Nickel Alloy N7M
UNS J30007, N10665 · ASTM A494 N7M
N7M is the cast low-carbon Ni-Mo grade of ASTM A494 (J30007), the casting counterpart of wrought Hastelloy B-2 (N10665).
Reference datasheet — N7M 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
N7M tempers and conditions
N7M is supplied in 4 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for all ASTM A494 N-7M castings — required for full corrosion resistance and ductility. | 310 | 585 | 30 | 187 HB | 1.3 % IACS |
hot isostatically pressed then solution annealed | For thin-wall investment-cast pump and valve parts where microporosity must be eliminated for pressure-boundary or radiographic acceptance. | 320 | 620 | 38 | 190 HB | 1.3 % IACS |
As fabricated | Only for non-corrosion structural or trial parts — interdendritic Mo segregation and carbides lower ductility and acid resistance. | 330 | 520 | 12 | 16 HRC | 1.2 % IACS |
As-welded deposit | Low-carbon chemistry allows weld repair without post-weld solution treatment for many services; re-anneal if maximum HCl resistance is required. | 330 | 560 | 22 | 13 HRC | 1.3 % IACS |
What is N7M?
N7M is the cast low-carbon Ni-Mo grade of ASTM A494 (J30007), the casting counterpart of wrought Hastelloy B-2 (N10665). It resists hydrochloric and other non-oxidizing acids without embrittlement, and is supplied as sand and investment castings rated 310 MPa yield, 585 MPa tensile, 30 % elongation and 187 HB (92 HRB) in the solution-annealed condition. Service is capped near 450 °C and the alloy is unsuited to oxidizing media; where both oxidizing and reducing conditions occur, a cast Ni-Cr-Mo grade such as CW-2M (Alloy 22 type) is the usual alternative. Machinability rates 22 of 100, so cast close to net shape. N7M has a density of 9.22 g/cm³ (0.333 lb/in³), heavier than 97% of nickel alloy grades. It melts at 1,330°C (2,426 °F). N7M has a yield strength of 310 MPa (45 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 74% of nickel alloy grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
What is N7M used for?
- hydrochloric acid pumps
- chemical process valves
- acid recovery equipment castings
Limitations
- Low electrical conductivity — 1.3 % IACS, worse than 97% of nickel alloy grades
- Limited service temperature — 450°C (842 °F), worse than 86% of nickel alloy grades
- Limited formability — 20/100, worse than 75% of nickel alloy grades
N7M properties
Typical room-temperature values for N7M-SA; bars are the position among nickel alloy grades.
Physical3
N7M has a density of 9.22 g/cm³ (0.333 lb/in³), heavier than 97% of nickel alloy grades. It melts at 1,330°C (2,426 °F).
Mechanical14
N7M has a yield strength of 310 MPa (45 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 74% of nickel alloy grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal5
N7M is rated for continuous service to 450°C (842 °F). It conducts heat at 11.1 W/m·K (6.41 BTU/hr·ft·°F), worse than 54% of nickel alloy grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
N7M conducts electricity at 1.3 % IACS, worse than 97% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (84/100), better than 70% of nickel alloy grades.
Sustainability4
Producing a kilogram of N7M takes about 180 MJ of energy and emits 13.5 kg of CO₂ — more than 69% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability8
N7M's machinability is poor (22/100, better than 64% of nickel alloy grades); weldability good (68/100); formability poor (20/100).
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 nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. N7M is highlighted; hover a dot for its name, or open the interactive family chart.
Working with N7M
Is N7M easy to machine?
Slow speeds, heavy positive-rake carbide, rigid setup and flood coolant — the alloy work-hardens fast and never break the cut dwelling in one spot.
Can N7M be welded?
GTAW/GMAW with matching ENiMo-7 / ERNiMo-7 (B-2) filler, low heat input, interpass below ~100 °C; the low-carbon chemistry usually permits weld repair without re-annealing.
Can N7M be formed, bent or molded?
Sand or investment cast from vacuum/argon-protected melts; generous risering and rapid solidification are needed to limit Mo microsegregation, then solution anneal and quench.
N7M 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 |
|---|---|---|
| Mo | 30 – 33 | 31.5 |
| Fe | ≤ 3 | 1.5 |
| Cr | ≤ 1 | 0.5 |
| C | ≤ 0.07 | 0.03 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Niremainder, typically ~65–68 % | balance |
What surface finishes work on N7M?
Pickle in HF–HNO₃ or grit-blast plus passivation to remove casting scale; mechanically polishes well, no anodizing or plating normally applied.
Surface treatments FabDigit runs on nickel alloy 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).
Plating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Nickel Alloy N7M in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J30007N10665
- ASTM
- A494 N7M
How much does N7M cost?
N7M is a high-cost nickel alloy ($$$$), 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.
N7M — frequently asked
What is N7M used for?
N7M is typically used for hydrochloric acid pumps, chemical process valves and acid recovery equipment castings. In short: cast Hastelloy B-2 equivalent; top cast HCl resistance; non-oxidizing acid specialist.
What is the yield strength of N7M?
N7M has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 74% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is N7M easy to machine?
Not especially — machinability is rated poor (22/100, better than 64% of nickel alloy grades). Slow speeds, heavy positive-rake carbide, rigid setup and flood coolant — the alloy work-hardens fast and never break the cut dwelling in one spot.
Can N7M be welded?
Yes — weldability is rated good (68/100). GTAW/GMAW with matching ENiMo-7 / ERNiMo-7 (B-2) filler, low heat input, interpass below ~100 °C; the low-carbon chemistry usually permits weld repair without re-annealing.
What surface finishes work on N7M?
Pickle in HF–HNO₃ or grit-blast plus passivation to remove casting scale; mechanically polishes well, no anodizing or plating normally applied.
Can N7M be formed, bent or molded?
Sand or investment cast from vacuum/argon-protected melts; generous risering and rapid solidification are needed to limit Mo microsegregation, then solution anneal and quench.
What is the maximum service temperature of N7M?
N7M is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between N7M-SA and N7M-F?
SA is the default condition — standard supply condition for all ASTM A494 N-7M castings — required for full corrosion resistance and ductility. F: only for non-corrosion structural or trial parts — interdendritic Mo segregation and carbides lower ductility and acid resistance. Yield strength is 310 MPa in SA versus 330 MPa in F.
How much does N7M cost?
N7M is a high-cost nickel alloy ($$$$), 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
- ASTM A494/A494M — Castings, Nickel and Nickel Alloy (Grade N-7M) — ASTM International (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- HASTELLOY B-2 alloy (N10665) technical data — Haynes International (2020)
- Corrosion of Nickel-Base Alloys in Reducing Acids — NACE/AMPP (2018)
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.