JPS61135454A - Apparatus for producing thin metallic strip - Google Patents

Abstract

PURPOSE:To prevent the oxidation and nitrogen absorption of a thin metallic strip in a title device consisting of high-speed rotating rolls by filling an inert gas into a cover for covering the rolls and providing a means for preventing the outdoor air flow to be intruded into the cover. CONSTITUTION:The rolls 1, 1' are rotated at a high speed in the directions opposite from each other and a molten metal is poured from a pouring nozzle 2 into the spacing between the rolls 1 and 1'. The molten metal is quickly cooled and solidified at the circumferential surfaces of the rolls by which the thin metallic strip 3 is produced. The circumferential surface in the upper part of the rolls 1, 1' and the molten metal discharged from the nozzle 2 are covered by the cover 4. Air charging pipes 5 for supplying the inert gas to the inside of the cover 4 and jets 6 for blowing the confronting flow of the outdoor air flow intruded and entrained into the cover 4 by the rotation of the rolls 1, 1' are inserted and fixed into the cover. The intrusion of the air into the cover 4 is thus prevented and the inert atmosphere is maintained in the cover 4. The pipes 5 are directed in the direction perpendicular to the circumferential surface of the rolls or toward the nozzle 2 and the jets 6 are directed toward the outside of the cover 4.

Description

[Detailed Description of the Invention] (Industrial Application Field) High M! This specification describes an apparatus for continuously manufacturing a metal ribbon by rapidly cooling and solidifying molten metal on the circumferential surface of a rotating roll. The technical content described in 2 is to propose a device useful for preventing oxidation and nitrification of the metal ribbon by blocking air from flowing into the molten metal and maintaining the surrounding area in an inert atmosphere.

Research is underway to develop a method for directly producing metal ribbon from molten metal, in which the molten metal is brought into contact with the surface of a rotating roll, rapidly cooled, and solidified.

[Prior art] Conventionally, as a device for carrying out the method listed in 1, there is a device disclosed in Japanese Patent Application Laid-Open No.
, No. 76432 and Japanese Unexamined Patent Publication No. 56-62660.

In the former method, inert gas is sprayed onto the roll surface just before the pouring starts to block the air flow, but since there is no cover around the pouring area and it is in contact with the atmosphere, oxidation or nitrogen absorption is not sufficiently prevented. It cannot be prevented.

The latter covers the roll with a cover and blows out gas, but it requires a clearance between the roll and the cover, which makes it impossible to sufficiently block the air flow sucked in the direction of rotation of the roll on the roll surface. Since the gas is actively exhausted, the entrainment of airflow becomes more pronounced.

(Problems to be Solved by the Invention) It is an object of the present invention to provide an apparatus in which molten metal discharged from a pouring nozzle is kept in an inert atmosphere by shielding it from the air, thereby excluding the influence of outside air.

(Means for Solving the Problems) This invention includes a roll that rotates at high speed, a pouring nozzle that supplies molten metal onto the cylindrical generatrix of the roll, and a region for discharging the molten metal from the pouring nozzle. It has a cover that covers the main part of the circumferential surface of the roll, a means for filling the internal compartment of the cover with an inert gas, and a counterflow to the outside air flow that is drawn into and entrained within the cover by the rotation of the column. This is a metal ribbon manufacturing apparatus comprising means for blowing out.

The internal compartment of the guide bar may be filled with inert gas by connecting a tube communicating with a source of inert gas to the cover, or by inserting the tube into the cover. In addition, a rare gas such as Ar is used as the inert gas.

Further, as a means for blowing out a counterflow to the outside air flow that is drawn into the cover and entrained by the rotation of the roll, it is sufficient to blow the gas from the inside of the cover to the outside using a jet that is tilted in the tangential direction of the roll circumferential surface. The gas that blows out includes
For example, an inert gas such as Ar is desirable.

Now, the apparatus shown in FIG. 1 will be explained in detail. The figure shows the configuration of an apparatus for producing metal ribbon using twin rolls.
, 1' are rolls that rotate at high speed in opposite directions, and molten metal is supplied between the rolls 1111 from the pouring nozzle 2,
The metal ribbon 8 is produced by rapid cooling and solidification on the circumferential surface of the four-ring. Further, the upper peripheral surface of the roll 1.1' and the molten metal discharged from the pouring nozzle 2 are covered by a cover 4.

Furthermore, a filling pipe 5 that supplies inert gas to the inside of the cover 4
and a jet 6 that blows out a counterflow of outside air that is drawn into the cover 4 and entrained by the rotation of the rolls 1 and 1' are inserted and fixed into the cover 4. This prevents air from flowing into the cover 4 and maintains the inside of the cover 4 in an inert atmosphere. Further, the filling pipe 5 is oriented perpendicular to the circumferential surface of the roll 1 or 1' or toward the pouring nozzle 2, and the jet 6 is oriented toward the outside of the cover 4. Furthermore, an insertion hole 7 into which the pouring nozzle 2 is inserted is formed on the upper surface of the cover 4, and a gap formed when the pouring nozzle 2 is inserted into the insertion hole, and a side surface between the cover 4 and the roll 1.1'' are formed. The structure is such that the inert gas escapes to the outside through the gap between the
It is supplied from

Furthermore, although the twin-roll device is described in FIG. 1, the present invention can also be applied to a single-roll device. Further, the number of stages of charging pipes and jets may be further increased.

(Function) In the apparatus shown in Fig. 1, the filling pipe is used to control the atmosphere inside the cover, and the amount of inert gas supplied varies depending on the width of the roll, for example, 2 to 50 gas per 1 cm of roll width.
lr may be supplied within the range of 00/S. This is 200
If it is less than 78, air will flow into the cover, and if it is less than 500
This is because if it exceeds c/8, the pouring flow will be disturbed.

Further, the counterflow from the jet prevents outside air from flowing into the cover, and the amount of air blown from the jet is varied depending on the circumferential speed of the roll. As the circumferential speed of the roll increases, the amount of air involved also increases and nitrification becomes significant, so it is necessary to increase the gas flow rate. Roughly speaking, as the gap difference between the roll and the cover and the length of the roll body increase, the amount of air involved also increases, so it is necessary to increase the gas flow rate. Preferably, the gas flow rate Q (007B) is controlled according to the following equation: Q>h-va: a quantity proportional to the gap difference between the roll and the cover and the roll body length V: four-wheel circumference (m/s).

As an example, the length of the roll in the device shown in Figure 1 is 1)
QQIIIK, +7 from the charging pipe) Ar amount to 500 C
Circumferential speed of the roll when o /s, A from the jet
The relationship between the flow rate of m” and the amount of nitrogen absorption in the manufactured metal ribbon was determined as follows.
As shown in the figure.

In addition, regarding the silicon steel quenched ribbon, in which nitrogen absorption during pouring is a problem in terms of magnetic properties (particularly iron loss), the amount of nitrogen absorption in the ribbon produced using the device of this invention and the conventional device. A comparison was made regarding. The silicon steel ribbon produced is 5159m long.
The width is 250 μm and the thickness is 250 μm. As shown in Fig. 8, the amount of nitrogen adsorption in each case is shown in Fig. 8.
There is nitrogen absorption of 15 to 20 ppm, and in the case where inert gas is simply injected just before pouring (comparison 2), there is nitrogen absorption of 15 to 20 ppm, and there is almost no effect of preventing nitrogen absorption. In addition, the amount of g and nitrogen in the combination of the cover and the gas jet (comparison a) was reduced to about 10 ppm, but this was not sufficient.

It can be seen that the apparatus of this invention is extremely effective in reducing the amount of nitrogen absorbed to 5 ppm or less.

(Effects of the Invention) As explained above, according to the present invention, a metal ribbon can be manufactured in an inert atmosphere to prevent oxidation and nitrification of the metal ribbon, thereby providing a metal ribbon of excellent quality. becomes possible.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the configuration of the metal ribbon manufacturing equipment - Figure 2 is a graph showing the relationship between roll circumferential speed, nitrogen absorption amount, and lr amount Figure 8 is the metal ribbon manufactured by each equipment It is a graph showing the amount of nitrogen absorbed.

Claims (1)

[Claims] 1. A roll that rotates at high speed, a pouring nozzle that supplies molten metal onto the cylindrical generatrix of the roll, and essential parts of the circumferential surface of the roll, including a discharge area of the molten metal from the pouring nozzle. and a means for filling an internal compartment of the cover with an inert gas, and a means for blowing out a counterflow to the external airflow entrained within the cover by rotation of the roll. Metal ribbon manufacturing equipment.