effect of AL in AISI430

[1366060]

Dear All,

according to AISI, 430 grade should have 1.2 % of AL content, as well as ch15ju5 according to Russian Gost Standard.

because of some limitation in material supply, we are going to substitute 430 for ch15ju5. to do so, we took a sample from supplier of 430 stainless steel and have it elemental analysis. result shows that the sample 430 does not contain AL, but other elements are as ch15ju5.

intended application is that 430 stainless steel would be used as a resistive element in a grid brake resistor. the temperature would increase up to 750 Celsius for some moments. off course there will be a cooling fan to cool the elements of resistor.

would lack of AL be a matter? how does it affect the stainless steel?

any comment would really be appreciated.


best regards.

 

[MagBen]

typical 430 is not supposed to add Al. When Al is added, sometimes up to 4%, the main purposes are to increase resistivity and oxidation resistance. In your case where it is used as resistor, the resistivity may matter.

 

[IRstuff]

Shouldn't you ask whoever specified the 430 in the first place?

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[EdStainless]

Dear OP, There is no version of 430 (UNS S430XX) with Al in it.
I am sure that such alloys exist in other countries, but not in the ASTM part of the world.
Ben is correct, the Al will improve oxidation resistance.
And you had better measure measure the actual resistance values, I don't think that amount of Al will have an impact, but it could.

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[MagBen]

ED, FYI
We have a bunch of electrical resistance ferritic SS. Varying aluminum contents provide different resistivities for greater adaptability to resistor design. Al seems very effective on adjusting resistivity. A well-known example may be electrical steels where Al (often <1%) and Si are added to boost resitivity for a lower core loss.

 

[1366060]

dear All thank you for your reply.


Dear MagBen

thank you for your comment

could you please give a reference for Ferritic SS?
there is a Russian alternative for original stainless steel with around 4 % Al in content. and 14-16 percent of Chrome. I think the Al here is very important and specify resistance periscopes.

finally what would you advise? I need the elements with 22 Meter long, 1.5 mm thickness and 60 mm width. so according to the Resistance formula R=p*L/S the p(resistivity) is determiner which will mainly depend on Al.

any comment would be appreciated.