Is it possible to identify the lam material by the grain structure? Not precisely but perhaps to tell if it's silicon steel or nickel alloy? Would be very convinient without needing to wind a coil to test the permeability
Well I read on some forum thread that you can identify the nickel content in iron-nickel lams.
And that "Nickel lams dont rust like that"
followed by this low res picture:
And that "Nickel lams dont rust like that"
followed by this low res picture:
In the first place , Nickel alloy is much more shiny than what you have there , I don't know if it would rust .
https://images.app.goo.gl/xUS2hB268thytuSu9
https://images.app.goo.gl/xUS2hB268thytuSu9
Doesn't nickel oxidize and turn to a black color?
That picture you linked could just be a manufacturer placeholder or whatever. You can find pictures of any type of steel alloy that all look the same. While irl they look way different.
For example: https://im01.itaiwantrade.com/8c789...e073/5a772a21-bf4d-42ca-9f2d-be2ed8e8043d.jpg
https://selmag.en.taiwantrade.com/product/773821
Which is "Nickel lamination for audio transformer"...
A few old C-cores I have, have turned almost completely black.
Meanwhile power transformer lamination I have just turn rusty and not black. Although I have had few that look like that image that I linked.
For example this one:
Which should be M470-50A NOES. But from what I read, it looks like GOSS.
It would be easy to tell them apart if I just had a reference for how the grain structure looks of silicon steel vs nickel steel.
That picture you linked could just be a manufacturer placeholder or whatever. You can find pictures of any type of steel alloy that all look the same. While irl they look way different.
For example: https://im01.itaiwantrade.com/8c789...e073/5a772a21-bf4d-42ca-9f2d-be2ed8e8043d.jpg
https://selmag.en.taiwantrade.com/product/773821
Which is "Nickel lamination for audio transformer"...
A few old C-cores I have, have turned almost completely black.
Meanwhile power transformer lamination I have just turn rusty and not black. Although I have had few that look like that image that I linked.
For example this one:
Which should be M470-50A NOES. But from what I read, it looks like GOSS.
It would be easy to tell them apart if I just had a reference for how the grain structure looks of silicon steel vs nickel steel.
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Real high content Nichel laminations are pretty shiny like in my pictures , you can't miss a Nickel core when you see it , I have transformers from '80 and are not tarnished in any way . What some vendors sell who knows ... and what Nickel content they put in .
I have some 49% nickel cores which show signs of some surface rust. I know they are 49% as they measure and perform as well as some
brand new 49% ones. All the 80% nickel ones I have dont show any signs of rust even the fairly old ones. I think its just the higher iron content
in the 49%.
brand new 49% ones. All the 80% nickel ones I have dont show any signs of rust even the fairly old ones. I think its just the higher iron content
in the 49%.
Power distribution transformers use Fe-Si steel, nickel is not preferred.
Nickel is also very expensive compared to most other metals.
Nickel is also very expensive compared to most other metals.
Very probably you can, but you need a Metallurgical microscope, grain is too small for accurate naked eye detection.
I guess it will also take some chemical (acid) etching "to bring the grain out".
I still use various Metallurgical tests for parts production, but more at a "macro" level if you wish: mechanical properties: whatever's needed for machining, or plating or heat treatment in my speaker parts or stamping/punching/bending for frames and chassis or magnetic (transformer cores) but never so deep as crystalline structure, simply not needed.
In your case, I guess measuring actual magnetic properties is more relevant.
"The proof of the pudding lies in the eating" 😉
If your steel core behaves as Nickel or one of its alloys, so be it.
Actual grain or "rustability" is a secondary parameter compared to that.
I guess it will also take some chemical (acid) etching "to bring the grain out".
I still use various Metallurgical tests for parts production, but more at a "macro" level if you wish: mechanical properties: whatever's needed for machining, or plating or heat treatment in my speaker parts or stamping/punching/bending for frames and chassis or magnetic (transformer cores) but never so deep as crystalline structure, simply not needed.
In your case, I guess measuring actual magnetic properties is more relevant.
"The proof of the pudding lies in the eating" 😉
If your steel core behaves as Nickel or one of its alloys, so be it.
Actual grain or "rustability" is a secondary parameter compared to that.
Well if anyone viewing this thread is looking for actual answers, here's what I found.
It seems that the very grainy dark color Means it's annealed nickel. Which reduces the inductance by half, but reduces the eddy currents.
The alternative is (idk), which is shiny, almost chrome colored for nickel lams.
It might be steam oxide just like it is for silicon steel lams, but I'm not sure... steam oxide I think is what gives steel lams their grey color, which the nickel lams don't have.
The more nickel content, the more shiny grains in the annealed lam it seems.
-From that website store I linked
The one on top is 50% Nickel annealed, next to a "regular" nickel lam
The one on the bottom is 80% Nickel annealed.
The third one is Permalloy, not annealed.
The one I posted which is M470-50A must get the grainy texture from the silicon content, In that case the way to tell apart silicon steel vs nickel steel is by the grain size, which is small for nickel lams, and large for silicon
An odd thing about those lams is that to me they look grain-oriented, but there's no grain oriented steels that are 0.5mm thick.
Maybe it's a quirk of whatever process was used resulting in slightly oriented grains.
Maybe it's like this
Shiny chromy lams = non-annealed nickel steel
Greyish "course" texture lams = steam oxide coated silicon steel
Dark grainy lams = annealed nickel steel
Dark lams without shiny grains = annealed silicon steel?
And that sort-of coincides with whatever transformers are lying around my desk and what they were designed for.
It seems that the very grainy dark color Means it's annealed nickel. Which reduces the inductance by half, but reduces the eddy currents.
The alternative is (idk), which is shiny, almost chrome colored for nickel lams.
It might be steam oxide just like it is for silicon steel lams, but I'm not sure... steam oxide I think is what gives steel lams their grey color, which the nickel lams don't have.
The more nickel content, the more shiny grains in the annealed lam it seems.
-From that website store I linked
The one on top is 50% Nickel annealed, next to a "regular" nickel lam
The one on the bottom is 80% Nickel annealed.
The third one is Permalloy, not annealed.
The one I posted which is M470-50A must get the grainy texture from the silicon content, In that case the way to tell apart silicon steel vs nickel steel is by the grain size, which is small for nickel lams, and large for silicon
An odd thing about those lams is that to me they look grain-oriented, but there's no grain oriented steels that are 0.5mm thick.
Maybe it's a quirk of whatever process was used resulting in slightly oriented grains.
Maybe it's like this
Shiny chromy lams = non-annealed nickel steel
Greyish "course" texture lams = steam oxide coated silicon steel
Dark grainy lams = annealed nickel steel
Dark lams without shiny grains = annealed silicon steel?
And that sort-of coincides with whatever transformers are lying around my desk and what they were designed for.
11/0.44 kV transformers use 0.27 mm thickness CRGO.
See this: (just off the net, no links to me)...
https://www.worldofsteel.com/pages/types-of-crgo/
See this: (just off the net, no links to me)...
https://www.worldofsteel.com/pages/types-of-crgo/