Monel 404 (UNS N04404) - Low-Resistivity Electronic Alloy Supplier of Round Bars, Wire & Strip | Shanghai Hangbo Alloy Group

By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 Certified | Est. 2012

Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360

Quick Answer: What Is Monel 404?

Monel 404 (UNS N04404) is a premium nickel-copper electronic alloy with approximately 54% nickel and 45% copper that delivers the lowest electrical resistivity of any Monel grade (~0.49 micro-ohm-m) combined with near-zero thermoelectric EMF against copper -- essential for transistor lead frames, hermetic package feedthroughs, waveguide components, and precision electronic connectors where both conductivity and corrosion resistance are required. Shanghai Hangbo Alloy Group supplies Monel 404 as cold-drawn wire, round bar, and strip with ASTM B164/B127 certification.

Industry Pain Point: Semiconductor packaging engineers specifying lead-frame materials face a narrowing selection window: copper has ideal conductivity but zero corrosion resistance (failing HAST / autoclave reliability testing within 96 hours), while standard Monel 400 has excellent corrosion resistance but 32x the resistivity of copper. Monel 404 -- with resistivity only 2x higher than Monel 401 in practical terms and seawater corrosion resistance 100x superior to copper -- occupies the narrow performance window where electronic performance meets environmental reliability.

Key Properties at a Glance

Product Overview

Monel 404 is the electrical specialist in the Monel family. While Monel 400 (63-70% Ni) is optimized for corrosion resistance and Monel K-500 for precipitation-hardening strength, Monel 404 is metallurgically designed around a single property: low, controlled electrical resistivity.

The alloy's composition -- 52-57% nickel, balance copper with strict limits on manganese (<=0.10%), silicon (<=0.10%), and aluminum (<=0.05%) -- produces a clean, single-phase FCC microstructure with minimum solute scattering of conduction electrons. The result is resistivity approximately 10% lower than Monel 400, combined with thermal EMF against copper so low that it does not corrupt microvolt-level DC signals in precision instrumentation.

Key performance attributes:

• Ultra-low resistivity -- the lowest of all commercially available Monel grades.
• Near-zero thermal EMF vs. copper -- eliminates DC offset errors in connector junctions for strain-gauge bridges, thermocouple data loggers, and nanovoltmeter inputs.
• Essentially non-magnetic -- permeability ~1.001, suitable for RF waveguide and magnetic-sensitive electronic packaging.
• Good seawater corrosion resistance -- retains the characteristic Monel resistance to chloride environments, enabling subsea electronic connectors.

Shanghai Hangbo Alloy Group supplies Monel 404 in cold-drawn wire (the dominant product form for lead-frame and connector applications), round bar (for machined contacts), and cold-rolled strip (for stamped lead frames and waveguide components).

Executive Standards

Chemical Composition (wt.% per ASTM B164 - OES Verified)

Key distinction from Monel 401: Monel 404 has higher nickel (52-57% vs 40-45%) and ultra-low manganese (<=0.10% vs <=2.25%), producing even lower resistivity and better thermal EMF stability -- the premium electronic grade.

Physical & Mechanical Properties

Physical Properties

Mechanical Properties

Heat Treatment

Solution Annealing: 760-870C (1400-1600F), 15-60 min soak, air cool or water quench. This is approximately 100C lower than Monel 400 due to lower recrystallization temperature.

Stress Relief: 400-540C (750-1000F), 1-2 hours, air cool.

No precipitation hardening -- Monel 404 is solid-solution strengthened only. Cold work provides the only strength increase mechanism.

Industry Applications

Quality Assurance (7-Stage)

1. Raw material: electrolytic Ni (>=99.95%) and cathode Cu analyzed by OES
2. Melt chemistry: Ni:Cu ratio verified; C controlled
3. Electrical resistivity: four-point probe per ASTM B193 -- must be 0.47-0.51 micro-ohm-m
4. Thermal EMF vs. copper: verified <=5 micro-V/C per heat
5. Mechanical testing: tensile per ASTM E8
6. Dimensional: laser micrometer on wire; X-ray gauge on strip
7. EN 10204 3.1 MTC with full electrical certification. SGS/TUV witness available

Frequently Asked Questions

Q1: What is Monel 404 used for?

Transistor lead frames, hermetic package feedthroughs, RF waveguide components, subsea electronic connectors, thermocouple extension leads, and precision electrical contacts -- combining low resistivity with corrosion resistance.

Q2: What is the density?

8.91 g/cm3 -- similar to Monel 400 (8.83).

Q3: What is the electrical resistivity?

~0.49 micro-ohm-m -- the lowest of all Monel grades, ~10% lower than Monel 400.

Q4: What is the thermal EMF vs. copper?

<=5 micro-V/C -- negligible, critical for precision DC instrumentation.

Q5: Is Monel 404 magnetic?

Essentially non-magnetic (permeability ~1.001). Suitable for RF and magnetic-sensitive applications.

Q6: How does Monel 404 compare to Monel 401?

Monel 404 has higher nickel (52-57% vs 40-45%), lower manganese (<=0.10% vs <=2.25%), producing lower resistivity and better thermal EMF stability. 404 is the premium electronic grade; 401 is the general electrical grade.

Q7: What is the tensile strength?

380-480 MPa annealed; up to 830 MPa in spring temper.

Q8: What heat treatment?

Annealing at 760-870C. Stress relief at 400-540C. No precipitation hardening.

Q9: Is Monel 404 weldable?

Yes, GTAW/GMAW with ERNiCu-7 filler. For critical electrical paths, silver brazing produces lower joint resistance.

Q10: What is the price per kg?

$25-40/kg EXW. Higher nickel content than Monel 401. Contact sales@hangboalloy.com.

Q11: What product forms?

Cold-drawn wire (0.05-10 mm), round bars (6-150 mm), cold-rolled strip (0.1-4.0 mm), plates (5-50 mm), tubes.

Q12: International shipping?

Yes -- FOB/CIF/DAP to 40+ countries. Stock 2-4 weeks; mill 8-12 weeks.

Q13: What standards?

ASTM B164 (bar/rod), ASTM B127 (plate/sheet/strip), ASTM B165 (pipe/tube).

Q14: Why choose Monel 404 over copper?

Copper has better conductivity but zero corrosion resistance. Monel 404 provides adequate conductivity with seawater corrosion resistance 100x superior.

Q15: What is the Curie temperature?

Near room temperature (~25C) -- the alloy is essentially non-magnetic at typical operating temperatures.

Q16: How is electrical resistivity certified?

Four-point probe per ASTM B193 on annealed samples from each heat. Certified 0.47-0.51 micro-ohm-m.

Contact Shanghai Hangbo Alloy Group