Steel milling

The machinability of steel differs, depending on alloying elements, heat treatment and manufacturing process (forged, cast, etc.)

Main issues

• In soft, low carbon steels, built-up edge and burr formation on the workpiece are the main issues.
• In harder steels, the positioning of the cutter becomes more important to avoid edge chipping.

Suitable cutters and inserts

• Most CoroMill cutters are well suited for steel machining with a comprehensive assortment of insert grades and geometries.
• Note that CoroMill Century (with steel body) and CoroMill 790, originally developed for aluminum, also perform very well in finishing steel.
• The only tools not suitable for steel are the AUTO-cutters dedicated for gray cast iron.
• PL, PM, PH and WL, WM, WH geometries
• The GC4200-series of MT-CVD coated grades are the basic choice. However, for smaller diameter cutters, below D_c 1.260 inch (32 mm), and for shoulder milling cutters, ψ_r=0°, grade GC1030 is the first choice.
• In harder steels, use GC1030 and GC1010.​

Recommendations, such as positioning of the cutter to avoid a large chip thickness on the exit, and to always run dry without cutting fluid, should always be considered, especially in roughing operations.

Grade guideline – face milling​