SU1669637A1 - Method of depositing powder coats - Google Patents

Abstract

The invention relates to powder metallurgy, in particular, to methods of coating the internal surfaces of complex geometric shapes. The goal is to expand the technological capabilities by coating spherical surfaces such as spline. The powder of the coating material is sprayed onto the mandrel, the mandrel is applied with the powder applied inside the part, the part is heated to the sintering temperature, and the coating material is pressed on it by rotating the part with the mandrel at a certain speed. 3 il.

Description

The invention relates to powder metallurgy and can be used when applying coatings of powdered materials on the inner surfaces of complex geometric shapes.

The purpose of the invention is the expansion of technological capabilities.

FIG. 1-3 illustrate an apparatus for carrying out the method.

The device consists of a spindle 1, which is used to fasten and ensure rotation of the part 2 prepared for coating, which interacts with a mandrel 3 made of ceramic. The profile of the mandrel corresponds to the profile of the inner surface of the part. The mandrel 3 is inserted into the chuck 5 with the aid of the shank 4. A powder layer 7 is sprayed with the aid of the device 6.

The spindle 1 is mounted with the coating part 2. Using the device b, the mandrel 3 sprays the powder 7. The adhesion of the sprayed to the ceramic is practically absent. The porosity of the sprayed layer is 25-30%. The mandrel 3 is then introduced into the preheated bed 2. The part is heated by means of a heating source such as an LPZ-267M high-frequency generator. The dimensions of the mandrel and the thickness of the sprayed layer are chosen taking into account that the layer can be pressed by means of the mandrel. powder in radial and axial directions is

ABOUT

oh oh with vj

it prevents particles from moving along the inner surface of the part and leads to good adhesion of the coating and the part. The mandrel with the powder layer and the product rotate with speed

with ip-,

/ Um r

where Stg is the yield strength,

UE is the density of the powder layer;

g is the inner radius of the coating, and the product and the powder layer are heated to a temperature of 0.7-0.9 TPl; after the end of the process, the inner surface of the powder layer is calibrated with a mandrel.

The whole process is carried out in a protective atmosphere of endogas.

Example 1. BROF 10-1 bronze powder was sprayed onto a ceramic mandrel using a UPTP-78-1 installation. The thickness of the sprayed layer is 4 mm, the inner radius of the coating is mm. The speed of rotation of the mandrel when spraying 120 rpm Then the mandrel with the powder layer is inserted inside the part and the part and the powder layer are heated by high-frequency currents using an external inductor to 850-870 ° C, which is controlled using an Apir C pyrometer.

Ш2:

which for these conditions is 3650 rpm.

Burn time, isothermal exposure 50 s.

The porosity of the coating after deposition was 25–30%, and after sintering to the base, 3–4%. Adhesion strength 250-260 MPa.

Example 2. The application of the powder layer on the support.

A mandrel having a spherical surface at the end is fixed in the spindle of a lathe and using a UPTR-1-85 installation, a layer of powder of a thickness of 3.5-3.7 mm is sprayed. Spindle speed 100 rpm Sputtering distance 200 mm. Spray time 35 s

Then the mandrel with the powder layer is inserted inside the support, and the powder layer is heated to 840-880 ° C.

The rotation speed is 625 s 1.

The value of the inner radius of the coating is chosen to be the smallest so that the condition of the formula is satisfied for the entire coating.

Isothermal shutter speed 50 s. After the end of baking, the heating is switched off by axial movement of the mandrel pro0

five

0

five

Sub-pressing of the coating is exhausted. Displays the mandrel from the part, turns off the rotation. After cooling, the parts are machined,

Example 3. Technological process of applying a powder coating on a sleeve with an inner conical surface.

The mandrel with the outer working conical surface is installed in the spindle of the lathe. The rotation speed of the spindle is set to 100 rpm. A layer of powder with a thickness of 3.8-4 mm is sprayed. Spray distance 200 mm. Spray time 40s.

A mandrel with a powder layer is inserted into the sleeve with a conical surface. Both are asked to rotate with a speed of 553.

Isothermal shutter speed 50 s.

After heating is turned off by axial displacement of the mandrel, the coating is pre-calibrated. Pulling the mandrel out of the coated part. Turn off the rotation.

After cooling, the parts are machined.

Uvolich

i.e. sh

speed of rotation of the part leads to a decrease in

the time of transfer of the powder layer from the mandrel to the part. This process takes 3-5 seconds. After reaching the sintering temperature, which constitutes an insignificant part of the isothermal holding time, the increase in speed affects the compaction process slightly.

Claims (1)

Invention Formula The method of coating powdered materials, including applying the powder of the coating material to the mandrel, placing the mandrel with the coating layer in the part cavity, heating to the sintering temperature, and pressing the coating material onto the surface of the part, characterized in that coating spherical surfaces with through holes and on a spline type surface, pressing is carried out by rotating the part with a mandrel with by speed sh where 7g is the yield strength of the coating material at the sintering temperature; yn is the density of the powder layer after application to the mandrel; g - the inner radius of the mandrel with a coating and after the process is completed, the inside surface of the part is calibrated with a mandrel. figure 1 Fig2 V7 ) Hulk