Abstract: An ultra-low carbon steel slab having a carbon content of about 0.01 mass percent or less is produced by casting at a casting speed of more than about 2.0 m/min using a mold provided with a casting space having a short side length D of about 150 to about 240 mm and an immersion nozzle provided with discharge spouts each having a lateral width d, the ratio D/d being in the range of from about 1.5 to about 3.0. Accordingly, a ultra-low carbon steel slab can be obtained having superior surface quality without performing slab conditioning such as scarfing.

Abstract: An ultra-low carbon steel slab having a carbon content of about 0.01 mass percent or less is produced by casting at a casting speed of more than about 2.0 m/min using a mold provided with a casting space having a short side length D of about 150 to about 240 mm and an immersion nozzle provided with discharge spouts each having a lateral width d, the ratio D/d being in the range of from about 1.5 to about 3.0. Accordingly, a ultra-low carbon steel slab can be obtained having superior surface quality without performing slab conditioning such as scarfing.

Abstract: A hot-rolling process prevents surface deterioration of the stainless steel sheet which forms during hot rolling of a stainless steel slab after heating in a heating furnace, and does not cause damage to the heating furnace nor a decrease in yield of the steel sheet. The hot-rolling process for a stainless steel slab includes heating a stainless slab containing 10 weight percent or more of chromium in a heating furnace and hot-rolling the slab. A surface treatment, which is used prior to the heating, composition is composed of a mixture containing at least one of a Ca compound and a Ba compound and a binder for binding the mixture to a slab surface and for forming a coating film on a slab surface.

Abstract: This invention proposes a continuous casting method for austenitic stainless steel capable of simultaneously establishing productivity and an excellent surface quality of steel sheet. For this purpose, the invention lies in a method of continuously casting austenitic stainless steel by pouring melt of austenitic stainless steel from a tundish through an immersion nozzle into a continuously casting mold of a continuous slab caster, solidifying it in the mold and continually drawing the resulting slab of given size out from the mold, characterized in that a high-speed continuous casting is carried out so as to satisfy a relation of casting speed, superheating degree of molten steel in the tundish, sectional area of discharge port in the immersion nozzle and slab width represented by the following equation:0.30.ltoreq.V.sup.0.58 .multidot.W.sup.-0.04 .multidot..DELTA.T.multidot.d.sup.-0.96 .ltoreq.0.85whereinV: casting speed (m/min)W: slab width (mm).DELTA.T: superheating degree of molten steel in tundish (.

Abstract: In a process of withdrawing castings while vertically oscillating a mold formed with long side walls and short side walls, the long side walls are moved apart from the castings by operating a hydraulic cylinder in the time zones for which the castings are applied with a large frictional force. On the contrary, the separated long side walls are made to move together to the casting in the other time zones for which the casting is not applied with the large frictional force. By repeating the separation and approaching of the long side walls, it is possible to obtain castings which are reduced in the depths of oscillation marks and suppressed in segregations at oscillation mark trough portions.

Abstract: A mold powder for use in continuous casting, containing specified amounts of CaO, Al.sub.2 O.sub.3, TiO.sub.2, Li.sub.2 O, BaO, MgO, F and Na.sub.2 O, and further containing at least one of BN and C as aggregate. The mold powder, when used in continuous casting of a steel rich in strong reducing metal elements such as Al, Ti, REM and so forth, remarkably suppresses generation of deterioration in the surface quality of the slab and break out of the slab which are attributable inferior lubrication.

Abstract: Steel is continuously cast while adding a mold powder using a vertical continuous casting mold having two pairs of mold surfaces which form a casting cavity, wherein the surface temperature of the mold is kept at 700.degree. C. or more by forming the mold surfaces of a Ni-Cr alloy, and a mold powder having a solidifying point lower than the surface temperature is used so that the mold powder is maintained in a liquid-phase state.

Abstract: A continuous casting process introduces the factor of rate temperature change for detecting break out in the cast metal. Introduction of rate of temperature change as a parameter representative of the cast metal condition is successful for avoiding the influence of variation of the casting condition, fluctuation of the powder to be introduced between the casting mold wall and the cast metal, casting speed and so forth. For achieving accurate detection of break out of the cast metal by introducing the temperature change factor, casting mold wall temperatures are measured at various measuring points which are circumferentially aligned. Rates of temperature change at each measuring point and average rate of temperature change of all measuring points are derived and compared for making judgement of possible break out when the difference of the rate of temperature change at each measuring point and the average rate of temperature change becomes greater than a predetermined value.

Abstract: A method of oscillating a mold of a vertical continuous caster of the type having a pair of longer side frames and a pair of shorter side frames. The mold is oscillated vertically during the casting. A pair of mold walls, e.g., the longer side frames, are moved towards and away from the cast metal in synchronization with a vertical oscillation of the mold, so as to control the condition for supplying a mold powder into the gap between the mold walls and the cast metal.

Abstract: A method and apparatus for continuous casting of an elongated thin metal strip achieves substantially high yield without allowing break-out or sticking. The method for casting a continuous elongated metal strip includes a step of driving endless belts at a varying speed so as to apply jerks to the slightly and half-solidified metal that release the metal from the surfaces of the stationary side walls. Applying jerks to the casting chamber by varying the driving speed of the endless belt ensures that the solidifying metal will travel smoothly and thus ensures a high manufacturing yield.

Abstract: A method and apparatus for continuous casting of an elongated thin metal strip achieves substantially high yield without allowing break-out or sticking. The method for casting a continuous elongated metal strip includes a step of driving endless belts at a varying speed so as to apply jerks to the slightly and half-solidified metal that release the metal from the surfaces of the stationary side walls. Applying jerks to the casting chamber by varying the driving speed of the endless belt ensures that the solidifying metal will travel smoothly and thus ensures a high manufacturing yield.