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Metals/Melting in induction furnace (follow up question)

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Question
Than for your answere:
Upon your answer, we run our heat, the temperature was below 1500'c in dusction furnace and the carbon was also 0.12 in the bath sample. The bundles we pushed in the furnace was of 700-750'c.  Even then the lining erased from the middle at the top and the metal leaked to the copper tube passing lining. I need to know, that this time does some gas is formed? if yes, which gas and how to handle that.

Thanks

Alok

Answer
There is a possibility that the iron oxide formed is gathering nitrogen and oxygen  from the air via the electric magnetic field and making a nitric acid gas.  I suggest that you protect the preheated metal with a cheap inert gas like argon. As you mentioned that the corrosion is near the top, it suggests still that the atmosphere is causing the corrosion.  Since you are trying to control the carbon content in the melt, argon may be the best solution.  Remember, your troubles only started when you decided to preheat the steel.  It has to be the corrosive action of iron (2) oxide that is causing the problem.  The carbon content isn't reactive enough to solve this problem.  If you encase the conveyor belt with a shield and pass the argon from the bottom up to the top, you will stop the oxidation of the preheated metal. Make sure also that the pre-heater is in the reducing phase.  FYI; nitric acid is manufactured by passing atmosphere through an electric arc system, then into water. There is no reason why it wouldn't react with hot iron.---Doctor Poe

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Christopher Poe

Expertise

The processing/refining of precious metals including chalcogenic ores like tellurides and selenides.

Experience

32 years experience in ore assaying and refining. Presently head chemist and chief refiner of a Philippine metals company.

Publications
Gold Refining Forum

Education/Credentials
Doctor of Geochemical Research

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