Machinability Of Hy-Tuff steel
Machining Hy-Tuff in the Normalized & Tempered state (311BHN)has issues...the material is 'gummy' and has a tendency to build on the edge of cutting tool inserts, producing surface-finish issues and broken inserts. Is there a cutting tool geometry, or intermediate heat treatment process that can improve the machineability of this material?Pete Owen
Mfgr Engineer (Aerospace) - Oakville, Ontario, Canada
Hy-Tuf (SAE AMS 6418 or 6425) has optimum machinability in the Normalized & Tempered condition, although your hardness is a little high-- a maximum of 285 HB is recommended. This is obtained by tempering at 1200 F (650 C).
You didn't provide any information on the current setup, insert types, etc., so all I can provide is some general information. Coated inserts will provide better lubricity and reduce the formation of built-up edge. TiN is a one such coating. Have you investigated multilayer coated tools such as the GC4000 series from Sandvik? No matter what, you really should discuss this issue with your tool supplier.Toby Padfield
Automotive module supplier - Michigan