Can't drill 4340 annealed

[mjd]

hello,

I am a rookie here.   Our co. processes a good amt of 4340 rd  material.  Cust specs sometimes dictate we rouigh machine in the annealed condition.  We can turn the OD and face, but the issue is we have a very hard time dirlling this stuff.    Various sizes from 2" ID - 6" ID typically.  Altered feeds and speeds.  Still no luck.  

If we heat treat it, it drills fine.  But we then have to re-heat treat  anyway after putting the hole in it.  

Anyone else ever experiecne this and how do you solve it?

Thank you for any help.

mjd

  

[jeff]

No issues here.

What drill are you trying?

Lathe? Mill?

Speeds and feeds?

We need more info.

[nickbe10]

I have always found 1/2 hard to be much easier to deal with, even if it causes extra steps at heat treat. But some aerospace process specs don't allow this, so it depends on the customer what you can get away with.

The problem is that it is difficult to make good chips with annealed 4000 series because it is so soft and gummy. And if you can't make good chips it usually turns into a battle.....