i have a stainless steel cart (old restaurant) that a magnet will stick to. Then a got a stainless steel tray from work that a magnet will not stick to. I know there are there different grades of stainless, or does it pertain to thickness that make a magnet stick to it or not? Jim
stainless steel
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fatfillup
Well-known member
I don't think it has anything to do with the thickness. Has to do with iron content I would think.
4 FN 27
ALLIANCE MEMBER
The Magnetic Stainless is 400 Series. The Non-Magnetic is 300 series...simplest answer...
Ferritic Stainless Steels are "generally" magnetic while Austenitic Stainless Steels are not.
Ferritic Stainless Steels are "generally" magnetic while Austenitic Stainless Steels are not.
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drewvdw
Well-known member
I've always wondered this...thanks for the answers.
Boilerhouse
Well-known member
Plus the martensitic family, also 400 series, also magnetic.
Yep, and sometimes a 300-series item (like a sink) will become mildly magnetic after it has been drawn or work hardened.
Nope.
Whether a stainless steel alloy (or other metal or metal alloy) is magnetic or not depends on the internal 'crystal' structure. As well as the mix of the different elements in the alloy.
As mentioned, most austenitic stainless steel alloys (the 200 and 300 series) are (mostly) non-magnetic. But may become slightly magnetic when cold worked.
Most of the ferritic stainless steel alloys are magnetic, as the most of the martensitic stainless steels.
anndel
Well-known member
Love all the discussion on SS. My buddy who died several years ago was a metallurgist/materials engineer and used to tell me about metals for knives, cars, etc.
Richard Cranium
Well-known member
thanks for the info.
fatfillup
Well-known member
Nope.
Whether a stainless steel alloy (or other metal or metal alloy) is magnetic or not depends on the internal 'crystal' structure. As well as the mix of the different elements in the alloy.
As mentioned, most austenitic stainless steel alloys (the 200 and 300 series) are (mostly) non-magnetic. But may become slightly magnetic when cold worked.
Most of the ferritic stainless steel alloys are magnetic, as the most of the martensitic stainless steels.
Ok, I did a little googling and now have just enough info to be dangerous
Here is a link to Martensitic stainless and it contains iron so I am partially right, I think.
https://en.wikipedia.org/wiki/Martensitic_stainless_steel
Here is a link as to why a magnet is only attracted to iron, nickel and cobalt.
https://www.quora.com/Why-does-a-magnet-only-attract-objects-made-of-iron-nickel-and-cobalt
Since Ferritic stainless contains chrome and a magnet will stick to chrome, it sticks. And since ferritic would infer ferrous and to me ferrous relates to iron, I am again partially right
https://en.wikipedia.org/wiki/Ferrous
Now, here is the crux. I am a layman and this explanation is close enough for a guy who will never forge a tool or device. For the professional metallurgist, my explanation is full of assumptions, misstatements and is overly simplified I know. But we all can't be experts in everything.
rlitman
Well-known member
Iron content has little to do with it. I cannot read your quora link, but no, iron nickel and cobalt are NOT the only ferromagnetic materials, and simply putting ferromagnetic materials together does not a magnet make.
Ferritic stainless contains chrome. So does martensitic stainless, and austenitic stainless. Typically (but not in all cases) austenitic stainless contains the most chrome of these three. Yet, while you say that chrome is magnetic, austenitic stainless is the least magnetic of the three. In most cases, it is hardly magnetic at all.
Ferritic stainless contains chrome. So does martensitic stainless, and austenitic stainless. Typically (but not in all cases) austenitic stainless contains the most chrome of these three. Yet, while you say that chrome is magnetic, austenitic stainless is the least magnetic of the three. In most cases, it is hardly magnetic at all.
monkeyspanners
Well-known member
Food grade stainless is non magnetic, cheaper stainless is magnetic.
PelicanPines
ALLIANCE MEMBER
I have gotten into so many arguments over this topic. A lot of people say stainless can't be magnetic... and I open my big mouth and explain what you fine people explain clearly that always escapes my brain when I need the details.
THANKS !!!
THANKS !!!
davethorik
Well-known member
Not necessarily true, 400 series stainless steels (and
possibly others) can be heat treated similar to steel alloys. This makes them very very tough and wear resistant.
velocipede
ALLIANCE MEMBER
So...they could have made my refrigerator door out of magnetic stainless, but chose not to to deprive us of the pleasure of seeing the grand kids pictures every time we go for a snack! That's so low.
monkeyspanners
Well-known member
My experience is only in the dairy industry here, all the milk vessels are non magnetic food grade stainless, the outer skin on the vessels are generally made of the same grade but there are a few cheaper tanks which are magnetic.
A correction on terminology being tossed about:
ALL steels are mostly iron. By definition. If it is steel, it is at least 50% iron, and will have some carbon, but no more than 2.1%. This is true whether it is a mild steel, stainless steel, low alloy, high alloy, or any of the more exotic steels.
ALL steels are mostly iron. By definition. If it is steel, it is at least 50% iron, and will have some carbon, but no more than 2.1%. This is true whether it is a mild steel, stainless steel, low alloy, high alloy, or any of the more exotic steels.
allinon72
Well-known member
Work with stainless a lot at work - we check to see if it's magnetic and if it is, we generally view it as lower grade stainless. And it tends to rust as well.
owenst7
Well-known member
Not true. Many things such as fasteners are required to be magnetic so that sensors will pick them up and set alarms.
mnoeltne
Well-known member
DeLorean body panels are 304 stainless. Non-magnetic.
Just my fun fact for the day.
Just my fun fact for the day.
BMWED
Well-known member
Stainless comes in different grades. Basically the more steel it has in it will affect how well a magnet sticks to it.
All stainless steels are approximately the same percentage of Fe.
Magnetism is directly related to atomic structure. Austenite is the primary allotrope present in non-magnetic stainless steels. Some of them can be cold worked to become slightly magnetic- this happens because the cold work process can change a low percentage of Austenite into other magnetic allotropes.