RU2087251C1 - Method of vibration treatment of crystallizing metal and device for its embodiment - Google Patents

Abstract

FIELD: foundry. SUBSTANCE: the offered method includes application of vibration to mold in course of metal crystallization in horizontal, vertical and inclined at 45 deg directions, and treatment of crystallizing metal with vibrations different in directions to attain change of value of resulting angle of application of vibration by various combination of horizontal, vertical and inclined directions which are selected depending on the type of treated metal and its properties. The device for embodiment of the offered method has mold, working table, bed, flexible member and vibratory base in form of cubical frame with diagonal plane on whose sides and on its diagonal plane, pneumatic ball exciters are installed. Application of the offered method and device for its embodiment result in increased mechanical properties of metal due to more complete removal of nonmetallic inclusions, fine-grained structure and higher density of metal. EFFECT: higher quality of ingots and castings due to higher efficiency of vibration treatment of metals and alloys with various physical properties. 2 cl, 2 dwg

Description

 The invention relates to the field of foundry and can be used for vibration processing of liquid or crystallizing metal, in particular for vibration processing of the mold at the time of casting and crystallization of the casting.

 A device for vibration processing of molten metal [1] containing a mold placed on a plate with a vibration exciter, which is equipped with a vertically located torsion bar is known. The use of a ball vibration exciter in the device, as well as the arrangement of the plate, mold and vibration exciter on the upper end of the torsion bar, the lower end of which is mounted on the base, allows the rotational and horizontal vibrations to be simultaneously communicated to the mold. The disadvantage of this device is the inability to inform the form of vibration in the vertical plane.

 The closest in technical essence to the proposed technical solution is the method of producing ingots selected as a prototype and described in [2], in which the crystallizing metal is acted simultaneously in horizontal and vertical planes and which is implemented in an installation containing a mold for pouring metal, vibration base for vibrators mounted on springs, a remote control for controlling and monitoring vibration modes. Using the method allows to reduce the size of the primary grain by 2 times, increase the hardness by 6%, the density by 5%, reduce the shrinkage by 4.5%. The disadvantage of this method is the need to alternately reduce and increase the frequency of vibration in the vertical direction, which greatly complicates the process of vibration processing, as well as the fact that metal vibration in the horizontal and vertical directions is often ineffective, because different metals and alloys, due to their different specific gravity and different physical properties, require different angles of application of vibrations.

 The objective of the invention is to improve the quality of ingots and castings by increasing the efficiency of vibration processing of metals and alloys with various physical properties.

The problem is solved due to the fact that by the method of vibration processing of crystallizing metal, including the application of vibrations to the mold in the process of crystallization of metal in horizontal and vertical directions, according to the invention, inclined vibrations are additionally applied to the mold in the direction at an angle of 45 ^o and the crystallized metal is processed multidirectional vibrations, and a change in the value of the resulting angle of application of vibrations reach different combinations Horizontal, vertical and inclined directions, and directions oscillatory combination is selected depending on the type of metal and its crystallizing properties.

 To implement the method in a device for vibration processing of crystallizing metal, including a mold, a work table, a vibration base for pneumatic ball vibration exciters mounted on an elastic element, and a bed, vibration base according to the invention is made in the form of a cubic shape with a diagonal plane, and pneumatic ball vibration exciters are installed on the sides of the frame and on its diagonal plane.

 The authors are not aware of the use of multidirectional vibrations applied to the mold in order to improve the quality of castings and ingots, and therefore the proposed technical solution can be considered appropriate to the inventive step.

 In FIG. 1 shows a device for vibration processing.

 In FIG. 2 shows the layout of vibration exciters and the resulting angles corresponding to the directions of vibrations applied to the metal during operation of the combinations of vibration exciters indicated in Table 1.

The method of vibration processing of crystallizing metal is carried out by applying to the casting form vibrations in the horizontal, vertical and inclined directions in various combinations, the inclined vibrations having an application angle of 45 ^o , which, as it is established, provides optimal combinations with horizontal and vertical vibrations to obtain the necessary resulting application angle vibrations to crystallizing metal. The application of multidirectional vibrations to the crystallizing metal allows you to change the resulting angle of the direction of vibration in the process of crystallization of the metal.

где V_вкл. скорость удаления включений;
R радиус включения;
η_распл. кинематическая вязкость расплава;
d_распл. плотность расплава;
d_вкл. плотность включения;
a_в ускорение вибрации;
ω частота вибрации;
t время виброобработки;
a угол наклона вектора виброколебаний к вертикали,
например для алюминия и его сплавов, оптимальный угол приложения виброколебаний в начальной стадии кристаллизации составляет 30^o, а в заключительной стадии 60^o. Предлагаемый способ виброобработки дает возможность менять угол приложения вибрации в процессе его реализации, изменяя сочетание включенных в работу вибровозбудителей. Ориентировочно, угол приложения к кристаллизующемуся металлу виброколебаний в зависимости от сочетания работающих вибровозбудителей можно определять согласно схеме, представленной на фиг. 2. Например, угол приложения виброколебаний 30^o получается при работе b и d или c и d вибровозбудителей, а угол 60^o при работе a и e или a и d вибровозбудителей. Более точно такие углы определяются экспериментально при наладке установки, т.к. они зависят от применяемого источника сжатого воздуха, давления в системе, габаритов установки и т.д.It was experimentally established that the angle of application of vibrations affects the maximum rate of removal of non-metallic inclusions, at which the melt is most completely cleaned during the crystallization period, and, as a result, has the highest properties: tensile strength at break, elongation, hardness, density. Moreover, according to the calculations by the formula

where V _on inclusion removal rate;
R inclusion radius;
η _spread kinematic viscosity of the melt;
d _spread melt density;
d _incl. inclusion density;
a vibration _in acceleration;
ω vibration frequency;
t vibration processing time;
a angle of inclination of the vibration vector to the vertical,
for example, for aluminum and its alloys, the optimal angle of application of vibration in the initial stage of crystallization is 30 ^o , and in the final stage 60 ^o . The proposed method of vibration processing makes it possible to change the angle of application of vibration during its implementation, changing the combination of vibration exciters included in the work. Tentatively, the angle of application of vibrations to the crystallizing metal, depending on the combination of working vibration exciters, can be determined according to the circuit shown in FIG. 2. For example, the angle of application of vibrational vibrations of 30 ^{o is} obtained during operation of b and d or c and d of vibration exciters, and the angle of 60 ^o during operation of a and e or a and d of vibration exciters. More precisely, such angles are determined experimentally during setup, as they depend on the source of compressed air used, the pressure in the system, the dimensions of the installation, etc.

 To implement the method, it is proposed to install the following design.

The mold 1 is mounted on a work table 2, which is connected to a vibration base 3. The vibration base is a cubic frame with a diagonal plane 4 fixed inside the frame at an angle of 45 ^o . On the lateral sides of the vibration base in horizontal and vertical planes and on an inclined diagonal plane, pneumatic ball vibration exciters 5 are installed, each of which is connected to a compressed air system. The vibration base is mounted on an elastic element that is fixed to the bed of the device 6. The elastic element consists of a working spring 7 installed between the upper 8 and lower 9 supporting flanges. The lower support flange is connected to the bed. Upper support flange with vibration base. The elastic element is equipped with a centering rod 10 passing through the bed, the working spring and the support flanges. An additional spring 11 is mounted on the upper end of the rod protruding above the upper support flange and the entire structure of the elastic element is fixed from above and below by nuts 12.

 Example. During the crystallization period, a cylindrical casting weighing 5 kg from an AL-2 alloy (eutectic silumin) was subjected to vibration processing.

The metal was prepared in an induction furnace IST-0.06 in a graphite chamotte crucible. The liquid metal was poured into a casting mold installed and fixed on a vibrating machine at a temperature of 950 975 K. The vibration exciters were turned on immediately after the pouring was completed. The vibration processing time was 2 min; the vibration frequency was 50 Hz. The resulting angle of vibration at the beginning of vibration processing was 30 ^o , which included exciters b and d mounted on the vertical side and on the diagonal plane of the vibration base of the installation (see Fig. 2). A minute after the start of vibration processing, the angle of application of vibration was increased to 60 ^o , for which they switched compressed air to vibration exciters a and d mounted on the horizontal side and on the diagonal plane of the vibration base. For comparison, the castings were processed under the same conditions at an angle of application of vibrations of 0 ^o (vertical) and 90 ^o (horizontal vibrations), as well as with simultaneous vibrations in horizontal and vertical planes (prototype). From the obtained ingots, Gagarin samples were prepared for mechanical tensile testing of metal, determination of hardness and density of metal.

 In the table. 2 shows the test results.

As can be seen from the data presented, the highest properties are casting processed by applying vibrations to the crystallizing metal at an angle of 30 60 ^o to the vertical. Improving the properties of the metal occurs due to a more complete removal of non-metallic inclusions, grinding of the structure and increasing the density of the metal.

Claims (2)

 1. The method of vibration processing of crystallizing metal, including the application of vibrations to the mold during crystallization of metal in horizontal and vertical directions, characterized in that the inclined vibrations are additionally applied to the mold.  2. A device for the vibration processing of crystallized metal, containing a mold mounted on a work table connected to an vibration-mount elastically mounted on the bed, on which vibration exciters are mounted, characterized in that the vibration base is made in the form of a cubic frame with a diagonal partition, and the vibration exciters are mounted on it faces and on the diagonal partition.

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