VT machining offers CNC Turning for 440C Stainless Steel (UNS S44004 / 1.4125 / SUS440C), typically supplied annealed or hardened. Highest hardness/wear resistance of stainless; hardened parts are finish-ground.
CNC Turning Notes for 440C Stainless Steel
On the lathe 440C Stainless Steel needs chip-breaker inserts and constant chip load to avoid long, stringy swarf.
For estimating, a 100 × 100 × 10 mm block of 440C Stainless Steel weighs about 0.77 kg.
Starting Parameters for CNC Turning 440C Stainless Steel
| Cutting speed (carbide) | 105-195 m/min |
|---|---|
| Feed | 0.08-0.25 mm/rev |
| Spindle speed, Ø25 mm bar | 1340-2480 rpm |
| Insert / tool class | ISO M — positive-rake PVD/CVD carbide |
| Coolant | Flood emulsion (8-10%) or high-pressure coolant |
Starting values for 440C Stainless Steel, Annealed or hardened; optimised on the first article.
440C Stainless Steel Data Relevant to CNC Turning
| Equivalent designations | UNS S44004 / 1.4125 / SUS440C |
|---|---|
| Key composition | Cr 16-18%, C 0.95-1.2% |
| Typical supply condition | Annealed or hardened |
| Hardness (typical) | Up to ~58-60 HRC |
| Machinability rating | 40% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 440C Stainless Steel Differs
Highest hardness/wear resistance of stainless; hardened parts are finish-ground.
Typical applications: Bearings, valve seats, nozzles, knives.
440C Stainless Steel vs Similar Grades
| 440C Stainless Steel | 431 Stainless Steel | 430 Stainless Steel | 17-4 PH Stainless Steel | |
|---|---|---|---|---|
| Key composition | Cr 16-18%, C 0.95-1.2% | Cr 15-17%, Ni 1.25-2.5% | Cr 16-18% | Cr 15-17.5%, Ni 3-5%, Cu 3-5%, Nb |
| Hardness | Up to ~58-60 HRC | ~25-40 HRC | ≤88 HRB | ~28-44 HRC by condition |
| Tensile (MPa) | ≥760 annealed | ~860 (H&T) | ≥450 | 930-1310 |
| Machinability % | 40 | 45 | 54 | 48 |
| Typical use | Bearings, valve seats, nozzles, knives | Pump shafts, marine fittings, aircraft fasteners | Appliance panels, trim, magnetic parts | Aerospace, oil & gas, medical instruments |
More on CNC Turning Stainless Steel
Finishing options, quality documentation and general cnc turning guidance for all stainless steel grades are on our CNC Turning Stainless Steel page.
No drawing yet? Sketch the part in our free 3D + 2D builder and send it with your RFQ.
Quoting CNC Turning 440C Stainless Steel
Send a STEP/IGES model or PDF drawing, confirm 440C Stainless Steel and its condition (we usually see it supplied annealed or hardened), the quantity, critical tolerances and any finish or certificate requirements.
440C Stainless Steel in Other Processes
Related
Send the drawing, the 440C Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
What tolerances can you hold for CNC Turning 440C Stainless Steel?
Achievable tolerances for 440C Stainless Steel turning depend on the alloy, geometry and feature size. Turning holds diameter tolerances to around ±0.005 mm with concentricity within 0.01 mm. Exact figures are confirmed against your drawing callouts.
What is the typical lead time and minimum order for CNC Turning 440C Stainless Steel?
CNC Turning prototypes for 440C 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.
What surface finish is achievable on 440C Stainless Steel with CNC Turning?
Surface finish on 440C Stainless Steel is controlled to your specification; we confirm the achievable Ra against your callout.
Does CNC Turning 440C Stainless Steel require dedicated tooling?
Most 440C Stainless Steel turning work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.