General Information:
Material Group P - Steel
Sub-Group Tool Steel
Tensile Strength 1100-1300 [N/mm^2]

Machining Steel 40CMD8

Steel 40CMD8 is a Tool Steel (High-alloy steel) that has on top of the 0.4% of carbon an additional 3.6% of manganese, chromium, and molybdenum. (See details in the below table). Steel 40CMD8 has a machinability rating of 50%.

Steel 40CMD8 belongs to the "P series" of tool steels. They are classified as Plastic Mold Tool Steel and contain medium carbon content (around 0.4%) and chromium content of around 2%. Tool Steels in this series (P2-P20) have a machinability rating of 50-60%. They are realtivly easiy to machine due to the low carbon and chromium content comapred with other tool steels. They are used mainly for plastic molds, and components for plastic pressure dies. P series steels maintain good strength in high temperatures and can reach a hardness of up to 50 HRC after heat treatment.

You can find here a list of machinability Ratings for different Tool Steels.


  • For turning operations on Steel 40CMD8, it is best to use inserts with thick CVD coating and medium hardness. For milling, any all-around carbide grade is suitable.
  • For detailed carbide grades recommendations, check the Below Chart, or use the Grades Wizrad.
  • Recommended Cutting speed range for turning at stable conditions is 610 - 820 [SFM] / 185 - 250 [m/min].
  • Recommended Cutting speed range for milling with stable clamping and short overhang is 380 - 510 [SFM] / 115 - 155 [m/min]
  • For detailed cutting speed recomendations, check the Below Table, or use our Speed and Feed Calculator.
  • Equivalent International Designations for Steel 40CMD8

    Standard Name

    Chemical Composition for Steel 40CMD8

    Element Amount
    Chromium (Cr)1.75-2.15%
    Manganese (Mn)1.35-1.65%
    Carbon (C)0.35-0.45%
    Silicon (Si)0.2-0.4%
    Molybdenum (Mo)0.15-0.30%

    Cutting Speeds Recomendations for Steel 40CMD8

    * 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 Steel 40CMD8

    * If you don't 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 Steel 40CMD8

    Honing Size:0.05-0.08 mm / 0.002-0.003"
    Rake Angle:11° -13°
    Land Angle:Positive
    Land Width:0.20-0.30 mm / 0.008-0.012"

    Learn more about carbide inserts Cutting-Edge Geometry Parameters.

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