Optimizing A514 Grade Q

Hi all,

I'm cutting A514 Grade Q for the first time. My tool life is much shorter than expectations.

IE. 3" Facemill, 8 inserts. Removing about 10lbs of material each part. Inserts need rotated/changed every 3 parts.

5/8" 6flt chip breaker rougher Removing about 5lbs of material each part. 450sfm, .007"ipt, 5% stepover. About 5 parts.

1/4" 4flt rougher. 450sfm, .0032ipt, 5% stepover. And, helical milling at 350sfm, 2 deg, 12ipm. About 3 parts.

All coated carbide. Facemill is TIALIN. end mills are proprietary.

I've found this steel work hardens easily, so I'm using coolant. Would it be better to cut these dry?

Does my wear sound expected?

We run 'machine feet' for Canrig that are A514 weldments.
We have to mill, drill, and counterbore through 1" thick of weld bead.
Gorilla or Imco powerfeed 4fl, hp, tialn coated carbide mills are the current choices.

Back in 2008, I ran a comparison on different brands.
Link --> https://www.practicalmachinist.com/...anita-varimill-vs-yg1-v7-heads-up-test-156067
The parameters have changed a few times since 2008.

The following were parameters ran from 2015 - 2019
Slotting 1xD = 350sfm @ 13IPM (across welded intersections)
Profile 0.25" radial x .5 axial = 400SFM @ 30.5IPM (0.0025 IPT) chip thinning the feed.
Typically we got about 800 cubic inches of material prior to swapping tools.

In 2020, we changed the parameters to increase throughput, without too much loss in tool life.

Slotting 1XD = 450SFM @ 33IPM (0.0024 IPT)
Profile 0.25" radial x 0.5" axial = 550SFM @ 47IPM (0.0028 IPT)
On the last run we were able to squeak 760 cubic inches before swapping cutters.
We ran out of parts before we could cut 200 cubic inches on the second cutter.

We got great tool life out of the mills, in less than optimal conditions, on a Cat40.
The material is tough, but not too hard.

Of course, this only addresses solid carbide tooling.
For face milling we run Iscar, Feedmills, '16 mills' and a 2" HM90, but I will need to pull up the post to see what we are running for those.

Just my $0.02

Doug

Thank you very much Doug!

I did turn off coolant on the facemill and got 2.5x the tool life. Looks like I still have a lot to gain though. Appreciate you sharing your numbers.