Semi-processed Electrical Steel

[geoffriong]

I've tried a search on the internet and do not have access to any technical manuals (I'm away on business). Does anyone know where I can find technical data on semi-processed electrical steel BEFORE the quality anneal? The material is specifically 26M47. I emphasize the 'before' because there are many sites that list properties AFTER the anneal, but I cannot seem to find data(Core Loss, etc) on pre-annealed material.
Thanks.

 

[aolalde]

The reason you can not find characteristics “before annealing” is that such type of steel needs the proper annealing and core plating to develop electric steel properties.
If you do not have the facilities to properly anneal and core plate it, use a “fully cured” grade.

 

[geoffriong]

Thanks for the fast reply. I am particularly interested in an estimate for Core Loss. Everything I have read states, very, very clearly that when using a semi-processed steel a post-process anneal is required to achieve full magnetic properties. I am dealing with a situation where we are being asked to use semi-processed steel (cost?) but the necessity for the post-anneal vs buying a fully processed steel is being completely overlooked. If I could get my hands on an estimated Core Loss on a non-annealed, semi-process steel I could fortify the need for fully processed steel or, less desireable, a post-process anneal. Thanks again.

 

[sreid]

Data for unprocessed electrical steel is probably difficult to find under any circumstances. As you have found, the propertities are only guaranteed after full processing.

This make sense because for large volume production; double processing just adds an unnecessary cost.

Perhaps the following comments might help your position.

1) The post processing anneal removes both the pre and post punching stresses.

2)The post process anneal is also used to further de-carburize the steel (most important for low hysistersis loss).

3) The black oxide insulation is usually formed as part of this process.

In a continuous process, the anneal/oxide formation adds little cost.

 

[aolalde]

The core losses of semi-processed steels are similar to a low carbon SAE 1010 commercial steel. Expect 10 to 12 watts per pound at 85 kL/sqin. If it does not have a core plating insulation, the losses will run out of control, developing hot spots with very high temperature.

When core plated and properly annealed, they develop superior performance as compared to a fully processed steel and with the advantages posted above by Sreid.