JPS61103651A - Production of quickly cooled thin strip by twin roll method - Google Patents

Abstract

PURPOSE:To stabilize a solidifying stage and to make possible the production of a defectless thin strip in a process for twin-roll type production of the quickly cooled thin sheet by limiting the linear contact pressure with the thin strip in the kiss part between cooling rolls within a prescribed range. CONSTITUTION:Heat is extracted from the surface of cooling rolls 2, 3 to grow solidified shells 6 while a molten metal 4 teemed from a pouring nozzle 1 is supplied to a pouring basin 5 formed between the rolls 2 and 3. The shells are joined at a solidification completion point 10 to form the thin strip 11. The linear contact pressure P with the strip 11 at the kiss part 7 between the rolls 2, 3 exerted with rolling forces 8, 9 is limited to the range of the equation 0<P<=50kgf/mm, by which the breakout and two-pieces sheet are eliminated and the injury of the rolls 2, 3 is prevented. The stable production of the defectless thin strip is thus made possible.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing a quenched ribbon by a twin-roll method, and in particular to a method for producing a sound ribbon by advantageously controlling the solidification process of the ribbon. The aim is to achieve stable manufacturing.

(Prior art) In recent years, a so-called liquid quenching direct plate making method has been developed in which molten gold F1 is continuously supplied onto a cooling body whose cooling surface is renewed and moves at high speed, forcing the molten metal to rapidly solidify and form a thin strip. , has gradually come into practical use.

The single-roll method, twin-roll method, and drum method have been proposed as methods for producing such quenched ribbons, but the twin-roll method has attracted attention because the ribbons with particularly beautiful surface properties are produced. ing.

(Problems to be Solved by the Invention) However, when producing a quenched ribbon using the twin roll method, as described below, (1) damage to the cooling roll due to excessive load on the roll reduction blade; (2) Problems such as breakout or formation of two sheets due to reheating of the ribbon directly under the roll due to the underload of the roll reduction blade remained.

(Means for solving the problem) Therefore, the inventors have decided to solve the above problem (after carefully studying the solidification process of the ribbon, the rolling edge at the kissing part of the twin rolls is limited to a predetermined range. It has been found that the intended purpose can be advantageously achieved by doing so.

This invention is derived from the above findings.

That is, the present invention provides a method for manufacturing a quenched ribbon using a twin roll method in which molten metal is supplied between a pair of cooling rolls rotating at high speed and rapidly solidified into a ribbon.
Line contact reduction blade P with the ribbon at the kissing part of both cooling rolls
The following (1) 2〇<P≦50kgf/n+m--
This is a method for producing a quenched ribbon using a twin roll method, which is characterized in that the temperature is limited to the range of (1).

This invention will be specifically explained below.

FIG. 1 illustrates the solidification form of an ideal quenched ribbon according to the present invention. Number @1 in the diagram is a pouring nozzle for pouring molten metal, 2.
3 is a cooling roll, 4 is a molten metal flow, 5 is a pool, 6 is a solidified shell, and 7 is a kissing part. This is where the rolls 2.3 touch each other when the reduction blades 8, 9 are applied. Note that 10 is the solidification completion point, and 11 is the obtained quenched ribbon.

Now, in the place shown in Fig. 1, the molten metal flow 4 poured out from the pouring nozzle 1 creates a pool 5 in the space formed between the pair of cooling rolls 2.3 rotating at high speed, and both The surfaces of the rolls 2 and 3 are temporarily heated to grow solidified shells 6, and these solidified shells 6 are combined at a solidification completion point 10 to form a ribbon 11. As shown here, when the solidification completion point 10 coincides with the center line 12 connecting the axes of each cooling roll 2.3, the best result is increased by 1, but generally this solidification completion point As shown in FIGS. 2 and 3, the points 10 are located above and below the kiss portion 7 and are not constant.

In the example shown in FIG. 2, the solidification completion point 10 is located above the center line 12, and in this case, the roll surface receives an excessive load at the kiss portion 7, resulting in significant roll wear.

On the other hand, in the example shown in FIG. 3, on the contrary, the solidification completion point 10 is
) When the temperature is below the center line 12, there is still unsolidified molten metal inside the roll directly under the roll, i.e., even when it is air-cooled, in this case breakout may occur due to reheating, or 2 It becomes a single plate.

This invention attempts to solve the above-mentioned problems by aligning the ideal solidification form, that is, the solidification completion point 10, with the center line 12 in the twin roll method, as shown in FIG. This is based on the new knowledge that such an ideal solidification form can be easily obtained by controlling the rolling blade of the cooling roll.

In such an ideal solidification form, the rolling blade of the roll should theoretically be O. However, in actual operation, it has been found that a certain amount of contact pressure is necessary because of disturbances such as sliding resistance of the roll chock. Therefore, the inventors conducted numerous experiments to determine the appropriate pressure value, and as a result, the line contact reduction blade P between the cooling roll and the ribbon at the kissing part was determined by the following formula (1) % formula % (1) They discovered that if the conditions are met, the intended purpose will be achieved.

(Example) 300 kg of molten metal having a composition of 4.5 wt% 5i-Fe was rolled with a roll diameter of 400 mm and a roll body length of 500 n.
+m, Roll sleeve: A pair of internal water-cooled cooling rolls made of copper alloy, Roll circumferential speed: 3 to 12 m
/s and line contact reduction blade at kiss part: 6.7k
Plate thickness: 0 by twin roll method under gf 7mm condition
．． A quenched ribbon having a length of 2 to 0.6111 m and a plate width of 300 mm was produced.

For comparison, only the line contact reduction blade at the kissing part was
An attempt was made to manufacture a quenched ribbon under the same conditions except that the conditions were changed to 66.7 kgf/rntn.

Table 1 below summarizes the observation results of the state of the ribbon directly under the roll during each production and the surface properties of the roll after the experiment.

(Effects of the Invention) Thus, according to the present invention, in the production of quenched ribbons by the twin roll method, breakout and formation of two sheets, which were concerns in the past, are not caused, and roll wear is significantly reduced. A stable and sound thin ribbon can be produced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the ideal solidification form of the quenched ribbon, and FIGS. 2 and 3 are cross-sectional views showing the solidification form of the quenched ribbon that causes harmful effects, respectively.

Claims (1)

[Claims] 1. When molten metal is supplied between a pair of cooling rolls rotating at high speed and rapidly solidified to form a thin ribbon, a line between the thin ribbon at the kissing part of both cooling rolls is A method for producing a quenched ribbon by a twin roll method, characterized in that the contact reduction blade P is limited to the following formula (1): 0<P≦50 kgf/mm (1).