CN-122029307-A - Apparatus for removing scale from steel sheet, apparatus for producing steel sheet, method for removing scale from steel sheet, and method for producing steel sheet

Abstract

The scale removal apparatus of the present invention is a scale removal apparatus for a steel sheet for removing scale from a steel sheet being transported, wherein a 1 st pickling device for pickling the steel sheet with a 1 st acid solution, a destruction device for mechanically destroying scale, and a 2 nd pickling device for pickling the steel sheet with a 2 nd acid solution are disposed in this order from the upstream side in the transport direction of the steel sheet.

Inventors

• TANAKA TAKAAKI
• OKUBO TOMOYUKI

Assignees

• 杰富意钢铁株式会社

Dates

Publication Date

20260512

Application Date

20241010

Priority Date

20231020

Claims (10)

1. 1. An apparatus for removing scale from a steel sheet, which is an apparatus for removing scale from a steel sheet being transported, characterized in that, A1 st pickling device for pickling the steel sheet with a1 st acid solution, a breaking device for mechanically breaking the scale, and a2 nd pickling device for pickling the steel sheet with a2 nd acid solution are arranged in this order from the upstream side in the conveying direction of the steel sheet.
2. 2. The apparatus for removing scale from steel sheet according to claim 1, wherein an acid pickling inhibitor is added to said acid solution 2.
3. 3. The apparatus for removing scale from a steel sheet according to claim 1 or 2, wherein an acid pickling accelerator is added to the 1 st acid solution, and the time for acid pickling in the 1 st acid pickling is 10 to 30[ s ].
4. 4. A scale removal apparatus for a steel sheet according to any one of claims 1 to 3, wherein a pre-breaking device that mechanically breaks the scale is provided on the upstream side of the 1 st pickling device in the conveying direction of the steel sheet.
5. 5. A steel sheet manufacturing apparatus is provided with: a hot rolling apparatus for obtaining a hot rolled sheet by hot rolling a steel raw material; a hot-rolled sheet annealing device for performing hot-rolled sheet annealing on the hot-rolled sheet as required; an oxide scale removing apparatus for removing oxide scale from the hot rolled sheet or the hot rolled sheet subjected to the annealing of the hot rolled sheet; A cold rolling apparatus for obtaining a cold rolled sheet by cold rolling the hot rolled sheet from which the scale is removed, and A final annealing device for annealing the cold-rolled sheet to obtain a cold-rolled annealed sheet, The scale removing apparatus for steel sheet according to any one of claims 1 to 4 is used as the scale removing apparatus.
6. 6. A method for removing scale from a steel sheet, characterized in that the steel sheet is pickled by a 1 st pickling device for pickling the hot-rolled steel sheet with a 1 st acid solution, the surface of the steel sheet pickled by the 1 st pickling device is mechanically damaged by a damage device, and the steel sheet treated by the damage device is pickled by a 2 nd pickling device with a 2 nd acid solution.
7. 7. The method for removing scale from a steel sheet according to claim 6, wherein an acid pickling inhibitor is added to the acid solution 2.
8. 8. The method for removing scale from a steel sheet according to claim 6 or 7, wherein a pickling accelerator is added to the 1 st acid solution, and the pickling time in the 1 st pickling device is 10 to 30 s.
9. 9. The method for removing scale from a steel sheet according to any one of claims 6 to 8, wherein the treatment for mechanically breaking the scale is performed by a pre-breaking device disposed upstream of the 1 st pickling device in the conveying direction of the steel sheet.
10. 10. A method for manufacturing a steel sheet, comprising: a hot rolling step of hot-rolling a steel raw material to obtain a hot-rolled sheet; A hot-rolled sheet annealing step of performing hot-rolled sheet annealing on the hot-rolled sheet as required; An oxide skin removing step of removing oxide skin of the hot rolled sheet or the hot rolled sheet subjected to the annealing of the hot rolled sheet; A cold rolling step of cold rolling the hot rolled sheet from which the scale is removed to obtain a cold rolled sheet, and A final annealing step of annealing the cold-rolled sheet to obtain a cold-rolled annealed sheet, The method for removing scale from a steel sheet according to any one of claims 6 to 9, wherein the step of removing scale is performed.

Description

Apparatus for removing scale from steel sheet, apparatus for producing steel sheet, method for removing scale from steel sheet, and method for producing steel sheet Technical Field The present invention relates to a steel sheet scale removal apparatus, a steel sheet manufacturing apparatus, a steel sheet scale removal method, and a steel sheet manufacturing method. Background Electromagnetic steel sheets mainly used as iron core materials for electric equipment are classified into non-oriented electromagnetic steel sheets and oriented electromagnetic steel sheets, and Si and Al are generally contained in a large amount to improve the inherent resistance of steel in order to reduce the iron loss. The above-mentioned non-oriented electrical steel sheet is generally produced by melting a steel having been adjusted to a predetermined composition, producing a slab as a steel raw material by a continuous casting method or the like, hot-rolling the slab, and if necessary, annealing the hot-rolled sheet, pickling, cold-rolling, and subjecting it to final annealing for recrystallization. The grain-oriented electrical steel sheet is generally produced by melting steel adjusted to have a predetermined composition, and producing a steel raw material (slab) by a continuous casting method or the like. Then, hot rolling is performed, if necessary, hot rolled sheet annealing, pickling, cold rolling, and if necessary, recrystallization annealing and cold rolling for the 2 nd time, primary recrystallization annealing, which also serves as decarburization annealing, is performed, and after an annealing separating agent is applied, final annealing is performed to recrystallize the sheet. The hot-rolled sheet annealing is a step of subjecting a steel sheet (hot-rolled steel sheet) after hot rolling to a homogenization treatment. By performing the homogenization treatment, it is possible to eliminate the shortage of recrystallization of the hot rolled sheet, coarsen and granulate the crystal grains before cold rolling, and to improve the texture of the steel sheet before cold rolling to a texture favorable for magnetic properties, or to suppress wrinkles. Therefore, a high-grade electromagnetic steel sheet having a large Si addition amount is often subjected to hot-rolled sheet annealing. Pickling is a step of removing scale (deoxidized skin) from the surface of a steel sheet before cold rolling. If a steel sheet in which oxide scale formed on the surface of the steel sheet by hot rolling and annealing of the hot rolled sheet remains is cold rolled without pickling, the following problems may occur. That is, the scale is pressed into the surface of the steel sheet by the roll, or the peeled scale adheres to the roll surface, and the surface defect is caused by transfer, which significantly impairs the surface quality of the final product. As the acid solution used for the acid washing, any of hydrochloric acid, sulfuric acid, hydrofluoric acid, and a mixed acid obtained by mixing these acids can be used. The scale of the hot rolled steel sheet for electromagnetic steel sheets containing a large amount of Si and Al is composed of an outer scale and an inner scale. The external scale is formed of FeO, fe 3O4、Fe2O3, or the like formed by diffusion of Fe from the inside to the outside of the steel sheet. The internal oxide scale is formed of Si oxide such as SiO 2、Fe2SiO4 or the like, al 2O3 or the like, which is formed by diffusion of oxygen from the outside into the steel sheet. In particular, it is known that the deoxidizing skin property of the internal oxide skin containing SiO 2、Al2O3 is remarkably poor. Therefore, in the deoxidized skin of a hot rolled steel sheet for an electromagnetic steel sheet, the deoxidizing property is improved by performing a mechanical descaling treatment such as shot blasting before pickling to mechanically break the oxidized skin. However, in the case of high-grade electromagnetic steel sheets having a large Si content, if hot-rolled sheet annealing is performed to secure magnetic properties, the crystal grain size becomes large, and embrittlement of the steel sheet becomes a problem. In particular, if the Si content exceeds 2.5% by mass, there is a problem that the surface of the steel sheet is subject to twin deformation by shot peening for improving the descaled property, and sheet breakage is likely to occur at the time of cold rolling starting from the twin deformation. Patent document 1 discloses a technique of reducing the amount of strain introduced to the surface of a steel sheet and suppressing twin deformation by reducing the energy of particles striking the surface of the steel sheet by reducing the diameter of shot particles projected in shot blasting to less than 0.35[ mm ]. Further, patent document 2 discloses a technique of suppressing twinning deformation which is easily generated under a low-temperature high-strain rate condition by heating an electromagnetic steel sheet containi