Machining DataSheet for

General Information:
Material GroupM - Stainless Steel
Sub-GroupAustenitic Stainless Steel
Tensile Strength500-700 [N/mm^2]

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Machining Stainless Steel 303

303 is a free-machining stainless alloy providing the best machinability among the austenitic stainless alloys. It is primarily used on Swiss-type Machines (Screw Machines) when productivity is a crucial factor. The machinability rating is approximately 75%.

The sulfur addition, which is accountable for the enhanced machinability in 303 stainless, decreases its corrosion resistance and toughness to below that of 304 and 316 alloys.
It has 1.5% carbon (compared to around 0.08% in 304/316); thus, it is less soft, therefore less likely to develop 'build-up edge' , and is more manageable with chip control.


  • For general Turning of Stainless Steel 303 at stable conditions use a grade with a Semi Hard substrate and CVD coating.
  • In case you are running at a cutting speed that is lower than 390 SFM (120 m/min), it is better to use a grade with a
  • Semi Hard substrate and PVD coating.
  • For general Milling use a grade with a Semi Hard substrate and PVD coating.
  • For detailed carbide grades recommendations, check the Below Chart, or use the Grades Wizrad.
  • Recommended Cutting speed range for turning at stable conditions is 890 - 1180 [SFM] / 270 - 360 [m/min].
  • Recommended Cutting speed range for milling with stable clamping and short overhang is 560 - 750 [SFM] / 170 - 230 [m/min]
  • For detailed cutting speed recomendations, check the Below Table, or use our Speed and Feed Calculator.

  • Equivalent International Designations for Stainless Steel 303

    Standard Name
    bs303S21, 58M
    uniX10CrNiS 18.09

    Chemical Composition for Stainless Steel 303

    Element Amount
    Chromium (Cr)19.5%
    Nickel (Ni)10.5%
    Silicon (Si)2.00%
    Manganese (Mn)1.50%
    Molybdenum (Mo)0.60%
    Sulfur (S)0.30%
    Carbon (C)0.16%
    Phosphorus (P)0.04%

    Cutting Speeds Recomendations for Stainless Steel 303

    * Click on the speeds below for higher precision in specific conditions!

    ApplicationVc (m/min)Vc (SFM)

    Important! The speed estimation is given for an ideal situation:

    • Most suitable carbide grade
    • Stable tool clamping
    • Stable workpiece clamping
    • Good quality raw material
    • A short overhang of the cutting tool.
    • Nominal hardness of the material.
    • etc.
    Click on the speeds in the above table to get better precision for specific parameters
    Or use our Speed and Feed Calculator

    Recommended Carbide Grades for Stainless Steel 303

    * If you do nott understand the below table? Read This Explanation to make the most out of it!

    Grade for Turning

    Grade for Parting Off

    Grade for Grooving

    Grade for Milling (Indexable)

    Recommended Insert Cutting Edge Geometry for Stainless Steel 303

    Honing Size:0.03-0.05 mm / 0.001-0.002"
    Rake Angle:9° -11°
    Land Angle:Positive
    Land Width:0.20-0.30 mm / 0.008-0.012"

    Learn more about carbide inserts Cutting-Edge Geometry Parameters.