Material · Stainless Steels
Stainless Steel 303
The machinist's stainless: sulfur additions cut machining cost ~30% versus 304 on turned parts.
Price index: $$$
Material properties
| Parameter | Value |
|---|---|
| Tensile strength | ~620 MPa (cold drawn) |
| Yield strength | ~415 MPa (cold drawn) |
| Hardness | ≤228 HB |
| Density | 8.00 g/cm³ |
Choose it when
The right stainless for high-volume turned parts: faster speeds, better chip control and longer tool life than 304 usually save more in machining than the small material premium.
Look elsewhere when
The same sulfur that aids cutting causes hot cracking in welds and pit initiation in chlorides — for welded assemblies or marine service, specify 304 or 316L instead.
Compatible finishes
As-Machined
The baseline finish: straight off the machine, fastest and cheapest.
Passivation
Chemical hygiene for stainless: strips embedded iron so the steel can be as stainless as advertised.
Electropolishing
Reverse plating that brightens, deburrs and passivates stainless in one step.
Bead Blasting
The uniform matte look: erases tool marks, hides fingerprints, preps perfect anodizing.
Brushed Finish
The appliance-grade look: directional satin grain on panels, bezels and show faces.
Polishing
Progressive abrasives down to mirror: the finish for optics, molds and show surfaces.
Vibratory Tumbling
Batch deburring by the bowl-full: every edge broken, every burr gone, at volume prices.
Laser Marking
Permanent identification with zero dimensional change: serials, logos and codes burned in, not stuck on.
Typical applications
- High-volume turned fittings and adapters
- Shafts, bushings and standoffs
- Swiss-machined pins and inserts
Compared with similar grades
| Property | Stainless Steel 303 | Stainless Steel 304 | Stainless Steel 316L | Stainless Steel 17-4 PH |
|---|---|---|---|---|
| Tensile strength | ~620 MPa (cold drawn) | 515 MPa | 485 MPa | 1310 MPa (H900) |
| Yield strength | ~415 MPa (cold drawn) | 205 MPa | 170 MPa | 1170 MPa (H900) |
| Hardness | ≤228 HB | ≤201 HB | ≤217 HB | 40–44 HRC (H900) |
| Density | 8.00 g/cm³ | 8.00 g/cm³ | 7.98 g/cm³ | 7.75 g/cm³ |
| Price index | $$$ | $$$ | $$$ | $$$$ |
| Machinability | 4/5 | 3/5 | 3/5 | 2/5 |
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