Can you HT 4140 without controling the atmosphere?

[A Zone]

I need to HT a finished part and wonder what would happen if I just popped it in my oven at 1550 F, held for 20 min. and quenched it in peanut oil? would the part be usable or would it have a lot of scale/pitting?
Thanks

 

[Bruce Bump]

It will have scale but could be sanded off. Is your piece at finished size already or do you have room to sand off a few thousands?

 

[A Zone]

Finished size. It's a custom nut w/ flange. The thread is non standared and has been cut on a cnc mill. We don't have any way to clean up the thread after ht except to maybe remove some light scale with a round wire brush chucked up in a lathe. Of course the part has to be ready by yesterday so we can't order a tap in time. How should I ht this part(I have some Turco, but no foil)?

 

[KennyC]

you could try using an anti-scale compound.

Kenny

 

[Bruce Bump]

Ive never used turco but I like PBC from Brownnells. It is an anti-scale compound. Why do you need it hardened?

 

[A Zone]

The customer specified that the part be made of 4140 treated as hard as possible. Last night I treated the nuts(4) with Truco on all surfaces except the threads. It was the only thing I could think of. They came out ok but needed a lot of wire brushing. The threads felt snug on the bolts after a wire brush clean up.

I may have to do this again in the future and I wonder how is this situation is best handled.

Thankes for the help,
zone

 

[rlinger]

Brownell's PBC comes off in boiling water. You may have to wire brush the part alittle.

RL