Provided is an apparatus of removing foreign substances from a hot-rolled steel strip, including a reverse direction injection unit provided to inject high-pressure water in the reverse direction of a moving direction of the strip toward the strip moving to the entrance of the winder by the side guide, wherein the reverse direction injection unit includes a plurality of upper reverse direction injection nozzles arranged along a width direction of the strip to inject high-pressure water to an upper surface of the strip, and the plurality of upper reverse direction injection nozzles is arranged such that an interval of the upper reverse direction injection nozzles located in a central area along the above arrangement direction is narrower than an interval of the upper reverse direction injection nozzles located in both edge areas.

A filter for a high-pressure nozzle having a tubular section and a cap section. The cap section and/or the tubular section are provided with a plurality of filter slots which extend in the longitudinal direction of the tubular section and each have a first end situated on the side of the tubular section and a second end situated on the side of the cap section. A sleeve is arranged coaxially with the tubular section and covers the filter slots in the region of the first end of the filter slots.

A method for descaling a sheet of metal include first and second descaling components that each have a only one motor driven slurry propelling impeller mounted on a top and bottom of an enclosure. The top and bottom mounted impellers of the first component are configured to propel slurry onto a sheet of metal passing through the enclosure across the entire width of the sheet of metal in a first direction extending from one lateral side to an opposite lateral side of the enclosure. The top and bottom mounted impellers of the second component are configured to propel slurry onto a sheet of metal passing through the enclosure across the entire width of the sheet of metal in a second direction opposite the first direction and extending from the opposite lateral side to the one lateral side of the enclosure.

A method for descaling a sheet of metal include first and second descaling components that each have a only one motor driven slurry propelling impeller mounted on a top and bottom of an enclosure. The top and bottom mounted impellers of the first component are configured to propel slurry onto a sheet of metal passing through the enclosure across the entire width of the sheet of metal in a first direction extending from one lateral side to an opposite lateral side of the enclosure. The top and bottom mounted impellers of the second component are configured to propel slurry onto a sheet of metal passing through the enclosure across the entire width of the sheet of metal in a second direction opposite the first direction and extending from the opposite lateral side to the one lateral side of the enclosure.

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.