Re: [CAD_CAM_EDM_DRO] 4130 4140 how to heat treat ?

For what you are making you have select the wrong
steel. You should have used air hardening. The
water quench will twist all over the place. The
oil quench will twist some but not as much. To
avoid high heat scale you should warp them in a
stainless steel foil. Warp them so you can get
them open very fast when ready to quench. I do not
remember the hardening temperature some where
around 1800 degrees Put them in a cold furnace and
bring to temperature. Then soak for 1/2 hour and 5
extra minutes for each inch of thickness. When
ready to remove rip the stainless off an quench as
fast as you can. They will be around 60 to 64
rockwell. Then you must draw them so they will not
be brittle. It depends what hardness you want to
finish with. I suggest 56 to 58 R. The Temperature
you draw at will determine the final hardness. I
suggest you talk to the steel co you got the steel
from and they will help you with this project.
Also an oil quench of water hardening steel will
give you poor results. Water quench of oil
hardening steel will make it so brittle that it
may break into pieces while quenching.
Larry

smcd