Nickel Alloy Monel 401-SR (Stress relieved)
Heat-treated state
UNS N04401
Cold-worked material given a 260–370 °C stabilizing treatment to lock in resistance value and reduce residual stress/drift.
Values for the SR condition
Other Monel 401 tempers and conditions
Monel 401 is listed in 6 conditions; see the grade overview at Monel 401.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition: maximum ductility for stamping, drawing and coil winding, most stable resistivity. | 170 | 470 | 42 | 115 HB | — |
Quarter hard | Choose when slightly higher stiffness and better blanking edge quality are needed but forming is still required. | 350 | 550 | 25 | 150 HB | 3.6 % IACS |
Half hard | Balance of strength and remaining bend ductility for contacts, clips and formed terminals. | 470 | 620 | 15 | 185 HB | 3.5 % IACS |
SRThis page Stress relieved | Cold-worked material given a 260–370 °C stabilizing treatment to lock in resistance value and reduce residual stress/drift. | 600 | 700 | 8 | 210 HB | 3.5 % IACS |
Hardened | Maximum strength and hardness from cold work; use for flat springs, straight wire and machined parts needing good chip control. | 620 | 730 | 6 | 20 HRC | 3.5 % IACS |
Spring Temper | For coil and flat springs, contact fingers and resistance elements needing high elastic limit. | 720 | 830 | 3 | 22 HRC | 3.5 % IACS |
What is Monel 401-SR?
Monel 401-SR is Monel 401 heat treated to SR — cold-worked material given a 260–370 °C stabilizing treatment to lock in resistance value and reduce residual stress/drift. Monel 401-SR has a yield strength of 600 MPa (87 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 8% and the elastic modulus is 165 GPa (23.9 Msi). Monel 401-SR has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 85% of nickel alloy grades. It melts at 1,260°C (2,300 °F). ANN is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Easy to machine — 39/100, better than 98% of nickel alloy grades
- Low embodied carbon — 7.5 kg CO₂/kg, better than 96% of nickel alloy grades
- High electrical conductivity — 3.5 % IACS, better than 91% of nickel alloy grades
- Conducts heat well — 21 W/m·K (12.1 BTU/hr·ft·°F), better than 88% of nickel alloy grades
- High strength — 600 MPa (87 ksi), better than 81% of nickel alloy grades
Limitations
- Low stiffness — 165 GPa (23.9 Msi), worse than 91% of nickel alloy grades
- Limited service temperature — 425°C (797 °F), worse than 90% of nickel alloy grades
- Limited ductility — 8%, worse than 87% of nickel alloy grades
Monel 401-SR properties
Typical room-temperature values for Monel 401-SR; 21 are specific to this condition. Other listed values are Monel 401 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Monel 401-SR has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 85% of nickel alloy grades. It melts at 1,260°C (2,300 °F).
Mechanical14
Monel 401-SR has a yield strength of 600 MPa (87 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 8% and the elastic modulus is 165 GPa (23.9 Msi).
Thermal6
Monel 401-SR is rated for continuous service to 425°C (797 °F). It conducts heat at 21 W/m·K (12.1 BTU/hr·ft·°F), better than 88% of nickel alloy grades. Thermal expansion is 14.2 µm/m·K (7.89 µin/in·°F).
Electrical3
Monel 401-SR conducts electricity at 3.5 % IACS, better than 91% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 77% of nickel alloy grades.
Sustainability4
Producing a kilogram of Monel 401-SR takes about 105 MJ of energy and emits 7.5 kg of CO₂ — less than 94% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
Monel 401-SR's machinability is fair (39/100, better than 98% of nickel alloy grades); weldability good (60/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Monel 401-SR
Is Monel 401 easy to machine?
Work-hardens rapidly — use sharp, positive-rake carbide, heavy positive feed, rigid setup, low-to-moderate speed and flood sulfur-free coolant; avoid dwelling.
Can Monel 401 be welded?
GTAW/GMAW with Monel-type Ni-Cu filler (ERNiCu-7); keep parts free of sulfur, lead and grease, use low heat input and no post-weld hardening treatment.
Can Monel 401 be formed, bent or molded?
Excellent cold formability in the annealed temper (deep drawing, coiling, stamping); interstage anneal at 760–870 °C followed by rapid cooling after heavy reductions.
What surface finishes work on Monel 401?
Not anodizable; pickle or bright-anneal to remove oxide, then polish, or electroplate Ni/Ag/Au for solderable, low-contact-resistance surfaces.
Monel 401 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 |
|---|---|---|
| NiNi + Co | 40 – 45 | 43 |
| Mn | ≤ 2.25 | 1.6 |
| Fe | ≤ 0.75 | 0.3 |
| C | ≤ 0.1 | 0.05 |
| Si | ≤ 0.25 | 0.1 |
| S | ≤ 0.02 | 0.01 |
| Cubalance, approx. 53–57 % | balance | — |
Monel 401-SR — frequently asked
What is Monel 401-SR used for?
Monel 401-SR is typically used for electrical resistors, thermostat components and corrosion-resistant springs. In short: controlled-resistivity Monel; corrosion-resistant spring material; high cold formability annealed.
What is the yield strength of Monel 401-SR?
Monel 401-SR has a typical yield strength of 600 MPa (87 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 81% of nickel alloy grades. Strength varies by condition: see the 6 listed tempers.
Is Monel 401-SR easy to machine?
Not especially — machinability is rated fair (39/100, better than 98% of nickel alloy grades). Work-hardens rapidly — use sharp, positive-rake carbide, heavy positive feed, rigid setup, low-to-moderate speed and flood sulfur-free coolant; avoid dwelling.
Can Monel 401-SR be welded?
Yes — weldability is rated good (60/100). GTAW/GMAW with Monel-type Ni-Cu filler (ERNiCu-7); keep parts free of sulfur, lead and grease, use low heat input and no post-weld hardening treatment.
What surface finishes work on Monel 401-SR?
Not anodizable; pickle or bright-anneal to remove oxide, then polish, or electroplate Ni/Ag/Au for solderable, low-contact-resistance surfaces.
Can Monel 401-SR be formed, bent or molded?
Excellent cold formability in the annealed temper (deep drawing, coiling, stamping); interstage anneal at 760–870 °C followed by rapid cooling after heavy reductions.
What is the maximum service temperature of Monel 401-SR?
Monel 401-SR is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Monel 401-ANN and Monel 401-SPR?
ANN is the default condition — standard stocked condition: maximum ductility for stamping, drawing and coil winding, most stable resistivity. SPR: for coil and flat springs, contact fingers and resistance elements needing high elastic limit. Yield strength is 170 MPa in ANN versus 720 MPa in SPR.
Sources
- Monel alloy 401 product data (Ni-Cu resistance alloy) — Special Metals Corporation (2005)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 13B: Corrosion — Materials — ASM International (2005)
- UNS N04401 designation (Metals & Alloys in the Unified Numbering System) — SAE/ASTM (2017)
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.