JPH0621293B2 - Rolling method for high silicon iron plate - Google Patents

Description

The present invention relates to a method for rolling a non-oriented silicon iron sheet.

[Conventional technology and its problems]

Conventionally, a silicon iron plate having a Si content of less than 4 tw% is classified into a directional silicon iron plate and a non-oriented silicon iron plate depending on the manufacturing method, and is mainly used for laminated iron cores, wound iron cores or electric shields for various electromagnetic induction devices. It is processed and molded into a case, etc. for practical use.

However, in recent years, there has been a strong demand for miniaturization and high efficiency of electromagnetic electronic components from the viewpoint of resource saving and energy saving, and materials having excellent soft magnetic characteristics, particularly iron loss characteristics, have been demanded. It is known that the soft magnetic properties of a silicon iron plate improve with the addition amount of Si, show the highest magnetic permeability especially near 6.6 wt%, and have a high specific electric resistance, so that the iron loss is small.

However, the workability of the silicon iron plate rapidly deteriorates when the Si content exceeds 4.0 wt%, and thus it was conventionally impossible to manufacture a high silicon iron plate on an industrial scale by the rolling method. .

In contrast to such a rolling method, a method called an ultra-rapid solidification method has been researched and developed in recent years. However, the high silicon foil strip produced by this method is inferior in surface properties and surface flatness, and has a large thickness and thickness. The plate width is limited, and in addition, the productivity is low and the production cost is high.

[Means for solving problems]

Therefore, the present inventors have repeatedly studied the cold rolling property of the high silicon iron alloy in order to manufacture the non-oriented high silicon iron plate by the rolling method, and as a result, the high silicon obtained by the hot rolling is obtained. High-silicon iron hot-rolled sheet can be cold-rolled or warm-rolled (hereinafter referred to as low-warm rolling) by selecting the rolling conditions according to the Si content and crystal structure of the iron hot-rolled sheet. Found out.

That is, the present invention hot-rolls the iron alloy slab containing Si 4.0 ~ 7.0 wt%, after descaling the hot rolled sheet obtained,
In producing a high silicon iron plate by rolling and annealing, rolling after descaling is performed at a rolling temperature (plate temperature) of 400 ° C. or lower.
Moreover, the rolling temperature T (° C.) and the rolling reduction R (%) per pass are However, the basic feature is that λ: average grain size in the plate thickness direction of rolled material (mm) X: Si content (wt%) is satisfied.

Hereinafter, the present invention will be described in detail.

Figures 1 to 3 show the effects of rolling temperature and rolling reduction per pass on the rollability of high silicon iron alloys at 4.5 wt%, 5.
This is an examination of silicon-iron alloys with respective contents of 5 wt% and 6.5 wt%. These are made by rolling material with different fineness of crystal structure by changing hot rolling conditions,
The drawing shows the boundary line between possible and impossible rolling when the rolling temperature (sheet temperature, the same applies hereinafter) is changed by changing the rolling reduction per pass. The fineness of the crystal structure is represented by the average grain boundary spacing in the plate thickness direction. The plate thickness direction average grain boundary spacing is an average particle size measured in the plate thickness direction, in the case of a layered or fibrous structure, the average particle size in the plate thickness direction, in the case of an equiaxed structure, usually Match the grain of.

According to FIGS. 1 to 3, if the rolling conditions are selected according to the Si content of the rolled material and the fineness of the structure, low and warm rolling of high silicon steel sheet is possible, and It can be seen that there is a quantitative relationship between the state and the rolling conditions that enable rolling.

Then, 100λ + 48X−360, where λ: average grain boundary spacing in the plate thickness direction (mm), X: Si content (wt%), and parameters indicating rolling conditions, However, if T: rolling temperature (° C) R: rolling reduction (%) per pass, and plotting the results of Figs. 1 to 3,
As shown in FIG. 4, the rollable range and the unrollable range can be separated by a straight line passing through the origin and having an inclination of +1. That is, By satisfying the above condition, low / warm rolling is possible. The relationship of this equation (1) is satisfied at any value of T if R exceeds 0%, but if T is 400 ° C or more, the sheet thickness accuracy deteriorates. It is necessary to perform the process at a temperature of 400 ° C. or lower and satisfy the relationship of the above formula (1).

The method of the present invention is applied to a silicon iron plate containing 4.0 to 7.0 wt% of Si. Silicon iron plate has a soft magnetic peak near Si: 6.6 wt%, and its magnetic properties are inferior at less than 4.0 wt% and more than 7.0 wt%. Therefore, 4.0 to 7.0 wt% Si is targeted.

〔Example〕

Example (1) A slab of alloy A shown in Table 1 was hot-rolled to obtain a hot-rolled sheet having an average grain boundary spacing of 320 μ in the sheet thickness direction. This was rolled at a cumulative rolling reduction of 75% under the conditions shown in Table 2 to determine whether rolling was possible or not. The results are shown in Table 2. In the table, "unrollable" means that a crack of 3 mm or more was generated from the edge after rolling (the same applies hereinafter).

Example (2) A slab of alloy B shown in Table 1 was hot-rolled to obtain a hot-rolled sheet having an average grain boundary spacing of 210 μ in the sheet thickness direction. This was rolled at a cumulative rolling reduction of 75% under the conditions shown in Table 3 to determine whether rolling was possible or not. The results are shown in Table 3.

Example (3) A slab of alloy C shown in Table 1 was hot-rolled to obtain a hot-rolled sheet having an average grain boundary spacing of 200 µ and 610 µ in the sheet thickness direction. This was rolled at a cumulative rolling reduction of 75% under the conditions shown in Table 4 to determine whether rolling was possible or not. The results are shown in Table 4.

[Effects of the Invention] According to the present invention described above, a non-oriented high silicon iron plate having Si of 4 wt% or more can be efficiently manufactured by a rolling method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 3 show the effects of rolling temperature and rolling reduction per pass on the rolling property of high silicon iron alloys. FIG. 4 shows the relationship between the rolling condition parameters and the rolling property.

Claims (1)

[Claims] 1. An iron alloy slab containing 4.0 to 7.0 wt% of Si is hot-rolled, the obtained hot-rolled sheet is descaled, and then rolled.
When manufacturing a high silicon iron plate by annealing, the rolling after the descaling is performed at a rolling temperature (sheet temperature) of 400 ° C. or less, and at the rolling temperature T (° C.) and a rolling reduction R (%) per pass. ) And so as to satisfy the following formula: Where λ: average grain size in the plate thickness direction of rolled material (mm) X: Si content (wt%)