Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Monel 400 Mechanical Properties - UNS N04400 Yield, Tensile, Hardness and Modulus
Monel 400 mechanical properties (also Monel 400 yield strength, Monel 400 tensile strength, Monel 400 hardness, Monel 400 hardness HRC, Alloy 400 mechanical properties, UNS N04400 mechanical properties, Monel 400 elongation, Monel 400 modulus) are set by ASTM B164 (rod, bar, wire), ASTM B127 (plate, sheet), ASTM B564 (forgings) and ASTM F468 (bolts). The alloy ships annealed, hot-worked, cold-worked stress-relieved or cold-worked as-worked. Annealed UNS N04400 carries 25 ksi (170 MPa) min yield, 70 ksi (480 MPa) min tensile, 35 percent min elongation in 2 in. and a typical hardness of 110 to 149 HB per ASTM B164 Table 1. Monel® is a trademark of Special Metals Corporation.
Annealed Mechanical Properties per ASTM B164, B127, B564
The annealed condition is the baseline for Monel 400. ASTM B164 Table 1 sets 70 ksi (480 MPa) tensile min, 25 ksi (170 MPa) yield min at 0.2 percent offset and 35 percent elongation min in 2 in. across all rod and bar sizes. ASTM B127 sheet and plate and ASTM B564 forgings honour the same 70 / 25 / 35 minima for N04400 in the annealed condition. Hot-worked rod up to 12 in. carries a higher 80 ksi (552 MPa) tensile floor at 40 ksi (276 MPa) yield with 30 percent elongation.
| Property | B164 Annealed Rod/Bar | B164 Hot-Worked Rod | B127 Sheet/Plate | B564 Forging Annealed |
|---|---|---|---|---|
| Tensile strength, min | 70 ksi (480 MPa) | 80 ksi (552 MPa) | 70 ksi (480 MPa) | 70 ksi (480 MPa) |
| Yield 0.2% offset, min | 25 ksi (170 MPa) | 40 ksi (276 MPa) | 28 ksi (193 MPa) | 25 ksi (170 MPa) |
| Elongation in 2 in., min | 35% | 30% | 35% | 35% |
| Reduction of area, typical | 60% | 55% | - | 55% |
| Hardness, typical | B60 to B75 HRB | B75 to B95 HRB | 110 to 149 HB | B60 to B80 HRB |
The annealed values are specification minima, not targets. Mill heats typically clear yield by 5 to 10 ksi. Verify the EN 10204 type 3.1 MTC on receipt and back the record with a tensile retest where the value is governing.
Cold-Worked and Stress-Relieved Mechanical Properties
Cold work raises yield three to four times over the annealed floor at the cost of ductility. ASTM B164 Table 1 separates cold-worked as-worked (highest strength, lowest elongation) from cold-worked stress-relieved (the practical fastener and shaft condition).
| Condition | Diameter, in. (mm) | Tensile min, ksi (MPa) | Yield min, ksi (MPa) | Elongation min, % |
|---|---|---|---|---|
| Cold-worked, as-worked | Rounds < 1/2 (12.7) | 110 (760) | 85 (585) | 8 |
| Cold-worked, stress-relieved | Rounds < 1/2 (12.7) | 84 (580) | 50 (345) | 10 |
| Cold-worked, stress-relieved | Rounds 1/2 to 3-1/2 (12.7 to 88.9) | 87 (600) | 60 (415) | 20 |
| Cold-worked, stress-relieved | Rounds 3-1/2 to 4 (88.9 to 101.6) | 84 (580) | 55 (380) | 20 |
| Cold-worked, stress-relieved | Hexagons/squares ≤ 2 (50.8) | 84 (580) | 50 (345) | 20 |
| Hot-worked rod | Up to 12 (305) | 80 (552) | 40 (276) | 30 |
Hardness (HRC, HRB, HBW) and the NACE MR0175 Sour-Service Ceiling
Monel 400 hardness is reported in Rockwell B (HRB) for soft conditions, Brinell (HBW) for sheet and plate, and Rockwell C (HRC) only for cold-worked fastener and shaft stock. The two governing caps are the ASTM F468 bolt cap of 25 HRC and the NACE MR0175 / ISO 15156-3 sour-service ceiling of 35 HRC for the nickel-copper alloy group. The F468 cap is tighter; for a sour service bolt order both caps apply and the F468 25 HRC governs.
| Condition | Hardness range | Source |
|---|---|---|
| Annealed rings and disks | B60 to B75 HRB | ASTM B164 Table 1 |
| Hot-worked rings and disks | B75 to B95 HRB | ASTM B164 Table 1 |
| Annealed sheet and plate (typical) | 110 to 149 HB | ASTM B127 typical mill data |
| Cold-worked bar (typical) | 175 to 240 HB | Cold-worked stress-relieved range |
| ASTM F468 Ni 400 bolt, 0.250 to 0.750 in. | 75 HRB to 25 HRC (max) | ASTM F468 Table 2 |
| ASTM F468 Ni 400 bolt, 0.875 to 1.500 in. | 60 HRB to 25 HRC (max) | ASTM F468 Table 2 |
| NACE MR0175 N04400 sour-service ceiling | 35 HRC (max) | NACE MR0175 / ISO 15156-3 |
For an H2S sour-service bolt the F468 ceiling sits 10 HRC below the NACE ceiling, so the bolt clears both. For a shaft, valve stem or pump impeller in nickel-copper, the 35 HRC NACE cap governs and the supplier should witness hardness inspection on the as-supplied product.
Elevated and Cryogenic Temperature Behaviour
Monel 400 retains useful tensile strength to about 480 degrees Celsius and clears notch toughness down to -196 degrees Celsius (liquid nitrogen) without a ductile-to-brittle transition, the reason the alloy is specified for LNG cryogenic service. Above 540 degrees Celsius the alloy is substituted with Inconel 600 (N06600) or Monel K-500 (N05500) for sustained stress duty.
| Temperature | Yield retention vs RT | Tensile retention vs RT |
|---|---|---|
| -196 degrees Celsius (LN2) | ~115% | ~125% |
| +24 degrees Celsius (room temperature) | 100% | 100% |
| +260 degrees Celsius | ~92% | ~96% |
| +480 degrees Celsius | ~80% | ~85% |
| +540 degrees Celsius | ~65% | ~70% |
Modulus, Density, Thermal Expansion and Conductivity
The physical and elastic constants for Monel 400 are independent of cold work and govern design checks (deflection, thermal growth, fit-up) that strength values cannot reach. The elastic modulus is from Special Metals product data and ASME BPVC Section II Part D for N04400. Full detail on the density and physical properties page.
| Property | Value | Units |
|---|---|---|
| Density | 8.80 | g/cm3 (0.318 lb/in3) |
| Elastic (Young) modulus | 179 | GPa (26.0 x 10^6 psi) |
| Shear modulus | 66 | GPa (9.6 x 10^6 psi) |
| Poisson ratio | 0.32 | - |
| Mean thermal expansion (20 to 100 C) | 13.9 | micrometre/m per degree Celsius |
| Thermal conductivity (20 C) | 21.8 | W/m per Kelvin |
| Specific heat (20 C) | 427 | J/kg per Kelvin |
| Electrical resistivity | 0.547 | microhm metre |
| Melting range | 1300 to 1350 | degrees Celsius |
Monel 400 vs Monel R-405 vs Monel K-500 Mechanical Comparison
Within the nickel-copper family, Monel 400 and free-machining Monel R-405 share the strength envelope; Monel K-500 (UNS N05500) sits on a separate band because the aluminium plus titanium addition forms Ni3(Al,Ti) precipitates during age-hardening, lifting yield to 90 to 130 ksi.
| Property | Monel 400 (N04400) annealed | Monel R-405 (N04405) annealed | Monel K-500 (N05500) age-hardened |
|---|---|---|---|
| Tensile, ksi (MPa) | 70 - 85 (480 - 585) | 70 - 85 (480 - 585) | 130 - 165 (895 - 1140) |
| Yield 0.2%, ksi (MPa) | 25 - 50 (170 - 345) | 25 - 50 (170 - 345) | 90 - 130 (620 - 895) |
| Elongation min, % | 35 | 30 | 20 |
| Hardness | B60 to B80 HRB | B60 to B80 HRB | 24 to 37 HRC |
| Strengthening route | Solid solution | Solid solution + S | Gamma-prime precipitation |
Frequently Asked Questions
What is the yield strength of Monel 400? Annealed Monel 400 rod and bar carries a 25 ksi (170 MPa) minimum 0.2 percent offset yield per ASTM B164 Table 1. Cold-worked stress-relieved rounds 1/2 to 3-1/2 in. carry 60 ksi (415 MPa) min yield. Hot-worked rounds up to 12 in. carry 40 ksi (276 MPa) min yield. ASTM F468 Ni 400 bolts in the 0.250 to 0.750 in. range carry 40 ksi yield minimum.
What is the hardness of Monel 400? Annealed rings and disks measure B60 to B75 HRB per ASTM B164 Table 1; hot-worked rings and disks measure B75 to B95 HRB. ASTM F468 caps Ni 400 bolt hardness at 25 HRC, tighter than the NACE MR0175 ISO 15156-3 sour-service ceiling of 35 HRC.
Is Monel 400 magnetic? Monel 400 is paramagnetic at room temperature with a relative magnetic permeability close to 1.0 above 51 degrees Celsius (the Curie temperature) and weakly ferromagnetic below it. Detail on the magnetic permeability page.
Does cold work change Monel 400 properties? Yes. Cold-worked as-worked rounds under 1/2 in. reach 110 ksi (760 MPa) tensile and 85 ksi (585 MPa) yield against 70 ksi tensile and 25 ksi yield for the annealed condition. Cold work raises yield three to four times and drops elongation from 35 percent to 8 percent.
Related Pages
Properties and standards: chemical composition, density and physical properties, heat treatment, machinability, welding, corrosion resistance, magnetic permeability, ASTM B164, ASTM B127, ASTM B564, ASTM F468, UNS N04400, vs Monel K-500, vs stainless steel, bolts, round bar, plate, Monel 400 reference, pricing.
Request a Quote. For Monel 400 rod, bar, plate, sheet, forgings or fasteners against a specific ASTM B164, B127, B564 or F468 mechanical brief, send drawing, quantity and certification class (EN 10204 type 3.1 or 3.2) to info@torqbolt.com or WhatsApp +91-22-66157017. Heat-numbered MTC plus Mumbai ex-stock price inside one working day; export through JNPT.
References. ASTM B164 Table 1 (Rod, Bar, Wire). ASTM B127 (Plate, Sheet, Strip). ASTM B564 Table 2 (Forgings). ASTM F468 Table 2, Ni 400 grades F 468U and F 468U4 (Bolts). NACE MR0175 / ISO 15156-3 (H2S service). ASME BPVC Section II Part D (elastic constants). Special Metals Corporation product handbook (physical properties).
Satisfaction Survey
