ARGON OXYGEN DECARBURIZATION FOR METAL PRODUCTION

Steeling the lead

Today, over 75% of the world’s stainless steel is made using the Argon Oxygen Decarburization (AOD) process invented by Praxair. AOD provides an economical way to produce stainless steel with a minimal loss of precious elements. It is part of a duplex process in which scrap or virgin raw materials are first melted in an electric arc furnace (EAF) or induction furnace. The molten metal is then decarburized and refined in a special AOD vessel to less than 0.05% carbon. The key feature in the AOD vessel is that oxygen for decarburization is mixed with argon or nitrogen inert gases and injected through submerged tuyeres. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium.

AOD is widely used for the production of stainless steels and specialty alloys such as silicon steels, tool steels, nickel-base alloys and cobalt-base alloys. The process is so popular because it combines higher metallic yields with lower material costs. Other benefits include pinpoint accuracy in chemistry control down to 0.01% carbon and lower, rapid desulfurization to less than 0.001%, and lead removal to less than 0.001%. When the end result is a cleaner metal coupled with increased productivity, it’s no wonder why Praxair-invented AOD is at the heart of the stainless steel industry.

Improving Quality and Productivity with AOD