RU1836479C - Mixture for manufacturing composite sintered material - Google Patents

Abstract

The invention relates to powder metallurgy, in particular to the production of composite sintered material. SUMMARY OF THE INVENTION: A batch is provided for producing a composite sintered material of the following composition, wt.%: Cast iron powder with a particle size of 200-630 microns 55-65, brass powder from 35-40% in May. zinc with a particle size of 100-200 microns 5-15. sulfur powder 0.25-0.75, iron powder with a grain size of 200 microns - the rest, and the powder of cast iron has the following composition, wt.%: carbon 2.0-3.0, silicon 2.5-3.8, manganese 0.4-0 , 9, phosphorus 0.1-0.3, sulfur 0.05-0.1. iron is the rest. 1 tab.

Description

The invention relates to the field of powder metallurgy, in particular to the composition of the mixture to obtain a composite sintered material and is used in the manufacture of anti-friction and structural parts

An object of the invention is to increase the hardness and wear resistance of a composite sintered material under dry friction.

The goal is achieved in that the mixture to obtain a composite sintered material containing iron powder, brass powder with 35-40 wt.% Zinc, additionally contains sulfur powder and cast iron powder with a grain size of 200-630 microns composition (wt.%): Carbon 2.0- 3.0; silicon 2.5-3.8; manganese 0.4-0.9; phosphorus 0.1-0.3; sulfur 0.05-0.1; iron - the rest, powder

it contains brass with a particle size of 100-200 microns, and iron powder - with a particle size of 200 microns, in the following ratio of components, wt.%:

Cast Iron Powder55-65

Brass Powder5-15

Sulfur Powder 0.25-0.75

Iron powder

The introduction of cast iron powder of the indicated composition into the charge is explained by its high antifriction and strength properties. When changing the chemical composition of cast iron powder; For the purpose of the proposal is not achieved due to changes in the shapes of graphite inclusions and the structure of the material. The size of the cast iron powder in the range of 200-630 microns gives the material the necessary heterogeneous structure, high hardness and wear resistance. When applying

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cast iron powder with a particle size of more than 630 microns reduces the compressibility of the charge and as a result, strength, hardness and wear resistance are reduced. When the size of the cast iron powder is less than 200 microns, the degree of heterogeneity of the structure of the material is reduced, which also negatively affects its wear resistance. When the content of cast iron powder in the charge is less than 55%, the degree of heterogeneity of the material structure is reduced, which negatively affects its wear resistance during dry friction. When the cast iron content is more than 65%, the compressibility of the charge is reduced, which leads to a decrease in the density of the compacts, and hence the complex properties of the sintered material.

Brass powder content from May 35-40. % of zinc in the mixture ranges from 5 to 15% by weight. In case of a decrease in the content of brass in the mixture of 5 wt.%, The hardness and wear resistance of the samples are reduced due to the deterioration of the overall strength of the sintered material. An increase in the content of brass in the charge of more than 15 wt.% Leads to an increase in viscosity and, as a result, a decrease in the hardness and wear resistance of the samples. When brass powders with a particle size of 100 microns are used in the charge, it increases the homogeneity of the material structure, which negatively affects the wear resistance of the samples. An increase in the particle size of 200 μm brass powders also leads to a decrease in the overall strength of the sintered material with all the ensuing consequences,

The sulfur content in the charge of 0.25 wt.% Reduces the hardness and wear resistance of the composite sintered material due to a decrease in the number of sulfide compounds in the structure. At the same time, an increase in the sulfur content in the charge of 0.75 wt.% Reduces the overall strength of the sintered material due to the significant placement of iron and zinc sulfides between the matrix crystals.

Example. The mixture for producing composite sintered material contained the following powders, wt.%: Iron, ПЖРВ grade (GOST 9849-86) 2. 200-28, 20-40, cast iron 55-65, brass with 35-40 wt.% Zinc (GOST 15527-70) 6-15 and sulfur (GOST 127-76E 0.25-0.75, The chemical composition of cast iron powder consists of elements in wt.%; Carbon 2.0-3.0; silicon 2.5-3, 8; manganese 0.4-0.9; phosphorus 0.1-0.3; sulfur 0.05-0, iron - the rest.The size of cast iron powder was in the limit of 200-630 microns, brass powder 100-200 microns and powder iron 200 μm. Mixing was carried out in a Y-shaped mixer for 3.6 ks, the mixture was pressed under a pressure of 1000 MP on a HPM-100S hydraulic press. The resulting compacts — prismatic samples 55x10x10 mm in size were sintered in a conveyor-type furnace at a temperature of 1200 ° C with isothermal exposure in a sintering zone of 3.6 ks in an endothermic gas medium. 2M according to GOST 9013-59. The wear of the material during dry friction was determined on a SMTS-2 machine according to GOST 26614-85. according to the scheme, a prismatic sample-sleeve made of steel 45, hardened to a hardness of 50 HRC. The friction pair pressure was 2 MPa at a sliding speed of 1.0 m / s. The method for determining wear was in accordance with GOST 26614-85.

The table shows the compositions of the claimed charge and the properties of the sintered material from it in comparison with the composition of the known charge and with the properties of the material from it. As follows from the data in the table, the proposed mixture (compositions 1-3) provides, in comparison with the known mixture (composition 6}, an increase in the hardness and wear resistance of the composite sintered material. cast iron beyond the stated limits, the purpose of the proposal is not achieved (compositions 4, 5).

Claims (1)

SUMMARY OF THE INVENTION A mixture for producing a composite sintered material containing iron powder, brass powder with 35-40 wt.% Zinc, characterized in that it additionally contains sulfur powder and cast iron powder with a particle size of 200-630 microns, wt.%: Carbon 2.0-3.0 Silicon 2.5-3.8 Manganese 0.4-0.9 Phosphorus 0.1-0.3 Sulfur 0.05-0.1 Iron the rest, it contains brass powder with a particle size of 100-200 microns, and iron powder - with a particle size of 200 microns in the following ratio of components, wt.%: Cast Iron Powder55-65 Brass Powder5-15 Sulfur Powder 0.25-0.75 Iron powder