Do rotary broaches work in stainless steel?
Rotary broaching stainless steel is possible. Two changes can be made from a standard rotary broaching set-up to make many broaching jobs work in stainless steel. The first change is with the broach material, and the second change is with the speeds and feeds.
The best grade for broaching stainless steel of all types is PM M-4. This powdered metal has a super-fine grain size and carbide microstructure resulting in extremely versatile high speed steel which provides a unique combination of high wear resistance with high impact toughness. Polygon Solutions recommends PM M-4 for broaching stainless steel and improving tool life in general.
When broaching stainless steel, please also consider these recommendations to speed and feed modifications.
1. SLOW THE FEED RATE FROM STANDARD .002-.003 IPR TO .001 IPR
2. SLOW THE SPEED TO 50-100 RPM UNTIL ENGAGED .005-.010″ THEN RAMP UP TO 700-800 RPM
3. ORDER THE BROACH WITH A SMALL CORNER RADIUS OF .005″