Can You Grade Stainless Steel with a Magnet?
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- เผยแพร่เมื่อ 24 ส.ค. 2024
- 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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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).
Did you try a 304 sample made in China or just 201?
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.
It depends wildly on the grade. I have several NSF certified (so... professional grade) stainless kitchen tables that are magnetic and they don't rust. I have long suspected they're in the 400 family, but not the same end of it that something like a commodity grade automotive exhaust might be (which do rust easily, but slowly).
I think the real fool's stainless of white goods these days is just straight-up vinyl wrap over mild steel. The wraps are getting so good that it's getting tough to tell the difference.
Ever seen what bleach does to stainless? There are warnings on the big milk tanks at the farms warning about using too high of a concentration of chlorine, it will case the stainless to start to rust, fast, and I’m not sure there is a way to stop it and save the tank, they have to cut that section out, and if it’s near the internal cooling tubes it can be a total loss.
@@TheBrokenLife yep them cheap ass supposed high quality steak knives that get a nice rust dot or 2 after going thru the dishwasher🤦
Ah ,no biggie ,doc said get more iron.
I don’t mind the cell phone video. I just appreciate the good info. Thanks for teaching us diy people.
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.
@@JackHudler pretty much the same with me. Neighbor wanted a bunch of odd shaped magnetic kitchen surfaces. Nibblers are great for making filler strips.
We had to replace a stainless piping from a large holding tank to a packaging line. Kraft BBQ sauce wouid eat through 303 in about 2 years. I forget the name of the process but we used portable maching and weld ring between 2 pipes in a run. The machine automatically welded going around the joint, controlling the time and heat so the joint was near perfect. I stopped buying that brand of BBQ sauce but did think of trying it as a rust remover. I will say that 430 is pretty pricy and with the whole process and training it was around 4x the price as 303 to buy and install.
@@311jbknight that's funny. 430 is specifically resistant to corrosion from nitric and organic compounds, so it's perfect for BBQ sauce.
Os it cheaper than 304 ,316. (Austinetic)
400 series is martensitic stainless, a two phase structure unlike austenite. This means there is ferrous in the structure that is magnetic. It’s always tempered bc martensite is so hard it’s unusable, so not as easy to work but stronger than austenitic stainless.
Thank you for holding your phone correctly and not making this a "short" upvote just for that
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.
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 🇦🇺
304 sheets at work are non-magnetic full sheets but the slugs from the punch end up becoming magnetic, now I know why!
wonderful, short, and information packed video. much appreciated!
If I could only watch 5 channels. This channel would in that 5. Thank again.
When are we getting an update on that mini truck?
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.
even better, label the material when you get it and do not cut the label off
I've ever noticed the difference in stick rods and tig fillers that are from China and not from China. they absolutely weld different because the filler material is lower quality...and with TIG you can SEEEEE the junk floating in the pool between china fillers and non. it's crazy.
The scrappers I went to had one of those. It seemed to take forever so I said just give me base price mate, no it's all good he replied and continued test the different types of SS, end result was I received twice the $$ than what I was expecting.
always great stuff Justin......cheers, Paul
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.
304 work hardens.
@@notanymore9471 it does, just not to the same level.
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.)
Oh wow, I never knew that it was more magnetic at the bend that is so cool
I did a welding course a while back, I found the composition and properties of metal the most interesting part. Shoulda become a metallurgist 😅
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?
Telling me some stainless is magnetic was worse than telling me the Easter Bunny isn't real.
To make yet again even worse yet, _most_ stainless is magnetic if we're talking about it in terms of what is out there in the world.
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.
Cold working of 304 and similar will make it somewhat magnetic. Stainless is famous for work-hardening, and for example can be a nightmare to drill if you relax pressure or pause etc.
Only fully annealed 316 is non-magnetic. Any cold work in particular can make it slightly magnetic.
Thread forming 304 makes it magnetic AND cold work hardens the material about twice the rockwell of the material.
"It's half the price because it has half the stuff in it". @4:00
That's a bit harsh, isn't it? Yes, type 201 has half the _nickel_ in it, but that's compensated by adding manganese and by allowing more nitrogen to be present. In fact, there is slightly more manganese added than nickel is taken out.
Type 304 is allowed to have up to 2 wt% Mn, but doesn't need any per se, while 201 has to have between 5,5 and 7,5 wt% Mn.
201 is a lot cheaper than 304 because manganese is cheaper than nickel.
Have you done a video on the bumper boats?
Good video. Referring to one of your comments below regarding grade 409 SS which apparently is not as good as grade 201, how do you tell the difference. I purchased a replacement "stainless steel" muffler for my Vanguard 35 hp motor and most of it was highly magnetic. Is there a way to tell the difference?
Very informative.,thanks for the awesome service. I'm Andrew.
great explanation 😁👍
Is back purging less critical with 201 or 409 vs 304?
Wow how do you do that so well?
Production value is fine. The content of the video was very good. One thing I might add to bolster your point is that there is a 304 and there is a 304L, which in most automotive uses is really basically inconsequential (but will behave the same with a magnet test), and without stenciling or ink or the XRF gun, we can’t tell the difference in them; which I only bring up because it reenforces your point about MTRs and controlled supply chains to know what we’re messing with. Short of that, just make sure you’re welding mystery joints with 316L. Lol.
Aside: will you be at Fabtech next month?
I'll be running around Fabtech.
Quickest way to identify what grade of stainless steel your exhaust is made out of is to get a X-ray fluorescence (XRF) gun. Ask them to shoot your exhaust to get the material composition. Commonly found at scrap yards.
I can make AISI 316L magnetic. Just by heating and pulling the material from austenittic and into pherritic phase. It's all about applying energy in a certain manner. So destinguish materials with magnet is not a good solution.
Food manufacturing or food process piping, how does it hold up for say, exhaust work? I don't do much welding, but I do almost zero stainless steel.
Great piece of information 😁
I want to see more bumper boat videos!!!!
Is stainless 410 strong manetic ?
I had a set of stock corvette stainless headers and they seemed to put off a lot more heat. Is this indicative of stainless?
sooooo the question that
comes to my mind is:
by welding 304ss to 201ss, will there be a bi-metal corrosion effect due
to the disimilar metals? and, if so, will the high heat accelerate the corrosion?
No. He addressed that in the last video.
Wanna see an all out battle with them bumper boats.looks fun.snooky pa.👍
the boats are the boom bro
Great job this was a very informative video.
Do you have any input on identifying 321?
I need to build an exhaust for a Harley turbo project I'm starting. I want to use 321 tubing. Is there any way the average person (me) can tell if I ordered and received real 321 or is it something of a lesser quality?
I would need to order it since I'm in the middle of nowhere in GA.
Or maybe even better if you know of any reputable companies I could order from that doesn't have a minimum order requirement.
Thanks
Do you weld much 316?
How many times we had an argument with storeman who ordered 304 bolts and nuts and tried to prove with a magnet they’re not ‘stainless’ usually I’m like OK, I’ll take em to my garage, cheers😂
I'm not sure if you misspoke or I'm being pedantic, but not all stainless 308 and above will be non-magnetic. As far as I'm aware, all 400 series is magnetic.
Maybe you just meant in the family of austenitic stainless?
What ever happened to your project cars? The mighty max and the cnc bagged lego car? I’ve been holding out for the finish of those for years!
สุดยอดมากๆครับ
Work hardened stainless can also become magnetic.
I like raw footage. You asked in the last vid.
Actually any austenitic steel should be non-magnetic. It's not about nickel as it is but the austenite itself. Were the magnetic parts work-hardened? I mean, it seem they are welded from stamped sheet, so if they weren't tempered after the welding they probably are, and that solves the mystery of magnetic stainless steel. Or the material itself isn't actually 201 because some scam =)
Fun fact: a strong enough magnet (RE) can stick to even 316L.
I think some aluminum will too sometimes,if it's small enough.
I've had it on some oil drain plugs before and it was definitely aluminum stuck to the magnetic drain plug.
what about 316 stainless steel is it worth using it over the others in automotive (cars )
In addition to being significantly more expensive, 316 is lots harder to find in the different forms you may need. It should be more corrosion-resistant in automotive applications, but 304 may be plenty good enough.
The vent piece was bent with a steel die the threaded 303 was threaded with a steel die
what is the best stainless to make a turbo manifold out of ? 305 ?
Gasoline engine? 321. Why? Operation temperature is in the sensitive range for carbide depletion of chromium, causing corrosion. 321 has a small percentage of titanium which binds the carbon stronger than chromium.
Keep in mind, you need 347 filler because it uses columbium instead of titanium since Ti can burn out during welding . Columbium is also known as niobium and is very expensive.
Next best is extra low carbon 300 series, like 304L. Or use 309L filler.
@@keithjurena9319 thanks and yes gasoline engine e85 gas
Different grades of Stainless depends on how much Chromium is in it.
Do you encounter 316 anymore ?
More a case of eliminating alloys used, than confirming them, then?
great info, thanks
400 series ferritic stainless steels will be magnetic.
Damn! I need a bumper boat
what about 409? which is very magnetic
400 series stainless is ferritic & martensitic, which are both magnetic. the more nickel any grade of stainless has, the less magnetic it becomes, regardless of grade. magnet really only tells you how much nickel is in the stainless. martensitic 316 is not magnetic at all, where martensitic 409 is very magnetic. 10% nickel vs 0.5% nickel
Interesting. Ever seen how aluminum is affected by magnets? Doesn’t stick but is affected. Same with silver. Like if you half a magnet from a string and swing it like a pendulum, if it’s very close to like a silver coin, it will actually move the coin when it goes by. Also, they use aluminum rails with holes cut in them and make a sled for some fire escapes, and changing the size and shape and how often the holes are it can act like a brake which is crazy. I think the magnetic field induces a voltage and basically make an electromagnet out of the aluminum. Sorry for the ramble, still interesting.
Yea a strong enough magnet slid over aluminum will make you feel like youre dragging it through thick mud. RE magnets are fun 😂
Yea - that's Lenz's Law. The moving magnet induces an electric current and magnetic field in the alumin(i)um or silver - it's this temporary magnetic field that makes the coin move Roller coasters often use this type of braking.
@@alextyrer4136 thanks! My memory isn’t what it used to be, or is it, I forget.
Yeah I was saying above ,I've drained oil and had aluminum on the magnetic drain plug.
My pops said the simple answer was the particles were so small, and the magnet was powerful enough to make em slightly magnetic.
@@MrTheHillfolk yeah and may have been some alloy that something ferrous in it too.
more bumper boat vids xD
Out with the magnets, in with the laser analysing pew pews.....
That must be what my rusty stainless kitchen knives are made of
201 rusts/corrodes considerably faster. I mean, it's real crummy if you are looking for corrosion resistance.
I have a lot of 2” heavy wall (1/4”) square tube, 304 stainless, that is magnetic enough it holds a standard torpedo level while checking plumb. Always said it’s just low quality 🤷🏻♂️
Yes, it depends on the grade. Some "oriental" stainless is junk, it is magnetic and even rusts after a short time.
@@JackHudler Some of it is junk. Sold as "stainless steel" cutlery but with in a year it's starting to rust. Same with some other domestic junk from the Orient.
Umm, gonna need some videos on those bumper boats! You can't just tease us with that crap and then pull it away.... Otherwise excellent content as usual!
Ahahah laser analyzing pew pews amazing XRF gun but pretty much
Funniest 'Hi' ever 😅
304=Not fun to machine!
201 will eventually rust, 304 will not
Oh god, we have an actual nonmagnetic steel in our mashine shop. I don't know what the actual designation, it's just known as submarine steel and we usually get it directly from the customer.
And let me tell you it is A BITCH to Maschine, file grind or do anything
I had some metal like that before. I still have no clue what it was but it was insanely dense and it seemed everything struggled to work with it.
@@TheFabricatorSeries A4 aka 316 stainless is usually used on boats . It is probably that one.There are some worse than 316 but that's most commonly used stainless steel that is hard to machine .
Worse like 317 ,321 and 347 from austenitic stainless steel family or 440c ,446 and absolute bitch ams 6532 from martensitic family.
@Not a Panther-I don't know if what you're describing is what we use or not. We build pressure vessels out of quenched tempered steel, very similar to what submarine hulls are fabricated with. It is SA517-E material, 110,000 PSI plate. It's tough as a two dollar steak. Our consumables must be within 10%, so for reference, repairs are made with 10018 rod. Once fabrication finished, we have to post weld heat treat the entire vessel. Our oven is 10' x 10' x 60' in lenght. Basically, it is a pressure vessel grade of "T-1" plate. "T-1" is a registered trade mark of US Steel's QT material. Hope this is of interest?
Magnetic... crap, not magnetic...good. got it
Quick recap : don't use C.C.S. grade stainless.
( cheap chinese stuff )
🇺🇸🇺🇸💪💪🇺🇸🇺🇸
Only stainless that is 400 or higher series
the cheaper the stainless the magnetize is going to be
300 series is magnetic