Can I use heat to work 304 stainless?

[WS6HUMMER]

I'm building a merge for a turbo setup & I need to make a round pipe to go into a rectangular flange. I played around with a peice after work today, I used the torch to heat it until orange but not to bright and used a metal working hammer to shape it from the inside of the pipe out. Didnt know if this would weaken the pipe too much or make it rust, any input? If I quench it when I'm done will it strengthen like mild steel does?

[mrmikey]

I can't comment on the strength only on my experience making an exhaust for an old 75o Suzuki.
I used 1 1/4" .065 s/s tubing (all I had) and had the elbows bent at our local muffler shop, they did an ok job but none of the angles were right on.
I ended up heating them up and pulled them into the correct alignment. All said and done it looked good after polishing...but, they would oxidize and darken a lot faster where I had to heat them. The weld zone was fine, just where I had to heat them up.
As for the other questions I'm sure someone else will come along.....Mike

[WS6HUMMER]

I can't comment on the strength only on my experience making an exhaust for an old 75o Suzuki.
I used 1 1/4" .065 s/s tubing (all I had) and had the elbows bent at our local muffler shop, they did an ok job but none of the angles were right on.
I ended up heating them up and pulled them into the correct alignment. All said and done it looked good after polishing...but, they would oxidize and darken a lot faster where I had to heat them. The weld zone was fine, just where I had to heat them up.
As for the other questions I'm sure someone else will come along.....Mike

Thanks Mike, I appreciate any help I can get.

[William McCormick Jr]

I'm building a merge for a turbo setup & I need to make a round pipe to go into a rectangular flange. I played around with a peice after work today, I used the torch to heat it until orange but not to bright and used a metal working hammer to shape it from the inside of the pipe out. Didnt know if this would weaken the pipe too much or make it rust, any input? If I quench it when I'm done will it strengthen like mild steel does?


I will sometimes make a round end on an ornamental piece of pipe. By heating it and hammering over the end. But I have noticed stress fracturing in the metal. This tubing though is a Japanese stainless. It is hardened. It is probably better to just buy the ready made caps.

But sometimes the job is being installed the next day, and you don't have any, so I just get out the torch and customize them a bit.

You really have to heat up the stainless before it goes. Because of all the chromium in it.

It is not like steel.

If you get American made stainless, annealed, you could probably work it a little bit without heat. It is that soft.


Sincerely,


William McCormick

[Broccoli1]

Some SS info

http://www.ssina.com/view_a_file/fabricate.pdf


just learning about SS meeself.

[mrmikey]

Nice gate Will....Mike

[WS6HUMMER]

I will sometimes make a round end on an ornamental piece of pipe. By heating it and hammering over the end. But I have noticed stress fracturing in the metal. This tubing though is a Japanese stainless. It is hardened. It is probably better to just buy the ready made caps.

But sometimes the job is being installed the next day, and you don't have any, so I just get out the torch and customize them a bit.

You really have to heat up the stainless before it goes. Because of all the chromium in it.

It is not like steel.

If you get American made stainless, annealed, you could probably work it a little bit without heat. It is that soft.


Sincerely,


William McCormick

Some SS info



http://www.ssina.com/view_a_file/fabricate.pdf


just learning about SS meeself.


Thanks.

[Ries]

304 stainless can only be hardened by working it- there is no heat treating that will harden it.
To anneal 304, heat it to red hot, then quench immediately in water, and it will get as soft as it can ever get, which still isnt very soft.

I forge 304 stainless every day, several tons of it a year- and it doesnt really matter whether its annealed or hardened, as once you heat it up to cherry red or so, that all goes away.

Usually it will crack, or fracture, while forging it, if you are working it too cold- it likes to be forged in the lemon yellow to bright orange range- down in the reds its getting too cold, and thats when its likely to crack.

When you get it to the shape you want, you should reheat to a bright red, and then immediately quench in water- this will make it the least likely to rust and discolor. Then, you should sand it with brand new sanding discs or flap discs.
Never use grinding wheels, sandpaper, or wire brushes on stainless that have previously been used on mild steel- they will embed little piece of mild in the stainless, and the little bits will rust. The stainless is still stainless, and the rust wont spread, but even grinding mild near stainless, and letting the grinding sparks hit it, can lead to rust spots on your stainless.

[Broccoli1]

304 stainless can only be hardened by working it- there is no heat treating that will harden it.
To anneal 304, heat it to red hot, then quench immediately in water, and it will get as soft as it can ever get, which still isnt very soft.

I forge 304 stainless every day, several tons of it a year- and it doesnt really matter whether its annealed or hardened, as once you heat it up to cherry red or so, that all goes away.

Usually it will crack, or fracture, while forging it, if you are working it too cold- it likes to be forged in the lemon yellow to bright orange range- down in the reds its getting too cold, and thats when its likely to crack.

When you get it to the shape you want, you should reheat to a bright red, and then immediately quench in water- this will make it the least likely to rust and discolor. Then, you should sand it with brand new sanding discs or flap discs.
Never use grinding wheels, sandpaper, or wire brushes on stainless that have previously been used on mild steel- they will embed little piece of mild in the stainless, and the little bits will rust. The stainless is still stainless, and the rust wont spread, but even grinding mild near stainless, and letting the grinding sparks hit it, can lead to rust spots on your stainless.

Thanks for the info:drinkup:

[hotrodder]

Hummer,
Mild steel can't be 'strengthened' by heat treatment either. What wall thickness are you using? The austenitics (3xx series) DO work harden quickly but are pretty formable. All the shaping in this manifold modification was done cold... http://weldingweb.com/showthread.php?t=21709 (http://weldingweb.com/showthread.php?t=21709)

I typically use 16swg mandrel bends... rough out the change of shape so it fits into the flange, tack it where it fits and then finish off the shaping. If you're working with heavier wall pipe and need heat then an alternative to sanding it out to allow a fresh passive layer to form would be pickling paste- less labour intensive but potentially nasty chemicals although there are more 'green' versions available these days

[WS6HUMMER]

304 stainless can only be hardened by working it- there is no heat treating that will harden it.
To anneal 304, heat it to red hot, then quench immediately in water, and it will get as soft as it can ever get, which still isnt very soft.

I forge 304 stainless every day, several tons of it a year- and it doesnt really matter whether its annealed or hardened, as once you heat it up to cherry red or so, that all goes away.

Usually it will crack, or fracture, while forging it, if you are working it too cold- it likes to be forged in the lemon yellow to bright orange range- down in the reds its getting too cold, and thats when its likely to crack.

When you get it to the shape you want, you should reheat to a bright red, and then immediately quench in water- this will make it the least likely to rust and discolor. Then, you should sand it with brand new sanding discs or flap discs.
Never use grinding wheels, sandpaper, or wire brushes on stainless that have previously been used on mild steel- they will embed little piece of mild in the stainless, and the little bits will rust. The stainless is still stainless, and the rust wont spread, but even grinding mild near stainless, and letting the grinding sparks hit it, can lead to rust spots on your stainless.

WOW! Thank you so much for the help, this info is very valuable to me.

Hummer,
Mild steel can't be 'strengthened' by heat treatment either. What wall thickness are you using? The austenitics (3xx series) DO work harden quickly but are pretty formable. All the shaping in this manifold modification was done cold... http://weldingweb.com/showthread.php?t=21709 (http://weldingweb.com/showthread.php?t=21709)

I typically use 16swg mandrel bends... rough out the change of shape so it fits into the flange, tack it where it fits and then finish off the shaping. If you're working with heavier wall pipe and need heat then an alternative to sanding it out to allow a fresh passive layer to form would be pickling paste- less labour intensive but potentially nasty chemicals although there are more 'green' versions available these days

Thanks also for the input, you know exactly what I'm trying to do based on the link I saw. I'm trying to make 2 2.5" straight peices of .065 into a T4 flange. Any other info you have is gladly welcomed. I plan on building a merge then cutting the top off the merge where its closest to the opening of the T4 flange, tacking it in on the sides that fit and then hammering it into the corners, Wish it was as easy as it sounds, I'm not good with angles though, and building that merge is probably going to be a huge PITA for me. I want one peice to exit straight and one peice to exit at a 45. (like the one in the pic)

[hotrodder]

There's loads of different ways to do this each with pros and cons.

Generally i prefer to size the flange so that the runners/collector fit through it. Terminate it around 2/3 to 3/4 through the flange and you have a nice fit for a lap weld. Very little flange distortion this way as the weld is closer to the flanges neutral axis

With a merged collector (especially if the taper is all on one side) reshaping is a little harder...
23616
The area circled is easy enough as long as the circumferences of the pipe and flange match. The other side (red line) needs to become a 'reverse curve' to fit through the flange which is one of the hardest shapes to form in sheet metal

If there's room my approach would be to add a short straight section to the end of the collector so that less reshaping is required. If you look at the thread i linked to earlier, laying around in one of the pics is a couple of strips of pattern paper. These were used to measure the 'circumference' of the flanges i was matching to. By making the ends of the pipe i added match, circumference wise, all i had to do was change their shape. At the turbo flange the pipe was simply squashed in a vice and worked with a hammer/dolly to deal with the 2 sides that obviously bowed out due to the 'vice squashing'. This got it very close but not exact enough to fit in the flange so i 'bowed in' the long sides a little too far so it'd fit and then tacked, adjusted, tacked etc

If there's not room to add a straight section then it'd be easier to weld the collector to the face of the flange. The reshaping needs to be done 'freehand' but as long as the circumferences match... If the reshaping is defeating you, you can cut out a piece of plate to match the ID of the flange, taper its sides and use it as a 'hammer form' once you're close

[WS6HUMMER]

There's loads of different ways to do this each with pros and cons.

Generally i prefer to size the flange so that the runners/collector fit through it. Terminate it around 2/3 to 3/4 through the flange and you have a nice fit for a lap weld. Very little flange distortion this way as the weld is closer to the flanges neutral axis

With a merged collector (especially if the taper is all on one side) reshaping is a little harder...
23616
The area circled is easy enough as long as the circumferences of the pipe and flange match. The other side (red line) needs to become a 'reverse curve' to fit through the flange which is one of the hardest shapes to form in sheet metal

If there's room my approach would be to add a short straight section to the end of the collector so that less reshaping is required. If you look at the thread i linked to earlier, laying around in one of the pics is a couple of strips of pattern paper. These were used to measure the 'circumference' of the flanges i was matching to. By making the ends of the pipe i added match, circumference wise, all i had to do was change their shape. At the turbo flange the pipe was simply squashed in a vice and worked with a hammer/dolly to deal with the 2 sides that obviously bowed out due to the 'vice squashing'. This got it very close but not exact enough to fit in the flange so i 'bowed in' the long sides a little too far so it'd fit and then tacked, adjusted, tacked etc

If there's not room to add a straight section then it'd be easier to weld the collector to the face of the flange. The reshaping needs to be done 'freehand' but as long as the circumferences match... If the reshaping is defeating you, you can cut out a piece of plate to match the ID of the flange, taper its sides and use it as a 'hammer form' once you're close

Thanks, I like the hammer form Idea, I really appreciate the advice.

[Capnbondo]

I would cut a approx. 2" long pie piece out at each corner and add a corner piece made from sheet metal in (2 triangular pieces of flat welded at a 90 degree angle to fit in the corner.)

I bet that makes now sense. Things like this would be easier to show than explain.

Also use the thickness of the turbo flange to you advantage- stick a die grinder in there and blend the transition once it is reasonably close (within 3/16" or so).

[WS6HUMMER]

I would cut a approx. 2" long pie piece out at each corner and add a corner piece made from sheet metal in (2 triangular pieces of flat welded at a 90 degree angle to fit in the corner.)

I bet that makes now sense. Things like this would be easier to show than explain.

Also use the thickness of the turbo flange to you advantage- stick a die grinder in there and blend the transition once it is reasonably close (within 3/16" or so).


Thanks.

[William McCormick Jr]

304 stainless can only be hardened by working it- there is no heat treating that will harden it.
To anneal 304, heat it to red hot, then quench immediately in water, and it will get as soft as it can ever get, which still isnt very soft.

I forge 304 stainless every day, several tons of it a year- and it doesnt really matter whether its annealed or hardened, as once you heat it up to cherry red or so, that all goes away.

Usually it will crack, or fracture, while forging it, if you are working it too cold- it likes to be forged in the lemon yellow to bright orange range- down in the reds its getting too cold, and thats when its likely to crack.

When you get it to the shape you want, you should reheat to a bright red, and then immediately quench in water- this will make it the least likely to rust and discolor. Then, you should sand it with brand new sanding discs or flap discs.
Never use grinding wheels, sandpaper, or wire brushes on stainless that have previously been used on mild steel- they will embed little piece of mild in the stainless, and the little bits will rust. The stainless is still stainless, and the rust wont spread, but even grinding mild near stainless, and letting the grinding sparks hit it, can lead to rust spots on your stainless.

While rolling sheet they sometimes roll it hot, and quench it in cooler rollers. This will heat treat it.

We used to mostly use 321 heat treated stainless steel. However I know a couple times we had 304 with heat numbers. Years ago 304 used to come magnetic. Today it comes and it is not magnetic. Was this due to a cold mechanical hardening? Perhaps. But I cannot say with any authority.

However we do not buy it from the mill. So there is certainly room for error. I know a few times a suppliers salesmen has confessed, that they actually only have 316 material, but sell both the 304 and 316 at the same price, so they interchange them. I thought that a bit scary. I had the same thing happen with 301 and 304 material.

What does this mean to me, I really don't know. However I do know from welding stainless steel, that it can develop cracks while welding it, unless you are slow and hot.

I would totally agree with you that when it gets cold it is susceptible to fracture, while mechanically working it. But when you are working with ornamentals it is often unwanted to soften the entire piece. Because of the damage that might be caused to the geometry of the part. So we just super heat the end and work it. And surely this is part of the fault.

I also totally agree that with normal heating and working in a forge you could probably get really great results. However I have seen where high temperatures alone have left stainless steel frail and brittle. Mostly due to surface oxidation. That must be ground off to fresh material. That is why we used to always have to grind every weld, for the same reason, to remove the heat damaged material and stress fracturing.

To me stainless steel has its uses, but its strength is precarious.

I prefer the hardened 321 for structural purposes over 301,304 and even 316 material. Because as you mention a little working cold or while it is red can cause fracturing. That is not a good thing for a metal, especially a structural metal. That could face heat. The hardened 321 has a much better spring to it then the 301,304 or 316 material.


Sincerely,


William McCormick

[WS6HUMMER]

I ended up working it cold, it turned out OK

http://img246.imageshack.us/img246/5586/1001641cd4.jpg (http://imageshack.us)

[William McCormick Jr]

I ended up working it cold, it turned out OK

http://img246.imageshack.us/img246/5586/1001641cd4.jpg (http://imageshack.us)


I tried a couple times I could not get that image.

Glad you got it done.


Sincerely,


William McCormick

[William McCormick Jr]

I ended up working it cold, it turned out OK

http://img246.imageshack.us/img246/5586/1001641cd4.jpg (http://imageshack.us)


The problem may have been on my end. Because I get the picture now. It looks good.

We always put the pipes on top of the flange. But If you fillet weld around the top of the flange it should be great.



Sincerely,


William McCormick

[WS6HUMMER]

The problem may have been on my end. Because I get the picture now. It looks good.

We always put the pipes on top of the flange. But If you fillet weld around the top of the flange it should be great.



Sincerely,


William McCormick

Thanks.

[welder155]

i didnt read all the posts but no one has mentioned that if you get anytype of stainless TOO HOT (not sure of exact temp) it can be turned into just expensive steel. because it take away the corrosion resistent properties.

but hey im not a metallurgist :)

[Ries]

Well, I am not a metallurgist either- I dont even play one on TV.
But I dont think you are quite right.
304 stainless is 17 to 20% Nickel, and 8 to 11 % Chromium, which is what makes it rust resistant.

To actually cook all of that nickel and chromium out would require melting it to a puddle.
However, it is true that heating it above a certain temp, probably around 2000, you can put the chromium carbides into a new form, and then it will tend to get some surface rust more easily.
This is fixable, by reheating to a nice orange, then immediately quenching in water.

I have forged literally tons of 304 stainless, gotten it yellow hot, beat it into new shapes, and then quenched and electropolished it. I have projects that have been out in the weather for up to ten years, with no rust. So heating it, in and of itself, does not make it rust.

[William McCormick Jr]

Well, I am not a metallurgist either- I dont even play one on TV.
But I dont think you are quite right.
304 stainless is 17 to 20% Nickel, and 8 to 11 % Chromium, which is what makes it rust resistant.

To actually cook all of that nickel and chromium out would require melting it to a puddle.
However, it is true that heating it above a certain temp, probably around 2000, you can put the chromium carbides into a new form, and then it will tend to get some surface rust more easily.
This is fixable, by reheating to a nice orange, then immediately quenching in water.

I have forged literally tons of 304 stainless, gotten it yellow hot, beat it into new shapes, and then quenched and electropolished it. I have projects that have been out in the weather for up to ten years, with no rust. So heating it, in and of itself, does not make it rust.

It is the iron that is left. The chlorine gets to the iron oxide, that forms on stainless steel, and turns it into ferric chloride. Once you have ferric chloride etching at it 24 hours a day seven days a week. It is not long before deep cracks occur. Then the problem will not go away until you grind away the stress fractures in the surface.

At different times of the day, and during damp and dry times. The chemical actions reverse. Back and forth. The oxygen protects the iron that is attached to the nickle and the chromium. When the chlorine comes it attaches to the iron and separates the iron from the chrome and nickle.
When oxygen is present during dampness or when it is wet. The oxygen can now go deeper into the metal and oxidize more iron. Then the chlorine comes and turns it into ferric chloride again. Every now and then water or wind removes some of the ferric chloride.

We have had rails that have had rust splashed on them. And they will start to rust. Even 316 stainless steel.

I have noted that if you heat stainless up till it turns blue that it will rust there. That only takes 400 degrees to do. In the presence of common airborne contaminates.

Sincerely,


William McCormick

[zapster]

Hey William..
Glad to see your still around..:drinkup:

...zap!

[William McCormick Jr]

Hey William..
Glad to see your still around..:drinkup:

...zap!


Good to be around here. How are you doing?

How is your shop doing?

I have been over on a science forum giving them heck.

Sincerely,


William McCormick

[Ryer]

It is the iron that is left. The chlorine gets to the iron oxide, that forms on stainless steel, and turns it into ferric chloride. Once you have ferric chloride etching at it 24 hours a day seven days a week. It is not long before deep cracks occur. Then the problem will not go away until you grind away the stress fractures in the surface.

At different times of the day, and during damp and dry times. The chemical actions reverse. Back and forth. The oxygen protects the iron that is attached to the nickle and the chromium. When the chlorine comes it attaches to the iron and separates the iron from the chrome and nickle.
When oxygen is present during dampness or when it is wet. The oxygen can now go deeper into the metal and oxidize more iron. Then the chlorine comes and turns it into ferric chloride again. Every now and then water or wind removes some of the ferric chloride.

We have had rails that have had rust splashed on them. And they will start to rust. Even 316 stainless steel.

I have noted that if you heat stainless up till it turns blue that it will rust there. That only takes 400 degrees to do. In the presence of common airborne contaminates.

Sincerely,


William McCormick

Hi William, if you don't mind. Were does the chlorine come from? From the water when quenching it or was it already in the ss. I understand that once you heat up ss to hot that chrome lets go of oxygen because the electron count of the elements don't like to be with each other. And the chrome will grab the carbon. Forming chromium carbides, so now there is no oxidation to fight the corrosion. I dont understand why it is said the elements are cooked out. They are still there just in a different structure. Which now the steel is very ridged and brittle, no ductility. So I'm just having problems understanding were chlorine came in at. And I'm asking with all respect no disrespect.