Heat treating, yes or no?

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jnjproto
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Heat treating, yes or no?

Post by jnjproto » Tue May 09, 2017 11:33 pm

I am just finishing up my first form 1 can. Ti tube and 17-4 cones. It is a 30 caliber however it will mainly live on an M-4 .223, 300 BO and 30-30. The baffles are not heat treated now and I am undecided as to whether heat treating would provide enough benefit for longevity. I can heat treat myself so there is no extra cost.

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John A.
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Re: Heat treating, yes or no?

Post by John A. » Wed May 10, 2017 10:35 am

Honestly, I doubt it would do much of anything.

If you're a high volume shooter and like to do a lot of full auto fire, it may take longer before starting to see bore erosion if you heat treat it, but if you're heating it to make it stronger, it's plenty strong enough now.

If you can heat treat it, I don't see a reason why you shouldn't, other than making sure you don't make it too hard (and brittle), but the gains from heat treating 17-4 cones aren't really necessary in my opinion.
I don't care what your chart says

bnmorgan
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Re: Heat treating, yes or no?

Post by bnmorgan » Wed May 10, 2017 11:18 am

Would think case hardening or something shallow would be best and left pretty hard on the skin. Otherwise a good full hard and nice draw temper shouldn't be too bad. Depends what you are starting with, I haven't looked into heat great for 17-4 that I can recall

cdakers
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Re: Heat treating, yes or no?

Post by cdakers » Wed May 10, 2017 4:46 pm

bnmorgan wrote:Would think case hardening or something shallow would be best and left pretty hard on the skin. Otherwise a good full hard and nice draw temper shouldn't be too bad. Depends what you are starting with, I haven't looked into heat great for 17-4 that I can recall
17-4 is easily heat treated to H900 condition with a 1 hour soak at 900*. Definitely worth it if you have a way to do it. A ceramic/pottery kiln, or even your lead casting pot with a good PID controller will work.

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yondering
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Re: Heat treating, yes or no?

Post by yondering » Wed May 10, 2017 8:51 pm

cdakers wrote:
bnmorgan wrote:Would think case hardening or something shallow would be best and left pretty hard on the skin. Otherwise a good full hard and nice draw temper shouldn't be too bad. Depends what you are starting with, I haven't looked into heat great for 17-4 that I can recall
17-4 is easily heat treated to H900 condition with a 1 hour soak at 900*. Definitely worth it if you have a way to do it. A ceramic/pottery kiln, or even your lead casting pot with a good PID controller will work.
That's how I do it. A spray with moly dry lube before heat treating seems to help get the lead off again afterwards.

I heat treat all my 17-4 baffles. Some here have claimed they warp like potato chips if you do that after machining, but I haven't seen any significant warping at all, maybe the material or maybe the lead bath is the difference.

jnjproto
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Re: Heat treating, yes or no?

Post by jnjproto » Wed May 10, 2017 10:41 pm

I think I will try one baffle to start. Then check for warpage. I've always heard 17-4 is very stable in heat treating. All my baffles except the blast baffle are .050 on the cone and .020 for the skirt. I think the most I would do to heat it up would be 4 or 5 shots at a running coyote with the M-4.

cdakers
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Re: Heat treating, yes or no?

Post by cdakers » Thu May 11, 2017 2:37 pm

All of my research indicates 17-4 is very resistant to warp during heat treating. It is used extensively in the aeronautics industry - think jet engine turbines. Something that had issues with warping couldn't possibly be used for the extremely tight tolerances required in those applications.

Most techniques I have seen wrap the cones in stainless steel foil pouches and then use various methods to purge the air from inside the pouch. This will help to eliminate any scale buildup on the parts that can occur during the treatment. Tons of info available on the web if you do a little bit of searching.

1rosta
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Re: Heat treating, yes or no?

Post by 1rosta » Thu May 11, 2017 9:44 pm

If using the lead treatment, is the baffle pulled and that let to air dry or is it dunked in oil?
Your Techniques will be appreciated.

Rich V
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Re: Heat treating, yes or no?

Post by Rich V » Thu May 11, 2017 10:31 pm

17-4 SS is the easiest metal I know to heat treat. Take your finished part heat to 900F for 1 hour then air cool. Result is a tensile strength around 200,000 PSI and a Rc of ~42. It does not warp in heat treat but it does shrink ~ 0.001in per 1inch web.

No need to protect it from the air, the parts come out as a nice straw yellow/gold with zero scaling.

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yondering
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Re: Heat treating, yes or no?

Post by yondering » Thu May 11, 2017 11:05 pm

1rosta wrote:If using the lead treatment, is the baffle pulled and that let to air dry or is it dunked in oil?
Your Techniques will be appreciated.
Air cool.

And +1 to what Rich said, no need for foil, especially with a lead bath; there is no scaling.

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