Is some Stainless Steels slightly magnetic?

[Runner]

Hi all,

the title says it all. I received some stainless steel rod from a supplier in various sizes. Having co-mingled it with silver steel rod, I performed the magnetic test using a strong magnet from an old HDD. What I suspected as being stainless did produce slight magnetic attraction whereas other sizes did not. Is some Stainless Steels slightly magnetic?

Thanks in advance

Brian

 

[rleete]

Yes. We use stainless almost exclusively (plating tank solutions are corrosive) and some of the grades are magnetic. Nickel is magnetic as well.

 

[dman]

yes as far as i know it's mostly 400 series and some can be ferromagnetic or non ferromagnetic depending on the temper condition.

magnetism is weird. it depends on rotating electrons and ferro magnetism (magnetism as we see it in iron and what most people are talking about when they say magnetism) is a result of iron having 3 unbalanced electrons that for some reason all rotate in the same direction. other materials can have ferro magnetism. the way atoms of different materials align and how electrons move in the cloud depends on so much physics that im not totally familiar with but a material being magnetic or non magnetic can depends on alloying elements to isotopes of the same element to temper condition to temperature. all can change what electrons are doing.

 

[Runner]

Thanks rleete and dman.

So it seems that all Stainless Steels are not created equally in terms of magnetic attraction. My residual concern is that I am in fact using a Stainless Steel i.e won't rust, and not silver steel, for applications exposed to a steam environment. Is there any foolproof method that I can easily apply to ensure that I am using Stainless Steel?

I applied the magnetic test to my Mitutoyo Dial Vernier Caliper which states that it is Stainless Steel and it was slightly magnetic.

Brian

 

[dman]

not exactly unless you know a guy at a foundry in qc or maybe a metal recycling plant. there is a test that measures effects of eddy currents that can be acomplished with a hand-held device that can tell you to a pretty good accuracy what type of metal it is but i can't remember what the device is called or what the proper name for the test is. i'm sure it's too expensive to purchase one for your own use. i know i'm not being too helpful but my memory is a little fuzzy right now....

there are other inexpensive ways such as a spark test which isn't by any means a definative test. the concept of a spark test is you grind the metal and compare the sparks to a chart and description. there is a lot of room for operator bias as you can see. certain qualities of the sparks will give an idea of what's in it. you'd look for if the sparks were red, orange, or white, and how much sparking there is... i beleive orange indicates nickel which would be an indication that it might be a stainless steel... you may want to google the subject...

 

[Niceonetidy]

You could pop a bit of swarf in a open container, half cover the swarf with water ans see if it rusts?

Stainless can be martenistic or austenitic, but you can't identify them anyway. So maybe a simple test is the only way?

 

[velocette]

Stainless can be martensitic or austenitic, but you can't identify them anyway. So maybe a simple test is the only way?
__________________
Niceonetidy is correct in the definitions.

In my my dealing with stainless steels is that Austenitic steel (Used for structural and pipework) is almost always NON Magnetic.

High strength and extreme wear resistance (Cutting Shearing and and mixing As in the food Industry) (Hard faced welding for Abrasion resistance on earth moving equipment) Is almost always Magnetic.

In short if if it is Magnetic Beware when attempting to machine it Grrinding is the prefered option.

Eric

 

[KenErickson]

As stated above 300 series stainless is generally not magnetic while 400 series is.
I work with 410 and 416 stainless quite a bit. I routinely drill and mill both with 416 being the free machining grade.I can definitely tell the difference between 410 and 416. I also surface grind 410/416 on my magnetic chuck.

 

[Chriske]

I applied the magnetic test to my Mitutoyo Dial Vernier Caliper which states that it is Stainless Steel and it was slightly magnetic.

Brian

Mine to...!

:wall:

 

[bazmak]

If the only problem is keeping the stainless steel separate from the silver steel then mark with coloured electrical tape
Any you are not sure of try hardening 1 end heat and quench if its hard its silver steel,also silver steel will corode slightly more than s/s

 

[Runner]

Thanks all for responding to my query. The KISS principle IMHO and determined by trial and error is that stainless steel can be slightly magnetic or non-magnetic whereas silver steel is very magnetic. But I add one word of caution performing the magnetic test using a strong magnet can magnetise the silver steel rod or stainless steel and that has it's own problems. In my earlier post I said that I found that my stainless steel Mitutoyo Dial Vernier Caliper was slightly magnetic when performing the magnetic test, now if I put in down near iron filings it attracts them like a bear to honey.

Brian

 

[Cogsy]

It won't help you with your problem, but just for your info, most stainless is at least slightly magnetic.

When I worked in bearing supply, I once had to source some 1/4 stainless balls of a very specific grade for a customer - one of the very few that are completely non-magnetic. From memory it was one of the 300 series but not a common one. His deep hole drilling company had designed a probe to insert down the hole and then mechanically wedge the balls in place to check the orientation of the hole (presumably to keep the hole straight). He tells me the high iron content of the holes being drilled would potentially produce a high level of magnetism and skew the result if magnetic balls were used. I sourced the 5000 balls in the grade specified, but he returned them claiming incorrect grade. None of the magnets I had would attract the balls, but he produced a rare-earth magnet (the first I'd ever seen) and slightly attracted the balls. That $3000 package of balls were returned to the supplier and I sourced another set from elsewhere. This time, the rare-earth magnet didn't make the balls even twitch.