any ideas for milling super duplex!!!

[gallzer]

Hey guys,

Super Duplex!!!!

Has anyone got some advice for milling this stuff? I'm milling pockets 600mm x 100mm and 40mm deep, just wondering about feeds, speeds and depths of cuts. I've been running at 355rpm and 100mm/min with 2.5mm depths of cut but i'm only managing 2 passes and the tips need changing.

Any advice will be appreciated

Cheers gallzer.

[kalmah]

Do you have to machine austenitic duplex stainless steel ??

Use 10-12mm carbide roughing end mill with 4 flute (variable pitch) with straigh cutting edge and the cutting length should be more than 40mm.
Don't use chip breaker. The hardness of your material will break the profile of your chip breaker

If it's the case:

1) Go in the center of pocket (outside the material)
2) Go into the material with helical path (10mm of depth) and diameter of your helical milling is 20mm. The depth of your first helical milling = 10mm
(Vc = 50m/min, fz = 0.03, slope of your helical milling = 1-2°)
3) Remove the material only by shouldering (ae = 1mm, ap = 10mm, Vf = 500mm/min Vc = 50m/min)
4) Repeat this operation four times

Here is a video in order to explain what I mean

http://www.sgstool.com/resources/videos.asp

Look Z-carb videos

Of course, don't use dry lubrication and the feedrate is lower is your material. Austenitic stainless steel is more difficult to cut.

[gallzer]

Thanks for that, I've been using a 32mm tipped cutter to rough then 16mm endmill to finish, the duplex is austenitic.

Any more info on this would be great

Thanks

[Hogger]

I don't know about milling it but I had somewhat good luck on a lathe by taking small cuts about .030/.050 deep and lots of feed at about 150/200 FPM speed, if I tried to take a big cut the tip of the insert would burn off. Good luck, I hate that stuff.

[kalmah]

Originally Posted by Hogger I don't know about milling it but I had somewhat good luck on a lathe by taking small cuts about .030/.050 deep and lots of feed at about 150/200 FPM speed, if I tried to take a big cut the tip of the insert would burn off. Good luck, I hate that stuff.

Austenitic duplex stainless steel is difficult to cut but not so difficult than superalloy (Inconel, Monel, Whaspalloy)

You can go in Z- with helical tool path whatever the material. Of course the slope must be very low (2°).
After, when you do shouldering, the radial depth of cut and your cutting speed depends of the machined material