RU2472866C2 - Wear-resistant powder material, and method for its manufacture - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: wear-resistant powder alloy includes wear-resistant component in the form of powder wastes of solid alloys and plastic matrix based on copper containing chrome and titanium. Component ratio of wear-resistant alloy, wt %, is the following: copper 25-30; chrome 0.8-1.0; titanium 0.1-0.2; wastes of solid alloys are the rest. Mixture of powders is loaded to a prefabricated and degreased container; container is sealed, heated to the temperature of 1150-1200°C and exposed during 15-30 minutes; after that, it is cooled to temperature of 950-1000°C and pressed at pressure of 150-200 MPa.

EFFECT: improving wear resistance of material at reduction of its prime cost.

3 cl, 1 tbl

Description

The invention relates to the field of powder metallurgy, in particular to the manufacture of powder wear-resistant material, and can be used in mechanical engineering to protect machine parts from wear.

Known hardwearing wear-resistant material [RF patent No. 2164200]. The material as a wear-resistant phase contains VK8 carbide particles obtained by crushing the waste of carbide elements of cutting tools, and nickel powder as a matrix binder. The disadvantage of this material is the high melting point of nickel, which makes it difficult to use it in the infiltration of hard alloy particles. In addition, the increased scarcity and cost of nickel limit the possibility of using the proposed material.

The material for a wear-resistant coating [RF patent No. 2349621] contains a binder and a filler, while it contains a copper alloy - brass as a binder (in% wt: Sn 1-4; Zn 30-39; Cu - the rest). Filler is industrial waste of high hard materials, including waste of hard alloys based on tungsten carbide with cobalt. Too large (2-4 mm) hard alloy particles do not provide a uniform distribution of the filler in the alloy structure, and therefore, reduce the wear resistance of the material.

A common drawback of the above analogues is the possibility of oxidation and contamination of the material with impurities, which leads to a decrease in its mechanical properties and wear resistance.

A known method of obtaining a wear-resistant structural powder steel [RF Patent No. 2171159]. The method includes preparing a powder mixture of components, compressing the mixture in a closed mold to obtain a porous briquette, heating it in a protective atmosphere and hot working with pressure, while the high-temperature fluorine-lignin polymer is additionally introduced into the powder mixture, pressing the briquette from the powder mixture in a closed press -form is carried out until the residual porosity is achieved, and the subsequent heating of the briquette is carried out with a certain speed and exposure. The disadvantage of this method is the high residual porosity of the material.

A known method of manufacturing low-porous powder materials [RF patent No. 2167741]. The method includes molding a two-layer porous powder billet by filling the substrate powder into a mold and pressing it with pressure, followed by filling a fusible material of a certain mass, sintering the billet combined with impregnation, using non-ferrous non-ferrous chip waste as a fusible material on the surface layer of a billet copper base, at a certain pressure. The disadvantage of this method is the possibility of oxidation of the material during sintering and impregnation or the need to use expensive means of protection against oxidation.

As a prototype of the selected material of the matrix of diamond and abrasive tools and the method of its manufacture "[RF patent No. 2136479]. The matrix material of diamond and abrasive tools contains relit in the following ratio of components, wt.%: Tungsten carbide 31-59, cobalt 1.5-8, relit 20, copper 37-41, nickel 4. The disadvantage of this material is its high cost, since expensive primary powders of tungsten carbide, relite and cobalt are used as the initial charge.

A method of manufacturing the material involves mixing the components, pressing the mixture on hydraulic presses in molds with a specific pressure of 30 to 80 MPa, heating the compacts together with the impregnating alloy with high frequency currents to a temperature of 500-600 ° C at a speed of 20-30 ° C / min followed by heating to a temperature of (1083-1140) + 20 ° C at a speed of 90-100 ° C min and holding for infiltration of the impregnating alloy in a liquid state and pressing the material for 120-240 s. The disadvantages of the method are the oxidation of the material and a decrease in its mechanical properties and wear resistance due to heating to 1140 ° C and exposure to infiltration. Carrying out this operation in a protective atmosphere to prevent oxidation will require the use of sophisticated and expensive equipment.

The objective of the invention is to increase the wear resistance of the material, reducing its cost.

A powder wear-resistant material is proposed that contains powders from solid alloy waste as a wear-resistant component, and copper, chromium and titanium in the following ratio, wt.%: Copper 25-30; chrome 0.8-1.0; titanium 0.1-0.2; hard alloy waste - the rest.

A method of manufacturing a powder wear-resistant material is proposed, which consists in pouring a mixture of powders into a prefabricated and fat-free container, sealing the container, heating it to a temperature of 1150-1200 ° C, keeping it for 15-30 minutes, and then cooling to a temperature of 950- 1000 ° C and pressed at a pressure of 150-200 MPa.

The container may be made of low carbon steel.

The solution to this problem is provided by the fact that:

- the material contains solid alloy waste as a wear-resistant component, which significantly reduces its cost, and the copper matrix provides the necessary viscosity and ductility. The material contains chromium, which dissolves in copper and gives it increased strength, and titanium, which absorbs gases when heated, which ensures an increase in the mechanical properties of the material;

- in the method, heating and holding the powder mixture at high temperature in an airtight container prevents oxidation and contamination of the mixture, and hot pressing of the mixture in an airtight container eliminates residual pores and increases the mechanical properties of the material and wear resistance.

The combination of distinctive features is necessary and sufficient to solve the problem.

Copper in an amount of 25-30% fills the pores between the particles of the hard alloy and regulates the ratio of hardness and strength of the material. When the copper content is less than 25%, individual pores remain unfilled and the strength of the material decreases. When the copper content is more than 30%, the hardness of the material decreases. When the chromium content is less than 0.8%, the strengthening effect is not fully realized. A chromium content of more than 1.0% does not create additional hardening. When the titanium content is less than 0.1%, its sorption capacity is insufficient to absorb all gases. A titanium content of more than 0.2% does not affect the porosity, but increases the cost of the alloy. At a container heating temperature of less than 1150 ° C, liquid copper does not have sufficient fluidity to fill small pore channels. Heating to temperatures above 1200 ° C is not required for technical reasons and will lead to excessive energy consumption. Exposure of the container with the powder mixture for 15-30 minutes is required for complete infiltration of the wear-resistant component with a copper alloy. With a shutter speed of less than 15 minutes, pores that are unfilled with a copper alloy may be present in the material. Exposure for more than 30 minutes leads to excessive energy consumption. Cooling the container with the infiltrated powder material to 950-1000 ° C is necessary for the solidification of the copper alloy, since subsequent pressing of the container in the presence of a liquid phase in it is unacceptable for safety reasons. Cooling to temperatures above 1000 ° C does not guarantee the complete absence of a liquid phase. Cooling to a temperature below 950 ° C will increase the resistance of the material to compaction during subsequent pressing. The pressing pressure in the range of 150-200 MPa ensures the elimination of residual porosity and discontinuities in the container formed as a result of possible shrinkage of the material. At a pressure of less than 150 MPa, it is possible that the structure of the material contains increased porosity. At a pressure of more than 200 MPa there is an excessive energy consumption and increased wear of technological equipment.

To obtain material and implement the method, a thin-walled box-shaped container is preliminarily made from low-carbon, well-welded steel, for example, Art. 10, Art. 20. The powders obtained by mechanical grinding of a hard alloy, for example, VK6 alloy, are mixed with powders of copper, chromium and titanium in a given ratio. The powder mixture is poured into the container and sealed by welding the lid. The container with the powder mixture is loaded into a heating device, for example, in a muffle electric furnace, heated to a predetermined temperature, maintained for a predetermined time for infiltration, cooled to a predetermined temperature, and pressed (deposited) under pressure at a given pressure.

Quality control material is performed on the bending strength (σ _mfd), hardness (HV) and the presence of residual pores. Quality was considered satisfactory when σ _mfd ≥1200 MPa, HV≥3000 MPa and porosity ≤1%. Specific examples of carrying out the invention with different initial parameters are presented in the table.

Experience number Cu% Cr% Ti% Hard alloy waste% t _n ° C T min t _oh ° C R MPa σ _ex MPa HV MPa % Por. one twenty 1,0 0.2 78.8 1200 thirty 950 200 1180 3300 ≤1 2 25 1,0 0.2 73.8 1200 thirty 950 200 1200 3210 ≤1 3 27 1,0 0.2 71.8 1200 thirty 950 200 1225 3120 ≤1 four thirty 1,0 0.2 68.8 1200 thirty 950 200 1245 3010 ≤1 5 35 1,0 0.2 63.8 1200 thirty 950 200 1260 2770 ≤1 6 thirty 0.6 0.2 69.2 1200 thirty 950 200 1150 2900 ≤1 7 thirty 0.8 0.2 69.0 1200 thirty 950 200 1210 3110 ≤1 8 thirty 0.9 0.2 68.9 1200 thirty 950 200 1225 3230 ≤1 9 thirty 1,0 0.2 68.8 1200 thirty 950 200 1250 3300 ≤1 10 thirty 1,0 0.1 68.9 1200 thirty 950 200 1200 3120 ≤1 eleven thirty 1,0 0.15 68.85 1200 thirty 950 200 1245 3150 ≤1 12 thirty 1,0 0.2 68.8 1200 thirty 950 200 1270 3190 ≤1 13 thirty 1,0 0.3 68.7 1200 thirty 950 200 1290 3200 ≤1 fourteen thirty 1,0 0.2 68.8 1100 thirty 950 200 1190 2800 ≤1 fifteen thirty 1,0 0.2 68.8 1150 thirty 950 200 1200 3100 ≤1 16 thirty 1,0 0.2 68.8 1175 thirty 950 200 1260 3060 ≤1 17 thirty 1,0 0.2 68.8 1200 thirty 950 200 1290 3000 ≤1 eighteen thirty 1,0 0.2 68.8 1200 10 950 200 1050 2600 ≤1 19 thirty 1,0 0.2 68.8 1200 fifteen 950 200 1200 3150 ≤1 twenty thirty 1,0 0.2 68.8 1200 25 950 200 1240 3100 ≤1 21 thirty 1,0 0.2 68.8 1200 thirty 950 200 1270 3000 ≤1 22 thirty 1,0 0.2 68.8 1200 thirty 900 200 1090 2900 ≤1 23 thirty 1,0 0.2 68.8 1200 thirty 950 200 1240 3100 ≤1 24 thirty 1,0 0.2 68.8 1200 thirty 975 200 1260 3050 ≤1 25 thirty 1,0 0.2 68.8 1200 thirty 1000 200 1290 3000 ≤1 26 thirty 1,0 0.2 68.8 1200 thirty 1100 200 1240 2900 ≤1 27 thirty 1,0 0.2 68.8 1200 thirty 950 one hundred 1185 2700 ≥5 28 thirty 1,0 0.2 68.8 1200 thirty 950 150 1200 3000 ≤1 29th thirty 1,0 0.2 68.8 1200 thirty 950 175 1220 3140 ≤1 thirty thirty 1,0 0.2 68.8 1200 thirty 950 200 1245 3260 ≤1 31 thirty one 0.2 68.8 1200 thirty 950 250 1270 3350 ≤1 Prototype 1050 2520 ≥10 t _n , t _ox is the temperature of heating and cooling the container with the powder mixture; T is the exposure time when heated; P is the pressing pressure.

The proposed wear-resistant material obtained by the method described above has high strength (σ _ar - 1200 MPa) and hardness (HV≥3000 MPa), low porosity (≤1%), and low cost.

Claims (3)

1. A wear-resistant powder alloy containing a wear-resistant component in the form of a hard alloy powder and a plastic matrix based on copper, characterized in that the alloy contains solid alloy waste powder as a wear-resistant component, and the copper-based matrix additionally contains chromium and titanium, in the following ratio alloy components, wt.%:
copper 25-30 chromium 0.8-1.0 titanium 0.1-0.2 hard alloy waste rest 2. A method of manufacturing a powder wear-resistant alloy according to claim 1, comprising mixing the powders, filling the mixture into a prefabricated and fat-free container, sealing the container, heating it to a temperature of 1150-1200 ° C, holding for 15-30 minutes for infiltration, followed by cooling to a temperature of 950-1000 ° C and pressing at a pressure of 150-200 MPa. 3. The method according to claim 2, characterized in that the container is made of low carbon steel.