JPS63310917A - Production of oriented magnetic steel sheet having excellent glass film adhesion and low iron loss - Google Patents

Abstract

PURPOSE:To obtain the title oriented magnetic steel sheet having excellent glass film adhesion and low iron loss by forming specified ruggednesses on the surface of a silicon steel sheet before or after decarburizing annealing, and forming an oxide partially occluded in the steel sheet iron by decarburizing annealing or finish annealing. CONSTITUTION:The silicon steel slag contg. 0.04-0.10% C, 2.0-4.0% Si, and AlN, MnS, etc., as an inhibitor is hot-rolled, then annealed once or process- annealed, and cold-rolled more than twice. The cold-rolled silicon steel sheet is decarburizing-annealed, coated with an annealing separating agent, and then finish-annealed to obtain the desired oriented magnetic steel sheet. In this case, sharp and fine ruggednesses having 90-380 surface roughness in PCI are formed on the steel sheet surface before or after the above-mentioned carburizing annealing. By this method, an oriented magnetic steel sheet having excellent glass film adhesion can be industrially and stably obtained on a production line.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a directional external voltage V! with excellent adhesion and tension effect of the glass film and low core loss. This invention relates to a method for manufacturing L steel plates.

[Conventional technology]

Grain-oriented electrical steel sheets are mainly used as cores for electrical equipment such as transformers and generators, but it is important that they have good magnetic core loss and excitation properties, as well as excellent glass coating properties. be.

Normally, grain-oriented electrical steel sheets are produced by hot rolling a silicon steel material containing 4% or less of Si, annealing the hot rolled sheet if necessary, and performing one or more cold rolling processes to achieve the final thickness of the cold rolled sheet. After decarburization annealing, an annealing separator containing MgO as a main component is applied and final annealing is performed to develop secondary recrystallized grains with Goss orientation, and further remove impurities such as S and N. It is manufactured by removing glass and forming a glass film. Furthermore, flattening annealing and insulation coating treatment are performed as necessary.

Incidentally, a glass coating is being considered as a method for improving the magnetic properties, particularly the core loss properties, of grain-oriented electrical steel sheets.

For example, in JP-A-50-71526, a grain-oriented electrical steel strip that has been cold-rolled to its final thickness is pickled to remove 3 glrd or more of its surface layer before decarburization annealing. Then, the surface deposits and the surface layer of the steel are removed, the decarburization reaction and the oxide formation reaction proceed evenly, and after decarburization annealing, an annealing separator is applied and finish annealing is performed to improve uniformity and adhesion. This forms a good MgO-310w insulating film.

Furthermore, in JP-A-57-101673, after decarburizing a grain-oriented electrical steel strip that has been cold-rolled to the final thickness and before applying an annealing separator such as M[0, the surface of the steel strip is coated on one side. 0 at
．． 025~0.5g/rrr is removed by grinding or pickling to remove the oxide film on the surface layer of the steel plate, then an annealing separator is applied and finish annealing is performed to create a glass with good adhesion and a uniform gray appearance. It is described that it forms a film.

In JP-A-61-96082, before decarburization annealing, the surface of the steel plate is ground with an abrasive made of a soft material containing gerborundum abrasive grains or alundum abrasive grains to make it smooth, and also to remove deposits. , iron oxide, remove dirt, smooth 5iO
It is described that an oxide film such as t is formed to form a uniform and dense glass film.

[Problem that the invention seeks to solve]

According to these methods, the surface of the grain-oriented electrical steel sheet is cleaned or smoothed before or after decarburization annealing,
Since the properties of the glass film are improved, certain effects will be achieved.

However, in order to reduce the power loss and improve the performance of electrical equipment, it is necessary to reduce the iron loss of grain-oriented electrical steel sheets and further improve the film properties such as the adhesion and tension effect of the glass film.

The applicant of the present application further believes that when sharp, fine irregularities are formed on the surface of a steel sheet before or after decarburization annealing, oxides that partially penetrate into the base steel of the steel sheet during decarburization annealing or finish annealing are generated. It was discovered that the adhesion, tension effect, etc. of the glass film could be improved by the anchoring action, and the iron loss could also be reduced.
A patent application was filed under No.

The present invention has been further studied with the aim of industrially stably obtaining a grain-oriented electrical steel sheet with excellent glass coating properties and low core loss on a production line.

[Means for solving problems]

As a result of the study, in order to achieve the above objective, the form of the unevenness formed on the surface of the steel sheet before or after decarburization annealing is important, and the surface roughness is 90 or more in terms of roughness indication PCI 38.
It has been found that when the roughness is reduced to a range of 0 or less, the reactivity between the steel plate surface and the annealing atmosphere increases, and oxides that partially penetrate deep into the steel plate base metal on the on-site production line are stably formed.

The present invention was made based on this knowledge, and the gist thereof is to hot roll a silicon steel slab, annealing it, and then cold rolling it once or twice or more with an intermediate annealing in between to decarburize it. , in a method for manufacturing a grain-oriented electrical steel sheet in which an annealing separator is applied and finish annealing is performed, roughness with a surface roughness PCI of 90 or more and 380 or less is formed on the steel sheet surface before or after decarburization annealing, and decarburization annealing or A method for producing a grain-oriented electrical steel sheet with excellent glass film adhesion and low core loss, which is characterized by forming oxides that partially penetrate the base steel of the steel sheet during final annealing.

The oxides used in the present invention include Stow, SiO□
It refers to oxides generated on the surface of steel sheets, such as iron oxides containing Sing or reaction oxides of iron oxides containing Sing and an annealing separator.

The present invention will be explained in detail below.

It is not necessary to specify the steel composition and manufacturing conditions of the grain-oriented electrical steel sheet to which the present invention is applied until cold rolling, and for example, C is 0.04 to 0.10%, Si is 2.0 to 4. 0%
, AIN, MnS, RN, etc. are used as appropriate inhibitors, and if necessary, Sn+Cr.

Elements such as N i + M o + S b are contained.

An electromagnetic steel slab is hot rolled, annealed, and then cold rolled once or twice or more with intermediate annealing to achieve a desired final thickness.

Before or after decarburization annealing, sharp and fine irregularities are formed on the surface of the steel sheet. The term "before decarburization annealing" may mean any time before decarburization annealing, and it may be formed during cold rolling.

Also, "after decarburization annealing" means up to final annealing.

In the present invention, irregularities with a PCI roughness of 90 or more and 380 or less are formed on the surface of a steel plate.

PCI is the roughness curve parallel to the center line of the steel sheet surface roughness curve.
Scanning length 10 m that intersects the count level of 0.2 a
It is displayed as the number of hits.

The roughness of the steel plate surface will be described based on experimental data.

The sample material is C: 0.069%, Si: 3.10%, M
n: 0.075%, Al: 0.025%, S
: 0.0021%, Cu: 0.06%, Sn:
A silicon steel slab consisting of 0.10%, N: 0.075%, the balance being iron and unavoidable impurities was hot rolled, annealed and cold rolled by a known method to form a steel plate with a thickness of 0.200゛.
A brush roll with abrasive grains is used to polish a steel plate to a surface roughness of 25.70.90.150.260.
．． It was polished to have fine irregularities of 330, 390, and 500.

Thereafter, decarburization annealing and optional annealing with application of an annealing separator were performed. Next, an insulating coating liquid was applied, heat flattened, and the film adhesion and iron loss characteristics of the manufactured and finished plates were measured, and the results are shown in FIGS. 1 and 2, respectively. As can be seen from this figure, when the steel plate surface roughness is PCI 90 or higher, the adhesion of the coating is excellent even when the fin is bent by 10 fins without any separation at the edges.

From the viewpoint of adhesion, there is no need to limit the upper limit of the surface roughness PCI.

On the other hand, the iron loss decreases from a PCI of 390 or higher, and it is thought that the improvement in adhesion contributes to this through the tension effect. When the surface roughness PCI exceeds 380, iron loss deteriorates.

The above-mentioned trends in film properties and iron loss properties were the same when the above-mentioned irregularities were formed on the surface of the steel sheet after decarburization annealing.

For this reason, in the present invention, irregularities with a surface roughness Pd1 of 90 or more and 380 or less are formed on the surface of the steel sheet before or after decarburization annealing. This forming means does not need to be specified, and for example, a metal wire brush roll, an abrasive grain-containing brush roll, a resin brush roll, a grinder, an abrasive belt, a cold rolling roll, a shot, etc. can be used.

The unevenness is formed on both sides or one side of the steel plate, and is applied to, for example, 80% or more of the entire surface of the steel plate. The depth of the unevenness is desirably about 2 to 151 mm, and the unevenness may be formed in any direction.

As mentioned above, PCI forms fine irregularities and activates the steel plate surface, so decarburization annealing or finish annealing can reduce the
Oxides, etc. with a high proportion of are formed thickly.More importantly, oxides are formed by partially penetrating the base steel sheet.

The SiO□-based oxide makes the glass film produced by the reaction with the annealing separator of high quality, and since the oxides are incorporated into the base steel, the adhesion of the glass film is extremely good.
Furthermore, the film tension increases.

After decarburization annealing, an annealing separator containing MgO as the main component and one or more additives such as Ti0z, B compounds, SrS, SnS, CuS, etc. added as necessary is applied, dried, and finished annealed. will be applied.

If fine, sharp irregularities of 90 or more are formed in the PCI after decarburization annealing, a glass film is formed together with oxides that have partially entered the base steel sheet during final annealing.

Note that "partially" refers to a state of being discontinuous or continuous at non-uniform or equal intervals.

Next, the present invention will be explained with reference to examples.

〔Example〕

Next, examples will be shown.

<Example 1> Weight 9AteC: 0.065, Si: 3.
10, Mn: 0.06B.

Al: 0.026, S: 0.022, Cu
:0.06. A silicon steel slab consisting of Sn: 0.11 and balance iron was hot-rolled, annealed and cold-rolled by a well-known method to obtain a steel plate with a thickness of 0.3000, which was used as a "before treatment" test material. The steel plate has a steel plate surface roughness of P CI te 380,2.
90, 180, 150.90 (7) Polishing was performed so that the surface roughness of the treated area in which the unevenness was formed was 90%.

Next, after carrying out the steps of decarburization annealing, application of an annealing separation agent, and final annealing, the film properties and magnetic properties of the finished plate subjected to insulation coating application and heat flattening treatment were measured. The results are shown in Table 1.

In addition, in the investigation of film adhesion, two of the normal bending conditions were used.
0 to 5011φ, all of them, including the "untreated" material, did not peel and were in good condition, so even more severe bending conditions IQ
It was performed using mmφ.

Table 1 [Effects of the Invention] As described above, according to the present invention, a grain-oriented electrical steel sheet with excellent adhesion of the glass coating and low iron loss can be obtained.

[Brief explanation of drawings]

FIG. 1 is a graph showing the experimental results of the steel plate surface roughness affecting the adhesion of the film in the present invention, and FIG. 2 is a graph showing the experimental results of the steel plate surface roughness affecting the iron loss in the present invention.

Claims (1)

[Claims] 1. A silicon steel slab is hot rolled, annealed and cold rolled once or twice or more with intermediate annealing in between, and decarburized annealed;
In a method for producing a grain-oriented electrical steel sheet in which an annealing separator is applied and finish annealing is performed, roughness with a surface roughness PC1 of 90 or more and 380 or less is formed on the steel sheet surface before or after decarburization annealing, and decarburization annealing or A method for producing grain-oriented electrical steel sheets with excellent glass film adhesion and low iron loss, characterized by forming oxides that partially penetrate the base steel during final annealing.