Control of inclusions in a resulphurised steel

Abstract

The formation of non‐metallic endogenous inclusions in ladle‐furnace treatment of a resulphurised C‐Mn Al‐killed steel was investigated. A model based on equilibrium reactions and using as input data compositions and temperatures measured at various stages of secondary steelmaking was developed and applied to different routine and experimental heats. Microstructural analyses were carried out on samples systematically extracted from ladle and from tundish. Detailed characterisation of inclusion morphology and composition was carried out to investigate their properties in the present resulphurised steel and to evaluate reactions taking place during different phases of ladle treatment. The experimental results were also used to validate the theoretical model. A good agreement between predicted concentrations of inclusions and experimentally measured values was obtained.

Investigation of failure and damages on a continuous casting copper mould

“…The main function of the mould is to produce and stabilize a solid shell resistant enough to contrast the metallic pressure of the liquid core and, thus, contain the liquid phase at the entry of the secondary spray cooling zone. If the mould system does not work properly, a break-out can take place and the hot liquid steel core can burst open, pouring liquid steel onto the machine and causing a very dangerous situation [1,2].…”

Effects of Titanium Addition on Precipitate and Microstructural Control in C-Mn Microalloyed Steels.

“…Irrespective of the steel examined, the inclusions detected by SEM and EDX microprobe analyses, namely those having a size larger than about 2 mm, consisted of calcium aluminates (XCaO · YAl 2 O 3 ) of different compositions and containing relevant amounts of Mg, combined with (Ca, Mn)S type sulphides, as expected from known steelmaking theory. 17,18) Traces of Ti were found also in the above inclusions, in relatively small amounts, in the Ti-modified steel. It is worth noting that light elements such as O, C and N could not be quantitatively detected by the microprobe system adopted for the present investigation.…”

Microstructural Investigation on a Medieval Sword Produced in 12th Century A.D

“…The presence of those little nonmetallic inclusions are due to the applied process in which the ore reduction certainly has taken place in the solid phase, actually in the Mediterranean and European area the production of liquid pig iron is not known. 10,11) These observations suggest that the ancient metallurgical artisans have developed a particular formulation of the slags involved in the reduction operation and in the welding one which could improve the result of their own effort during the forging of the reduced bloom and of the strips to be welded. Actually, the formation of slags featured by a low-melting point during the iron ore reduction by the addition of SiO 2 -based materials can improve the efficiency of the hammering operation performed in order to remove the trapped slags.…”