Stainless steel conductivity

[vidgolob]

Hi there.

Does anyone know what is the stainless steel with highest electrical conductivity out there? I tried some google searching but I cant seem to get any useful information... The product ( resistive furnace ) will be exposed to temperatures up to 2300° C for up to two hours during the process.

Any help would be much appreciated.

Best regards,
Vid Golob

 

[IRstuff]

What do you intend to do this conductivity?

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[EdStainless]

They are all fairly low.
How much corrosion resistance do you need? What about other properties?
409 will have the best electrical (and thermal) conductivity, but it is barely stainless and not real easy to work with.

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P.E. Metallurgy, Plymouth Tube

 

[vidgolob]

Thank you for your answers.

@IRstuff - I am making a resistive furnace. Electrical current will flow through material and therefore I need as much conductivity as possible.

@EdStainless - I am affraid that since there are a lot of aggresive materials present in the process ( chlorides and fluorides ) good or at least solid corrosion resistance is a must. Steel would be directly exposed to this materials only in case of leakege but still I cant afford to make a product that will start corroding after a short period of time. As far as other properties go I dont really have any demands or limitations. Having a material you can easily work with would be a huge plus ( lower machining cost ) but I guess you cant have it all . I will definitely take the material with better conductivity over one that is easier to work with.

 

[EdStainless]

What temperature are you designing for?
You need to consider both how resistance changes with temperature and how the material reacts at temperature.
Use Nichrome, a very traditional heating element material with good oxidation and corrosion resistance.
There are some modern versions of the alloy, start googling resistance heater alloys.

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P.E. Metallurgy, Plymouth Tube

 

[vidgolob]

Furnace reaches 2300 °C during operation for up to two hours.

Thank you. You have been very helpful.

 

[btrueblood]

Not even Nichrome will get you to 2300 C, any nickel/iron/cobalt alloy would melt before then. You would need refractory alloys, and a way to keep them in inert gas or vacuum to prevent rapid oxidation.

 

[EdStainless]

Elements at that temperature operate in vacuum and are either Mo or graphite.
Not many options, and I am not sure that you can run Mo above 2000C for very long.

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P.E. Metallurgy, Plymouth Tube

 

[IRstuff]

Moly or tungsten seem to be popular for heating refractory furnaces. Haven't seen anyone offering steel heating elements. Also, molybdenum silicide, but that supposedly is only good to about 1900 C

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[Compositepro]

This sounds like a hobby project. The only practical way to get to temperatures above 2000C, without resorting to exotic and very expensive materials is to use burning charcoal or coke, like blacksmiths do.

 

[EdStainless]

Or to use induction, simple coils and power supplies.
I have used them to melt ceramics.

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P.E. Metallurgy, Plymouth Tube

 

[Maui]

Vig, did you mean 2300F?

Maui

 

[vidgolob]

Actually this is not a hobby project - my company is developing a new product ( a MCVD furnace ).

2300 °C is actually the temperature of the process going on inside. I checked the testing logs of a very similar furnace we allready made out of stainless steel and the highest temperature this material will be exposed to is about 500 °C. The flanges will be water cooled of course ( as they are in all of our furnaces ). Sorry to mislead you, but I was really swamped with work yesterday and I didnt really think before replying.

Sorry about that.

Actually the answer form EdStainless was allready what I was looking for -> Use Nichrome, a very traditional heating element material with good oxidation and corrosion resistance.
There are some modern versions of the alloy, start googling resistance heater alloys.

But again, thank you for all of your help.