Dear all,

Looking into information on machining Super duplex stainless steels.

Except carbide tools, is anybody using something more efficient?

They are getting confused very fast.

Some literature to read would also be appreciated.

Thanks,

Herc

The following link has some specific guidelines for machining Outokumpu 2507:

http://tools.outokumpu.com/spt/pub/upload/pubs_120...

Here is an excerpt from another Outokumpu document:

Machining
The high strength will of course effect the machinability, but not as much as expected. Some information, good to have in mind when machining duplex, is given below:

Stable setup
Due to the higher strength the cutting forces will be higher. That will increase the risk of vibrations. The trick is to have a stable setup. Use the shortest possible tool extension good and rigid clamping.

Sharp Tools
Use cutting tools with a positive geometry. The duplex grades are very adaptive to work hardening. A dull geometry will generate a hard surface and decrease the tool life.

Avoid “build up edge”
Stainless steels have a tendency to stick to the tool. Problems occur when the cutting speed is too low. The biggest difference between carbon steel and stainless steels when machining is that you face into problems if you are running too slow. The result will be bad surface finish and short tool life. The problem is solved by increasing the cutting speed.

My experience has been this
a generous amount of depth of cut is required.
304 SS is tough , 316 is tougher to machine, duplex is even tougher.
with the deeper depth of cut the surface speed has to be adjusted.
if it is skim cut this stuff it will work harden.

Mfgenggear

Torque is required.
Because of the low cutting speeds typical 66m/min you need machines that have HIGH TORQUE at low revs.
Most machines do not have enough power at low revs, pick a machine that has a gearbox spindle that gives high poweer at low revs