Does 404 SS anneal and become malleable?
- tornitore45
- Posts: 2078
- Joined: Tue Apr 18, 2006 12:24 am
- Location: USA Texas, Austin
Does 404 SS anneal and become malleable?
I need to make a tapered chimney and plan to start with a seamless tube, cut out a triangular slit and coerce the rest into a tapered "round" tube.
I need not to spring back too much.
4" Long Small OD=0.825" Big OD=1.062 Wall=0.04
I need not to spring back too much.
4" Long Small OD=0.825" Big OD=1.062 Wall=0.04
Mauro Gaetano
in Austin TX
in Austin TX
Re: Does 404 SS anneal and become malleable?
I have not encountered 404 stainless in all my many years in the shop, so I am unable to provide any guidance. However, it is reputed to be easy to fabricate.
You might consider boring a sleeve in which you can drive the piece of tubing, so it will be formed to the desired configuration. Once the wedge is removed, you should be able to push the tube in with a press, or it may even go willingly with a few hammer taps on a block of aluminum placed over the end. Once in place, a tack at each end so it can then be removed for final welding. You also might consider making it a little too long, so you can trim each end.
I'd enjoy reading how you accomplish the task, and I know you will.
H
You might consider boring a sleeve in which you can drive the piece of tubing, so it will be formed to the desired configuration. Once the wedge is removed, you should be able to push the tube in with a press, or it may even go willingly with a few hammer taps on a block of aluminum placed over the end. Once in place, a tack at each end so it can then be removed for final welding. You also might consider making it a little too long, so you can trim each end.
I'd enjoy reading how you accomplish the task, and I know you will.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Does 404 SS anneal and become malleable?
Type 404's chemical composition includes a trace amount of carbon and a small amount of nickel, but much less nickel than typically found in 300-series alloys, which sort of makes 404 an austenitic/ferritic hybrid. 404 will not respond to heat treatment, but can be annealed by raising it above its transformation range (~1510° F to ~1600° F), followed by rapid air cooling.
404 finds a lot of use in sheet metal products as a replacement for type 304, which tells me its forming properties are at least as good as the latter, and likely better due to the lower nickel content. So I'd be inclined to think you shouldn't have to anneal the material before you work it.
As stainless alloys go, it's easy to weld via the tungsten-inert-gas (TIG) process, using tri-mix as the shielding gas and a compatible filler. The extremely low carbon content helps to prevent the formation of chromium carbide in the fusion zone, which would otherwise compromise corrosion resistance. In many respects, 404 is similar to 304, but with better mechanical properties.
I've only run into 404 once—years ago, but I was making to guide rods out of 404 round, so I can't comment on how easy or difficult it might be to do what you want. I did have to weld it and found its welding properties were just like 304L.
404 finds a lot of use in sheet metal products as a replacement for type 304, which tells me its forming properties are at least as good as the latter, and likely better due to the lower nickel content. So I'd be inclined to think you shouldn't have to anneal the material before you work it.
As stainless alloys go, it's easy to weld via the tungsten-inert-gas (TIG) process, using tri-mix as the shielding gas and a compatible filler. The extremely low carbon content helps to prevent the formation of chromium carbide in the fusion zone, which would otherwise compromise corrosion resistance. In many respects, 404 is similar to 304, but with better mechanical properties.
I've only run into 404 once—years ago, but I was making to guide rods out of 404 round, so I can't comment on how easy or difficult it might be to do what you want. I did have to weld it and found its welding properties were just like 304L.
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Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Re: Does 404 SS anneal and become malleable?
Why not Argon?BigDumbDinosaur wrote: ↑Tue Jan 12, 2021 1:46 amAs stainless alloys go, it's easy to weld via the tungsten-inert-gas (TIG) process, using tri-mix as the shielding gas and a compatible filler.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
- tornitore45
- Posts: 2078
- Joined: Tue Apr 18, 2006 12:24 am
- Location: USA Texas, Austin
Re: Does 404 SS anneal and become malleable?
Can you expand on that?followed by rapid air cooling.
Steel is normally annealed by slow cooling.
Brass can be allowed to cool slowly, speeding up cooling is only for convenience.
All the welding capability I have is silver brazing and flux core which it usually turns out looking like solidified volcanic lava all round the intended spot.
I will braze it including finishing turning rings at the ends.
Until I learn to control the flux wire welding it will be limited to non critical/non cosmetic projects.
Mauro Gaetano
in Austin TX
in Austin TX
Re: Does 404 SS anneal and become malleable?
Argon is suitable but the weld quality may not be as cosmetically pleasing. In my experience, tri-mix seems to be more forgiving with stainless alloys. It depends a lot on the weldor's skill.GlennW wrote: ↑Tue Jan 12, 2021 9:39 amWhy not Argon?BigDumbDinosaur wrote: ↑Tue Jan 12, 2021 1:46 amAs stainless alloys go, it's easy to weld via the tungsten-inert-gas (TIG) process, using tri-mix as the shielding gas and a compatible filler.
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Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Re: Does 404 SS anneal and become malleable?
404 is an exception. If you are still in doubt look it up.tornitore45 wrote: ↑Tue Jan 12, 2021 9:49 amCan you expand on that?followed by rapid air cooling.
Steel is normally annealed by slow cooling.
Brazing a stainless alloy is not something I would do. Brazing is a form of hard soldering, a process that doesn't work well with high-chromium-content steels. You really need to weld this material to achieve satisfactory results, TIG being the preferred process (MIG is possible, but won't be very pretty). Spot welding is an alternative if seams overlap. If you can't do it this would be a good case for paying a skilled weldor to do it for you. It all depends on how critical the joint's structural integrity is.All the welding capability I have is silver brazing and flux core which it usually turns out looking like solidified volcanic lava all round the intended spot. I will braze it including finishing turning rings at the ends.
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Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Re: Does 404 SS anneal and become malleable?
I suspect that brazing will border on the impossible. Stainless has a considerable expansion coefficient, so unless the item can be fully restrained while it is brazed, it will open when heat is applied. A difficult process, to be sure.
H
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Does 404 SS anneal and become malleable?
Can't say that i have ever heard of or seen a reference to using tri mix for TIG welding stainless. MIG, yes.BigDumbDinosaur wrote: ↑Tue Jan 12, 2021 4:40 pmArgon is suitable but the weld quality may not be as cosmetically pleasing. In my experience, tri-mix seems to be more forgiving with stainless alloys. It depends a lot on the weldor's skill.GlennW wrote: ↑Tue Jan 12, 2021 9:39 amWhy not Argon?BigDumbDinosaur wrote: ↑Tue Jan 12, 2021 1:46 amAs stainless alloys go, it's easy to weld via the tungsten-inert-gas (TIG) process, using tri-mix as the shielding gas and a compatible filler.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
Re: Does 404 SS anneal and become malleable?
I'd add that the cone shaped form to force it into is fine, but just tacking at the ends isn't going to keep the middle from wanting to open up. If I was going to go that route, I'd machine a slot along the seam so it could be tacked in several places along the seam before pulling it out of the form. If I was going to make this part, though, I'd turn a tapered form to place the part over and then hammer form with a nylon hammer.
Dave
Dave
Re: Does 404 SS anneal and become malleable?
I agree. With just end tacks, once removed, a center tack would likely work, however, but unless one has access to TIG, this is likely of little use to the OP.
I'd thought about the idea of simply leaving the formed piece in place, and doing the welding/brazing insitu. Problem is, one would need a form that didn't absorb heat, and provided resistance to soldering the piece in the form. Not much of a challenge, eh?If I was going to go that route, I'd machine a slot along the seam so it could be tacked in several places along the seam before pulling it out of the form.
Having worked on enough stainless to be concerned, that might just be a lot harder than it sounds. Stainless, very unlike copper alloys, doesn't really respond well to that kind of treatment. It likely would work if heated, though, but now the form is also softened. Little chance of heating just the thin material and retaining any substantial heat.If I was going to make this part, though, I'd turn a tapered form to place the part over and then hammer form with a nylon hammer.
It's going to be interesting to read how this works out in the end. We all stand to gain some knowledge.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Does 404 SS anneal and become malleable?
Back in my (full-sized) railroad days I regularly TIG-welded stainless with tri-mix, mostly because it was available and tended to make for prettier welds. Technically speaking, tri-mix is "wrong" for stainless, but it does work.GlennW wrote: ↑Tue Jan 12, 2021 8:50 pmCan't say that i have ever heard of or seen a reference to using tri mix for TIG welding stainless. MIG, yes.BigDumbDinosaur wrote: ↑Tue Jan 12, 2021 4:40 pmArgon is suitable but the weld quality may not be as cosmetically pleasing. In my experience, tri-mix seems to be more forgiving with stainless alloys. It depends a lot on the weldor's skill.
Incidentally, I do all my steel MIG welding with 75/25, and can produce acceptable stainless welds with it. The arc isn't as aggressive as with the more economical CO2, resulting in better weld quality and less spatter. Only thing is 75/25 makes for shallower penetration. That, of course, is a plus when welding sheet metal. I rarely weld sections thicker than 1/4", so 75/25 is practical for me.
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Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Music isn’t at all difficult. All you gotta do is play the right notes at the right time!