Magnetizing 304ss Tube

I'm not going to say it can't be done. I'm sure, eventually, someone will figure out how to permanently magnetize wood. Unfortunately, the compound content of 304SS does not lend itself to magnetism, much less permanent magnetism. If you've ever tried sticking a magnet to your kitchen sink, you've noticed that it will barely stick, if it sticks at all. If you were able to magnetize SST of nearly any grade, it would be a very weak magnetism, and would be temporary.

If you were die hard set on it, however, the best way to magnetize metal is to pass a high amperage current through it. A car battery can do it, or a few in parallel; just make sure not to leave the current flowing long enough to overheat and damage the batteries. Because overheated car batteries explode, in case you didn't know. A TiG welding power supply is best, if you're friends with any welders or have a local fab shop that's willing to work with you on it. If you don't mind me asking, what is it that you are trying to build/achieve? Also, you say tube, how thick is the wall of the tubing?

just curious, do you have any details on exactly how to use the tig welder to magnetize a piece of metal? I tired a car battery but wasn't strong enough to achieve the results I want and have been seeking another way. I would really appreciate your help on this.

Do not use a car battery to circulate current through any metal unless you have a high wattage High resistance resistor or carbon pile to reduce the current. If you use just a piece of metal the only limiting factor of the current is the battery's internal resistance and the piece of metal your using. This is Dangerous!!! DON"T Do it! Many people and equipment have been hurt do to the shorting of batteries.

Marty Nelson

JEA PdM Electrical Analyst Cat III Cert.

Try to go from this link

:http://www.azom.com/details.asp?ArticleID=1140

May I ask "What good will be a foot-long 1" pipe magnetically-ever"?

thanks for the response.
the part is for a racing exhaust and the rules state that "it must magnetic".

It need not be 304 ss ,just happen to have some . I know some 400 series is magnetic but can't seem to locate any.will something else work?It needs to be between .040 and .080 wall. I copied this next part so you know better what I'm trying to achieve.
"Typical 1010 carbon (mild) steel conducts 219% more heat per foot than do the types of stainless steel we use in header fabrication. By contrast, quite a bit more heat stays inside the stainless header tubes and does not get passed into the surrounding air. By not allowing the contraction of the cooling gases as they flow down the tubes, more exhaust velocity is retained which promotes better scavenging at the collector. This retention of velocity increases the overall header efficiency." thanks for your input

AISI 410>>> Series(13% Cr, Nickel-free) is not ROLLED as sheet-- because nobody buys it - it has poor corrosion resistance.

As there is no sheet in market , nobody makes ERW tubes out of 400 series SS.

If avoiding cooling of exhaust gas is your net goal,-ignore the Race Rulebook--just wrap Asbestos fibre on 1010 Steel tube 1mm wall thickness and replace this often!

By the way, 400 series is also not permanent "Magnetic" .Yes ,it will be pulled by a Permanent Magnet. How does this help in racing?

Magnetized and magnetic are two different things. Magnetized means that it possesses a strong magnetic field, i.e. capable of attracting ferromagnetic materials. Magnetic just means that it will be attracted to a magnet, or vice-versa. It appears that, in this case, the racing authority is simply using it as a benchmark for the amount of ferric material to be contained in the exhaust system. This also gives the inspectors an easy method of examining the vehicle.

If the "must be magnetic" is the only caveat in the rules, and if you want to take the risk, find the strongest magnet that you can (hard drive magnet, or one of the rare earth magnets-on-crack you can get off of Ebay that can lift 10,000 times their weight) and you might be able to get it to stick to the stainless. Just be prepared for the hard-assed judges that give you the stink eye and tell you that you can't compete anyway.

Why magnetic? Surely the heat generated will degrade the magnet proprties with time. How can the fact of having a magnetic steel increase or otherwise effect the cars performance? I am at a loss. I always thought stainless wass just to make the thing last longer. Do these people have shares in the auto supply business? The big racing boys F1 us titanium. I cant remembere if this is magnetic, but it shore glows nicely when they rev up those engines.

304 is austenitic stainless.

Austenitic stainless is not ferromagnetic. at room temperatures.

I have seen some academic literature that suggests change in permeability at cryogenic temperatures.

The following technical note provides a good not to abstruse explanation suitable for non-engineers.

www.bssa.org.uk/publications/files/SSAS2.81-Magnetic%20Properties.pdf

The last half of the tech sheet points out that after severe cold work, it is possible to transform some of the austenite to martensite, which is magnetic. Of course, the magnitude of the magnetic effect will be a function of the volume fraction transformed to martensite, that is to say slight. Nevertheless, a severely cold worked austenitic stainless that was subsequently cryogenic treated to pull out as much martensite as possible might display some slight magnetic attractive properties sufficient to satisfy your judges. Especially around sharp edges. I'm not at all sure how such a treatment would effect the fit form and function of your part.

As others have posted, good luck on finding 304 tubing... I generally see it as solid bar stock for machining.

milo

<good luck on finding 304 tubing... I generally see it as solid bar stock for>

That was a typing slip!

YOU MEANT 410>>>>>>

"Eagle makes a variety of square, rectangular, & oval tubing in various OD dimensions with light to standard wall sizes.
Special shapes are also available to be made. Send us your drawing or sketch for us to quote on. No minimum footage required."

http://www.eagletube.com/customtubing.asp

Magnetic means it must have enough ferrous material for the magnet to show some adhesion...probably so it won't melt...

thanks milo. that was the page I've been looking for.

You're welcome!

Good luck.

milo

Do the rules state that the actual metal has to be magnetic or can you just bolt some magnets directly onto the exhaust?

no magnets

You never explained WHY IT HAS TO BE MAGNETIC I fail to under stand this requirement. How does it effect performance? An answer would help.

He said something like that in#3

<By contrast, quite a bit more heat stays inside the stainless header tubes and does not get passed into the surrounding air. By not allowing the contraction of the cooling gases as they flow down the tubes, more exhaust velocity is retained which promotes better scavenging at the collector. This retention of velocity increases the overall header efficiency." >

Not He--Race authorities think that way ! To get that extra 0.1% thrust due to hot-hotter exhaust at end?

You are giving way to much credit to race authorities, in my opinion..

I just think its a bureaucratic rule unrelated to performance.

I'd bet dollars to Atkins low carrb donuts that Magnetic steel headers are Stock (magnetic equals non stainless = cheap; Stainless headers = non magnetic = Custom.

Where custom is bad.

Withoutknowing the class of racing, ie the full statement of problem, all of us are recirculating hot gas of lack of knowledge. That's my hot air fortonight.

milo"back tomy itunes chores, case studyon krispy kreme is done"

I guess like so many of the answers to posts it is mostly guess work because the original poster does not know or is just to lazy to answer a simple question.

...stir the pot and see what rises up indeed!

milo