Stainless Steel N-155 (Multimet)
UNS R30155 · also Multimet
N-155 (R30155, Multimet) is an iron-nickel-cobalt-chromium solid-solution austenitic alloy of superalloy class, formerly Grade 661, developed for gas-turbine hot sections.
Reference datasheet — N-155 (Multimet) is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SA condition
N-155 (Multimet) tempers and conditions
N-155 (Multimet) is supplied in 6 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard stocked condition for sheet, plate, bar and forgings; best ductility and formability, and the condition from which parts are welded and formed. | 415 | 815 | 45 | 200 HB | — |
As-welded deposit | Typical joint properties for fabricated combustion-liner and duct hardware welded in the solution-annealed condition. | 430 | 760 | 25 | 14 HRC | 1.9 % IACS |
Hot rolled | As-hot-worked bar and plate where subsequent solution treatment will be done by the part maker, or where moderate strength suffices. | 500 | 880 | 35 | 20 HRC | 1.9 % IACS |
solution annealed then aged ≈730–760 °C / 16 h | Choose when higher room- and elevated-temperature yield strength and creep-rupture life are needed, at the cost of ductility and toughness. | 560 | 930 | 25 | 24 HRC | — |
Cold drawn | Cold-drawn bar and wire for fasteners and small machined parts needing higher strength, straightness and surface finish. | 760 | 1,000 | 20 | 30 HRC | 1.9 % IACS |
CR 1/2-Hard | Cold-rolled strip where springback-tolerant higher strength is needed in thin sheet parts (clamps, seals, shims). | 900 | 1,100 | 12 | 34 HRC | 1.9 % IACS |
What is N-155 (Multimet)?
N-155 (R30155, Multimet) is an iron-nickel-cobalt-chromium solid-solution austenitic alloy of superalloy class, formerly Grade 661, developed for gas-turbine hot sections. Solution-annealed sheet, bar and forgings give 415 MPa yield, 815 MPa tensile and 45% elongation, with useful strength and oxidation resistance to 815 °C; aged, hot-rolled and cold-worked conditions are also on file. Formability (score 55) and machinability are limited by rapid work hardening, and above about 900 °C aluminizing or diffusion coatings are required. Alloy 800H is a lower-cost option where creep loads are lower. N-155 (Multimet) has a density of 8.19 g/cm³ (0.296 lb/in³), heavier than 100% of stainless steel grades. It melts at 1,300°C (2,372 °F). N-155 (Multimet) has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 815 MPa (118 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
What is N-155 (Multimet) used for?
- gas turbine combustors and afterburner parts
- jet engine exhaust components
- high-temperature fasteners
- aerospace superheater hardware
Advantages
- High service temperature — 815°C (1,499 °F), better than 77% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- High embodied carbon — 8 kg CO₂/kg, worse than 99% of stainless steel grades
- Difficult to machine — 20/100, worse than 98% of stainless steel grades
- Poor heat conductor — 12.3 W/m·K (7.11 BTU/hr·ft·°F), worse than 91% of stainless steel grades
- Low electrical conductivity — 1.9 % IACS, worse than 84% of stainless steel grades
N-155 (Multimet) properties
Typical room-temperature values for N-155 (Multimet)-SA; bars are the position among stainless steel grades.
Physical3
N-155 (Multimet) has a density of 8.19 g/cm³ (0.296 lb/in³), heavier than 100% of stainless steel grades. It melts at 1,300°C (2,372 °F).
Mechanical14
N-155 (Multimet) has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 815 MPa (118 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
N-155 (Multimet) is rated for continuous service to 815°C (1,499 °F). It conducts heat at 12.3 W/m·K (7.11 BTU/hr·ft·°F), worse than 91% of stainless steel grades. Thermal expansion is 14.4 µm/m·K (8 µin/in·°F).
Electrical3
N-155 (Multimet) conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental2
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of N-155 (Multimet) takes about 95 MJ of energy and emits 8 kg of CO₂ — more than 96% of stainless steel grades. Typical recycled content is 35%.
Manufacturability7
N-155 (Multimet)'s machinability is poor (20/100, worse than 98% of stainless steel grades); weldability very good (70/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. N-155 (Multimet) is highlighted; hover a dot for its name, or open the interactive family chart.
Working with N-155 (Multimet)
Is N-155 (Multimet) easy to machine?
Machine like a solid-solution superalloy: rigid setups, positive-rake carbide or ceramic tooling, low speed / heavy positive feed to cut under the work-hardened layer, flood coolant; avoid dwelling and rubbing.
Can N-155 (Multimet) be welded?
Readily GTAW/GMAW/EBW welded with matching N-155 or Ni-base (e.g. ERNiCrMo) filler, low heat input and no preheat; solution anneal after welding if maximum ductility or creep life is required.
Can N-155 (Multimet) be formed, bent or molded?
Formable in the solution-annealed condition but work-hardens rapidly — allow generous bend radii, use intermediate anneals for severe draws, or hot form at 1000–1180 °C.
N-155 (Multimet) 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 |
|---|---|---|
| C | 0.08 – 0.16 | 0.12 |
| Mn | 1 – 2 | 1.5 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.04 | |
| S | ≤ 0.03 | |
| Cr | 20 – 22.5 | 21 |
| Ni | 19 – 21 | 20 |
| Co | 18.5 – 21 | 20 |
| Mo | 2.5 – 3.5 | 3 |
| W | 2 – 3 | 2.5 |
| Nb+Tacolumbium plus tantalum | 0.75 – 1.25 | 1 |
| Nsolid-solution and nitride strengthener | 0.1 – 0.2 | 0.15 |
| Febalance, approx. 30 % | balance |
What surface finishes work on N-155 (Multimet)?
Not anodizable; passivate or pickle after heat treatment to remove oxide, and use aluminizing or diffusion/TBC coatings for extended service above ~900 °C.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel N-155 (Multimet) in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R30155
- Trade names
- Multimet
- Also called
- Grade 661N-155
- Other
- 5532/5768
How much does N-155 (Multimet) cost?
N-155 (Multimet) is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
N-155 (Multimet) — frequently asked
What is N-155 (Multimet) used for?
N-155 (Multimet) is typically used for gas turbine combustors and afterburner parts, jet engine exhaust components, high-temperature fasteners and aerospace superheater hardware. In short: superalloy-class austenitic; highest strength in family; gas-turbine hot-section sheet.
What is the yield strength of N-155 (Multimet)?
N-155 (Multimet) has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 815 MPa (118 ksi) — stronger than 62% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is N-155 (Multimet) easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Machine like a solid-solution superalloy: rigid setups, positive-rake carbide or ceramic tooling, low speed / heavy positive feed to cut under the work-hardened layer, flood coolant; avoid dwelling and rubbing.
Can N-155 (Multimet) be welded?
Yes — weldability is rated very good (70/100). Readily GTAW/GMAW/EBW welded with matching N-155 or Ni-base (e.g. ERNiCrMo) filler, low heat input and no preheat; solution anneal after welding if maximum ductility or creep life is required.
What surface finishes work on N-155 (Multimet)?
Not anodizable; passivate or pickle after heat treatment to remove oxide, and use aluminizing or diffusion/TBC coatings for extended service above ~900 °C.
Can N-155 (Multimet) be formed, bent or molded?
Formable in the solution-annealed condition but work-hardens rapidly — allow generous bend radii, use intermediate anneals for severe draws, or hot form at 1000–1180 °C.
What is the maximum service temperature of N-155 (Multimet)?
N-155 (Multimet) is rated for continuous use to about 815°C (1,499 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between N-155 (Multimet)-SA and N-155 (Multimet)-CD?
SA is the default condition — standard stocked condition for sheet, plate, bar and forgings; best ductility and formability, and the condition from which parts are welded and formed. CD: cold-drawn bar and wire for fasteners and small machined parts needing higher strength, straightness and surface finish. Yield strength is 415 MPa in SA versus 760 MPa in CD.
How much does N-155 (Multimet) cost?
N-155 (Multimet) is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AMS 5532 — Alloy Sheet, Strip and Plate, 21Cr-20Ni-20Co-3Mo-2.5W-1Cb — SAE International (2018)
- AMS 5768 — Alloy Bars, Forgings and Rings (N-155) — SAE International (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (heat-resistant alloys) — ASM International (1990)
- ASM Handbook Vol.16 — Machining (heat-resistant alloys) — ASM International (1989)
- UNS R30155 alloy data — SAE/ASTM Unified Numbering System (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.