Method of removing scales and preventing scale formation on metal materials and apparatus therefor
AssigneeNippon Steel Corporation
InventorsTooru Akashi, Yasumitsu Kondou, Shuuichi Hamausu, Masao Sakashita
Life of this patent
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Abstract
Suppression and removal of scales are efficiently carried out in a steel material hot rolling process and the time of pickling treatment as a successive step is greatly shortened. In a water cooling step of metallic material 11 at a temperature of 100° to 1,200° C., scales are removed by applying a direct current or an alternating current to metallic material 11 at 0.1 to 105 A/m2 of unit surface area from pinch rolls 2 to rolls 6 or apron guides 7 on the outlet side of a hot rolling mill 1 and/or by injecting cooling water at a pH value of −2 to 4 onto the metallic material 11 from cooling headers 4 and apron guides 7.
Claims28
A process for removing scales and preventing scale formation on a metallic material comprising:
- continuously hot rolling a metallic material, said metallic material having a surface;
- providing a cooling water step immediately following exit of the metallic material from the hot rolling;
- said cooling water step comprising contacting the surface of said metallic material with cooling water, wherein the surface of said metallic material has a temperature in a range from 200° C. to 1200° C. at time of initial contact with said cooling water;
- applying a direct current or alternating current to said metallic material through said cooling water during said cooling step at a current density of 0.1 to 105 A/m2 of unit surface area of said metallic material.
A process for removing scales and preventing scale formation on a metallic material comprising:
- continuously hot rolling a metallic material, said metallic material having a surface;
- providing a cooling water step immediately following exit of the metallic material from the hot rolling;
- said cooling water step comprising contacting the surface of said metallic material with cooling water, wherein the surface of said metallic material has a temperature in a range from 200° C. to 1200° C. at time of initial contact with said cooling water;
- wherein said cooling water has a pH of −2 to 4.
A process for removing scales and preventing scale formation on a metallic material comprising:
- continuously hot rolling a metallic material, said metallic material having a surface;
- providing a cooling water step immediately following exit of the metallic material from the hot rolling;
- said cooling water step comprising contacting the surface of said metallic material with cooling water, wherein the surface of said metallic material has a temperature in a range from 200° C. to 1200° C. at time of initial contact with said cooling water;
- wherein said cooling water has a pH of −2 to 4;
- applying a direct current or alternating current to said metallic material through said cooling water during said cooling step at a current density of 0.1 to 105 A/m2 of unit surface area of said metallic material.
A process for removing scales or preventing scale formation on a metallic material comprising:
- providing a metallic material which has been previously hot rolled, said metallic material having a surface;
- providing a pickling step comprising introducing said metallic material into a pickling solution, wherein the surface of said metallic material has a temperature in a range from 200° C. to 700° C. at time of introduction into said pickling solution;
- applying a direct current or an alternating current to said metallic material through said pickling solution during said pickling step at a current density of 0.1 to 105 A/m2 of unit surface area of said metallic material.
A process for removing scales or preventing scale formation on a metallic material comprising:
- providing a metallic material which has been previously hot rolled, said metallic material having a surface;
- providing a pickling step comprising introducing said metallic material into a pickling solution, wherein the surface of said metallic material has a temperature in a range from 200° C. to 700° C. at time of introduction into said pickling solution;
- wherein the pickling solution has a pH of −2 to 2.7.
A process for removing scales or preventing scale formation on a metallic material comprising:
- providing a metallic material which has been previously hot rolled, said metallic material having a surface;
- providing a pickling step comprising introducing said metallic material into a pickling solution, wherein the surface of said metallic material has a temperature in a range from 200° C. to 700° C. at time of introduction into said pickling solution;
- wherein the pickling solution has a pH of −2 to 2.7;
- applying a direct current or an alternating current to said metallic material through said pickling solution during said pickling step at a current density of 0.1 to 105 A/m2 of unit surface area of said metallic material.
A process for removing scales and preventing scale formation on a metallic material comprising:
- providing a metallic material at an elevated temperature, said metallic material having a surface;
- providing a cooling water step for said metallic material at the elevated temperature;
- said cooling water step comprising contacting the surface of said metallic material with cooling water, wherein the surface of said metallic material has a temperature in a range from 200° C. to 1200° C. at time of initial contact with said cooling water;
- applying a direct current or alternating current to said metallic material through said cooling water during said cooling step at a current density of 0.1 to 105 A/m2 of unit surface area of said metallic material.
A process for removing scales and preventing scale formation on a metallic material comprising:
- providing a metallic material at an elevated temperature, said metallic material having a surface;
- providing a cooling water step for said metallic material at the elevated temperature;
- said cooling water step comprising contacting the surface of said metallic material with cooling water, wherein the surface of said metallic material has a temperature in a range from 200° C. to 1200° C. at time of initial contact with said cooling water;
- wherein said cooling water has a pH of −2 to 4.
A process for removing scales and preventing scale formation on a metallic material comprising:
- providing a metallic material at an elevated temperature, said metallic material having a surface;
- providing a cooling water step for said metallic material at the elevated temperature;
- said cooling water step comprising contacting the surface of said metallic material with cooling water, wherein the surface of said metallic material has a temperature in a range from 200° C. to 1200° C. at time of initial contact with said cooling water;
- wherein said cooling water has a pH of −2 to 4;
- applying a direct current or alternating current to said metallic material through said cooling water during said cooling step at a current density of 0.1 to 105 A/m2 of unit surface area of said metallic material.
An apparatus for removing scales and preventing scale formation on metallic material, characterized by comprising a cooling apparatus, side guides and at least two pair of electrodes;
- the cooling apparatus, provided at a delivery side of a hot rolling mill, comprising cooling headers and/or cooling nozzles for supplying cooling water;
- the side guides, also provided at the delivery side of the hot rolling mill, for preventing leakage of cooling water from side edges of the metallic material;
- at least two pair of electrodes, provided in a water cooling tank installed at the deliver side of the hot rolling mill, used for a direct current application to the metallic material,
- where a positive electrode and a negative electrode are set at an interval facing each other and the positive electrodes and negative electrode are alternately arranged in parallel with one another;
- and
- the direct current is applied to the metallic material by the pair of negative and positive electrodes when the metallic material passes through between the pair of positive and negative electrodes.
An apparatus for removing scales and preventing scale formation on a metallic material, characterized by comprising a cooling apparatus, side guides, pinch rolls and apron guides;
- the cooling apparatus, provided at a delivery side of a hot rolling mill, comprising cooling headers and/or cooling nozzles for supplying cooling water;
- the side guides, also provided at the delivery side of the hot rolling mill, for preventing leakage of cooling water from side edges of the metallic material;
- the pinch rolls and apron guides, used for a direct current application to the metallic material, provided at the delivery side of the hot rolling mill;
- where the pinch rolls are in electric contact with the metallic material and the apron guides are in non-electric contact with the metallic material, and the pinch rolls and apron guides act as electrodes, and electric current is applied to the metallic material by allowing the electric current to flow between the pinch rolls and apron guides through cooling water.
Dependencies are inferred from the claim text.