SU954184A1 - Method of vibration moulding of powder articles - Google Patents

Description

(54) METHOD OF VIBRATION FORMING PRODUCTS

FROM POWDER

The invention relates to powder metallurgy, in particular, to the process of forming articles from powder materials, and can be used in the manufacture of articles from refractory materials, for example from tungsten or mopibden. There is a method of forming batches of powder materials by pressing 1. The disadvantage of the known method is the impossibility of obtaining uniform porosity and a sufficiently low density due to coagulation of particles of powder materials and the influence of high friction forces arising when moving particles of powders during the pressing process. Closest to the proposed method to the technical essence and the achieved effect is the method of forming articles from powder materials, which consists of b vibrating compaction of powder p in the mold when axial oscillations are applied to it often. 50-2400 Hz 2. The disadvantage of the known method is the low density of the products, especially when pressing porchkovka refractory metals, such as tungsten and molybdenum, which requires additional pressing in the mold. An uneven distribution of density over the volume of the product is observed. The purpose of the invention is to increase the density and uniformity of its distribution over the volume of products. This goal is achieved by the fact that in a method that includes vibrating compaction of a powder in a mold with the application of axial oscillations, axial oscillations of the press h) the molds are performed with a frequency of 2 O-3 kHz while simultaneously affecting the mold of phase-synchronized additional oscillations the same frequency with the resultant of both vibrations, directed at an angle of 10-20 to the axis of the mold. 395 Additional oscillations of the mold are carried out in the direction perpendicular to the axis of the mold with an amplitude of 0.2-O, 35 amplitudes of axial oscillations. Compaction is carried out with a change in the oscillation frequency in the molding process by 10%. The application of oscillations with a frequency of 2–30 kHz eliminates coagulation of individual particles of the material during compaction, reduces friction between the particles when they are mixed, and the application of additional vibrations ensures their uniform distribution in volume. by volume. Additional vibrations are applied perpendicularly to the axis of the mold, their amplitude is set at the level O, 2-O, 35 of the amplitude of axial oscillations. Such an amplitude value, an additional oscillation, allows one to obtain a deviation of the direction of the resultant oscillations from the mold axis by 10-20. It is advisable that the oscillation frequency in the compaction process be changed by 20-30%, which provides better compaction of the powder particles when the frequency of the natural oscillations of the material changes as the particles compact. The drawing shows the proposed device. 44 The method is carried out as follows: Powder 1 is poured into a collapsible matrix consisting of a center rod 2 and an outer cylindrical body 3 fixed rigidly with a ring 4 on an acoustic emitter 5, which is connected to a rod packet magnetostrictive emitter 6 .. The matrix is set an annular (radial) batch magnetostrictive emitter 7. Both emitter 6 and 7 are connected to an I ejector 8. A moving punch 9 with a load of 0.5 kg is mounted on the powder 1 embedded in the matrix 1. Then, vibratory compaction is performed with an oscillation frequency f. 25 kHz, and during the densification process, the oscillation frequency is smoothly changed in the range of 20-30 kHz ({i20%). Additional oscillations are transmitted to the matrix from the annular packet magnetostriction radiator 7, and the amplitude in these oscillations is set at a level of 0.25 amplitude of axial oscillations. The molding process lasts 10 s. The proposed method produces products of spherical molybdenum powder with particles up to 4 microns in the form of a hollow cylinder with an outer diameter of 4 mm, a height of 30 mm and a wall thickness of 5 mm, which are then subjected to sintering at a temperature of 16 ° C for 2 minutes. The table shows the results of the molding process with the proposed method.

Gum properties

25

20

5-10

25 5-10

25

30 5-10

25 5-10

25 5-10

30 5-10

1O

ZO 5-10

30 20 30 5-10

30 5-10

note;

if, is the frequency of axial oscillations, t is the frequency of additional oscillations; d1 — frequency variation during the densification process; And - amppituda axial oscillations; B - amplitude supplement with 1 oscillations;

o,:, is a condition for deviation of the resultant P from the axis of the mold; T is the time of the compaction process; k is the coefficient of compaction tg where. °

HO- height of the powder in the process-form; H is the height of the product after manufacture; R is the resultant of both oscillations; P - pressing force As follows from the baked data, the highest density of products was obtained at an axial frequency of 2,0-30 kHz additional - with an amplitude (0.20, 35) of the amplitude of axial oscillations. With these values of the molding process parameter, the deviation of the resulting two types of oscillations: axial and additional from the mold axis is 1020 Determining the uniformity of the distribution of porosity of the products by a metallographic method revealed its high uniformity over the product volume. The proposed method allows the molding of products from 1 increment.

PROJECTION OF GPPLNTSY

12

1O 10 1O 1O 10 10 1O 1O 10

0.32

16 34

20 0.42

7 0.35

Claims (1)

27 0.45 11 0.32 14 16 0.34 0.35 2O 0.42 powder materials, thus ensuring a high density of iadepium and a uniform porosity of the products according to the total. This makes it possible to obtain high-quality products with good mechanical properties and high metal utilization. Claims 1. A method of vibrating molding articles from a powder, mainly from refractory materials, comprising compacting the powder in a mold upon the application of axial vibrations, from n and