4140 straightening problem
4140 straightening problem
(OP)
Hello everybody,
We are having a lot of problems with heat treating round 4140 material. This part is .5" in dia & 25" long. It has a V groove machined into it. We just need the edges of the V groove to be hardened to about 55 Rc. Right now we are flam hardening the edges & this makes the part to bow severely. We then straighten the part in a manual press. I was wondering if it will be better to through harden the hole part instead of flame hardening? Is there any better way to straighten the part after heat treating? Can sombody help me with this?
Thank you
We are having a lot of problems with heat treating round 4140 material. This part is .5" in dia & 25" long. It has a V groove machined into it. We just need the edges of the V groove to be hardened to about 55 Rc. Right now we are flam hardening the edges & this makes the part to bow severely. We then straighten the part in a manual press. I was wondering if it will be better to through harden the hole part instead of flame hardening? Is there any better way to straighten the part after heat treating? Can sombody help me with this?
Thank you





RE: 4140 straightening problem
1. Obtain 4140 steel in the form of cold drawn bars xx.xx mm in diameter.
2. Machine features using single spindle lathe, etc. Final dimensions are...
3. Cut v-groove using vertical milling machine. Final dimensions are...
4. Flame harden using y velocity, z heating parameters
5. Quench into water with temperature = i, no agitation, remove after 10 minutes, etc...
RE: 4140 straightening problem
RE: 4140 straightening problem
Here is the process
1. We use pre-hardened 4140 turned, ground, and polished material. The diameter is .5" & 25" long.
2. Then we cut the V-groove in a vertical milling machine. We remove about 25% of material.
3. Then we flame harden the edges. We just use a torch & to flame harden the edges. We run cold water through the part as we move the torch across the part. This is purly a manual process. I know there is no real control over the process. But, this is all I have got to work with. We don't have a proper flame hardening equipment. Any recommendations for controlling the process better?
4. Then we straighten the bar in a mechanical press. Some times it would take about 3 hours to get the bar straight.
Thanks for your help TVP
RE: 4140 straightening problem
The core doesn't have to be hardened. I was just wondering if the through hardening process would have better control. I cannot induction het treat this part because I cannot put centeres on them. Do you think induction hardening would reduce the bowing?
RE: 4140 straightening problem
The part may still bow some, but it shouldn't be nearly as much.
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RE: 4140 straightening problem
RE: 4140 straightening problem
I don't have any room in the ends to hold these parts in a chuck. The outter surface of the bar doesn't have to be hardened. We are only concerned about the V-groove surface. Is there anyother material which is as strong as 4140 & has better resistance to heat treat distrosion?
RE: 4140 straightening problem
RE: 4140 straightening problem
RE: 4140 straightening problem
I understand there I cannot eliminate the straightening process. All I am trying to do is minimize the distortion so that the straightening process doesn't take as much time as now. What would be your recommendations to minimize the distortion?
Thank you
RE: 4140 straightening problem
RE: 4140 straightening problem
TVP,
If we were to use a proper flame hardening equipment, what would be your recommendations as far as y velocity & z heating parameters?
Thanks again