Magnetic Properties of 1005 steel

[mbfree]

Hello,
I posted this topic in the magnetic engineering forum earlier and got many useful replies. I was just wondering whether any of you have any inputs...

Heres the situation...We were using AISI 1008 low carbon steel, as a soft magnet for our electromagnetic application. We didnt have any problems yet, until recently when we switched to AISI 1005. We have been using low carbon steels for quite a long time now and expected 1005 to behave in a similar way, if not the same, as 1008.
The magentic behaviour of 1005 was very worse. Specifically, the permeability was low as well as the saturation point.


I was wondering what could be the contributor to this. We ran a lab test for the new material vs the old one and heres what we came up with.

AISI 1008
C-> 0.06
Mn-> 0.32
P-> 0.011
S-> 0.012
Al-> 0.07
B-> less than 0.001
Cr-> 0.03
Cu-> 0.02
Mo-> less than 0.01
Ni-> 0.01
Si-> 0.01

AISI 1005 (with added Boron)
C-> 0.04
Mn-> 0.17
P-> 0.003
S-> 0.012
Al-> 0.03
B-> 0.0025
Cr-> 0.01
Cu-> 0.03
Mo-> 0.01
Ni-> 0.01
Si-> 0.01

All values are in weight percent.

The basic difference I noted, apart from Boron is in Mn content. Could anyone have anything, to confirm its Mn. Or is it one of the other elements.

Also, there was a marked difference in hardness values between the two materials. 1008 gave a hardness value of HR B 50-60 and 1005 came up with HR B 30-40, which is understandeable because of the lower carbon content. How ever, we sent 1005 for annealing (around 1600 F for 2.5 hrs). The annealed ones behaved the same way, there was no difference in magnetic behaviour.

If anyone have any possible explanations, it would be a great help.