hey guys im not sure if this is in the right section but here goes i was at a flea market and found a 9 in x .5 in bar of steel and written on it was M-400 and i had never heard of this as a type of steel...do any of you have any info on this?

When I googled it I got a reference to a site where someone mentioned he had a transformer made from that steel. As a transformer core steel I'd guess it was quite low in carbon and may have some silicon in it.


Hmm deeper digging indicates it is an "oriented silicon steel" and cannot be hot worked as exceeding the phase change messes up the orientation

When I googled it I got a reference to a site where someone mentioned he had a transformer made from that steel. As a transformer core steel I'd guess it was quite low in carbon and may have some silicon in it.


Hmm deeper digging indicates it is an "oriented silicon steel" and cannot be hot worked as exceeding the phase change messes up the orientation

yeah i found something like that too but wasnt quite sure what it meant....but of course (me being bullheaded) went ahead with trying to forge it and i had no problem working it but it was really tough to work with it felt like the first time i worked with S-2 so im still not sure about the labeling because it was in faded sharpie and also because it was an incomplete steel description and it was from a flea market....so i dont know ill see how it goes and maybe i lucked out and got some S-2 or something similar

Hot working messes up the special properties you paid for if you bought it originally. Doesn't mean you can't forge it! it just won't be the same stuff.

Like taking a piece of pre-hardened tool steel and forging it. It will mess up the original heat treat but you can still use it (and in this case you could re-do the heat treat, the oriented silicon was probably done with rolling and so not a re-do option...)

Or like bending cold drawn piano wire to wrap a spring by getting it hot, getting it hot allows the grains to normalise and when it cools down its just ordinary wire (basically). The spring properties are caused by the elongation of the grains when being cold drawn.

Phil