WO2016119579A1 - Method for continuously producing metal semi-solid slurry - Google Patents

Abstract

A method for continuously producing semi-solid metal slurry, comprising the following steps: providing in a container (2) semi-solid metal slurry (1); obtaining from the container (2) a portion of the semi-solid metal slurry (3) for semi-solid processing; cooling the remaining semi-solid metal slurry (4) in the container (2) to increase a solid ratio thereof; adding molten metal (5) to the container (2) so as to form the new semi-solid metal slurry (1), and cooling the semi-solid metal slurry (1) to increase the solid ratio thereof; and repeating the above steps to continuously produce the semi-solid metal slurry. A process of the method is simple and easy to control, and has low production costs, thus facilitating achieving a large-scale industrial application.

Description

Method for continuously producing metal semi-solid slurry Technical field

The invention belongs to the technical field of semi-solid molding of metals, and in particular relates to a method for continuously producing a semi-solid metal slurry.

Background technique

It is well known that parts formed using metal semi-solid slurries have many advantages over conventional liquid-formed counterparts, such as fewer defects, better mechanical properties, etc.; therefore, semi-solid metal forming techniques have many advantages. It is regarded as an epoch-making new metal processing technology. In recent years, industrial applications of semi-solid metal forming technology have made great progress; at present, methods for preparing semi-solid metal pastes having a spherical crystal structure include mechanical stirring method, electromagnetic stirring method, ultrasonic stirring method, and the like. The process flow of these methods is relatively complicated, resulting in relatively high production costs, so that the semi-solid forming technology of metals has not been industrialized in a large scale so far.

Summary of the invention

It is an object of the present invention to provide a method for continuously producing a semi-solid metal slurry in view of the deficiencies of the prior art. The method overcomes the defects of the complicated process flow and high production cost in the existing semi-solid metal slurry manufacturing method, is easy to operate, has low production cost, and is easy to realize large-scale industrial application.

To achieve the above object, the present invention adopts the following technical solutions:

A method for continuously producing a metal semi-solid slurry comprising the following steps:

(a) providing a semi-solid metal slurry (1) in a container (2);

(b) removing part of the semi-solid metal slurry (3) from the vessel (2) for semi-solid processing (such as semi-solid die casting, semi-solid forging and semi-solid extrusion, etc.);

(c) cooling the semi-solid metal slurry (4) remaining in the vessel (2) to increase its solids ratio;

(d) adding molten metal (5) to the vessel (2) to form a new semi-solid metal slurry (1);

(e) Cooling the newly formed semi-solid metal slurry (1) to increase its solid ratio.

The semi-solid metal slurry (4) in the step (c) is completely solidified into a solid after being cooled.

The newly formed semi-solid metal slurry (1) in the step (e) is cooled to have a solid content of at least 1% by weight.

The newly formed semi-solid metal slurry (1) in the step (e) is cooled to have a solid content of at least 10wt%.

The newly formed semi-solid metal slurry (1) in the step (e) is cooled to have a solid content of at least 20% by weight.

The newly formed semi-solid metal slurry (1) in the step (e) is cooled to have a solid content of not more than 40% by weight.

The newly formed semi-solid metal slurry (1) in the step (e) is cooled to have a solid content of not more than 50% by weight.

The solid content of the newly formed semi-solid metal slurry (1) in the step (e) is not more than 60% by weight after cooling.

In actual production, the above process can be continually repeated to meet the needs of continuous production; that is, a part of the newly formed semi-solid metal slurry (1) will be taken away for semi-solid processing, and the remaining half The solid metal slurry is in turn added with a quantity of molten metal (5) to form more semi-solid metal paste (1).

According to one embodiment of the invention, after a certain period of cooling, the remaining semi-solid metal slurry (4) in the vessel (2) has completely solidified into a solid.

According to another embodiment of the invention, the time for cooling the remaining semi-solid metal slurry (4) in the vessel (2) may be zero; in the case of the above, generally the remaining semi-solid metal slurry The solids content of body (4) is already relatively high, so no further cooling is required to increase its solids ratio.

According to another embodiment of the present invention, the time for cooling the newly formed semi-solid metal slurry (1) may be zero; in the case of the newly formed semi-solid metal slurry (1) The solids content has reached the requirements for semi-solid processing, so no further cooling is required to increase its solids ratio.

In short, the length of the cooling time in actual production is selected according to the level of solid content in the semi-solid metal slurry and the actual needs. The solid content in the semi-solid metal slurry is high, and the cooling time is correspondingly shorter. The low solids content in the semi-solid metal paste results in a correspondingly longer cooling time.

According to a preferred embodiment of the invention, the newly formed semi-solid metal paste (1) has a solids content after cooling of at least 1% by weight, preferably at least 10% by weight, more preferably at least 20% by weight; the key is that a new formation The solid content of the semi-solid metal paste (1) should be selected to ensure that it inhibits the formation of metal dendritic structures and networks during further cooling and solidification.

According to another preferred embodiment of the present invention, the newly formed semi-solid metal slurry (1) has a solid content after cooling of not more than 60% by weight, preferably not more than 50% by weight, more preferably not more than 40% by weight; a higher solid content may be The slurry is not easily subjected to further semi-solid processing.

It should be noted that when the solid content of the newly formed semi-solid metal slurry (1) is less than 10% by weight, the viscosity thereof is relatively low; an additional stirring process (such as mechanical stirring, electromagnetic stirring, etc.) may be omitted to achieve the slurry. The purpose of body homogenization. However, when the solid content of the formed semi-solid metal slurry (1) is more than 20% by weight, the viscosity thereof is relatively high, and an additional stirring process (such as mechanical stirring, electromagnetic stirring, etc.) is generally required to achieve uniform slurry. Purpose.

The beneficial effects of the invention are:

1) The process of the invention is very simple and easy to control;

2) Applying the pulping method disclosed by the invention, the production cost of the slurry is extremely low;

3) The present invention is easy to implement large-scale industrial applications.

DRAWINGS

Figure 1 is a schematic view of the process of the present invention;

Figure 2 is a photomicrograph of a metal composition of one example of the invention comprising a spherical primary solid phase and a secondary solid phase formed during the cold quenching process.

detailed description

The invention is further illustrated by the following examples, but the scope of the invention is not limited to the following examples.

Figure 1 shows four separate steps in a preferred embodiment of the invention. Step 1 shows a container (2) containing a certain weight of semi-solid metal slurry (1). Step 2 shows the container (2) in step 1, the semi-solid metal slurry (1) in the container (2) has been taken out and placed in another container (6); half in the container (6) The solid metal paste (3) will be used for further processing, such as for semi-solid die casting, with some semi-solid metal slurry (4) remaining in the vessel (2). Step 3 shows the semi-solid metal slurry (4) remaining in step 2, and after a certain period of cooling, the solid ratio of the remaining semi-solid metal slurry (4) has increased; in some cases, half The solid metal slurry (4) can be cooled for a sufficient period of time to completely solidify into a solid. Step 4 shows a further container (7) in which the molten metal (5) is contained; a certain amount of molten metal (5) has been added to the container (2) and half of the step 3 Solid metal paste (4) mixed together to form a new half Solid metal paste (1). If necessary, the newly formed semi-solid metal slurry (1) can be further cooled to increase its solid ratio (not shown).

The solid ratio of the semi-solid metal paste (1) can be the weight of the molten metal (5) added, the weight of the remaining semi-solid metal paste (4), and the remaining semi-solid metal paste. The cooling time of the body (4) and the parameters such as the cooling time of the newly formed semi-solid metal slurry (1) are adjusted to control. In many cases, it is desirable to control the solid ratio of the semi-solid metal slurry (1) to be between 10 and 30%; since the semi-solid metal slurry (1) has sufficient solid content in this ratio range To prevent the generation of dendrites, while the semi-solid metal slurry (1) still has sufficient fluidity to be poured out of the container (2) (not shown).

In practical production applications, the above process can be continually repeated to meet the needs of continuous production; that is, a portion of the newly formed semi-solid metal slurry (1) will be removed for semi-solid processing, while the remaining The semi-solid metal slurry is in turn added with a quantity of molten metal (5) to form more semi-solid metal paste (1).

Example 1

The production method and apparatus for the Al-7wt% Si aluminum alloy semi-solid slurry are exemplified below.

First, a "clay-graphite" crucible having an inner diameter of about 130 mm, a wall thickness of about 16 mm, and a height of about 180 mm is heated to about 620 ° C; then about 5,000 g of molten Al - 7 wt % Si is poured into the crucible. Aluminum alloy, at which time the temperature of the aluminum alloy in the crucible is 625 ° C (the liquidus temperature of the Al-7 wt% Si aluminum alloy is about 616 ° C, the solidus temperature is about 572 ° C); then the aluminum in the crucible The alloy is naturally cooled, and the aluminum alloy is mechanically stirred. When the temperature of the alloy drops to 610 ° C, the stirring is stopped. At this time, the aluminum alloy in the crucible has become a semi-solid slurry; then about 3000 g is poured out from the crucible. The semi-solid slurry is ready for other use. At this time, about 2000 grams of semi-solid slurry remains in the crucible; then the remaining semi-solid slurry in the crucible is naturally cooled for 45 seconds, at which time the semi-solid in the crucible The temperature of the slurry is lowered to about 600 ° C; then about 3000 grams of a molten Al - 7 wt % Si aluminum alloy of about 630 ° C is added to the crucible, at which time the temperature of the aluminum alloy in the crucible is about 612 ° C, which is a new 5000 grams of semi-solid slurry has been formed; then the newly formed semi-solid slurry in the crucible However, while cooling with mechanical stirring for about 10 seconds, then a temperature of about 5000 grams of semi-solid slurry in the crucible falls below about 610 ℃. A small amount of the semi-solid slurry is taken out of the crucible and quenched in cold water; the resulting microstructure is shown in Figure 2; as can be seen from Figure 2, the semi-solid slurry produced using the method disclosed herein, Its primary solid phase is a spherical crystal structure. In actual production, the above The method disclosed by the present invention can be continuously reused for the purpose of continuous production.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should fall within the scope of the present invention.

Claims (8)

A method for continuously producing a metal semi-solid slurry, comprising the steps of: (a) providing a semi-solid metal slurry (1) in a container (2); (b) removing a portion of the semi-solid metal slurry (3) from the vessel (2) for semi-solid processing; (c) cooling the semi-solid metal slurry (4) remaining in the vessel (2) to increase its solids ratio; (d) adding molten metal (5) to the vessel (2) to form a new semi-solid metal slurry (1); (e) cooling step (d) of the newly formed semi-solid metal slurry (1) to increase its solids ratio. The method of continuously producing a metal semi-solid slurry according to claim 1, characterized in that the semi-solid metal slurry (4) in the step (c) is completely solidified into a solid after being cooled. The method for continuously producing a metal semi-solid slurry according to claim 1, wherein the newly formed semi-solid metal slurry (1) in the step (e) has a solid content of at least 1 wt% after cooling. . The method for continuously producing a metal semi-solid slurry according to claim 1, wherein the newly formed semi-solid metal slurry (1) in the step (e) has a solid content of at least 10% by weight after cooling. . The method for continuously producing a metal semi-solid slurry according to claim 1, wherein the newly formed semi-solid metal slurry (1) in the step (e) has a solid content of at least 20% by weight after cooling. . The method for continuously producing a metal semi-solid slurry according to claim 1, wherein the newly formed semi-solid metal slurry (1) in the step (e) has a solid content of not more than 40% by weight after cooling. . The method for continuously producing a metal semi-solid slurry according to claim 1, wherein the newly formed semi-solid metal slurry (1) in the step (e) has a solid content of not more than 50% by weight after cooling. . The method for continuously producing a metal semi-solid slurry according to claim 1, wherein the newly formed semi-solid metal slurry (1) in the step (e) has a solid content of not more than 60% by weight after cooling. .

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