Centro Sperimentale Metallurgico S.p.a.

Aldo Ramacciotti

Eugenio Repetto

Pietro Tolve

Emilio Marino

Paolo Sommovigo

Renato D'Angelo

A process for controlling continuous casting conditions in steel tapped from a furnace, which proceeds from a ladle into a tundish, and then via a submerged nozzle to a continuous casting mold. In either the ladle or the tundish, the liquid steel is subjected to radiation heating and convection heating from an electric heating device by which an electric current is made to pass through the liquid steel from this heating device to a return located downstream of the device, for example in the continuous casting mold. Preferably, the heating device is a transferred arc plasma torch. In addition, the nozzle between the tundish and the continuous casting mold is subjected not only to the passage of current but also to a direct magnetic field perpendicular to the steel stream.

Process for control of continuous casting conditions

A nozzle for the casting of aluminium-killed steel, which is prepared from pellets obtained by mixing 90-99% Ca(OH).sub.2, with at least one compound selected from the metal oxides Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3 and TiO.sub.2 and the chlorides CaCl.sub.2, NaCl and LiCl, in quantities between 1 and 10%, the mixture being pelletized, dried at 100.degree.-150.degree. C. and baked at 800.degree.-1500.degree. C., grounded and screened, the screened material then being further mixed with at least one compound selected from among the metallic oxides Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2, and Cr.sub.2 O.sub.3 and MoO.sub.3 and the chlorides CaCl.sub.2, NaCl and LiCl in quantities between 3 and 20% by weight, as well as with organic binders and carriers such as oil, paraffin, petroleum, lower alcohols and resins in quantities between 1 and 5%. The mix is pressed in molds at 500-1500 kg/cm.sup.2 and baked at 1500.degree.-1800.degree. C., the body thus obtained then being vacuum-impregnated with molten pitch and cooked at about 700.degree. C. in a reducing atmosphere.

Casting of aluminium-killed steels

A hot-top for the production of ingots using an electroslag remelting process, comprises a ceramic hot-top having non-consumable electrodes embedded in the radially inner side walls thereof, the exposed surfaces of the electrodes comprising 5 to 50% of the total area of the hot-top inner surface. The electrodes extend parallel to the axis of the hot-top, from the top edge of the hot-top down at least 50% of the height thereof, and may be graphite or hollow water-cooled metal electrodes. In use, the electrodes contact not only the molten metal but also its superposed layer of slag.

Hot-top for the production of ingots using an electroslag remelting

Unkilled steel is transferred, substantially without slag, from the refining reactor to a degassing reactor. The pressure in the degassing reactor is reduced to not more than 200 mm. Hg, and calcium carbide is added in a quantity such that calcium added is from 1 to 2 kg. per ton of steel. A vacuum is maintained for 10 to 20 minutes and then released. Preferably, the calcium carbide additive contains 5 to 25% by weight of calcium fluoride.

Deoxidizing and desulphurizing steel

Large steel ingots are produced without pipe and blow holes and with minimum segregation, by teeming the steel into an ingot mold having a hot top that tapers upwardly and whose open upper end is largely filled by an electrode that is spaced from the steel by an electrically conductive slag. During a first stage, current is passed from the electrode through the slag to the steel at a rate to keep the slag and the steel in the upper end of the mold molten. During a second stage, the current is increased and the electrode consumed to restore the liquid level that has fallen due to contraction upon solidification, the electrode having a lower content in segregating elements than the steel. During a third stage, the current and the metal addition are reduced until the ingot is completely solidified.

Process for the production of large steel ingots

A process for the two-stage reduction of iron ore in a rotary kiln, which is an improvement on U.S. Pat. No. 3,833,355. A layer of reducing agent such as coke is held against the side wall of a reactor that rotates about its vertical axis, by centrifugal force and its own friction. The next inner layer is a layer of iron ore. The improvement over the earlier patent is that reduction is conducted in two stages comprising a first relatively low temperature stage of 1 to 4 hours at 700.degree. to 1100.degree.C., which does not melt the ore, and a second relatively high temperature stage of 0.5 to 1.5 hours at 1450.degree. to 1550.degree.C., with removal of the reduced carburized liquid iron from the bottom of the reactor during the second stage.

Process for the two-stage reduction of iron ore in a rotary kiln

A compound meltable electrode for manufacturing metal articles by remelting under electroslag, consisting of a first solid metal meltable element, a second meltable element consisting of at least one of the substances selected from the group comprising metal powder, a binder, and slag, and a third metal meltable element containing and reinforcing said meltable layer.

Compound meltable electrode for manufacturing metal articles by

A self sintering compound tubular electrode suitable particularly for making metal articles by supply of metal with an electroslag process, consisting of a plurality of concentric walls, each pair of said concentric walls defining an annular cavity containing in the melting zone of the electrode a layer of sintered metal powder, and above said sintered layer, a second layer of powder not yet sintered.

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Rome, Italy

Aldo Ramacciotti