How to make duplex stainless
How to make duplex stainless
(OP)
Anyone tell me how to reduce the Nitrogen composition in the duplex stainless steel? What is the required materials, tools and hardware?
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How to make duplex stainless
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RE: How to make duplex stainless
~NiM
RE: How to make duplex stainless
Now, if you are casting and have the nitrogen too high you can reduce it by bubbling Argon through the molten metal. I seem to recall that coarse bubbles work best.
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Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: How to make duplex stainless
EdStainless is correct. Nitrogen is integral to this alloy. However, if you have added too much prior to casting, removal can be done through argon bubbling. I can't place the term "coarse" bubbles, but I seem to remember "slow and steady" as the terms I'd heard. (Large bubbles?)
~NiM
RE: How to make duplex stainless
It wasn't too sacastic. I have reduced the C content of pure iron after casting. It too two weeks of anneal, but we got there.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: How to make duplex stainless
Thanks a lot .
RE: How to make duplex stainless
The solubility of a gas in liquid steel is proportional to the square root of the partial pressure of the gas over the liquid steel (Sievert's Law). Thus, 1 atm of air pressure over liquid steel will be a source of nitrogen and oxygen. There is no need to introduce nitrogen-bearing compounds. You will need to use secondary steel making practices like AOD or VOD to actually degas the melt and control final chemical composition
RE: How to make duplex stainless
thanks guys.
Dony (Stainlees steel engineer of mb group indonesia)
RE: How to make duplex stainless
When I was a melting engineer in an electric arc furnace facility we used NitroVan (nitrogen impregnated vanadium alloy) to pick up nitrogen (for carbon steel). The metal was shrouded during casting (with argon) so little pickup was gained during casting. I don't remember there being a good recovery percentage on the NitroVan though. Another item, when I was the melting engineer in an induction furnace facility, we accidently forced air into a melt (nickel alloy) we were trying to control the nitrogen pickup on (argon was supposed to be forced in, blanketing the molten metal). The nitrogen content went from ~500ppm (normal, open air melting) to ~1000ppm. (With the proper blanketing we were able to stay <300ppm.) Proper shrouding during the teeming and casting process was also necessary to control the nitrogen pickup.
Coquette (Dony):
In your last post are you saying that you are seeing nitrogen pickup during your casting? If so, what kind of casting are you doing? There are certain methods that can be applied depending on the situation. Casting through a flux can indeed lessen the contact time with air but I'm not so sure about it modifying nitrogen content though it is entirely possible. Also, are you sure you're not getting a secondary recovery of nitrogen from a late addition?
~NiM
RE: How to make duplex stainless
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: How to make duplex stainless
RE: How to make duplex stainless
special to arunmrao , where can i get those specific material nitrovan? is it possible to our process because my comp . do the process by arc furnace 150 kgs? how about the step it should be fill to the molten metal? tempereature?
where is your last job experience? thanks guys
to others
how can i get the information the investment casting in all over the world? because i 've plan to make corporation for some our special order and also do research for specific material. a thousand honours for u all partners..
RE: How to make duplex stainless
US companies are directly offering these compounds to their vendors in India for introducing Nitrogen. I have no access to these proprietary products. Hence I had made a request in my earlier posting.
Coquette if you can become a member of SFSA or CDA in UK you can have information and professional assistance in your assignment.