Can You Grade Stainless Steel with a Magnet?

There are several grades of stainless steel out there, and some of them do attract a magnet. But can you identify the grade based on the magnet? Justin explains in this video.

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[TheFabricatorSeries]

Let me explain MORE for the people who missed it... I'm talking about austenitic stainless. I'm not talking about the other families/categories of stainless steel. Therefore, I have no 4XX series stainless in this video. The reason is I primarily work in the automotive industry where you only see ferritic 409 on stock exhaust systems which is what you usually rip off the car to replace with something upgraded (so who cares if a magnet sticks to it if you already know what it is and you dont want it).

[InchFab]

430 is a ferretic stainless. It's non hardenable but can be annealed, and not very ductile, so it's not used a ton in anything other than appliances/backsplashes in the kitchen and maybe some body panels. It's not fun to fabricate with.

[jake]

I used to work in a factory manufacturing specialized refrigerators for bars and restaurants. We used a lot of stainless components for customer-facing, ornamental work.

We called the magnetic stainless steel "fool's stainless" because it would corrode quickly but had the appearance of quality.

[rtarrc]

I don’t mind the cell phone video. I just appreciate the good info. Thanks for teaching us diy people.

[chris-graham]

cold working austenitic stainless causes martensite to form where work hardened. martensite is magnetic so that's why the bends are magnetic. rule of thumb, more nickel, less magnetic, even in martensitic areas, like 316.

[robertshelton]

Thank you for holding your phone correctly and not making this a "short" upvote just for that

[SpatialGuy]

Great video, I knew some but not all, even took notes. Thanks so much, more of this type of video would be welcomed. (More NiCr the better corrosion resistance too)
Michael 🇦🇺

[GingeAv]

304 sheets at work are non-magnetic full sheets but the slugs from the punch end up becoming magnetic, now I know why!

[hool]

Another way to check if it's stainless or non-stainless is by the spark pattern when you grind it. Best way though is to use a magnet or if you own a business and poorly separate your metal stock then I would advise getting a metal alloy analyser gun like you mentioned.

[davidsawyer]

If I could only watch 5 channels. This channel would in that 5. Thank again.

[_BLANK_BLANK]

I believe the 200 grade is called work hardening austenitic stainless. So through cold working it can be turned to martensite which is magnetic. So you're more likely to have some magnetic properties coming from it.

Like you mentioned with the bent part of the 304 stainless, it should technically convert more readily to martensite than something in the 300 grade.

[alexhb]

Telling me some stainless is magnetic was worse than telling me the Easter Bunny isn't real.

[simentalg]

When are we getting an update on that mini truck?

[SDKwarrior]

wonderful, short, and information packed video. much appreciated!

[Orxenhorf]

Hmmm... that might have been what we found at my parent's retirement place when they first moved in. There was a 3/16" thick plate about 2 foot by 3 foot buried in the dirt and weeds under the previous owner's pile of crap at the back of the property. Full force whacks with a pick axe didn't dent or even scratch it, there was no rust or corrosion of any kind, and a magnet did stick to it. (There was also a Halloween tombstone made of real stone buried back there too.)

[trxtech]

Oh wow, I never knew that it was more magnetic at the bend that is so cool

[JamieBainbridge]

I did a welding course a while back, I found the composition and properties of metal the most interesting part. Shoulda become a metallurgist 😅

[jwnickelson]

We use 316 stainless at work as we are pumping saltwater up to 325psi. We have done multiple magnet checks on out system (around 600 pump runs) I’ve had 1 SS nipple grab a magnet strong enough to question it. I called my higher ups and showed them video. After some research they said the lathe process can induce some magnetism into the part.

[mordantly]

Thread forming 304 makes it magnetic AND cold work hardens the material about twice the rockwell of the material.

[ShannonMarie-exid]

I definitely understand that cold working, different processes and all, play factors in magnetism. But should a threaded rod (10 or 12 inches) be so magnetic I can lift it and shake it without it falling off of the magnet if it's really 304 stainless?