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.

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.

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

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.

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.

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.

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.

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.

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.

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.