Abstract: The present invention relates to a high strength hot rolled steel sheet containing 0.15% or less C, 0.02 to 0.35% Ti, and 0.05 to 0.7% Mo by weight percentage and consisting essentially of a matrix of ferrite structure single phase and fine precipitates with a grain size of smaller than 10 nm dispersed in the matrix, for example, a high strength hot rolled steel sheet which consists essentially of 0.06% or less C, 0.5% or less Si, 0.5 to 2.0% Mn, 0.06% or less P, 0.005% or less S, 0.1% or less Al, 0.006% or less N, 0.02 to 0.10% Ti, 0.05 to 0.6% Mo by weight percentage, and the balance being Fe, wherein fine precipitates with a grain size of smaller than 10 nm are dispersed in a matrix of ferrite structure single phase at a number per unit volume of 5×104/&mgr;m3 or higher. This steel sheet, which has tensile strength of not lower than 550 MPa, high elongation and excellent stretch flangeability, is suitable for intricately shaped automotive chassis parts such as a suspension arm.

Abstract: The present invention relates to a high strength hot rolled steel sheet containing 0.15% or less C, 0.02 to 0.35% Ti, and 0.05 to 0.7% Mo by weight percentage and consisting essentially of a matrix of ferrite structure single phase and fine precipitates with a grain size of smaller than 10 nm dispersed in the matrix, for example, a high strength hot rolled steel sheet which consists essentially of 0.06% or less C, 0.5% or less Si, 0.5 to 2.0% Mn, 0.06% or less P, 0.005% or less S, 0.1% or less Al, 0.006% or less N, 0.02 to 0.10% Ti, 0.05 to 0.6% Mo by weight percentage, and the balance being Fe, wherein fine precipitates with a grain size of smaller than 10 nm are dispersed in a matrix of ferrite structure single phase at a number per unit volume of 5×104/&mgr;m3 or higher. This steel sheet, which has tensile strength of not lower than 550 MPa, high elongation and excellent stretch flangeability, is suitable for intricately shaped automotive chassis parts such as a suspension arm.

Abstract: A steel sheet for preparing a heat shrink band effective for preventing the color drift is provided by a steel sheet having 24 kg/mm2 or higher of yield stress and 400 or higher of the product between the permeability &mgr; under a magnetic field of 0.3 Oe and the sheet thickness.

Abstract: The present invention relates to a high strength hot rolled steel sheet containing 0.15% or less C, 0.02 to 0.35% Ti, and 0.05 to 0.7% Mo by weight percentage and consisting essentially of a matrix of ferrite structure single phase and fine precipitates with a grain size of smaller than 10 nm dispersed in the matrix, for example, a high strength hot rolled steel sheet which consists essentially of 0.06% or less C, 0.5% or less Si, 0.5 to 2.0% Mn, 0.06% or less P, 0.005% or less S, 0.1% or less Al, 0.006% or less N, 0.02 to 0.10% Ti, 0.05 to 0.6% Mo by weight percentage, and the balance being Fe, wherein fine precipitates with a grain size of smaller than 10 nm are dispersed in a matrix of ferrite structure single phase at a number per unit volume of 5×104/&mgr;m3 or higher. This steel sheet, which has tensile strength of not lower than 550 MPa, high elongation and excellent stretch flangeability, is suitable for intricately shaped automotive chassis parts such as a suspension arm.

Abstract: A hot-dip galvanized steel sheet is produced by rough rolling a steel, finish rolling the rough rolled steel at a temperature of Ar3 point or more, coiling the finish rolled steel at a temperature of 700° C. or less, and hot-dip galvanizing the coiled steel at a pre-plating heating temperature of Ac1 to Ac3. A continuous hot-dip galvanizing operation is performed by soaking a pickled strip at a temperature of 750 to 850° C., cooling the soaked strip to a temperature range of 600° C. or less at a cooling rate of 1 to 50° C. per second, hot-dip galvanizing the cooled strip, and cooling the galvanized strip so that the residence time at 400 to 600° C. is within 200 seconds. The steel sheet has a structure consisting essentially of ferrite and martensite.

Abstract: A hot-dip galvanized steel sheet is produced by rough rolling a steel, finish rolling the rough rolled steel at a temperature of Ar3 point or more, coiling the finish rolled steel at a temperature of 700° C. or less, and hot-dip galvanizing the coiled steel at a pre-plating heating temperature of Ac1 to Ac3. A continuous hot-dip galvanizing operation is performed by soaking a pickled strip at a temperature of 750 to 850° C., cooling the soaked strip to a temperature range of 600° C. or less at a cooling rate of 1 to 50° C. per second, hot-dip galvanizing the cooled strip, and cooling the galvanized strip so that the residence time at 400 to 600° C. is within 200 seconds. The steel sheet has a structure consisting essentially of ferrite and martensite.

Abstract: A heat shrink band steel sheet of the present invention comprises on the basis of percent in weight C: 0.1% or less, Si: 0.1% or less, Mn: 0.1 to 2%, P: 0.15% or less, S: 0.02% or less, sol Al: 0.08% or less, and N: 0.005% or less, or C: 0.005% or less, Si: 0.1% or less, Mn: 0.1 to 2%, P: 0.15% or less, S: 0.02% or less, sol Al: 0.08% or less, N: 0.005% or less, Ti: 0.02 to 0.06%, and B: 0.0003 to 0.005%, wherein the product of a magnetic permeability at the magnetic field of 0.3 Oe after heat shrinking treatment and a thickness (mm) is at least 350. A color CRT having a sufficient magnetic shielding characteristic and a less amount of color deviation can be realized by the steel sheet.

Abstract: A steel sheet for a heat-shrink band, which is to be thermally expanded and fitted over the outer periphery of the panel portion of a cathode ray tube, which has at least a 20% elongation at an ambient temperature and at least a 40 kg/mm.sup.2 stress of yielding point after the heating and cooling, in particular one comprised by a dual phase cold rolled steel sheet comprising a ferrite phase and a martensite phase or a cold rolled steel sheet containing a retained austenite.

Abstract: A steel slab containing not more than 0.005 wt % carbon, 1.0 to 4.0 wt % silicon, 0.1 to 1.0 wt % manganese, not more than 0.1 wt % phosphorus, not more than 0.005 wt % sulfur, and 0.1 to 2.0 wt % aluminum is directly sent to a hot rolling step without brief soaking, whereby Al and N are made soluble with respect to species other than AlN inevitably precipitated during hot rolling, and uniform and coarse AlN precipitation is formed by a subsequent annealing treatment in which the hot rolled plate is soaked at a temperature of 800.degree. to 1000.degree. C. for a period of time t defined as exp (-0.018T+19.4) .ltoreq.t.ltoreq.exp (-0.022T+25.4) wherein T is the soaking temperature (.degree.C.) and t is the soaking time (minutes). Uniform and satisfactory ferrite grain growth at the recrystallization annealing is provided thereby.

Abstract: A method of producing non-oriented electrical steel sheets having excellent magnetic properties which comprehends heating a steel at the low temperature for hot rolling, thereby to minimize re-solution of AlN particles when a slab is cooled, so that coarsening of AlN particles is facilitated during annealing the hot rolled sheet; and coiling at low temperatures for controlling the amount of scale generation. De-scaling is perfectly accomplished after the hot rolling, and the hot rolled sheet is annealed in a non-annealing atmosphere, thereby to control the oxidation and the nitriding to a minimum during annealing the hot rolled sheet, and the annealing conditions of the hot rolled sheet are specified for proper coarsening of the cohesion, taking into consideration the magnetic properties and the economics.

Abstract: Non-oriented electrical steel sheets having excellent magnetic properties are produced by carrying out a coiling at a low temperature for monitoring the amount of scale generation; de-scaling after hot rolling; and annealing the de-scaled hot rolled sheet in a non-oxidizing atmosphere to thereby minimize the oxidation and nitriding during annealing the hot rolled sheet. By determining a higher heating temperature for hot rolling, a magnetic property (magnetic flux density) is improved, and the hot rolled sheet is subjected to an open coil-annealing and annealing conditions therefor are specified in order to perfectly precipitate re-solute AlN particles by this heating and fully coarsen AlN particles.

Abstract: The present invention is to produce non-oriented electrical steel sheets having excellent magnetic property under low magnetic field by effectively checking thermal stress from introducing during cooling in a final annealing without decreasing productivity, for which when a silicon steel sheet having passed a cold rolling is cooled after a final continuous annealing, especial cooling conditions are specified only to a temperature range giving bad influences to the magnetic properties under the low magnetic field so as to prevent the introduction of the thermal strain.

Abstract: This invention is to save the energy by heating a slab at high temperature for producing non-oriented electrical steel sheets having excellent magnetic properties uniform over the full length thereof, without carrying out a long soaking, for which a continuously cast slab having a specified chemical composition is heated at a high temperature, and a heat cycle is then defined such that the slab is passed twice nearly around precipitation noses, thereby to coarse the AIN precipitates over the full length of the slab, and the slab is annealed under a specified condition after the hot rolling so that AlN is coarsened and the ferrite grains recrystallize and grow.

Abstract: The present invention is to produce non-oriented electrical steel sheet by a hot direct rolling. The slab is directly sent to the hot rolling without the brief soaking, whereby others than AlN inevitably precipitated check the precipitation of AlN, a roughing and a finish rolling are performed at determined reduction rates, and a delay time is taken between the roughing and the finish rolling, and besides a finish rolling is performed at not more than Ar.sub.3 so that precipitating nuclei of AlN are effectively introduced into the steel, and uniform and coarse AlN precipitation is formed by a coiling at temperature of more than 700.degree. C., thereby to enable to provide uniform and satisfied ferrite grain growth at the recrystallization annealing.

Abstract: The present invention provides a pickling method for electrical steel bands having excellent surface properties without requiring any especial treatment and increasing costs, where the pickling conditions of the hot rolled steel band are optimized not only in view of de-scaling properties but also interglanular corrosions, and the pickling is performed with hydrochloric acid for a period of a specified time determined by Si content of steel, temperature and HCl concentration of a pickling liquid.

Abstract: The present invention is to produce non-oriented silicon steel sheets having excellent magnetic properties in dependence upon a hot direct rolling, wherein the slab is directly sent to the direct rolling without maintaining the heat and soaking, whereby others than AlN precipitated during hot rolling check the precipitation of AlN, and a delay time is taken between the roughing and the finish rolling so that precipitating nuclei of AlN are introduced into the steel, and uniform and coarse AlN precipitation is formed by a subsequent annealing treatment, thereby to enable to provide uniform and satisfied ferrite grain growth at the recrystallization annealing.