Eliminating Oxide Scale Formation
Eliminating Oxide Scale Formation
(OP)
What are some methods that can be used to prevent Oxide scale from forming on carbon steel when heat treated in a lead bath furnace?
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Eliminating Oxide Scale Formation
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RE: Eliminating Oxide Scale Formation
What is your bath temperature?
What are you using for a sloat on the bath?
What is the material that you are heat treating?
RE: Eliminating Oxide Scale Formation
I'm not sure what you mean by what I am using for a Sloat on the bath... I assume you are asking what kind of insulating material I am using.. That is pea-coke, or graphite flakes depending on the product being produces at the time.
Material is everything from 1060-1080 steels to chrome silicon and chrome vanadium.
RE: Eliminating Oxide Scale Formation
It looks like you have the float covered. We normally used granulated carbon, with a max size of 1/16" or coke breeze. We tried to keep the size as fine as possible both for protecting the lead and a reducing atmosphere above the bath.
I assume you are quenching in oil and then tempering in a another lead bath?
The only way I've been able to mitigate oxide formation is to force an oxide prior to preheating and Austenizing from the lead bath.
How much oxide are you forming?
RE: Eliminating Oxide Scale Formation
Yes, I am oil quenching then tempering in a second lead bath.
How are you forcing oxide prior to austenizing? I am not using a preheat on this perticular furnace, but that isn't to say that I could.
I'm forming a pretty fair amount of oxide. It is fairly comparible than my competitions material, maybe alittle heavier. My first thought was to eliminate scale, but if that is not possible (as it is looking very tough on double lead) then I need to concentrate on forming a very tight adhering scale, so that it does not flake off later during the customers application.
I really appreciate your help so far Unclesyd. I'm fairly new to this industry, so any "old timers" tips or other information you can give would be very much appreciated.
RE: Eliminating Oxide Scale Formation
http://www.heatbath.com/park/product_details/25
Do you have an oven capable of 700F where you might experiment with forcing a steam/air bluing on the parts?
With your existing setup get some blued steel strapping and run it through your process to see how it behaves. If the bluing protects the steel then I would see if you could procure your materials already blued.
I don't have my old computer working yet so I'm at a slight disadvantage coming up with new approaches to your problem. Depend on you processing requirements and the end use of the steels based on the tempering temperatures you might get by with a Bainite Steel. No heat treating required.