JPS6027575Y2 - Rapid solidification metal material manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for obtaining a product having a uniform shape such as width and thickness of a rapidly solidified metal ribbon such as an amorphous metal ribbon or a metal ribbon.

BACKGROUND ART Recently, amorphous metal materials or high silicon-containing steel ribbons have attracted attention as new metal materials, and various manufacturing methods have been proposed accordingly.

For example, a method of manufacturing a ribbon by pouring molten metal onto the surface of rotating rolls and rapidly solidifying the metal material, or rotating two rolls and letting the molten metal flow down to the contact area between the rolls, passing between the rolls and quenching the material. The so-called twin roll method, which produces a ribbon by solidification, is known as a typical method.

However, these conventionally known methods have the following problems.

For example, in a method in which molten metal is rapidly solidified by flowing down onto the surface of a rotating roll, problems occur when the molten metal that has flowed down comes into contact with the roll.

FIG. 1 schematically shows a state in which molten metal 1 comes into contact with roll 2 and solidifies.

(In this figure, when comparing the length of the process in which the molten metal contacts the rolls and rapidly solidifies, and the radius of the rolls, the roll radius is much larger, so the curvature of the roll surface can be ignored and shown as a flat surface. be.

). Take the X axis along the moving direction of the plane (roll surface),
The molten metal is assumed to be in contact with the roll surface at a portion from x=0 to x=l.

When molten metal is cooled and solidified by contact with a flat surface,
As the surface moves in the direction of the arrow (rotation of the roll), it moves to the right in FIG. 1 and is held 1, and new molten metal is supplied from above.

At this time, the descending speed v8 of the molten metal and the thickness h of the solidified layer are
It is determined as a function of

i.e. However, U.

: Plane movement speed Te: Temperature of molten metal TC: Solidification temperature of molten metal Ts: Temperature of plane (roll) k: thermal diffusion coefficient in molten metal α: Correction coefficient This is the relationship.

FIG. 2 shows the relationship between X and Vs.

What is important here is the falling speed Vs of the molten metal.

That is, this v8 is determined by the forced flow and forced cooling of the molten metal due to the movement of the plane, and is independent of the supply drop rate VF at the molten metal supply source.

Therefore, at a given point X, v8 and VF generally do not match.

On the other hand, the distribution of the supply and fall speed of molten metal is approximately a constant value V in the width direction of the flow.

It is thought that.

However, it is almost impossible to intentionally create a distribution equal to 8 in the feed downward stream.

Therefore, considering Figure 2, VS and V. Point X where are equal.

To the right of , there is an excess supply of molten metal.

However, in this case, there is no problem because the width of the flow is adjusted by widening, but in the left part of xc, there is a shortage of molten metal, and the thin ribbon that solidifies and forms becomes intermittent. .

In other words, a ribbon with uniform width and thickness cannot be produced.

This phenomenon in which the falling velocity v8 of the molten metal becomes non-uniform is caused by the fact that the point x=0 in FIG. 2 is in contact with the atmospheric pressure.

In other words, this phenomenon can be described as Bernoulli's law. The following is an explanation using the relationship:

First, the pressure P in the above equation is pressure P.

Since it is in direct contact with the atmosphere of

However, if the vicinity of x=0 is isolated from atmospheric pressure by some means, the pressure P1, the descending speed Vs of the molten metal, etc. will change significantly.

First, the pressure P can be changed freely.

Therefore, vs can also change according to Bernoulli's law.

The metal is rapidly lifted from the vicinity of x=0 by the formation and movement of the solidified layer, but the fluid tries to maintain its original continuity by decreasing the pressure P and increasing the rate of descent v8.

This is possible until P=0.

Bernoulli's equation ignoring the water head for the reasons mentioned above %formula% You can get

Since this right-hand side is a fairly large value, it is possible to compensate for the lack of descending speed (8) by cutting off the atmospheric pressure.

Further, in the case of the twin roll method, it is very difficult to constantly supply an appropriate amount of molten metal to the roll contact surface.

The present invention solves the problems with the conventional method using extremely simple means.
A stabilizing plate is provided along the flow of the molten metal at a contact portion between the molten metal and the cooling surface and at a position opposite to the direction of movement of the cooling surface.

The gist of the present invention will be explained below with reference to the drawings.

In FIG. 3, the molten metal 1 is caused to flow down onto the surface of a rotating roll 2 and rapidly solidified. Reference numeral 3 designates a stabilizing plate provided so as to be in contact with a position A where the molten metal 1 begins to solidify.

By installing the stabilizer plate 3 in this way, atmospheric pressure is prevented from acting directly near the solidification start position A, and as a result, the pressure of the molten metal in that area can freely change depending on the flow rate. .

4 is a solidified metal ribbon. For example, the flow velocity near point A,
If we apply vAPA and Bernoulli's law to the pressures, we get Po for the surrounding pressure on one side and ■■ for the general descending flow rate.

Then, it is.

(However, the water head term does not change much on both sides, so it is excluded.

) ρ is the density of the molten metal.

Further, at a place where VS is large, PA decreases to a point where PA is approximately 0, while vA increases in an attempt to approach VS.

Therefore, the detailed calculation process will be omitted, but if we try to find a tentative value assuming PA = 0, Po = 1 atm = HPN/?
VA = 5.5m as 71″vo=1.4m/s
/ get s.

Also, finding the position X0 where VA=VS is X.

= 4.3 x 10-6m. On the other hand, X when there is no stabilizer.

The value of is 63 x 10-6 m, and it is clear that the improvement achieved by the present invention is extremely significant.

FIG. 4 shows a case where the molten metal 1 is applied to a roll 2, and the molten metal 1 is allowed to flow down diagonally onto a stabilizer plate 3.

In this case as well, as in the case of FIG. 3, the atmospheric pressure does not affect the solidification start point A, so there is no shortage of molten metal in that part.

As explained above, according to the present invention, a metal ribbon having a uniform width and thickness can be obtained with an extremely simple structure.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the solidification process of molten metal, Fig. 2 is a chart showing the relationship between the descending speed of molten metal and the distance traveled from the solidification start point, and Fig. 3 shows an example of the present invention. Schematic,
FIG. 4 is a schematic diagram showing another embodiment. 1: Molten metal, 2: Roll, 3: Stabilizer plate, 4: Metal thin plate.

Claims (1)

[Scope of utility model registration request] In an apparatus that produces rapidly solidified metal material by bringing molten metal into contact with a moving cooling surface, a molten metal is placed at a position where the molten metal contacts the cooling surface and in a direction opposite to the direction of movement of the cooling surface. A rapid solidification metal material manufacturing device characterized by a stabilizing plate provided along the flow.