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Re: Lamination availablity

4/26/1999 7:57 PM
Re: Lamination availablity
I am in the process of digging deeper.. I seem to have gotten a rather "one sided" story from this particular person in the tranny biz. I also, as I mentioned, have some factual issues.. (appologies to all) one of them being that M6 is probably not the only Si steel, but aside from M2 & M4 (uncommon & very hi-endy) it's the most commonly avail grain oriented steel.. The ASTM spec describing all this stuff expired in 1998.. (naturally!) looking for the new one presently. (no clear link on the web page!!)
4/27/1999 9:32 AM

Sometimes, ASTM specs "expire", and are not continued. Not because the materials or grades are not manufactured anymore, but because ASTM no longer has an interest in tracking them.  
An example is ASTM A120, a low grade carbon steel pipe, usually galvanized, used for fluids like water or natural gas with threaded fittings. The pipe is still manufactured, to the same old spec, but it's not monitored by ASTM anymore. So you won't find A120 in the newer books. (Hint: Don't throw away your old books just because you got a new one, or you got a nifty lazer disc file.)  
This type of situation seems to occur when an engineered material isn't popular anymore. We need to use more high grade audio transformers!
4/27/1999 10:20 AM

What spec number are you looking for? Although my employer doesn't have this particular section on file, the 1994 specs in reference to magnetic steels are all in Section (book) 3.04.  
My index lists:  
A345- Flat rolled electrical steel for magnetic applications  
A840- Colled rolled lamination steel  
A876- Flat rolled grain oriented silicon-iron electrical steel  
There are also various testing methods to determine electrical characteristics at power line frequencies, A343 & A347.  
A664 lists the definitions and coding for identifying material grades. F is non-oriented fully processed electrical grade steel, S is non-oriented semi processed, and G is grain oriented fully processed electrical steel.  
A340 shows terms, definitions, and conversion factors relating to magnetic testing. You know, all B-H stuff, ampere turns, permeability, etc.  
I have an old book, from 1973, which has all the numbers I've listed except (Murphy!) the essential A876.  
4/27/1999 11:34 AM

Great post! Thx!  
fwiw: A346 was the old spec which expired. The "new" one appears to be A345-98.  
Curious that grain oriented and non GO steel are not on the same spec.. (I guess to charge you for a 2nd set of data..)
4/27/1999 2:19 PM

The A345 I have says that grain oriented steel is normally supplied in thicknesses of .012 and .014". Also, the core loss tables list only these AISI types:  
M-7, M-8, M-9, M-10, M-14, M-15, M-17, & M-19.  
Types M-7, -8, -9, &-10 are the preferred grades, and contain appx. 3% silicon.  
A346 is a testing spec for laminated core specimens. It includes hookups & measuring bridge schematics in addition to suggested winding characteristics for standard test coils.  
You could contact Mike at Magnequest in Phila. He has knowledge of what lams are used for what. He owns the Peerless archives and has a lot of other transformer design drawings. He designs & builds high quality audio output transformers for a living.
4/27/1999 3:39 PM

Thanks Doc! I'll look him up. I'm getting into this stuff.. it's kinda cool. BH curves and all.
4/27/1999 6:48 PM

You're being seduced by the dark side of the iron... ;-)

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