Grain size of a deliverable metal product can be improved by pre-setting recrystallization-suppressing dispersoids during casting. The outer regions of a direct chill cast embryonic ingot can undergo reheating before casting is complete. Through unique wiper placement and/or other reheating techniques, the temperature of the ingot can be permitted to reheat (e.g., up to approximately 410? C. to approximately 420? C.), allowing dispersoids to form. Stirring and/or agitation of the molten sump can facilitate formation of a deeper sump and desirably fine grain size as-cast. The formation of dispersoids during and/or immediately after casting can pin the grain boundaries at the desirably fine grain size, encouraging the same grain sizes even after a later recrystallization and/or solutionizing step.

A method of controlling molten metal flow and an electromagnetic brake system for a metal-making process, including: a first magnetic core arrangement having a first and second long sides with N.sub.c teeth, and arranged to be mounted to opposite longitudinal sides of an upper portion of a mould, a first set of coils, each being wound around a respective tooth of the first magnetic core arrangement, and N.sub.p power converters, with N.sub.p being an integer that is at least two and N.sub.c is an integer that is at least four and evenly divisible with N.sub.p, wherein each power converter is configured to feed a DC current to its respective group of 2N.sub.c/N.sub.p series-connected coils.

A method of controlling molten metal flow and an electromagnetic brake system for a metal-making process, including: a first magnetic core arrangement having a first and second long sides with N.sub.c teeth, and arranged to be mounted to opposite longitudinal sides of an upper portion of a mould, a first set of coils, each being wound around a respective tooth of the first magnetic core arrangement, and N.sub.p power converters, with N.sub.p being an integer that is at least two and N.sub.c is an integer that is at least four and evenly divisible with N.sub.p, wherein each power converter is configured to feed a DC current to its respective group of 2N.sub.c/N.sub.p series-connected coils.

A method of making weathering steel by preparing a molten melt producing an as-cast carbon alloy steel strip with a corrosion index of at least 6.0 comprising, by weight, 0.02%-0.08% carbon, <0.6% silicon, 0.2%-2.0% manganese, <0.03% phosphorus, <0.01% sulfur, <0.01% nitrogen, 0.2%-0.5% copper, 0.01%-0.2% niobium, 0.01%-0.2% vanadium, 0.1%-0.4% chromium, 0.08%-0.25% nickel, <0.01% aluminum, and the remainder iron and impurities. The molten melt is solidified and cooled into a cast strip 4 mm in thickness in a non-oxidizing atmosphere. The strip is hot rolled in an austenitic temperature range above Ar.sub.3 to between 10% and 50% reduction, cooled at above 20 C./s and coiled below 700 C. to form a steel strip with a microstructure comprising bainite and acicular ferrite with more than 70% niobium in solid solution. Then, age hardening the strip resulting in a yield strength of at least 550 MPa and a total elongation of at least 8%.

The present invention provides a metal wire rod composed of iridium or an iridium alloy, wherein the number of crystal grains on any cross-section in a longitudinal direction is 2 to 20 per 0.25 mm.sup.2, and the Vickers hardness at any part is 200 Hv or more and less than 400 Hv. The iridium wire rod is a material which is produced by a -PD method, and has low residual stress and which has a small change in the number of crystal grains and hardness even when heated to a temperature equal to or higher than a recrystallization temperature (1200 C. to 1500 C.). The metal wire rod of the present invention is excellent in oxidative consumption resistance under a high-temperature atmosphere, and mechanical properties.

The present invention provides a metal wire rod composed of iridium or an iridium alloy, wherein the number of crystal grains on any cross-section in a longitudinal direction is 2 to 20 per 0.25 mm.sup.2, and the Vickers hardness at any part is 200 Hv or more and less than 400 Hv. The iridium wire rod is a material which is produced by a -PD method, and has low residual stress and which has a small change in the number of crystal grains and hardness even when heated to a temperature equal to or higher than a recrystallization temperature (1200 C. to 1500 C.). The metal wire rod of the present invention is excellent in oxidative consumption resistance under a high-temperature atmosphere, and mechanical properties.

The invention provides a fluoride-free continuous casting mold flux for low-carbon steel, comprising, based on weight, Na.sub.2O 5-10%, MgO 3-10%, MnO 3-10%, B.sub.2O.sub.3 3-10%, Al.sub.2O.sub.36%, Li.sub.2O<3%, C 1-3%, and the balance of CaO and SiO.sub.2 as well as inevitable impurities, wherein the ratio of CaO/SiO.sub.2 is 0.81.3. The mold flux has a melting point of 951150 C., a viscosity at 1300 C. of 0.1-0.3 Pa.Math.s, and a crystallization rate of 10-50% as determined according to the method described in the specification for examining crystallization property. The boron-containing, fluoride-free flux developed according to the invention has a moderate crystallization rate, can be used in a crystallizer to control transfer of heat from molten steel effectively, and has been applied successfully in a low-carbon steel slab conticaster with a metallurgical effect that arrives at the level of a traditional fluoride-containing flux to full extent.

The invention provides a fluoride-free continuous casting mold flux for low-carbon steel, comprising, based on weight, Na.sub.2O 5-10%, MgO 3-10%, MnO 3-10%, B.sub.2O.sub.3 3-10%, Al.sub.2O.sub.36%, Li.sub.2O<3%, C 1-3%, and the balance of CaO and SiO.sub.2 as well as inevitable impurities, wherein the ratio of CaO/SiO.sub.2 is 0.81.3. The mold flux has a melting point of 951150 C., a viscosity at 1300 C. of 0.1-0.3 Pa.Math.s, and a crystallization rate of 10-50% as determined according to the method described in the specification for examining crystallization property. The boron-containing, fluoride-free flux developed according to the invention has a moderate crystallization rate, can be used in a crystallizer to control transfer of heat from molten steel effectively, and has been applied successfully in a low-carbon steel slab conticaster with a metallurgical effect that arrives at the level of a traditional fluoride-containing flux to full extent.

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 ?m or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 ?m or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.