JPH0323042A - Manufacture of rolled metal strip using rapidly cooled and solidified cast strip as raw material - Google Patents

Abstract

PURPOSE:To improve cold-rolling property and to save consumed energy to the equipment by executing the prescribed work to a cast strip, which is obtd. by rapidly cooling and solidifying molten metal with single roll method or twin roll method. CONSTITUTION:The molten metal is continuously supplied on a cooling face composed of one surface or two surfaces shifted and renewed, and rapidly cooled and solidified to obtain the cast slab, and the rigid small particles are made to collapse on the surface of the obtd. cast strip to work the cast strip surface. Successively, after heating and annealing so as to obtain fine recrystallized particles in this worked range, the cold-rolling or hot-rolling is executed. By this method, the excellent cold-rolling property can be given to the metal strip and also energy saving effect caused by enlargement of practicality in a process for using the rapidly cooled cast strip as raw material omitting the hot rolling process, can be improved.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to soft iron plates, stainless steel plates, two-silicon steel plates, and Ni -Fe plate (permalloy) Co-Fe plate,
Ni plate. A method for manufacturing rollable metal plates using rapidly solidified thin cast plates that maintain good rolling shapes when manufacturing metal plates including various rollable alloys such as N plates and Cu plates. It is. (Prior Art) Conventional various rollable metal plates are produced by, for example, ({) continuous casting process into slabs of 200 mm thickness, (b) slab heating process, (c)
A product plate is produced through a hot rolling process, (2) a hot rolled material annealing process, (v) a cold rolling process, and (f) a processing heat treatment process as required. In addition, due to recent demands for cost reduction, etc., in order to omit the above steps (D) and (I1),
The so-called single roll method, in which molten metal is continuously supplied onto a cooling body with one or two cooling surfaces that moves and renews, and is rapidly solidified to obtain a thin cast plate with a thickness of about 10 mm from several 10 mm.
Various methods, typified by the twin-roll method, have been proposed.

Although it is possible to obtain rollable metals with good productivity and low cost using such single-roll and twin-roll methods, there are still some basic problems that need to be solved, so some products are Although it has been put into practical use, it is still an unfinished technology.

(Problems to be Solved by the Invention) The object of the present invention is to solve problems commonly associated with the production of rollable metal sheets using rapidly solidified thin cast sheets as a starting material by the above-mentioned single roll method, twin roll method, etc. The aim is to provide a method to solve the problem of deterioration in rolling properties, which is an important issue in the field of rolling, and to greatly overcome the fundamental difficulties in putting the single roll method and twin roll method into practical use. In other words, the surface of a thin slab obtained by a single-roll method or a twin-roll method generally has a number of thicknesses due to wrinkles, etc., compared to the smooth surface of a hot-rolled sheet produced by a normal hot rolling process. It is easy to have unevenness of 10% or more, and the thickness variation in the width direction is also large.

This is due to local differences such as shrinkage as the molten metal solidifies, and
This is a defect peculiar to the rapid solidification method due to thermal deformation of the roll surface, etc., and although it can be avoided to some extent by the design of the mechanical equipment and the operating method, there are limits. In rollable metal sheets, which are manufactured by a series of manufacturing processes in which cold rolling or warm rolling is an essential step, using a thin cast sheet that inevitably has such irregularities as a starting material, during rolling, the metal surface is The existing hot water wrinkles are crushed in the rolling direction, creating dented scratches on the board body, causing so-called "sagging scratches" in the industry term. In addition, such uneven portions are
In brittle materials, cracking may occur during cold rolling. In addition, recently, soft iron plates or stainless steel plates are cast to a thickness of several tens of micrometers to several hundred am using a single roll or twin roll method, and then annealed and cold rolled to a thickness of several micrometers.
Several methods have been proposed for manufacturing foil strips, but even in such cases, the unevenness of the thin cast sheet tends to cause shrinkage or breakage during subsequent cold rolling.

In addition to the above-mentioned birch method, the single-roll method and double-roll method not only have many advantages in terms of lower costs, such as fewer processes and less capital investment, than the conventional hot rolling method, but also have the advantage of reducing the cost by reducing the thickness of several tens of micrometers at once. Although it is an excellent manufacturing method that has the advantage of producing cold-rolled materials, it has not yet been put into practical use due to problems such as rollability.

(Means for Solving the Problems) The present inventors have made various studies in order to solve the problems of the prior art, and have found that in order to solve the problems such as the above-mentioned rollability, specific It was discovered that fine recrystallization of grains in the processed area by processing and subsequent annealing is extremely effective, and the present invention was brought to fruition.

That is, the gist of the present invention is that molten metal is
To obtain a thin cast plate by continuously supplying it onto a cooling body with one or two cooling surfaces that moves and renews and rapidly solidifies it, and to collide rigid small particles on the surface of the obtained thin cast plate to process it. The basic process includes heating and annealing so that the processed area becomes a fine recrystallized grain layer, removing surface oxides, etc. as necessary, and then cold or warm rolling. The present invention provides a method for manufacturing a so-called rollable metal plate having good rolling properties, which comprises carrying out a heat treatment in a broad sense if necessary.

When manufacturing rollable metal sheets using rapidly solidified thin cast sheets as a starting material using the single-roll method or twin-roll method, the surface smoothness and thickness of the sheets are lower than that of hot-rolled materials using conventional methods. controllability,
Although the cold rollability was extremely poor in terms of the frequency of occurrence of troubles such as fractures, according to the present invention, the cold rollability has been significantly improved by introducing the above-mentioned processing steps and a fine grain recrystallization step in the processing area. be done.

(Function) Next, the reason why the manufacturing conditions are limited as described above in the present invention will be explained in detail.

The present invention is not limited to a specific metal, but is carried out by a single-roll method or a double-roll method, in which molten metal is rapidly solidified by continuously feeding it onto a cooling body that has one or two cooling surfaces that move and renew. The starting material is a thin cast plate obtained by
: It can be advantageously applied to the production of various rollable metal or alloy plates such as o-Fa plates, Ni plates, 1M plates, and Cu plates.

However, this is because processing and annealing, which are the core of the present invention, enable fine crystallization in the processed region, and by creating such a state, cold rollability can be significantly improved.

Next, the thickness of the thin cast plate is preferably set to 6. 0 un or less,
The reason why it is set to 1 or more is that the thin cast plate is 6. When exceeding O rrm, not only the advantage of process saving decreases, but also
Even if there are some irregularities, they account for only a small percentage of the overall board thickness.
This is because relatively good rolling properties can be obtained without introducing the present invention, and the reason why the value is 10n or more is because the present invention is based on rolling, and there is no need to use a starting material with a thickness of less than 10μ. This is because there are very few of them, and it is virtually difficult to manufacture thin cast plates with a thickness of less than 10 mm.

A thin cast plate obtained by the rapid solidification method is then processed by colliding rigid small particles onto the surface. In other words, so-called blasting is performed in which countless particles of iron, sand, or other material are made to collide with the surface of a thin cast plate at high speed. The particles used in this process are so-called grit, which has an irregular shape with sharp edges, or shot, which has a relatively close to spherical shape. To cause these to collide at high speed, a centrifugal projection device that is accelerated by the blades of a rotating impeller, or a pneumatic spray device that utilizes the air velocity when compressed air is injected from a nozzle is generally used.

Such processing may be performed on both sides, both sides including the side end faces, or only one side, depending on the surface condition, but processing on both sides is preferred since warping is likely to occur if only one side is used.

Regarding the size of grit, shot, etc., if a large shot is used, the depth of the machining area will become deeper, but at the cost of this, the indentation will become larger and the surface roughness will increase. Generally, it is preferable to select a size that is several times to a fraction of the thickness of the thin cast plate. The blasting time varies depending on the type of metal, the degree of unevenness of the thin cast plate, the purpose, etc., but by annealing afterwards, at least the surface of the plate is covered with fine recrystallized grains, so that the unprocessed area is substantially covered with fine recrystallized grains. It should be processed so that it does not exist.

The thin cast plate processed in this way is then heated and annealed. The optimum temperature differs depending on the metal type, but for example, Si-F
650 for e-steel, stainless steel, and Ni-Fe
~1300°C, 350~900°CS for Cu
For I'J, it is preferable to heat at 300 to 600°C for 0 seconds to several hours.

The thin cast plate whose surface area is covered with fine recrystallized grains by such heat annealing is then subjected to cold or warm treatment according to each purpose after removing surface oxides etc. as necessary. The product is made into a product through a series of manufacturing processes, including rolling as the basic process, followed by processing and heat treatment in a broad sense as necessary. The mechanism by which the cold-rollability of the rapidly solidified thin cast sheet is improved by the present invention is considered to be as follows. First, grit and shot blasting have the effect of smoothing out the irregularities on the surface of the thin cast plate, especially in the boundary areas, and this smoothing effect reduces "heavy scratches" during rolling.

Furthermore, the greatest feature of the present invention is that the thin cast plate surface is cold-rolled in a state covered with fine recrystallized grains by heating annealing after blasting.

Considering the situation where a rolling roll is in partial contact with the surface of a thin cast plate where there are irregularities, if the surface grains are coarse grains,
In relation to the deformation mode, the surface of the uneven thin slab and the rolling roll surface have poor compatibility, but when the surface grains are fine recrystallized grains, the compatibility between the two is good and The entire surface can be easily flattened with a small amount of reduction. This difference in "fitting in" is due to the fact that when the surface grains are coarse grains, deformation due to the specific simple slip system occurs over a relatively wide range, and the restriction with adjacent grains is large, so the external shape of each grain is On the other hand, when the surface grains are fine grains, the deformation of each grain occurs within a narrow range, which is thought to be due to the difference in adhesion to the roll surface.

As described above, the present invention makes it possible to suitably manufacture a metal plate made from an industrially useful rapidly solidified thin cast plate.

Next, examples of the present invention will be described.

Example I CO. 053%, Cr18%, Nt 8%, balance Fe
Austenitic stainless steel [(StlS 304), which is made up of stainless steel and unavoidable impurities, was melted in vacuum, and a thin cast plate with a thickness of 3.0 mm was obtained by a twin roll method with a roll diameter of 400 mm. On the surface of the thin cast plate, there are raindrops with a height of 1 to 2 meters.
There were so-called ``hot water drips'' and ``wrinkles'' scattered all over the place.

The thin cast plates were divided into two groups, labeled A and B.

Among these, group B thin cast plates have a diameter of 0. 8
mm steel grit was blown onto the thin cast plate surface for about 20 seconds by means of a stream of compressed air. As a result, the entire surface of the thin cast plate is 0. It is covered with 2 to 0.5 inch roughened parts, and the average board thickness is 2.5 inch. It became 9mm. The thin cast plates thus processed were subjected to various types of heat annealing at temperatures of 600 to 1200'C for 0 seconds to 3 hours. At this stage, the temporary cross section was observed using a metallurgical microscope to determine whether the surface was covered with fine particles. Next, all samples of Groups A and B were cold rolled to IM using a four-high rolling mill with a roll diameter of 80 mm, and the surface properties were observed. The results are shown in Table 1.

It can be seen that the fine recrystallization generated materials of Group B according to the present invention have even better surface properties.

Example 2 Vermalloy Pc consisting of 76% Ni, 4.5% Cu, 4.5% Mo, balance Fe and inevitable impurities was melted in vacuum,
0.30ffI with twin rolls with a roll diameter of 300 mm
An fflO thin cast plate was obtained. There were sushi-shaped recesses and drips on the surface of this thin cast plate. The thin cast plates were divided into two groups, designated as A and B. Regarding group B,
Diameter 0. After sandblasting to a thickness of 4 mm, both A and B were heat annealed at 1100"C for 300 seconds, and after removing scale with aqua regia, they were rolled into 0.
It was rolled to 10 mm.

In addition, when checking the cross-sectional structure immediately after heat annealing, it was found that B
For group materials, the diameter is approximately 30 mm in the area of 0.1 + mm on the image surface.
A fine double layer of ~50n was evident. In addition, some of the A group materials developed holes and broke during cold rolling, whereas all of the B group materials could be rolled. This cold-rolled material was cut into 1 cm width, and Mg was added as an annealing separator.
After applying O, it was rolled into a toroidal shape, kept at 1100°C for 3 hours in a dry hydrogen stream, and then cooled in an oven at a cooling rate of 100°C per hour. When the magnetism was measured, as shown in Table 2,
It was found that the magnetic variation of the A group materials was large, but this was found to be due to variation in the cold rolled sheet thickness.

As described above, it has been found that according to the present invention, it is possible not only to improve cold rollability but also to suppress variations in magnetic properties by suppressing variations in cold-rolled plate thickness.

(Effects of the Invention) As described above, the rollable metal sheet made from the rapidly solidified thin cast sheet manufactured by the present invention has features such as cold rollability that are even more excellent than conventional metal sheets, and This method is extremely useful industrially, as it increases the practicality of the process using rapidly solidified thin cast sheets as a raw material by omitting the process, and saves energy and equipment investment.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram of the method of the present invention, and shows that the glint processing of the present invention eliminates acute angles at the dripping edges, and that the subsequent heat annealing forms a fine recrystallized grain layer on the plate surface. Show the situation. Figure 1

Claims (4)

[Claims] (1) To obtain a thin cast plate by continuously supplying molten metal onto a cooling body that has one or two cooling surfaces that move and update, and to rapidly solidify the metal, and to form a rigid body on the surface of the obtained thin cast plate. Rolling using a rapidly solidified thin cast plate, which consists of colliding and processing small grains, heating and annealing so that the processed area becomes a fine recrystallized grain layer, and cold or warm rolling. A method for manufacturing a metal plate. (2) The method for manufacturing a rollable metal plate using the rapidly solidified thin cast plate according to claim 1, wherein the thin cast plate has a thickness of 6.0 mm to 10 μm. (3) A method for manufacturing a rollable metal plate using a rapidly solidified thin cast plate according to claim 1 or 2, wherein surface oxides of the thin cast plate are removed after the heating and annealing step. (4) A method for manufacturing a rollable metal sheet using the rapidly solidified thin cast sheet according to any one of claims 1 to 3, wherein a broadly defined heat treatment is performed after the cold or warm rolling step.