CN105772654B - Mushy stage metal stirring mixing method - Google Patents

Abstract

A method for stirring and mixing solid and liquid metals includes the following steps: 1. Preparation of solid alloy rods: melting the alloy ingot and controlling its superheat within the range of 70-100°C, then refining the melt, removing slag, and then standing And control the superheat of the melt in the range of 60-80°C, pour the melt into a metal mold to cool and solidify to obtain a cylindrical or square alloy rod with a certain length; 2. Control the temperature of the metal melt: melt the melt during smelting The superheat of the melt is controlled within the range of 70-10°C, and then the melt is refined and slag removed, and then left to stand and the superheat of the melt is controlled within the range of 10-50°C; 3. Preparation of semi-solid slurry: the above The alloy rod obtained in step 1 is fixed on the rotating chuck of the stirring and mixing device, the screw motor and the chuck rotating motor are started, and the screw motor drives the rotating chuck to descend and immerse the rotating alloy rod into the melt; four, half Solid forming or semi-solid blank preparation.

Description

Stirring and mixing method of solid and liquid metal

technical field

The invention relates to a method for stirring and mixing solid and liquid metals.

Background technique

At present, semi-solid forming technology is a new forming technology that appeared in 1970's. It uses solid-liquid mixed metal slurry containing about 50% fine, spherical solid phase for pressure forming. Compared with full liquid metal, semi-solid metal solidifies and shrinks less, and due to the elimination of dendrite structure, it can greatly reduce or even eliminate shrinkage porosity; in addition, semi-solid metal can reduce its own Reynolds coefficient through its high apparent viscosity to achieve smooth filling. Can significantly reduce micro-porosity in parts. Therefore, semi-solid castings theoretically have relatively higher mechanical properties. Moreover, semi-solid castings can be secondary strengthened by heat treatment due to the reduction of pores.

The traditional method of semi-solid slurry preparation is to apply mechanical or electromagnetic stirring to the solidifying metal to break up the dendrites and obtain non-dendritic solidified grains in order to reduce defects and improve the performance of parts. However, in order to break up the dendrites suspended in the metal liquid phase, a higher stirring speed and a longer stirring time are necessarily required, and the required equipment has a complicated structure and a high cost. In addition, stirring inevitably entrains impurities or gases into the metal melt, resulting in inclusion defects. Therefore, the semi-solid forming technology of the mixing class has not been able to truly realize industrial application. In recent years, in order to improve production efficiency and simplify pulping equipment, some simple pulping technologies based on controlling grain nucleation and inhibiting their growth have been proposed at home and abroad. Existing methods mainly include the method of pouring by pipeline or pouring by inclined slope. These methods have problems such as difficulty in melt protection and easy solidification and crusting during metal pouring. Moreover, the preparation of large-volume semi-solid slurry is a practical problem faced by the industrial application of semi-solid technology. The above-mentioned pipeline-type and cooperative-type pulping methods are not conducive to the uniform cooling of the melt, so the tissue stability of large-size pulp is difficult to control.

Contents of the invention

The present invention aims to solve the problems existing in the above-mentioned prior art, and provides a solid-liquid state metal stirring and mixing method and device. In the traditional semi-solid slurry preparation technology, the dendrites that have been produced are relying on stirring to refine the crystal grains, and the performance of the alloy is not improved. Large, the semi-solid slurry prepared by this device forms a large number of crystallization cores through the chilling effect of multiple alloy rods on the melt to refine the grains, homogenize the structure, and overcome the coarse dendrites and alloy structures that appear during the casting and rolling process. to improve.

The technical scheme adopted by the present invention to solve the technical problem: the solid-liquid metal stirring and mixing device includes a fixed base, a crucible with heating function is installed on the front part of the fixed base, and a vertically installed guide rail is fixed on the rear end of the fixed base , a sliding seat is installed on the guide rail, and a screw and a screw motor that drive the sliding seat to slide up and down are installed on the top of the guide rail. A beam is fixed on the sliding seat, and a strip groove is opened on the beam. The chuck rotating motor is provided, the output shaft of the chuck rotating motor faces down and a rotating chuck is fixed, and a group of alloy rods arranged at intervals are installed on the bottom surface of the rotating chuck.

The heating function includes AC power supply, resistance wire and refractory material. The resistance wire is embedded in the refractory material and wrapped around the crucible, and the resistance wire is connected to the AC power supply through a wire. The lifting mechanism includes a guide rail, a sliding seat, a screw rod and a screw motor. The beam is vertically connected to the sliding seat through two rows of guide rails. The motor drives the screw rod to rotate so that the beam can move up and down on the column along the guide rail. The moving speed is adjusted by the motor. . The rotary chuck has a clamping, quick-change solid alloy disc, and the rotary chuck is connected to the motor through a coupling. There is a thermocouple inside the crucible, and the thermocouple can be inserted into the alloy liquid to monitor in real time and record the temperature parameters through the recording device.

Further improvement, there is a circle of through holes set at intervals on the rotary chuck, and a pair of clamping plates installed obliquely are installed in the through holes, the lower ends of the clamping plates are rotatably connected in the through holes, and the upper ends of the clamping plates are connected There are springs. The lower surface of the disc is equipped with a clamping device with a V-shaped clamping groove, which realizes the clamping of the solid alloy rod through an elastic device and can be changed quickly.

This solid-liquid state metal stirring and mixing method comprises the steps:

1. Preparation of solid alloy rods: Melt the alloy ingot and control its superheat within the range of 70-100°C, then refine the melt and remove slag, then let it stand and control the superheat of the melt at 60-80°C Within the range, the melt is poured into a metal mold to cool and solidify to obtain a cylindrical or square alloy rod with a certain length;

2. Control the temperature of the metal melt: control the superheat of the melt within the range of 70-10°C during smelting, then refine the melt and remove slag, then let it stand and control the superheat of the melt at 10-50 in the range of ℃;

3. Preparation of semi-solid slurry: fix the alloy rod obtained in the above step 1 on the rotary chuck of the stirring and mixing device, start the screw motor and the chuck rotation motor, and the screw motor drives the rotary chuck to descend and rotate The alloy rod is immersed in the melt; the depth of the alloy rod immersed in the melt is controlled according to the volume of the prepared semi-solid slurry and the temperature change of the melt. After the temperature of the melt drops to the semi-solid range, the semi-solid slurry can be obtained.

4. Preparation of semi-solid forming or semi-solid billet: pour the semi-solid slurry obtained in the above step 3 into the mold of the forming device to realize semi-solid rheological forming or prepare semi-solid billet for thixotropic forming.

The degree of superheat of the liquid metal in the pulping process is determined by the diameter of the alloy rod, the depth of immersion, and the time of immersion and stirring. There is a matching relationship between the three, that is, the smaller the diameter or the lower the penetration depth, the shorter the immersion and stirring time, and the greater the superheat of the melt. Conversely, the smaller the superheat. There is no problem of oxidation slag inclusion in melt flow and solidification crust during pouring.

The beneficial effects of the present invention are:

(1) When the alloy rod is used as the material to stir, it forms a chilling effect on the alloy liquid, which can quickly form a large number of crystallization cores in the alloy liquid, and the crystallization cores can quickly spread to all parts of the alloy liquid, thereby refining and homogenizing the alloy .

(2) The use of alloy rods as the stirring material will not introduce impurities, and does not require high-speed and vigorous stirring like traditional mechanical stirring devices, saving energy while greatly reducing the violent oxidation reaction caused by the interaction between the alloy and air.

(3) This device only uses two low-power motors, a set of simple brackets and a turntable, and can prepare high-quality semi-solid slurry without large investment. It is suitable for large-scale production models. Small and medium-sized enterprises can Prepare high-quality semi-solid slurry with outstanding cost performance.

Description of drawings

Fig. 1 is the front view of the present invention;

Fig. 2 is the three-dimensional structural diagram of the front of the present invention;

Fig. 3 is the three-dimensional structural diagram of the back side of the present invention;

Fig. 4 is a schematic structural view of the spin chuck in the present invention.

Explanation of reference numerals: fixed base 1, crucible 2, guide rail 3, sliding seat 4, screw mandrel 5, screw mandrel motor 6, beam 7, strip groove 7-1, chuck rotating motor 8, rotating chuck 9, alloy Rod 10, through hole 11, clamping plate 12, spring 13.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

With reference to accompanying drawing: in the present embodiment, solid-liquid state metal mixing method comprises the steps:

1. Preparation of solid alloy rods: Melt the alloy ingot and control its superheat within the range of 70-100°C, then refine the melt and remove slag, then let it stand and control the superheat of the melt at 60-80°C Within the range, the melt is poured into a metal mold to cool and solidify to obtain a cylindrical or square alloy rod with a certain length;

2. Control the temperature of the metal melt: control the superheat of the melt within the range of 70-10°C during smelting, then refine the melt and remove slag, then let it stand and control the superheat of the melt at 10-50 in the range of ℃;

3. Preparation of semi-solid slurry: fix the alloy rod obtained in the above step 1 on the rotary chuck of the stirring and mixing device, start the screw motor and the chuck rotation motor, and the screw motor drives the rotary chuck to descend and rotate The alloy rod is immersed in the melt;

4. Preparation of semi-solid forming or semi-solid billet: pour the semi-solid slurry obtained in the above step 3 into the mold of the forming device to realize semi-solid rheological forming or prepare semi-solid billet for thixotropic forming;

The stirring and mixing device includes a fixed base 1. A crucible 2 with heating function is installed on the front part of the fixed base 1. A vertically installed guide rail 3 is fixed on the rear end of the fixed base 1. A sliding seat 4 is installed on the guide rail 3. The guide rail 3 The top installation drives the screw mandrel 5 and screw motor 6 that sliding seat slides up and down, is fixed with crossbeam 7 on described slide seat 4, has strip groove 7-1 on crossbeam 7, is installed in the strip groove 7-1 The chuck rotating motor 8 located directly above the crucible 2, the output shaft of the chuck rotating motor 8 faces downward and is fixed with a rotating chuck 9, and a group of alloy rods 10 arranged at intervals are installed on the bottom surface of the rotating chuck 9. On the rotary chuck 9, there are through holes 11 arranged at intervals in a circle, and a pair of clamping plates 12 installed obliquely are installed in the through holes 11. The lower ends of the clamping plates 12 are rotatably connected in the through holes 11. Springs 13 are connected between the 11 inner walls.

During smelting, refining and pulping, protective gas is introduced to reduce metal oxidation and slag inclusion. During the pulping process of the alloy melt, the thermocouple is used to monitor the melt temperature in real time and adjust the rotation speed and immersion depth of the alloy rod.

AZ61 (Al 6.0, Zn 0.538, Mn 0.218) magnesium aluminum alloy was used to prepare semi-solid slurry. The liquidus temperature of AZ61 magnesium aluminum alloy is 595°C, and the solidus temperature is 470°C. Heat the alloy to 650°C and keep it warm for 10-15 minutes.

Install magnesium rods on the turntable, and the material of the magnesium rods is also AZ61. Then install the turntable on the output shaft of the motor through the coupling. When the alloy in the crucible was heated to 650°C, the heating was stopped and the alloy began to cool slowly. And turn on the motor, the magnesium rod enters the crucible under the action of the lifting platform and stirs. Stir until the temperature reaches between the solid-liquidus line of the magnesium alloy, that is, 470° C. to 595° C. In this experimental example, the temperature is controlled at about 540° C. to end the stirring.

After the stirring is completed, the semi-solid slurry of magnesium-aluminum alloy with spherical crystals can be obtained. At this time, the slurry can be directly poured into the mold and cast into a casting with excellent performance.

Although the invention has been shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made within the scope of the claims.

Claims (1)

1. A method for stirring and mixing solid-liquid metal is characterized in that: the method may further comprise the steps: 1. Preparation of solid alloy rods: Melt the alloy ingot and control its superheat within the range of 70-100°C, then refine the melt and remove slag, then let it stand and control the superheat of the melt at 60-80°C Within the range, the melt is poured into a metal mold to cool and solidify to obtain a cylindrical or square alloy rod with a certain length; 2. Control the temperature of the metal melt: control the superheat of the melt within the range of 70-10°C during smelting, then refine the melt and remove slag, then let it stand and control the superheat of the melt at 10-50 in the range of ℃; 3. Preparation of semi-solid slurry: fix the alloy rod obtained in the above step 1 on the rotary chuck of the stirring and mixing device, start the screw motor and the chuck rotation motor, and the screw motor drives the rotary chuck to descend and rotate The alloy rod is immersed in the melt; 4. Preparation of semi-solid forming or semi-solid billet: pour the semi-solid slurry obtained in the above step 3 into the mold of the forming device to realize semi-solid rheological forming or prepare semi-solid billet for thixotropic forming; during smelting, refining and During the pulping process, a protective gas is introduced to reduce metal oxidation and slag inclusion. During the pulping process of the alloy melt, a thermocouple is used to monitor the melt temperature in real time and adjust the rotation speed and immersion depth of the alloy rod; The stirring and mixing device includes a fixed base (1), a crucible (2) with heating function is installed on the front part of the fixed base (1), and a vertically installed guide rail (3) is fixed on the rear end of the fixed base (1). (3) is equipped with a sliding seat (4), and the top of the guide rail (3) is installed with a screw (5) and a screw motor (6) that drive the sliding seat to slide up and down. The sliding seat (4) is fixed with a beam ( 7), there is a strip groove (7-1) on the beam (7), and the chuck rotation motor (8) located directly above the crucible (2) is installed in the strip groove (7-1), and the chuck rotation motor The output shaft of (8) faces downward and is fixed with a rotary chuck (9). A group of alloy rods (10) arranged at intervals are installed on the bottom surface of the rotary chuck (9). There is a circle on the rotary chuck (9). Through-holes (11) arranged at intervals, a pair of clamping plates (12) installed obliquely are installed in the through-holes (11), the lower ends of the clamping plates (12) are rotatably connected in the through-holes (11), and the clamping plates (12) A spring (13) is connected between the upper end and the inner wall of the through hole (11).