JPS60213344A - Continuous casting of homogeneous unidirectionally solidified casting ingot - Google Patents

Abstract

PURPOSE:To cast continuously a unidirectionally solidified casting ingot having the compsn. uniform in the longitudinal direction with a casting mold which is supplied with a molten metal from one end and yields continuously the casting ingot from the other end by making the inflow speed of the molten metal having than the diffusion moving speed of solute. CONSTITUTION:Stationary solidification is effected faster and the casting ingot having the thoroughly uniform compsn. is obtd. longer except the part of an extremely short distance at the beginning end and final end of solidification of the casting ingot as a passage is made finer by ''constricted part'' of the passage for liquid and as the position of the ''constricted part'' is nearer the solidification end of the casting ingot. The continuous casting of the unidirectionally solidified casting ingot having the compsn. uniform in the longitudinal direction is thus made possible and the quality thereof is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously obtaining homogeneous IS unidirectional illumination ingots. More specifically, the present invention provides a method for making the strength of the resulting ingot uniform by keeping the concentration of solutes precipitated at the solidification interface of the ingot constant.

With the rapid development of the electronics industry, the ants used are becoming more precise and smaller, and as a result, the ants used are becoming more precise and smaller.
41#4 also became more flexible and thinner. In order to obtain such a material, the original material, the ingot, must be homogeneous, with no precipitates, gas, or segregation inside.

Conventional Ren&E! The first manufacturing method involves pouring bath water into a cooling WJ and solidifying it from the outer periphery, so the center of the resulting ingot is completely free from the formation of bubbles, gas bubbles, and segregation of impurities. It would be extremely difficult to prevent this from occurring. For this reason, there has been a strong desire for a method to continuously produce 11 ingots without central defects.

The inventor supplies molten metal from one end and f! ! By keeping the temperature of the inner wall surface of the mold for collecting the ingot from the end above the temperature inside the ring of the III Ikkin-Kakei, and by cooling the ingot only outside the mold, the surface is smooth and flat, and the surface is equiaxed. Continuous flow of unidirectional 71 solid ingots with no crystals and no central a-deposition or chemicals.
Heated mold continuous casting method (Patent No. 10491)
No. 46) was invented.

According to this method, a unidirectional aI solid ingot without central defects can be obtained, but the solute M in the longitudinal direction of the ingot can be obtained.
The disadvantage was that it was easy to fluctuate.

In order to completely suppress the deformation force of the composition in the longitudinal direction of the ingot and obtain an ingot with uniform strength, the present inventor has developed
As a result of continuous casting of various alloys such as steel alloys, lead alloys, zinc alloys, and aluminum alloys, which have different distribution coefficients of solutes, by changing the striations in various ways, and repeatedly investigating the control of solute distribution. The following conclusions were obtained.

That is, 1 in the length direction! : In order to continuously obtain ingots of high strength, the degree of melting and cutting formed at the solidification interface must be quickly brought to a high value of 1I11. In other words, '1lIi! 1. Promptly reduce the solute concentration in the liquid phase at the solid-liquid interface to a level where the composition of the solid phase is the same as that of the molten metal supplied to the container, and the solute concentration in the liquid phase at the solid-liquid interface is in equilibrium with the composition of the solid phase. It is necessary to reach this level without changing the solute concentration at the lacquer interface. For example, when an alloy solidifies, if the distribution coefficient t[i of the contained solute is less than 1, then Ii! i] Solute 11 degrees in the liquid at the liquid interface gradually increases, and ff1ll in the liquid approximately 1ll
If it does not match the target, it will eventually reach a constant value and steady coagulation will proceed. And finally the solute m degree increases again. Conversely, in the case of an alloy in which the equilibrium distribution coefficient of the solute contained in the alloy is greater than 1, there will be a deficiency of solute in the liquid at the solid-liquid interface, and if there is no II mechanical mixing in the liquid, For example, the degree of solute deficiency reaches a certain value, remains constant i, and finally the solute l:1 degree decreases again.

In this way, if there is no mechanical mixing at the solidification interface, for any alloy containing a solute with an equilibrium partition coefficient greater than 1 or less than 1, the degree of solute segregation at the aI solid interface will be a constant value, The amount of solid material that crystallizes from the solute i-layer can always be as large as that of the liquid being prepared.

However, in order to carry out such steady solidification, it is necessary to prevent the solute at the solid-liquid interface from migrating to the molten liquid (181II1). In order for the solute at the solid-liquid interface to form a segregation layer at the solid-liquid interface, the inflow velocity of the liquid must be such that the yl contribution M is constant. That is, a of the solute
It is necessary to move the molten metal to the solidified tip of the ingot at a faster speed than the speed at which it moves away from the solid surface. To achieve this, there is a method of pulling the mass out of the mold as quickly as the liquid flows into the rope at a speed higher than the diffusion speed of the solute. However, as the diameter and thickness of the ingot increases, the #1 production rate of the ingot decreases, so a more effective method is needed.

The most effective method is to create a narrow "constriction" in the channel of the moat so that the inflow velocity of the moat is greater than the diffusion movement of the solute.
Alternatively, the objective can be achieved by installing a ``weir''. In general, a molten metal holding furnace or a molten metal pool for supplying ya molten metal to the casting has a mechanical mixing action by 24 streams of ya molten metal. When such a mechanical mixing action is applied to the molten metal in the mold, the solute at the solidified tip of the ingot in # is solidified y1. It is not fixed in the bath water and moves to the side of the bath water holding furnace, and the welding R degree at the solidification interface is affected by the concentration of the crystallized solid phase. 8 It will be the same as 11 degrees of liquid phase,
It is not possible to maintain the solute concentration at even 1 μl and perform a constant via. Therefore, narrowing the flow path of the liquid is extremely effective in preventing the movement of solutes due to mechanical association of the liquid. Therefore, the narrower the flow path,
Also, the closer the position of the "tie" is to the tip of the ingot, the
Steady 711 prisoners can now be performed quickly, and ingots are 11
It is possible to produce an ingot with a completely uniform composition for a longer period of time, except for the short sections at the beginning and end of the ingot.

The present invention enables continuous casting of unidirectionally solidified ingots with a phase liquid that is uniform in the length direction, and makes an extremely innovative contribution to improving the quality of single-spring materials.

Claims (1)

[Claims] 1. Supply molten metal from one end, f! ! ! In #1 pear, which is used to continuously obtain ingots from the end, the molten metal filling speed is yl
The addition of ingots, which is characterized by being faster than the diffusion movement speed of trade! &v4 as equation n continuation addition method 2,>IF Addition of ingot according to claim 1, characterized in that a mold is used in which a weir or a squeeze is provided in the wave path of hot water! ! Continuous casting method for All1