SU1163993A1 - Apparatus for coating metallic powders - Google Patents

Description

one

The invention relates to powder metallurgy, in particular, to the coating of long products.

The purpose of the invention is the expansion of the technological capabilities of the process of coating on the surface of long products.

FIG. 1 shows the proposed device; FIG. 2, section A-A in FIG.

The device consists of a case I, inside of which a hollow screw 2 is located. At the end of the case is attached to the matrix 3 with a tubular mandrel fixed to it 4. Inside the tubular mandrel there is a spring 5 for feeding the slip mass into the molding zone and the forming element 6 connected with a tubular mandrel by means of a centering sprocket 7; At the end of the mandrel mating with the inner surface of the product 8, longitudinal grooves 9 are made around the perimeter, for removing the liquid phase and having a cross-sectional size smaller than the size of the pore fractions shka. To fix the forming element against axial movement, the rod 10 is connected to the base 11.

The cross-sectional size of the grooves made along the perimeter of the mandrel is within

1f,

Chfgp1p

mm

MX where d

maximum size of the section “PIA nor grooves;

minimum section size

min grooves;

d d

fraction size of powder particles;

the particle size of the powder mifter of the lowest fraction. The device works as follows.

The plasticized powder from the feed hopper is captured by the screw 2, compacted in the conical part of the die 3 and fed by a spring through the tubular mandrel 4 to the forming zone. Spring 5 is necessary to supply plasticized powder to the forming zone, since the screw does not allow powder to move with a significant length of the tubular mandrel. At the same time, the screw 2 creates in the matrix area a constant backwater and prevents the plasticizing flow 636332

bathing powder from a tubular mandrel, since one spring is not able to provide the necessary pressure in the zone of forming the leakage of powder 5 in the opposite direction. In the molding zone directly in front of the forming element 6, the liquid component is removed through the longitudinal grooves 9 under the action of capillary forces. Activating

A general factor contributing to the removal of the liquid component is the pressure created in the zone by a screw press due to the movement of the product relative to the forming element. Deletion

15 of the liquid component leads to the convergence of the powder particles among themselves and their deposition on the inner surface

products directly in the mold zone. When the product moves relative to the forming element due to a sharp increase in the coefficient of friction of the powder after removing the component, the powder is sucked into the gap formed by the conical surface of the forming element and the inner surface of the product to form a coating.

Data on the quality of the coating obtained using the proposed device are shown in the table.

Raw layer

Using liquid binder

Using solid binder (proposed)

Sintered layer

Using liquid binder

Using solid binder

Thus, the proposed device allows to apply coatings on the surfaces of long tubular products, unlike any well-known reysTV, the proposed device, groves the process of molding products, not

requires precise dosing of plastic powder, is easily automated, and can: be used in mass production to produce heat pipes and porous coatings on the surface of heat exchange pipes.

FIG. 2

Claims (1)

K57) DEVICE FOR MAKING COATINGS OF METAL POWDERS, including a housing, a hollow auger, a die and a loading hopper, characterized in that, in order to expand technological capabilities, it is equipped with a tubular mandrel, a spiral spring mounted inside the mandrel and rigidly connected to the end a screw and an asterisk located inside the mandrel and connected to the forming element, and one end of the mandrel is made with longitudinal grooves on the outer surface, and the other is fixed to the end of the matrix.