VT machining offers CNC Milling for 309 Stainless Steel (UNS S30900 / 1.4828), typically supplied annealed. Higher Cr/Ni for oxidation resistance to ~1000 °C.
CNC Milling Notes for 309 Stainless Steel
309 Stainless Steel mills well with conventional strategies; finishing passes are planned to meet flatness and finish callouts.
For estimating, a 100 × 100 × 10 mm block of 309 Stainless Steel weighs about 0.79 kg.
Starting Parameters for CNC Milling 309 Stainless Steel
| Cutting speed (carbide) | 90-165 m/min |
|---|---|
| Feed per tooth | 0.028-0.088 mm |
| Spindle speed, Ø10 mm end mill | 2860-5250 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 | 16.5 µm (CTE 16.5 µm/m·K) |
Starting values for 309 Stainless Steel, Annealed; optimised on the first article.
309 Stainless Steel Data Relevant to CNC Milling
| Equivalent designations | UNS S30900 / 1.4828 |
|---|---|
| Key composition | Cr 22-24%, Ni 12-15% |
| Typical supply condition | Annealed |
| Hardness (typical) | ≤95 HRB |
| Machinability rating | 40% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 309 Stainless Steel Differs
Higher Cr/Ni for oxidation resistance to ~1000 °C.
Typical applications: Furnace parts, heat shields, burner components.
309 Stainless Steel vs Similar Grades
| 309 Stainless Steel | 304L Stainless Steel | 309S Stainless Steel | 304 Stainless Steel | |
|---|---|---|---|---|
| Key composition | Cr 22-24%, Ni 12-15% | Cr 18-20%, Ni 8-12%, C ≤0.03% | Cr 22-24%, Ni 12-15%, C ≤0.08% | Cr 18-20%, Ni 8-10.5% |
| Hardness | ≤95 HRB | ≤92 HRB | ≤95 HRB | ≤92 HRB |
| Tensile (MPa) | ≥515 | ≥485 | ≥515 | ≥515 |
| Machinability % | 40 | 45 | 40 | 45 |
| Typical use | Furnace parts, heat shields, burner components | Welded assemblies, tanks, piping | Kiln fixtures, heat-treat baskets | Food equipment, enclosures, brackets, fittings |
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 309 Stainless Steel
Send a STEP/IGES model or PDF drawing, confirm 309 Stainless Steel and its condition (we usually see it supplied annealed), the quantity, critical tolerances and any finish or certificate requirements.
309 Stainless Steel in Other Processes
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Send the drawing, the 309 Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
Which industries use CNC Milling 309 Stainless Steel parts?
CNC Milling 309 Stainless Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 309 Stainless Steel components are required.
What surface finish is achievable on 309 Stainless Steel with CNC Milling?
Surface finish on 309 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 309 Stainless Steel?
CNC Milling prototypes for 309 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 309 Stainless Steel require dedicated tooling?
Most 309 Stainless Steel machining work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.