AISI 1005 vs AISI 1008 2

[mbfree]

We were using AISI 1008 low carbon steel for an electromagnetic application. We didnt have any problems yet, until recently when we switched vendors and started getting AISI 1005. The magentic properties are very worse and 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 is in Mn content. Could anyone have anything, to confirm its Mn. Or is it one of the other elements.

I only have this much information with me now. I dont have values for the exact amoutnt of electromagentic property deviation, but I know it was really bad for the 1005 compared to 1008.

 

[MagMike]

I just checked my copy of Bozorth's Ferromagnetism and Boron has be present in concentrations higher than 0.05% to have any significant effects (primarily on coercivity).

 

[mbfree]

Well..Mn was the primary suspect initially, but I am not sure anymore. We might do an analysis based on the Oxygen and Nitrogen content, which according to a source might also be culprits.

 

[MagMike]

Hello mbfree,

I should have noted my response was to sreid's question. My apologies for not being clear on that. I still don't think the Mn is an issue, not at the levels you reported.

I suggest that you send samples of the 1005 and 1008 material to a magnetic testing house. It would be useful to have an independent & quantitative evaluation of the difference between the two samples.

If you are based in the US, KJS Associates (a subsidiary of Magnetic Instrumentation) is very good at this sort of thing. They can run your samples through an initial magnetization curve as well as a complete BH loop.

 

[EdStainless]

yep Mike, Bozorth is the only real ref for this info. My copy is from '53.

mbfree, look at the microstructure. If there are no secondary phases then I suspect that you have some other problem. Impurities in solution will hurt the perm, but not B (much).

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