This nickel-copper alloy cuts slow, work-hardens fast and moves when you take heavy passes. We machine it on 127 CNC machines to ±0.005 mm and inspect every part before shipment.
If your current supplier quotes this grade like 316 stainless, one of these is already happening.
The alloy work-hardens under the tool. A shop running free-machining speeds on a 316 job will hold size on pass one and lose 0.03 mm on pass two. The part measures fine on the bench, then will not fit the mating bore.
Low thermal conductivity keeps cutting heat in the part and the edge. Threads tear, small holes gall, and the surface that has to seal against seawater arrives rough and out of round.
Roughing heat plus residual stress in the bar stock moves the part after clamping is released. A 1.5 mm wall on a 60 mm bore can spring 0.05 mm oval, so a seal leaks at test pressure.
One torn thread or one galled bore writes off the whole part. On a nickel-copper blank that costs more than the cutting time, a late catch turns a 20-piece lot into a re-order and a missed build slot.
The cutting strategy matters more than the machine list.
This alloy sits around 125–150 HB as supplied and climbs quickly once the edge rubs instead of cuts. We run sharp positive-rake carbide, climb milling, and depth-of-cut values that keep the tool under the hardened skin rather than skating on it. Speeds stay conservative; feed per tooth stays high enough to cut, not rub.
Coolant goes to the edge, not the chip pile. High-pressure through-tool coolant clears the heat that low conductivity would otherwise push back into the workpiece. On turning, we peck the bore in short passes so the insert never dwells.
Seawater hardware is rarely a simple turned blank. Valve bodies, pump housings and manifolds carry angled ports, blended radii and faces that must sit square to each other. A single five-axis setup cuts those features without re-clamping, which removes the stack-up error that comes from moving the part between three machines.
We hold 16 simultaneous five-axis centers, 16 mill-turn centers and a Ø400 mm rotary table. Maximum processing size runs to 4,000 mm, so long shafts and oversized housings stay in one program. Tighter geometry means fewer fittings that leak at hydro test.
Three questions decide it: what is in the fluid, how hot does it run, and what stress does the part carry.
| Service condition | Monel 400 (N04400) | Consider instead |
|---|---|---|
| Seawater, static or flowing | Standard choice, low corrosion rate | 316L if cost drives the decision |
| Hydrofluoric and hydrochloric acid | Good resistance in reducing media | Hastelloy for higher temperature |
| Caustic and alkaline service | Strong resistance, no chloride cracking | Carbon steel for dry caustic only |
| High-strength shafting | Work-hardens, needs slow speeds | 17-4PH if hardness is the priority |
| Marine fasteners and fittings | Common and proven | Monel K-500 for higher yield |
| Very high chloride at 200 °C+ | Check temperature limit first | Nickel alloys with more Mo |
From one prototype to a 10,000-part run, on the same process sheet.
Angled ports, blended fillets and contoured faces cut in one setup. 16 simultaneous five-axis centers.
Shafts, sleeves, bushings and threaded fittings. Cross-drilling handled without a second fixture.
Plates, flanges, covers and brackets. 27 three-axis and 12 four-axis machines in the pool.
One-off seawater test parts before the production tool is committed. No minimum order quantity.
Bead blasting, brushing, polishing, passivation and plating on nickel-copper parts.
Raw material check, in-process monitoring and final inspection. Reports on request.
Numbers below are what the shop floor actually runs, not catalogue limits.
| Item | Capability | Note |
|---|---|---|
| General tolerance | ±0.005 mm | ±0.0002 in on critical features |
| As-machined finish | Ra 1.6–3.2 μm | Standard milled and turned surfaces |
| Fine finish | Ra 0.2–0.8 μm | Where a seal or bearing fits |
| Maximum part size | 4,000 mm | Long shafts and housings |
| Rotary table | Ø400 mm | Angled features on round parts |
| Qualification rate | 99.99% | First-pass acceptance on shipped lots |
| Order quantity | 1 to 10,000+ | No minimum order quantity |
| Quotation | Within 12 hours | Includes free DFM analysis |
Six things you can check before you send the purchase order.
Machining difficult alloys since 2011. Process sheets are written for the material, not copied from a stainless job.
16 five-axis, 16 mill-turn, 27 three-axis and 12 four-axis centers. Capacity does not stall at one machine.
Not just on a first article. In-process checks catch drift before the lot is finished.
Drawings reviewed and quoted within 12 hours. Production can start within 24 hours.
Parts ship in 3–5 days once the process is released. Historical late-delivery risk stays under 2%.
Every part checked. Raw material certification and dimensional reports on request.
Pump housings, valve bodies and fittings that must survive continuous saltwater exposure without pitting at the seal face.
Parts for reducing-acid service where the alloy resists attack but the bore still has to hold a gasket seal under pressure.
Brackets, bushings and duct components where traceability and a stable process matter as much as the alloy choice.
Sensor bodies and fittings that see chloride-rich fluids and thermal cycling, with threads that must not gall on assembly.
Slower, and with more attention to the edge. The alloy work-hardens faster than 316 and carries heat into the part because thermal conductivity is low. Expect reduced surface speeds, positive-rake carbide, and a rigid setup.
A shop that treats it as a stainless job usually holds the first pass and loses size on the second. The tell is a tolerance that drifts in the same direction across the lot.
±0.005 mm on critical features, checked in process rather than only on the first article. As-machined surfaces come off at Ra 1.6–3.2 μm, and seal or bearing fits go to Ra 0.8–1.6 μm, with Ra 0.2–0.8 μm when the drawing calls for it.
Thin walls and long bores are the limits. Below roughly 1.5 mm wall thickness the part starts moving after unclamping, so we usually rough, stress relieve and finish in separate operations.
If the fluid is strongly oxidizing, or the temperature runs high with heavy chloride, a higher-molybdenum nickel alloy usually lasts longer. If hardness and yield strength drive the design, Monel K-500 or 17-4PH is the better fit.
Cost matters too. Nickel-copper stock costs more than stainless, so on a dry, mild-duty part there is no reason to specify it.
Yes, with a process built for it. Roughing passes leave stock, the part is allowed to stabilise, and finishing runs at light depth with coolant directed at the edge. Long bores are pecked rather than plunged.
We measure after the part returns to room temperature. A reading taken on a warm part is not a reading.
Yes. There is no minimum order quantity, so a single test part and a 10,000-piece run go through the same process sheet. Prototypes are useful for hydro test and fit checks before tooling or fixtures are committed.
Quotation and DFM feedback come back within 12 hours, and production can start within 24 hours of release.
Raw material check, in-process monitoring and final inspection on every lot. Parts are inspected 100% before shipment, and dimensional or material reports are provided on request.
We work to ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. Uploads stay confidential, and an NDA is available on request.
Bead blasting, tumbling, brushing and polishing are the common choices on nickel-copper parts. Electroless nickel, zinc, silver and gold plating are available where conductivity or wear calls for them.
Laser marking and engraving are available with a minimum character height of 1.5 mm. Tell us the environment the part sees and we will say which finish earns its cost.
Upload the STEP file, PDF drawing and quantity through the online quotation page. We return pricing and a free DFM analysis within 12 hours.
If the geometry is difficult to cut, the DFM note will say so and suggest a change before the first chip is made. That is cheaper than finding out at final inspection.
Upload the model and drawing, and we will come back with pricing, a DFM note and a process route within 12 hours.
12-hour quote100% inspectionNo minimum orderNDA on request
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Upload your 3D model or 2D drawing and get a quotation with a free DFM analysis. Maximum processing size 4,000 mm.
CNC Metals 13 grades
CNC Plastics 10 grades
Machines & processes 12 options
Surface & post-processing 10 options
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