Yeah, measuring cups – utterly mundane. Who would’ve thought that there could be anything strange about them. Well, it’s like this…

My measuring cups (cups hereafter) are stainless steel. Some SS is ferromagnetic, some isn’t. In an idle moment I wondered if my cups were, or weren’t. I probed the largest cup with a small magnet, and discovered this:

Its cylindrical side is ferromagnetic – down to about 1/2” from the bottom. But the lower 1/2” of the side, and its bottom surface, isn’t. There’s no visible boundary at the magnetic transition, inside or out, but there has to be a material transition. “Why a material transition?” I ask myself.

No answer, but I checked the other cups in the set and found that they’re similar. Just weird. But there’s more weirdness to come.

My set also has measuring spoons, so I got those out. The handles of the cups are attached by stout rivets, but the handles of the spoons are integral. Probing the largest spoon with my magnet I find:
* Its handle isn’t ferromagnetic.
* Its side is ferromagnetic.
* Its bottom isn’t ferromagnetic.
So two material transitions in each (apparently) monolithic spoon. Just weird.

You may be thinking that my set was an exotic purchase. Nope – just plain All-Clad brand from my local kitchen supply store.

Time for some research. My set of measuring cups and spoons are claimed to be made of 18/10 SS. Looking on the web I learn that 18/10 SS isn’t ferromagnetic. So that magnetic portion of the bowls ISN’T 18/10 SS. My guess (and it’s strictly a guess) is that 18/10 SS isn’t malleable enough to form the bowls from a sheet. So composite construction, even though material joins are undetectable by sight or touch.

In short, more than meets the eye here.

Not that it should matter much but does the thickness of the material change? Thicker bottom on the cup?

300 series stainless steels will become magnetic when they are cold worked. If you take a magnet to a set of headers constructed using 304 stainless you will find that the bends are magnetic and the straight sections are not magnetic when new. Then if the engine is run hard enough to make the headers glow red they will become non magnetic.

Steel and Stainless steel are somewhat odd to a layman's point of view, because the crystalline structure can actually change within the steel. For mild steel it's magnetic properties will disappear when it's heated past it's Transition Temperature but they return when it cools below the transition temperature. With the high chromium content 300 series stainless Work Hardening comes into play and it actually changes the structure of the crystalline structure of the metal from Face Centered Cubic (non magnetic) to Body Centered Cubic (magnetic).

SigForum has answers for everything.

Wow.

quote:

Originally posted by frayedends:
Not that it should matter much but does the thickness of the material change? Thicker bottom on the cup?

I don’t think so. As I noted in my OP, the ferromagnetic boundary of the largest cup is about 1/2” from the bottom. A significant thickness change there could easily be detected by touch, but I don’t sense it.

Strangeness aside, these All-Clad measuring cups are beauties – bac1023 probably has the same set. Even the smallest cup sits upright on my counter, even while empty.

All-Clad measuring cups:
https://www.all-clad.ca/en/TOO...oon-Set/p/2100034853

going off of Scooter's information about cold-work making the material magnetic, I'd assume your cups were originally discs that were then punch-extruded while cold, stretching the walls of the cup and making them magnetic.

When I need stuff like this, I go on ebay and find something 20, or more, years old. Most reliable.

quote:

Originally posted by Scooter123:
300 series stainless steels will become magnetic when they are cold worked. If you take a magnet to a set of headers constructed using 304 stainless you will find that the bends are magnetic and the straight sections are not magnetic when new. Then if the engine is run hard enough to make the headers glow red they will become non magnetic.

Steel and Stainless steel are somewhat odd to a layman's point of view, because the crystalline structure can actually change within the steel. For mild steel it's magnetic properties will disappear when it's heated past it's Transition Temperature but they return when it cools below the transition temperature. With the high chromium content 300 series stainless Work Hardening comes into play and it actually changes the structure of the crystalline structure of the metal from Face Centered Cubic (non magnetic) to Body Centered Cubic (magnetic).

Alright, that does it! All the politicians worry about AI and its effect on society. I am more concerned that there is way too much knowledge freely available on this thing call Sig-Forum.

Next thing you know, there will be "do-it-yourself brain surgery" instructions or "how to build your own battlefield nuclear weapon". I say it is time to dumb-down this site for good of the children! (Heaven knows the school systems have already done that to the children. )