VT machining offers CNC Milling for 904L Stainless Steel (UNS N08904 / 1.4539), typically supplied annealed. Super-austenitic grade for sulfuric acid and seawater; very gummy to cut.
CNC Milling Notes for 904L Stainless Steel
We use high-efficiency toolpaths with constant engagement on 904L Stainless Steel to keep cutting temperature and tool wear under control.
For estimating, a 100 × 100 × 10 mm block of 904L Stainless Steel weighs about 0.80 kg.
Starting Parameters for CNC Milling 904L Stainless Steel
| Cutting speed (carbide) | 70-125 m/min |
|---|---|
| Feed per tooth | 0.028-0.088 mm |
| Spindle speed, Ø10 mm end mill | 2230-3980 rpm |
| Insert / tool class | ISO M — positive-rake PVD/CVD carbide |
| Coolant | Flood emulsion (8-10%) or high-pressure coolant |
| Thermal growth, 100 mm part, +10 °C | 15 µm (CTE 15 µm/m·K) |
Starting values for 904L Stainless Steel, Annealed; optimised on the first article.
904L Stainless Steel Data Relevant to CNC Milling
| Equivalent designations | UNS N08904 / 1.4539 |
|---|---|
| Key composition | Cr 19-23%, Ni 23-28%, Mo 4-5%, Cu 1-2% |
| Typical supply condition | Annealed |
| Hardness (typical) | ≤90 HRB |
| Machinability rating | 30% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 904L Stainless Steel Differs
Super-austenitic grade for sulfuric acid and seawater; very gummy to cut.
Typical applications: Acid handling, heat exchangers, watch cases.
904L Stainless Steel vs Similar Grades
| 904L Stainless Steel | 17-4 PH Stainless Steel | 440C Stainless Steel | 431 Stainless Steel | |
|---|---|---|---|---|
| Key composition | Cr 19-23%, Ni 23-28%, Mo 4-5%, Cu 1-2% | Cr 15-17.5%, Ni 3-5%, Cu 3-5%, Nb | Cr 16-18%, C 0.95-1.2% | Cr 15-17%, Ni 1.25-2.5% |
| Hardness | ≤90 HRB | ~28-44 HRC by condition | Up to ~58-60 HRC | ~25-40 HRC |
| Tensile (MPa) | ≥490 | 930-1310 | ≥760 annealed | ~860 (H&T) |
| Machinability % | 30 | 48 | 40 | 45 |
| Typical use | Acid handling, heat exchangers, watch cases | Aerospace, oil & gas, medical instruments | Bearings, valve seats, nozzles, knives | Pump shafts, marine fittings, aircraft fasteners |
More on CNC Milling Stainless Steel
Finishing options, quality documentation and general cnc milling guidance for all stainless steel grades are on our CNC Milling Stainless Steel page.
No drawing yet? Sketch the part in our free 3D + 2D builder and send it with your RFQ.
Quoting CNC Milling 904L Stainless Steel
Send a STEP/IGES model or PDF drawing, confirm 904L Stainless Steel and its condition (we usually see it supplied annealed), the quantity, critical tolerances and any finish or certificate requirements.
904L Stainless Steel in Other Processes
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Send the drawing, the 904L Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
What is CNC Milling 904L Stainless Steel and how is it done?
CNC Milling 904L Stainless Steel refers to multi-axis milling cutters remove material to produce prismatic features, pockets, slots and contoured 3D surfaces. Applied to 904L Stainless Steel — corrosion resistant, strong and hygienic — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
Why is 904L Stainless Steel a good choice for CNC Milling?
904L Stainless Steel is corrosion resistant, strong and hygienic, which makes it well suited to CNC Milling. We tune the process to the alloy so the finished 904L Stainless Steel machining part meets your dimensional and functional requirements.
Can VT machining make custom 904L Stainless Steel parts to my drawing?
Yes. 904L Stainless Steel machining is made to order from your CAD/2D drawing. Share your geometry, material grade, tolerance and quantity and we will confirm feasibility, lead time and pricing.
What surface finish is achievable on 904L Stainless Steel with CNC Milling?
Surface finish on 904L Stainless Steel is controlled to your specification; we confirm the achievable Ra against your callout.
What is the typical lead time and minimum order for CNC Milling 904L Stainless Steel?
CNC Milling prototypes for 904L Stainless Steel can be produced quickly and scaled to series production. Send your drawing and quantity and we will advise lead time and any minimum order.
Does CNC Milling 904L Stainless Steel require dedicated tooling?
Most 904L Stainless Steel machining work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.