A secondary cooling control method for reinforcing surface solidification structure of microalloyed steel continuous casting bloom includes: in situ observing precipitation behavior of secondary phase particles of the microalloyed steel, and determining a concentrated precipitation temperature range; cooling the microalloyed steel at different cooling rates, obtaining a particle size and a volume fraction of the secondary phase particles of the microalloyed steel at different cooling rates; determining an optimal average cooling rate; determining an optimal average cooling rate r; determining an optimal average cooling rate; and determining an optimal average cooling rate range through intersection of the three optimal average cooling rates whereby the continuous casting secondary cooling is optimized. The present invention can enhance the surface solidification structure of continuous casting bloom and reduce surface and subsurface cracks of the microalloyed steel continuous casting bloom.

A device for the production of a metallic strip using a rapid solidification technology is provided. The device includes a movable heat sink with an external surface onto which a melt is poured and on which the melt solidifies to produce the strip, and which device includes a rolling device which can be pressed against the external surface of the movable heat sink while the heat sink is in motion.

The present disclosure discloses a method for producing high strength hot rolled steel. The method includes casting a steel slab of a composition, comprising in weight %: carbon (C) of about 0.45 wt. %-1.2 wt. %, manganese (Mn) of about 0.0-1.0 wt. %, silicon (Si) of about 0.0-0.5 wt. %, niobium (Nb) up-to 0.03 wt. %, sulphur (S) up-to 0.05 wt. % of S, phosphorous (P) up-to 0.05 wt. %, nitrogen (N) 0.002 wt. %-0.012 wt. % and balance being Iron (Fe) optionally along with incidental elements. The method also involves, heating, hot rolling, cooling, coiling the steel and retaining the steel at an ambient temperature to produce high strength hot rolled steel with 75-95% spheroid microstructure and 5-25% pearlite microstructure.

A non-oriented electrical steel sheet is provided which has a chemical composition that contains, in mass%, C: 0.0050% or less, Si: 0.10 to 1.50%, Mn: 0.10 to 1.50%, sol. Al: 0.0050% or less, N: 0.0030% or less, S: 0.0040% or less, and O: 0.0050 to 0.0200%, and contains one or more elements selected from a group of La, Ce, Zr, Mg and Ca in a total amount of 0.0005 to 0.0200%, with the balance being Fe and impurities. A number density N of suitable oxide particles is 3.0×10.sup.3 to 10×10.sup.3 particles/cm.sup.2, and a number density n of oxide particles containing La and the like satisfies the expression n/N≥0.01.

A steel sheet according to an aspect of the present invention has a predetermined chemical composition, in which a metallographic structure at a ¼ thickness portion includes, by volume percentage, a total of 50% or more of one or both of martensite and bainite and 8% or more of residual austenite, an average value of aspect ratios of prior austenite grains is 5.0 or more, number density of AlN is 3000 pieces/mm.sup.2 or more and less than 6000 pieces/mm.sup.2 at a depth position of 30 μm from a sheet surface, an internal oxidation layer in which at least a part of a crystal grain boundary is coated with an oxide is provided from the sheet surface to a depth of 5.0 μm or more, grain boundary coverage of the oxide is 60% or more in a region from the sheet surface to a depth of 5.0 μm, and a tensile strength is 980 MPa or more.

A method is used to fabricate a hot-rolled steel having a yield strength greater than 550 MPa and an impact toughness of at least 27 J at a temperature of -40° F. In one embodiment, the yield strength is greater than 690 MPa. The method includes melting steel to create melted steel. The melted steel is poured into a mold. The metal steel is continuously cast into a steel slab. The steel slab is heated to maintain a predetermined temperature. The steel slab is rolled to reduce the thickness to a predetermined thickness to create a hot-rolled steel sheet.

A steel member according to an aspect of the present invention has a predetermined chemical composition, in which a metallographic structure includes, by a volume %, 60.0% to 85.0% of martensite, 10.0% to 30.0% of bainite, 5.0% to 15.0% of residual austenite, and 0% to 4.0% of a remainder in microstructure. A length of a maximum minor axis of the residual austenite is 30 nm or longer. A number density of a carbide which exist in the steel member and has a circle equivalent diameter of 0.1 μm or more and an aspect ratio of 2.5 or less is 4.0×10.sup.3 pieces/mm.sup.2 or less.

A device for the production of a metallic strip using a rapid solidification technology is provided. The device includes a movable heat sink with an external surface onto which a melt is poured and on which the melt solidifies to produce the strip, and which device includes a rolling device which can be pressed against the external surface of the movable heat sink while the heat sink is in motion.

An apparatus and process for melting and using scrap pieces of lead or lead alloy from making a web of connected grids for a lead acid battery by forming holes through a solid strip of lead or lead alloy. The scrap pieces may be compacted into briquettes which are submerged in a pool of liquid lead or lead alloy below the top surface of the pool and melt in the pool. Liquid lead from the pool may be cast into solid strips from which webs of grids are made.

A system for producing electrodes for lead-acid batteries is disclosed. An electrode that has been produced comprises at least one upper and/or one lower frame element as well as a lattice-shaped region that extends away from said upper or lower frame element and has a plurality of openings, the upper and/or lower frame element being of a greater thickness than the lattice-shaped region. Said system comprises the steps of: a) producing a profiled strip-shaped blank using a casting method in which the strip-shaped blank is formed, solely by means of said casting method, to have a greater thickness on one side in at least one of the regions which should eventually form the upper or lower frame element, than the thickness in regions which should eventually form the lattice-shaped region, and b) producing said lattice-shaped region with the openings in a subsequent expanded metal process.