SRThis page Stress relieved | Applied to formed or welded assemblies to remove residual stress and stabilise carbides without fully recrystallising the structure. | 400 | 800 | 32 | 210 HB | 1.6 % IACS |
CR half hard | Intermediate strength/springiness for clips, shims and lightly formed brackets that will not be re-annealed. | 570 | 870 | 20 | 24 HRC | 1.6 % IACS |
Cold drawn | Use where higher room-temperature yield strength, straightness and a bright ground/drawn surface are needed on small-diameter bar. | 650 | 900 | 18 | 26 HRC | — |
CR hard | Highest room-temperature strength; only for cold-service springs and flat stock, since recrystallisation removes the strengthening above ~600 °C. | 820 | 1,030 | 8 | 33 HRC | 1.6 % IACS |
What is Nimonic 75-SR?
Nimonic 75-SR is Nimonic 75 heat treated to SR — applied to formed or welded assemblies to remove residual stress and stabilise carbides without fully recrystallising the structure. Nimonic 75-SR has a yield strength of 400 MPa (58 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 56% of nickel alloy grades. Elongation at break is 32% and the elastic modulus is 206 GPa (29.9 Msi). Nimonic 75-SR has a density of 8.37 g/cm³ (0.302 lb/in³), heavier than 55% of nickel alloy grades. It melts at 1,340°C (2,444 °F). SA is the default condition FabDigit quotes; SR is available on request or by drawing note.
Nimonic 75-SR properties
Typical room-temperature values for Nimonic 75-SR; 21 are specific to this condition. Other listed values are Nimonic 75 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Nimonic 75-SR has a density of 8.37 g/cm³ (0.302 lb/in³), heavier than 55% of nickel alloy grades. It melts at 1,340°C (2,444 °F).
Mechanical14
Nimonic 75-SR has a yield strength of 400 MPa (58 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 56% of nickel alloy grades. Elongation at break is 32% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Nimonic 75-SR is rated for continuous service to 950°C (1,742 °F). It conducts heat at 11.7 W/m·K (6.76 BTU/hr·ft·°F), better than 61% of nickel alloy grades. Thermal expansion is 12.7 µm/m·K (7.06 µin/in·°F).
Electrical3
Nimonic 75-SR conducts electricity at 1.6 % IACS, better than 70% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 71% of nickel alloy grades.
Sustainability4
Producing a kilogram of Nimonic 75-SR takes about 160 MJ of energy and emits 12 kg of CO₂ — less than 53% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability8
Nimonic 75-SR's machinability is poor (24/100, better than 71% of nickel alloy grades); weldability very good (75/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Nimonic 75-SR
Is Nimonic 75 easy to machine?
Work-hardening and gummy: use rigid setups, positive-rake carbide or sharp HSS-Co tooling, 15–30 m/min with heavy feed, flood coolant and no dwelling to avoid glazing.
Can Nimonic 75 be welded?
Readily joined by GTAW/GMAW/resistance welding with matching NiCr20Ti or Inconel 82/625 filler; keep interpass temperature low, use clean surfaces (S-free) and avoid heavy restraint.
Can Nimonic 75 be formed, bent or molded?
Excellent cold formability in the annealed state (deep drawing, spinning, bending) but needs ~2× the force of austenitic stainless; interstage anneal at 1020–1080 °C after heavy reductions; hot work 1000–1180 °C.
What surface finishes work on Nimonic 75?
Pickle/bright-anneal to remove Cr-rich scale before service; can be electropolished, ground and mechanically polished; not anodizable — use no coating for oxidation service or aluminide/Pt-Al diffusion coatings for very hot parts.
Nimonic 75 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cr | 18 – 21 | 19.5 |
| Ticarbide former | 0.2 – 0.6 | 0.4 |
| C2.4630 / low-C variants specify ≤0.10 | 0.08 – 0.15 | 0.11 |
| Fe | ≤ 5 | 2 |
| Mn | ≤ 1 | 0.3 |
| Si | ≤ 1 | 0.4 |
| Co | ≤ 2 | 0.3 |
| Cu | ≤ 0.5 | 0.1 |
| Al | ≤ 0.5 | 0.15 |
| S | ≤ 0.02 | 0.01 |
| B | ≤ 0.01 | — |
| Zr | ≤ 0.15 | — |
| Nibalance, min ~70 % | ≥ 70 (balance) | — |
Nimonic 75-SR — frequently asked
What is Nimonic 75-SR used for?
Nimonic 75-SR is typically used for gas turbine combustion chamber sheet parts, exhaust and afterburner components, furnace fixtures and thermocouple sheathing. In short: formable hot-section sheet alloy; oxidation resistant to 950 °C; weldable, moderate strength.
What is the yield strength of Nimonic 75-SR?
Nimonic 75-SR has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 56% of nickel alloy grades. Strength varies by condition: see the 6 listed tempers.
Is Nimonic 75-SR easy to machine?
Not especially — machinability is rated poor (24/100, better than 71% of nickel alloy grades). Work-hardening and gummy: use rigid setups, positive-rake carbide or sharp HSS-Co tooling, 15–30 m/min with heavy feed, flood coolant and no dwelling to avoid glazing.
Can Nimonic 75-SR be welded?
Yes — weldability is rated very good (75/100). Readily joined by GTAW/GMAW/resistance welding with matching NiCr20Ti or Inconel 82/625 filler; keep interpass temperature low, use clean surfaces (S-free) and avoid heavy restraint.
What surface finishes work on Nimonic 75-SR?
Pickle/bright-anneal to remove Cr-rich scale before service; can be electropolished, ground and mechanically polished; not anodizable — use no coating for oxidation service or aluminide/Pt-Al diffusion coatings for very hot parts.
Can Nimonic 75-SR be formed, bent or molded?
Excellent cold formability in the annealed state (deep drawing, spinning, bending) but needs ~2× the force of austenitic stainless; interstage anneal at 1020–1080 °C after heavy reductions; hot work 1000–1180 °C.
What is the maximum service temperature of Nimonic 75-SR?
Nimonic 75-SR is rated for continuous use to about 950°C (1,742 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nimonic 75-SA and Nimonic 75 CR-H?
SA is the default condition — standard stocked condition for sheet, plate, bar and tube; maximum ductility and formability with stable grain-boundary carbides. CR-H: highest room-temperature strength; only for cold-service springs and flat stock, since recrystallisation removes the strengthening above ~600 °C. Yield strength is 300 MPa in SA versus 820 MPa in CR-H.
Sources
- NIMONIC alloy 75 Publication SMC-080 — Special Metals Corporation (2004)
- BS HR1 / BS 3072-3076 wrought nickel alloy sheet & bar — BSI (1989)
- DIN 17742 / VdTÜV 383 — NiCr20Ti (2.4951, 2.4630) — DIN (2002)
- ASTM B637 / UNS N06075 designation listing — ASTM / SAE (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- BCR-661 Nimonic 75 certified reference material report — IRMM / EU JRC (2000)
- (GH3030 / NiCr20Ti) (2026)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.