Metal treatment – Process of modifying or maintaining internal physical... – Magnetic materials
Patent
1990-06-21
1993-04-27
Wyszomierski, George
Metal treatment
Process of modifying or maintaining internal physical...
Magnetic materials
148112, 156603, C21D 812, C30B 2802
Patent
active
052058727
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method of producing a crystal body having a controlled crystalline orientation, and more particularly to a method of producing crystal bodies having a predetermined orientation such as single metal crystal, grain oriented silicon steel sheet, bidirectional oriented silicon steel sheet and the like wherein the crystal body having the predetermined orientation is rapidly and simply produced by artificially planting a seed crystal of an adequate orientation irrespective of the size of the crystal body and hence the mass production can be made in industrial scale.
BACKGROUND ART
There are basically four known methods for obtaining crystal bodies having a desirable orientation.
(1) First, the simplest method is a method wherein a block-like single crystal is prepared and then a crystal body is cut out therefrom in a desired orientation in accordance with the measured result of single crystalline orientation.
In this method, however, the cutting takes a long time, the cost is high, and also the size of the single crystal to be prepared is critical. Therefore, the mass production can not be expected.
(2) Second, there is a so-called strain-slant annealing method. This method is a method of growing a single crystal of desirable orientation from an end of a sample, wherein a seed crystal is first prepared on the end of the sample and rotated in a desired direction to grow the whole of the seed crystal into a single crystal having the desirable orientation, and has been proposed by Fujiwara et al [T. Fujiwara and T. Hudita; J. Sci. Hiroshima Univ. A8 (1938), P293.about.296].
They have succeeded in the preparation of single crystals by the above method from aluminum and further from pure iron.
Thereafter, Dunn et all have applied the above method to silicon steel sheets having a large size [C. G. Dunn and G. C. Nonken: Metal Progress, 64 (1953) 6, P71.about.75].
According to their method for growing a plate crystal having a specified crystalline orientation, an end of a sample previously subjected to a strain is placed in a high temperature region of a temperature tilting furnace to prepare some seed crystals as shown in FIG. 1a, among which a crystal grain having an adequate orientation is selected and cut out as shown in FIG. 1b. Then, a necked portion of the cut out crystal grain is bent as shown in FIGS. 1c and 1d to align the seed crystal into a predetermined orientation with respect to the sample plate. Next, the seed crystal is annealed through heating in the temperature tilting furnace so as to grow over the whole of the plate, whereby the object is achieved.
In this method, however, it is necessary to strictly control the operation for selecting and cutting out a seed crystal having an adequate orientation from many crystal groups and the operation for bending the seed crystal into a predetermined orientation, which takes much labor and long time, so that the mass production can not be expected.
(3) Third, there is a method utilizing secondary recrystallization phenomenon.
The secondary recrystallization is a phenomenon that a seed of nucleating secondary grains largely grows through grain boundary energy of primary recrystallized grains as a driving force, which is widely utilized as a method of producing grain oriented silicon steel sheets as is well-known.
The grain oriented silicon steel sheet is required to have excellent magnetic properties in the rolling direction. That is, it is required that as the magnetizing force (magnetized properties), the magnetic flux density represented by B.sub.10 value (magnetic flux density in the rolling direction produced when the magnetizing force is 1000A /m) is high and the iron loss represented by W.sub.17/50, value (iron loss when being magnetized at a magnetic flux density of 1.7 T and a frequency of 50 Hz) is low so that it is fundamentally necessary to highly align <001> axis of secondary recrystallized grains in steel into the rolling direction. For this end, fine precipitates such as MnS, MnSe and the like
REFERENCES:
patent: 2700006 (1955-01-01), Dunn
patent: 4475980 (1984-10-01), Rhemer et al.
patent: 4519870 (1985-05-01), Matsuzawa et al.
Mitsunori Hiromi
Sadayori Toshio
Kawasaki Steel Corporation
Miller Austin R.
Wyszomierski George
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