Straightening 4140
Straightening 4140
(OP)
Hi I am new to this forum and am seeking advice on the best way to strighten 4140 Ht. I have so parts that have been machined and have bowed .015" ove 24". Is there a way to straighten this without heat. The thinest part is 3/4" and the thickest is 1.5".
Thanks in advance.
Noel
Thanks in advance.
Noel





RE: Straightening 4140
What condition is the steel in before machining, has it been quench-and-tempered or is it as-rolled?
At my company we straighten Q&T'd 4140 material with a at about the same size and length as your part at ambient temperatures using a Hydraulic Eitel machine.
My operators do prefer to work on them with heat, shortly after they come out of temper, or about 250F.
RE: Straightening 4140
RE: Straightening 4140
Thanks Noel
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RE: Straightening 4140
The only other pratical thing that I can think of is to use peening to straighten the parts.
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RE: Straightening 4140
But unless teh steel was ground it probably didn't have 0.002" flatness to begin with.
(or strip is high flatness requirement the best we can get teh mill to do is 2% of width. So for us thats a .100" wide to get 0.002" flatness. more like wire than strip.)
Heck can a milling machine cut a flat surface to 0.002"?
I know a surface grinder can.
RE: Straightening 4140
Noel
RE: Straightening 4140
Are you roughing the form, then finishing it after heat treatment, or are you trying to finish machine the part PRIOR to heat treatment? And what medium are you using to quench the part? Finally, are you utilizing any stress relief cycles prior to heat treatment?
RE: Straightening 4140
Noel
RE: Straightening 4140
RE: Straightening 4140