Research on Al-Killed Casting Steels Production Possibility.

In the first step of this studying project which is called "The study of Al-Killed steels production and casting possibility", the attempts are focused on assessing the subject scientifically and then technically and experimentally. In this report, subjects are divided into four chapters. In the first one, "Deoxidizing", the kinds of compound to deoxidize the steel are introduced and compared industrially. Using of Aluminum due to its high ability in deoxidizing is the common newest manner of producing high quality steels. In this chapter not only the thermodynamics and kinetics of this process are mentioned, but also the industrial conditions of aluminum using, shapes and ways of adding it to melt and effects of phosphorous return from slag to the melt. Also, the sources of oxygen absorption, re-oxidation and de-oxidation and ways of controlling it are discussed. In the second chapter, the basics of thermodynamics and kinetics of nucleation properties and growth in Al-killed steels are studied. Then, the ways of porosities dividing and Al2O3 morphology are surveyed. As Al2O3 content and shapes affect on steel properties and they cause clogging, the ways of controlling and changing of porosity morphology are discussed, especially through adding calcium. In addition of improving this manner, the using of inert gas blow and adding synthetic slag in different stages to decrease the porosity content and produce high quality products are studied. Nozzle clogging, especially in tundish, is the main problem of Al-Killed steel casting process, which is discussed in chapter three. Kinds of clogging, their causes and the ways of preventing them are mentioned. This is done through changing aluminum porosity morphology, decreasing the content of it and improving nozzle refractory materials. In chapter four, according to specifications and capacity of Isfahan Steel Co. Casting workshop, the evaluation possibility of this project is discussed on the title of "The present conditions and evaluation possibility analysis".