JP-7855739-B2 - Coating material, grain-oriented silicon steel sheet having a coating formed from the coating material, and method for manufacturing the same.

JP7855739B2JP 7855739 B2JP7855739 B2JP 7855739B2JP-7855739-B2

Inventors

ジ、ヤミン
ヤン、ヨンジエ
リ、グオバオ
ウ、メイホン
リン、チェン
ジャオ、ジペン
マ、チャンソン
グオ、ジエングオ

Assignees

バオシャンアイアンアンドスティールカンパニーリミテッド

Dates

Publication Date: 20260508
Application Date: 20230629
Priority Date: 20220629

Claims (14)

A coating material for surface coating of grain-oriented silicon steel, wherein the coating material is: It has a phosphate, wherein the phosphate is magnesium dihydrogen phosphate, aluminum dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, and/or manganese dihydrogen phosphate; It has colloidal silica ; Having a vanadate , wherein the vanadate is an orthovanadate and /or metavanadate of Ce, Mn, Co, Cu, or Fe; and Here, the coating material does not contain Cr, and the mass ratio of the vanadate to the phosphate is 0.2 to 2.0. The aforementioned coating material.
The coating material according to claim 1, comprising, by mass, 25-50% phosphate, 25-50% colloidal silica, and 10-50% vanadate.
The coating material according to claim 1, wherein the mass ratio of colloidal silica to the phosphate is 0.5 to 1.5.
The coating material according to claim 1, wherein the mass ratio of colloidal silica to the phosphate is 1.0 to 1.5, and/or the mass ratio of vanadate to the phosphate is 0.2 to 1.0.
The coating material further: It contains boric acid, wherein the boric acid content is 0.02 to 0.2 parts by mass per 100 parts by mass of colloidal silica. The coating material according to claim 1.
The coating material according to claim 1, wherein the particle size of the colloidal silica is 5 to 50 nm.
A grain-oriented silicon steel sheet comprising a substrate and a coating formed on the surface of the substrate, wherein the coating is formed using the coating material described in any one of claims 1 to 6.
The grain-oriented silicon steel sheet according to claim 7, wherein the phosphate in the coating forms a network or chain structure.
The grain-oriented silicon steel sheet according to claim 7, wherein the coating comprises vanadium phosphate.
The grain-oriented silicon steel sheet according to claim 7, wherein the amount of the dry film on one side of the coating is 2 to 10 g/ m² .
The grain-oriented silicon steel sheet according to claim 7, wherein the grain-oriented silicon steel sheet further has a magnesium silicate layer, and the magnesium silicate layer is located between the substrate and the coating of the grain-oriented silicon steel sheet.
The grain-oriented silicon steel sheet according to claim 7, wherein the coating of the grain-oriented silicon steel sheet has a tension of 7.1 to 10.5 MPa and a phosphorus elution content lower than 75 μg/150 cm² .
A method for manufacturing grain-oriented silicon steel sheets, the manufacturing method comprising the following steps, the steps being: 1) A step of applying the coating material according to any one of claims 1 to 6 onto the substrate of the grain-oriented silicon steel sheet; and, 2) A step of performing sintering to form a coating on the surface of the substrate of the grain-oriented silicon steel sheet, wherein the surface temperature of the substrate during sintering is 800 to 900°C, and the sintering time is 20 seconds or more. The aforementioned manufacturing method.
The manufacturing method satisfies one or more of the following conditions, and the conditions are: The coating material is applied to the substrate in a dry film amount of 2 to 10 g/ m² on each side; The manufacturing method further includes forming a magnesium silicate layer between the substrate and the coating. The manufacturing method according to claim 13.

Description

This invention relates to the field of steel sheet coating, and more particularly to a coating material for surface coating of grain-oriented silicon steel, a grain-oriented silicon steel sheet having the surface coating, and a method for manufacturing the same. Grain-grain silicon steel sheet refers to a steel sheet obtained by cold rolling and heat treatment processes, having a silicon content in the range of 2.8 wt% to 3.5 wt% and possessing a {110}<001> texture. Its magnetic properties along the rolling direction are significantly better than those along the transverse direction. Grain-grain silicon steel sheet is mainly used as a core material for transformers. To reduce energy loss and noise levels in transformers, grain-grain silicon steel sheet preferably has low iron loss and low noise. Currently, it is known that the iron loss and magnetostriction values of grain-grain silicon steel sheet can be reduced by applying appropriate tensile stress. Prior art typically solves the above problem by applying a chromium-containing coating to the surface of grain-oriented silicon steel sheets. Chromium-containing coatings have good insulating properties. Furthermore, the coating generates tensile stress on the steel sheet, thereby reducing iron loss and magnetostriction in the steel sheet due to the difference in thermal expansion coefficients between the coating and the steel sheet during heat treatment. However, because the coating solution used contains hexavalent chromium, the waste liquid generated during its manufacture contains large amounts of hexavalent chromium, which is harmful to the environment and would cause serious environmental pollution. In recent years, with growing concern for environmental protection, there has been an increased demand for products free from harmful substances such as chromium and lead. The development of chromium-free coatings (coatings without chromium) for grain-oriented silicon steel is also anticipated. However, grain-oriented silicon steel using chromium-free coatings typically suffers from significantly reduced moisture resistance and insufficient tensile strength. Therefore, chromium-free coatings are rarely used, or at least not feasible. A Chinese patent document (publication number: CN101790599A, publication date: July 28, 2010) titled "Insulating Coating Solution for Grain-Grain Electrical Steel Sheets and Method for Manufacturing Grain-Grain Electrical Steel Sheets with Insulating Coating" discloses a chromium-free insulating coating solution for grain-grain electric steel sheets, comprising at least one phosphate of Mg, Ca, Ba, Sr, Zn, Al, and Mn, and chelates of colloidal silica and titanium. It can improve adhesion and coating tension. However, the chelates tend to decompose during heat treatment to produce carbon, which negatively affects the coating tension. A Chinese patent document titled "Grain-oriented electrical steel sheet having a chromium-free insulating coating and insulating coating agent therefor" (Publication number: CN101223300A, Publication date: July 16, 2008) discloses a chromium-free insulating coating agent for grain-oriented electrical steel sheets. Its main components are phosphates, colloidal silica, and inorganic compounds of Fe, Ni, Co, Cu, Sr, or Mo with particle sizes of 15 nm or less, such as hydroxides, oxides, carbonates, silicates, and molybdates. However, the hydroxide colloid is unstable in phosphate solution systems and lacks sufficient ability to fix its free phosphate radicals, which can easily reduce the moisture resistance and anti-adhesion properties of grain-oriented silicon steel sheets. A Chinese patent document titled "Chromium-free coating agent for grain-oriented electrical steel sheets, method for preparing the same, electrical steel sheet using the same, and method for manufacturing the same" (Publication number: CN102119239A, Publication date: July 6, 2011) discloses a chromium-free coating agent for grain-oriented electrical steel sheets containing phosphate, colloidal silica, and hematite silicon sol. However, hematite silicon sol is difficult to maintain stably in a phosphate-based system, and its preparation is also difficult, making industrial production challenging. In light of the above problems, there is a need to obtain a coating material for grain-oriented silicon steel sheets that meets industrial production requirements, is chromium-free, remains stable during heat treatment, and possesses good coating performance. Furthermore, the surface coating of grain-oriented steel sheets obtained with this coating material will have good moisture resistance, corrosion resistance, heat resistance, and anti-adhesion properties, while also providing sufficient tensile strength to further reduce iron loss and magnetostriction in grain-oriented silicon steel. The object of the present invention is to provide a coating material for surface coating of grain-oriented silicon steel. This coating material is chromium