RU2450069C1 - Sintered antifriction iron-based material - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: sintered antifriction iron-based material contains the following components, wt %: chrome 0.3-0.5, manganese 9.0-10.8, silicon 5.1-5.8, carbon 3.1-4.9, copper 1-3, iron - balance.

EFFECT: produced material has high mechanical and tribotechnical properties.

1 tbl, 3 ex

Description

The invention relates to powder metallurgy, in particular to sintered antifriction materials intended for the manufacture of parts used in friction units without lubrication.

Known chromium-containing antifriction material based on iron of the following composition, wt.%: Chromium 2-4, carbon 2-4, copper 1.5-2.5, molybdenum disulfide 4-6, the rest is iron. (Copyright certificate No. 263161, 1961).

However, the material has low mechanical properties.

The closest to the proposed invention by essential features is a sintered antifriction material based on iron of the following composition, wt.%: Chromium 1.07-1.44, carbon 1.00-3.00, silicon 0.27-0.67, manganese 0.46-0.77, copper 3-8, the rest is iron. (RF patent No. 2101380 dated 01/10/1998).

The disadvantages of this material are low mechanical and tribological properties.

The objective of the invention is to obtain parts working in friction units without lubrication from a sintered antifriction material with enhanced mechanical and tribological properties.

The problem is solved in that the sintered antifriction material based on iron contains chromium, manganese, silicon, carbon and copper in the following ratio of components, wt.%:

Chrome 0.3-0.5

Manganese 9.0-10.8

Silicon 5.1-5.8

Carbon 3.1-4.9

Copper 1-3

Iron rest

Example No. 1

To implement this task, iron powder ПЖР 3.126.20 was selected, carbon 3.1% was introduced as a part of pencil graphite GK-2, GOST 4404-78. Manganese 9.0% and silicon 5.1% were introduced as part of ferroalloys. As a binder component, which increases the hardness and strength of the material, improves its structure, prevents the growth of sintered parts, copper 1% is taken. Chromium 0.3% was introduced together with manganese in the composition of ferromanganese FMn78.

The technological process for producing antifriction material based on iron includes the following basic operations: preparation of the starting components; weighting of the starting components; mixing the components of the mixture; dosage; cold pressing; sintering.

The operation of preparing the starting materials is to obtain powders of a fraction with particle sizes from 63 to 100 microns by sieving through sieves. Then, the powders were weighed on a balance accurate to ± 0.5 g.

In accordance with the quantitative ratio of the components of the mixture, the main component is iron powder, and the remaining components are alloying materials, in this regard, the sequence of filling the suspended components of the mixture into the mixer was observed as their percentage composition decreased. Mixing was carried out in a cone mixer for 4 hours. Zinc stearate was used as a plasticizer. After analyzing the chemical composition of the charge, a dosage operation follows, which was carried out on a technical balance with an accuracy of 0.1 g.

Samples were pressed in a mold on a hydraulic press with a specific pressing pressure of 400 to 600 MPa.

The container with the samples is loaded into a furnace heated to 700% C. Sintering was carried out in a chamber furnace of the SNOL type, in a protective environment of dissociated ammonia, by successively increasing the temperature from 500 ° C to 1150 ° C with holding for 1 hour and then cooling the container in air.

With this ratio of alloying components, the sintered antifriction material based on iron, in comparison with the prototype, has increased mechanical properties - hardness 15%, strength 20%, tribological properties - friction coefficient 10%, wear resistance 12%.

Example No. 2

To implement this task, iron powder ПЖР 3.126.20 was selected, carbon 4.0% was introduced as a part of pencil graphite GK-2, GOST 4404-78. Manganese 10.1% and silicon 5.4% were introduced as part of ferroalloys. As a binder component, which increases the hardness and strength of the material, improves its structure, prevents the growth of sintered parts, copper 2% is taken. Chromium 0.4% was introduced together with manganese in the composition of ferromanganese FMn78.

With this ratio of alloying components, the sintered antifriction material based on iron, in comparison with the prototype, has increased mechanical properties - hardness 15%, strength 20%, tribological properties - friction coefficient 10%, wear resistance 12%.

Example No. 3

To accomplish this task, iron powder ПЖР 3.126.20 was selected, carbon 4.9% was introduced as a part of pencil graphite GK-2, GOST 4404-78. Manganese 10.8% and silicon 5.8% were introduced as part of ferroalloys. As a binder component, which increases the hardness and strength of the material, improves its structure, prevents the growth of sintered parts, 3% copper is taken. Chromium 0.5% was introduced together with manganese in the composition of ferromanganese FMn78.

With this ratio of alloying components, the sintered antifriction material based on iron, in comparison with the prototype, has increased mechanical properties - hardness 15%, strength 20%, tribological properties - friction coefficient 10%, wear resistance 12%.

The boundaries of the carbon content in the proposed material are determined by the following factors: when the carbon content is less than 3.1%, the friction coefficient increases significantly, the wear of the sintered material increases, when the carbon content is more than 4.9%, the strength characteristics of the sintered antifriction material sharply decrease. The boundaries of the copper content are determined by the following factors: when the copper content is less than 1%, there are no obvious changes in the properties of the material, when the copper content is from 1-2%, the strength of the sintered material increases and there is practically no shrinkage, when the copper content is more than 3%, the strength of the sintered material decreases and growth increases briquettes. This is due to the fact that during sintering, the amount of dissolved copper increases and the volume of iron particles increases, leading to an overall increase in the volume of the workpiece. The increased content of silicon and manganese (compared with the prototype) can improve the physical and mechanical properties of the material. Since manganese decreases the activity of carbon, and silicon increases, the content of manganese and silicon in the range of 9.0–10.8 and 5.1–5.8, respectively, allows one to obtain carbon activity at the level of an undoped alloy.

The proposed sintered antifriction material based on iron with enhanced mechanical and tribological properties (Table 1) is intended for the manufacture of parts operating in friction units without lubrication.

Claims (1)

Sintered antifriction material based on iron, containing chromium, manganese, silicon, carbon and copper, characterized in that it has the following ratio of components, wt.%:
chromium 0.3-0.5 manganese 9.0-10.8 silicon 5.1-5.8 carbon 3.1-4.9 copper 1-3 iron rest