With a hot-rolled steel sheet for electrical steel sheet production having a scale layer on the surface, where the surface of the steel sheet has a lightness L* as defined in JIS Z 8781-4: 2013 satisfying 30L*50, and chromaticities a* and b* as defined in JIS Z 8781-4: 2013 satisfying 1a*2 and 5b*3 respectively, and with one end portion in the longitudinal direction of a coil as a reference, a color difference E.sub.ab* as defined in JIS Z 8781-4: 2013 at the central portion and at the opposite end portion satisfies E.sub.ab*8, it is possible to obtain a grain-oriented electrical steel sheet where the variation of properties in a product coil is small.

A device and a method for applying a liquid medium to a roll, and/or to a rolled material, a slab or a roughed strip and/or for removing the liquid medium, wherein the device has at least one spray nozzle, at least one row of spray nozzles or at least one cooling bar for spraying on the medium and at least one plate element, which is designed for collecting the medium. The roll is designed for rolling rolled material, wherein the rolled material, the slab or the roughed strip is conveyed in a conveying direction. In order to allow an improved cooling effect of a roll to be cooled or an improved removal of descaling water, the plate element has on one of its surfaces at least one directing element, which is designed for diverting medium into a transverse direction, which lies horizontally and transversely in relation to the conveying direction.

A process for secondary descaling of running metal strips, especially made of steel, during hot-rolling by-spraying water onto the surface of the running metal strips with spray rails having nozzles supplied with pressurized water, wherein the nozzles are supplied at a hydraulic pressure of from 3 to 30 bar, and wherein the nozzles are regulated so that heat flux density extracted from the strip (HF) resulting from the cooling of its surface by the sprayed water is between 6.5 and 20 MW/m.sup.2 for a strip temperature between 900 and 1100 C.

A process for secondary descaling of running metal strips, especially made of steel, during hot-rolling by-spraying water onto the surface of the running metal strips with spray rails having nozzles supplied with pressurized water, wherein the nozzles are supplied at a hydraulic pressure of from 3 to 30 bar, and wherein the nozzles are regulated so that heat flux density extracted from the strip (HF) resulting from the cooling of its surface by the sprayed water is between 6.5 and 20 MW/m.sup.2 for a strip temperature between 900 and 1100 C.

A press hardening steel by a thin slab casting and direct rolling has a tensile strength of 1500 MPa or more. The press hardening steel has a components by weight percent: C: 0.21-0.25%, Si: 0.26-0.30%, Mn: 1.0-1.3%, P0.01%, S0.005%, Als: 0.015-0.060%, Cr: 0.25-0.30%, Ti: 0.026-0.030% or Nb: 0.026-0.030% or V: 0.026-0.030%, or a mixture of two or more of the above in any proportion; B: 0.003-0.004%, and N0.005%. A method for producing the press hardening steel includes following steps: hot metal desulphurization; electric-furnace or converter smelting and refining; continuous casting; descaling, then entering a soaking furnace; heating and soaking; high-pressure water descaling, then entering a rolling mill; hot rolling; cooling; coiling; austenitizing; die deforming and quenching.

A press hardening steel by a medium and thin slab casting and direct rolling has a tensile strength 1900 MPa or more. The press hardening steel includes following chemical components by weight percent: C: 0.31-0.40%, Si: 0.36-0.44%, Mn: 1.6-2.0%, P0.006%, S0.004%, Als: 0.015-0.060%, Cr: 0.36-0.49%, Ti: 0.036-0.045% or Nb: 0.036-0.045% or V: 0.036-0.045%, or a mixture of the above two or more in any ratio, B: 0.004-0.005%, Mo: 0.26-0.35%, Ni: 0.11-0.20%, and N0.005%. A method for producing the press hardening steel includes following steps: desulphurizing molten iron; electric furnace or converter smelting and refining; continuous casting; descaling treatment before entering a soaking furnace; heating and soaking; high-pressure water descaling before entering a rolling mill; hot rolling; cooling; coiling; austenitizing; die deforming and quenching.

A press hardening steel by a medium and thin slab casting and direct rolling has a tensile strength 1900 MPa or more. The press hardening steel includes following chemical components by weight percent: C: 0.31-0.40%, Si: 0.36-0.44%, Mn: 1.6-2.0%, P0.006%, S0.004%, Als: 0.015-0.060%, Cr: 0.36-0.49%, Ti: 0.036-0.045% or Nb: 0.036-0.045% or V: 0.036-0.045%, or a mixture of the above two or more in any ratio, B: 0.004-0.005%, Mo: 0.26-0.35%, Ni: 0.11-0.20%, and N0.005%. A method for producing the press hardening steel includes following steps: desulphurizing molten iron; electric furnace or converter smelting and refining; continuous casting; descaling treatment before entering a soaking furnace; heating and soaking; high-pressure water descaling before entering a rolling mill; hot rolling; cooling; coiling; austenitizing; die deforming and quenching.

Disclosed is a steel sheet having excellent hydrophilicity and conductivity. The steel sheet having excellent hydrophilicity and conductivity according to an embodiment may include a joint structure on the steel sheet, wherein the joint structure includes microprotrusions having inter-pitch intervals of 1 to 500 nm in an area fraction of 20% or more.

Disclosed is a steel sheet having excellent hydrophilicity and conductivity. The steel sheet having excellent hydrophilicity and conductivity according to an embodiment may include a joint structure on the steel sheet, wherein the joint structure includes microprotrusions having inter-pitch intervals of 1 to 500 nm in an area fraction of 20% or more.

Disclosed is a steel plate with excellent hydrophilicity and conductivity. The steel plate with excellent hydrophilicity and conductivity according to an embodiment may include a joint structure on the steel plate and including fine protrusions having inter-pitch intervals of 1 to 500 nm, wherein the fine protrusions have a texture including a (111) orientation in an area ratio of 10% or more and a (001) orientation in an area ratio of 10% or more.