JPH03274246A - Nonoriented silicon steel sheet excellent in cuttability and blanking property - Google Patents

Abstract

PURPOSE:To improve the cuttability or blanking workability in a steel sheet at the time of core laminating by limiting the oxygen content in a steel and reducing oxide inclusions therein. CONSTITUTION:In a nonoriented silicon steel sheet, the content of Si is regulated to <=1%. The content of oxygen in the steel is limited to <=30ppm to reduce oxide inclusions. In this way, cut burrs after blanking are reduced and dulled and scratches on the steel sheet are almost eliminated. Thus, the efficiency of core manufacturing work can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a non-oriented electrical steel sheet with excellent cutting and punching properties, and in particular, the cutting burr of the cut or punched core is dull, making it suitable for lamination work, etc. Concerning easy non-oriented electrical steel sheets.

[Conventional technology]

Non-oriented electrical steel sheets are cold-rolled to a predetermined thickness, such as 0.50 m, and then annealed in an appropriate temperature atmosphere, and then coated on the surface for purposes such as improving punching properties and preventing rust. is normal.

These products include rotating equipment such as various motors.

Used in stationary equipment such as small transformers.

The core of these non-oriented electrical steel sheets is usually manufactured as follows. In other words, a wide coil of electric '6J & steel plate is first slit into hoops of an appropriate width depending on the application, then continuously punched, and processed into EI cocoa for motor cores and small transformers. . The punched cores are then laminated and used. Recently, automatic lamination within all molds has become popular.

The punched cores are stacked manually or using a semi-automatic core stacker, and a predetermined number of cores are welded on the side surfaces to be integrated, caulked with a bottle, or stacked using an automatic caulking method.

However, if the cutting burrs of the punched cores are too large, electrical short circuits will occur when the cores are laminated, so the clearance between the punch and die of the punching die must be adjusted to minimize the cutting burrs. do.

However, even if the cutting burr is intended to be small, the cutting burr may become sharp depending on the material, and when later stacking and blocking a predetermined number of sheets, the cores may scratch each other due to the cutting burr, lowering the resistance between the eyebrows or holding it manually. There were problems such as sometimes injuring one's hands, or getting caught in the middle of the EI Cocoa Stacker, reducing the efficiency of block formation.

[Problem that the invention seeks to solve]

An object of the present invention is to solve the problems of the prior art when laminating the core of a non-oriented electrical steel sheet, and to provide a non-oriented electrical steel sheet that has good cutting or punching workability.

[Means for solving problems]

The gist of the present invention is as follows.

That is, in a non-oriented electrical steel sheet containing 11% or less of 5i by weight, the oxygen content in the steel is 30p.
This is a non-oriented electrical steel sheet with excellent cutting and punching properties, which is characterized by less than pm and a small amount of oxide inclusions.

The limiting conditions according to the present invention will be explained.

Non-oriented electrical steel sheets with Si of 1% or less have a Si content of 1%.
This is because no variation phenomenon due to the sharpness of cutting burrs was observed when the cutting burr exceeded %.

The present inventors qualitatively investigated the fact that the cut burrs of the hit core are sharp, and as a result, it was found that this is because the tips of the cut burrs are jagged like the teeth of a saw.

The punched surface stands out from the sheared part and the fractured part, but the fracture origin of the fracture part is caused by spherical inclusions, and if there are many inclusions, there are many fracture origins, so the tip of the cutting burr becomes saw-like. It turned out that it felt jagged and sharp, like the teeth of a man. For this reason, it is necessary to reduce inclusions in steel, especially oxide inclusions, and to reduce oxygen to 30 ppm.
It has been found that cutting burrs do not become dull unless the conditions are below.

If it exceeds 30 ppm, the number of inclusions increases, the number of fracture bases increases, the cutting burrs become sharper, and the punched cores tend to scratch each other. There was also a problem with EI cocoa stacking. Therefore, the oxygen content in the steel was limited to 30 ppm or less.

〔Example〕

For non-oriented electrical steel sheet molten steel of the same composition, it was divided into two parts, one No. 1 was deoxidized by adding Afl, and the other No. 1 was deoxidized by adding Afl.
For No. 2 and No. 2, steel without AQ was produced. The components are shown in Table 1. These test materials No. 1, No. 2, and No. 2 were made into slabs by normal continuous casting, and then hot rolled into slabs of @1250 wm x thickness 2.
The dimensions were 5 ua, and the surface was descaled and then cold rolled to a thickness of 0.5 na.

Table 1 Each sample material was annealed in an atmosphere at an appropriate temperature and then coated with a semi-organic coating. The electromagnetic characteristics were as follows.

No, I W16/60: 7, 3
W/kgNO, 2W16/60: 7.4
W/kg These sample materials No. 011, No. 2, and No. 2 were each slit into the same width to produce EI cocoa using a continuous punching machine.

Cores made from sample materials No. 1 and No. 2 were punched out at the same time using the same die. When this core was stacked using an EI stacking machine, 30% of the stacking trouble occurred in N001.

No. 2 caused no trouble at all.

EI Cocoa - Iron loss is No. 1 is W12.6/60: 6, OO
For W/kg, No.2 is Wax, 5/60: 6,08
W/kg.

In addition, when examining the cutting burrs of the cores of O (sample materials No. 1 and No. 12), they are as shown in the micrographs of Figures 1 (A) and (B), respectively, and No. 1 is jagged like a saw. Furthermore, as shown in the electron micrograph of FIG. 2, it was found that spherical inclusions were present at the origin of fracture on the punched surface.

On the other hand, sample material No. 2, which satisfies the requirement of the present invention that the oxygen content is 30 ppm or less, had extremely few cutting burrs and no inclusions, as shown in FIG. 1(B).

[Effects of the Invention] Conventionally, in core forming operations after cutting and punching non-oriented electrical steel sheets, cutting burrs during cutting or punching were large, causing electrical short-circuits during lamination and other troubles. Non-oriented electrical steel sheets have an oxygen content of 3
By limiting the amount to 0 ppm or less, oxide inclusions can be reduced, cutting burrs after punching are significantly reduced and dulled, and scratches on the steel plate are almost eliminated, significantly improving the efficiency of core manufacturing work. I was able to do that.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are 100x micrographs showing the structures of sample materials No. 1, No. 2, and No. 2 after punching in the comparative test of the examples of the present invention, respectively; is sample material N
2000x micrographs showing inclusions in the o and l tissues.

Claims (1)

[Claims] (1) In a non-oriented electrical steel sheet containing Si: 1% or less by weight, the oxygen content in the steel is 30 ppm.
A non-oriented electrical steel sheet with excellent cutting and punching properties, characterized by having the following properties and having few oxide inclusions.