Method and device for preparing semi-solid slurry

Abstract

A method for preparing semisolid slurry. The method is achieved using a device for preparing semisolid slurry. The device includes a slurry vessel and a mechanical stirring rod. The mechanical stirring rod includes a first end and a second end extending into the slurry vessel. The method includes: S1. putting a molten alloy having a first preset temperature into the slurry vessel; S2. cooling the molten alloy to a second preset temperature, positioning the second end of the mechanical stirring rod to be 5-25 mm higher than the bottom wall of the slurry vessel, rotating the mechanical stirring rod and injecting a cooling medium into the mechanical stirring rod; and S3: allowing the temperature of the molten alloy to be 10-90 degrees centigrade lower than the liquidus temperature of the molten alloy, stopping stirring and cooling, to yield a semisolid slurry.

Claims

1. A method for preparing semisolid slurry comprising: placing a molten alloy having a first preset temperature into a slurry vessel, the first preset temperature being 30-120 degrees centigrade higher than a liquidus temperature of the molten alloy; in response to the molten alloy having been cooled to a second preset temperature that is lower than the first preset temperature and 20-60 degrees centigrade higher than the liquidus temperature of the molten alloy, starting to perform a stirring process on the molten alloy, the stirring process including: stirring the molten alloy using a mechanical stirring rod containing a cooling medium under a first condition, until the molten alloy is cooled to a third preset temperature that is lower than the second preset temperature and 0-10 degrees centigrade lower than the liquidus temperature of the molten alloy, the first condition including: a stirring speed of the mechanical stirring rod being a first stirring speed that is in a range from 100 to 400 rpm, and a temperature of the cooling medium being a first medium temperature that is in a range from 10 to 48 degrees centigrade; and continuing to stir the molten alloy using the mechanical stirring rod containing the cooling medium under a second condition, until the molten alloy is cooled to a fourth preset temperature that is lower than the third preset temperature and 10-90 degrees centigrade lower than the liquidus temperature of the molten alloy, the second condition including: the stirring speed of the mechanical stirring rod being a second stirring speed that is in a range from 410 to 900 rpm, and the temperature of the cooling medium being a second medium temperature that is in a range from 50 to 80 degrees centigrade; and in response to the molten alloy having been cooled to the fourth preset temperature, stopping stirring and cooling to obtain the semisolid slurry.

2. The method of claim 1, wherein: the first preset temperature is 75 degrees centigrade higher than the liquidus temperature of the molten alloy; the second preset temperature is 40 degrees centigrade higher than the liquidus temperature of the molten alloy, the first stirring speed is 250 rpm, and the first medium temperature is 20 degrees centigrade; the third preset temperature is 5 degrees centigrade lower than the liquidus temperature of the molten alloy, the second stirring speed is 650 rpm, and the second medium temperature is 50 degrees centigrade; and the fourth preset temperature is 50 degrees centigrade lower than the liquidus temperature of the molten alloy.

3. The method of claim 1, wherein the alloy includes at least one of aluminum alloy, magnesium alloy, copper alloy, or zinc alloy.

4. The method of claim 1, wherein the cooling medium includes at least one of water, heat conduction oil, or liquid organic solvent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow diagram of a method for preparing semisolid slurry of one embodiment of the disclosure; and

(2) FIG. 2 is a schematic diagram of a device for preparing semisolid slurry of one embodiment of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(3) The method for preparing semisolid slurry in the disclosure comprises the following steps:

(4) Step S1, putting a molten alloy having a first preset temperature into a slurry vessel, wherein the first preset temperature being 30-120 degrees centigrade higher than the liquidus temperature of the molten alloy;

(5) Step S2, when a temperature of the molten alloy being decreased to a second preset temperature, adjusting the location of a mechanical stirring rod, extending a second end of the mechanical stirring rod to a position of 5-25 mm from the bottom of the slurry vessel, rotating the mechanical stirring rod, a stirring speed of the mechanical stirring rod being 100-900 rpm, the second preset temperature being 20-60 degrees centigrade higher than the liquidus temperature of the molten alloy;

(6) meantime, cooling medium is injected into the mechanical stirring rod with a first preset flow rate, a temperature of the cooling medium being 10-100 degrees centigrade, and the first preset flow rate being 5-25 L/minute;

(7) Step S3, when a temperature of the semisolid slurry being 10-90 degrees centigrade lower than the liquidus temperature of the molten alloy, stopping stirring and cooling to yield semisolid slurry.

(8) Step S2 comprises step S21 and step S22, which are:

(9) Step S21, when the temperature of the molten alloy being 20-60 degrees centigrade higher than the liquidus temperature of the molten alloy, the stirring speed of the mechanical stirring rod being 100-400 rpm, the temperature of the cooling medium being 10-50 degrees centigrade, and a flow rate of the cooling medium being 10-25 L/minute;

(10) Step S22, when the temperature of the slurry being 0-10 degrees centigrade lower than the liquidus temperature of the molten alloy, the stirring speed of the mechanical stirring rod being 400-900 rpm, the temperature of the cooling medium being 20-80 degrees centigrade, and a flow rate of the cooling medium being 5-15 L/minute.

(11) The steps of the slurry preparation method will be described in detail by means of examples.

Example 1

(12) Step 101, putting molten aluminum alloy having a first preset temperature into a slurry vessel, the first preset temperature being 30 degrees centigrade higher than the liquidus temperature of the molten alloy;

(13) Step 102, when a temperature of the molten aluminum alloy being decreased to a second preset temperature, adjusting the location of a mechanical stirring rod, extending a second end of the mechanical stirring rod to the position of 5 mm from the bottom of the slurry vessel, rotating the mechanical stirring rod, a stirring speed of the mechanical stirring rod being 500 rpm, the second preset temperature being 20 degrees centigrade higher than the liquidus temperature of the aluminum alloy;

(14) meantime, cooling medium is injected into the mechanical stirring rod with a first preset flow rate, a temperature of the cooling medium being 100 degrees centigrade, and the first preset flow rate being 25 L/minute;

(15) Step 103, when a temperature of the semisolid slurry being 10 degrees centigrade lower than the liquidus temperature of the aluminum alloy, stopping stirring and cooling to yield aluminum alloy semisolid slurry.

Example 2

(16) Step 201, putting molten magnesium alloy having a first preset temperature into a slurry vessel, the first preset temperature being 70 degrees centigrade higher than the liquidus temperature of the molten alloy;

(17) Step 2021, when a temperature of the molten magnesium alloy being 40 degrees centigrade higher than the liquidus temperature of the magnesium alloy, adjusting the location of a mechanical stirring rod, extending a second end of the mechanical stirring rod to the position of 25 mm from the bottom of the slurry vessel, rotating the mechanical stirring rod, the stirring speed of the mechanical stirring rod being 100 rpm, the temperature of the cooling medium being 10 degrees centigrade, and the flow rate of the cooling medium being 10 L/minute;

(18) Step 2022, when a temperature of the slurry being 10 degrees centigrade lower than the liquidus temperature of the magnesium alloy, the stirring speed of the mechanical stirring rod being 400 rpm, the temperature of the cooling medium being 20 degrees centigrade, and the flow rate of the cooling medium being 5 L/minute;

(19) Step 203, when a temperature of the magnesium alloy semisolid slurry being 90 degrees centigrade lower than the liquidus temperature of the molten alloy, stopping stirring and cooling to yield magnesium alloy semisolid slurry.

Example 3

(20) Step 301, putting molten zinc alloy having a first preset temperature into a slurry vessel, the first preset temperature being 75 degrees centigrade higher than the liquidus temperature of the zinc alloy;

(21) Step 3021, when a temperature of the molten zinc alloy being 40 degrees centigrade higher than the liquidus temperature of the molten alloy, adjusting the location of a mechanical stirring rod, extending a second end of the mechanical stirring rod to the position of 15 mm from the bottom of the slurry vessel, rotating the mechanical stirring rod, the stirring speed of the mechanical stirring rod being 250 rpm, the temperature of the cooling medium being 20 degrees centigrade, and the flow rate of the cooling medium being 18 L/minute;

(22) Step 3022, when a temperature of the slurry being 5 degrees centigrade lower than the liquidus temperature of the zinc alloy, the stirring speed of the mechanical stirring rod being 650 rpm, the temperature of the cooling medium being 50 degrees centigrade, and the flow rate of the cooling medium being 10 L/minute;

(23) Step 303, when a temperature of the zinc alloy semisolid slurry being 50 degrees centigrade lower than the liquidus temperature of the zinc alloy, stopping stirring and cooling to yield alloy semisolid slurry.

Example 4

(24) Step 401, putting molten copper alloy having a first preset temperature into a slurry vessel, the first preset temperature being 120 degrees centigrade higher than the liquidus temperature of the molten alloy;

(25) Step 4021, when a temperature of the molten copper alloy being 60 degrees centigrade higher than the liquidus temperature of the copper alloy, adjusting the location of a mechanical stirring rod, extending a second end of the mechanical stirring rod to the position of 10 mm from the bottom of the slurry vessel, rotating the mechanical stirring rod, the stirring speed of the mechanical stirring rod being 400 rpm, the temperature of the cooling medium being 50 degrees centigrade, and the flow rate of the cooling medium being 25 L/minute;

(26) Step 4022, when a temperature of the slurry being decreased to the liquidus temperature of the copper alloy, the stirring speed of the mechanical stirring rod being 900 rpm, the temperature of the cooling medium being 80 degrees centigrade, and the flow rate of the cooling medium being 15 L/minute;

(27) Step 403, when a temperature of the copper alloy semisolid slurry being 40 degrees centigrade lower than the liquidus temperature of the molten alloy, stopping stirring and cooling to yield copper alloy semisolid slurry.

(28) The device for preparing semisolid slurry will be described below.

(29) As shown in FIG. 2, according to the schematic diagram of an example in working state, the device for preparing semisolid slurry comprises: a slurry vessel 2, a mechanical stirring rod 3, two stirring blades 8, a cooling medium controller 7, a cooling medium inlet pipe 4, a cooling medium recycling pipe 6, a first temperature measuring equipment 1 and a second temperature measuring equipment 5, the first temperature measuring equipment 1 is disposed in the slurry vessel 2, the second temperature measuring equipment 5 is disposed on the cooling medium inlet pipe 4, the mechanical stirring rod 3 is a hollow structure which comprising a first end 31 and a second end 32, the second end 32 is inserted into the slurry in stirring state, the two stirring blades 8 are inserted into the hollow structure of the mechanical stirring rod, and the vertical interval h1 between the stirring blades 8 and the second end 32 of the mechanical stirring rod is 42 mm; a first end of the cooling medium inlet pipe 4 and a first end of the cooling medium recycling pipe 6 are connected to the cooling medium controller 7 respectively, and a second end of the cooling medium inlet pipe 4 and a second end of the cooling medium recycling pipe 6 extend into the mechanical stirring rod.

(30) The distance between the second end of the cooling medium inlet pipe and the second end of the mechanical stirring rod is 15 mm, the distance between the second end of the cooling medium inlet pipe and the second end of the mechanical stirring rod is 325 mm.

(31) The mechanical stirring rod is provided with a coating agent, the stirring blades is H13 heat resisting die steel with its surface being nitrided.

(32) Furthermore, the mechanical stirring rod 3 is vertically inserted into the slurry vessel 2 along the central axis of the slurry vessel 2, the distance between the second end 32 of the mechanical stirring rod 3 and the bottom of the slurry vessel 2 can be adjusted along the central axis.

(33) Specially, the number of the stirring blade numbers is three, the vertical interval h1 is 50 mm, the distance between the second end of the cooling medium inlet pipe and the second end of the mechanical stirring rod is 10 mm, the distance between the second end of the cooling medium recycling pipe and the second end of the mechanical stirring rod is 300 mm.

(34) The number of the stirring blade numbers may be four or above four, the vertical interval h1 is 35 mm, the distance between the second end of the cooling medium inlet pipe and the second end of the mechanical stirring rod is 20 mm, the distance between the second end of the cooling medium recycling pipe and the second end of the mechanical stirring rod is 350 mm.

Test Example 1

(35) The aluminum alloy semisolid slurry is produced by using the methods and devices in the above examples. Its temperature is 600 degrees centigrade, and solid content is 42%. The aluminum alloy semisolid slurry is die casted to yield die casting products. The morphology of the metallographic structure of the die casting products is good, and the shape factor of the globular grains is 0.88.

Test Example 2

(36) The magnesium alloy semisolid slurry is produced by using the methods and devices in the above examples. Its temperature is 495 degrees centigrade, and solid content is 45%. The aluminum alloy semisolid slurry is die casted to yield die casting products. The morphology of the metallographic structure of the die casting products is good, and the shape factor of the globular grains is 0.78.

Test Example 3

(37) The aluminum zinc semisolid slurry is produced by using the methods and devices in the above examples. Its temperature is 390 degrees centigrade, and solid content is 52%. The aluminum alloy semisolid slurry is die casted to yield die casting products. The morphology of the metallographic structure of the die casting products is good, and the shape factor of the globular grains is 0.82.

Test Example 4

(38) The aluminum copper semisolid slurry is produced by using the methods and devices in the above examples. Its temperature is 860 degrees centigrade, and solid content is 56%. The aluminum alloy semisolid slurry is die casted to yield die casting products. The morphology of the metallographic structure of the die casting products is good, and the shape factor of the globular grains is 0.75.

(39) It can be seen from the above test examples that the method and device for preparing semisolid slurry in the disclosure have the benefits of high slurry preparation efficiency, high quality of the semisolid slurry, wide range of alloy application. Specifically, the benefits are:

(40) (1) high slurry preparation efficiency, high quality of the semisolid slurry: the stirring blades are inserted into the hollow structure of the mechanical stirring rod, the cooling medium exchanges heat with the slurry through the stirring apparatus, stirring and cooling are realized at the same time, and the controlling of the stirring and cooling procedures is combined with alloy phase diagram, to yield the semisolid slurry with high roundness of globular grains and high solid content.

(41) (2) wide range of alloy application: the operation of slurry preparation is combined with alloy phase diagram, the temperature, flow rate of the cooling medium and the mechanical stirring speed, etc. are controlled. The method and device provided in the disclosure can be applied for preparing semisolid slurry of multiple alloys, such as aluminum alloy, magnesium alloy, zinc alloy or cooper alloy.

(42) The above examples can be implemented individually and can be combined in various ways, all these variants are in the protection scope of the disclosure.

(43) The method and device of preparing the semisolid slurry combine the cooling apparatus and the stirring apparatus to yield high slurry preparation efficiency. The temperature, flow rate of the cooling medium and the mechanical stirring speed are controlled to yield the semisolid slurry with high quality. Also, the method and device have wide range of alloy application, can solve the problems of unstable solid content of slurry and low preparation efficiency, therefore, is suitable for semisolid die casting production.

(44) Unless otherwise indicated, the numerical ranges involved in the invention include the end values. While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.