SU1225873A1 - Wear-resistant cast iron - Google Patents

Description

The image is referred to as a region of wear-resistant cast irons operating under conditions of intense wear at elevated temperatures and specific pressures (for example, a sunset tool when processing the ends of tubular blanks, punches, hot pressing dies).

The purpose of the invention is to increase the wear resistance at 873 - 1273 K and a specific pressure of 10-50 Mlla.

The invention is illustrated by the examples in the table.

Boron with a high content of manganese forms complex carbides with it and iron, which increase wear resistance. Boron, the entrance to the cast iron, contributes to the uniform distribution of fine carbides over the cross section of the casting, increases the microhardness of cementite and the overall hardness, degasses the cast iron.

Aluminum contributes to the formation of intermetallic phases, and thereby increases the heat resistance of cast iron, which reduces the development of plastic deformation at high temperatures and maintains the profile of the product. The thief with aluminum and in the alloy forms solid particles of compounds ht. During the atomic interaction, a large number of ultradispersed particles are formed, which appears as crystal nuclei and nuclei, which leads to a refinement of the structure and an increase in wear resistance.

Manganese in the amount of 1.85-2.55 significantly reduces the viscosity of liquid high-chromium iron, thereby improving casting properties, and increases the dispersion of the structure. Maganet with aluminum forms the compound AfgMn, contributing to the increase of heat resistance. Manganese and iron with boron give complex carbides that increase the wear resistance of

The atomic interaction intermetallic compounds AEB and MnBj form a large number of ultrafine phases, which are germs of small grains and are located between the base of the metal matrix, which prevents the blocks of grains from sliding relative to each other. Thus, the resulting structure is strengthened by the listed intermetallic phases. A significant role in cast iron is performed by the AfB2 compound, located 1225873J

Subscribe to the grain boundaries

five

not only strengthens them, but also protects these boundaries from intermetallic corrosion in an oxidizing environment.

Possessing a great remedy for oxygen, aluminum forms a strong oxide. The addition of aluminum to cast iron results in continuous oxide films. These films are tightly bound to the metal surface, which in turn reduces the intensity to oxidation and contributes to the improvement of heat resistance and heat resistance, and especially increases wear resistance at elevated temperatures. Under the influence of aluminum in the cast iron, both the nature of the high carbon phases and the solid solutions change. The composition of the eutec-totoid may include carbide (the interatomic bonds in austenite and ferrite acquire a pronounced metallic character.

The occurring changes in cast iron when aluminum is introduced into it significantly change the whole complex of physicomechanical characteristics and especially increase the wear resistance of the proposed cast iron in the temperature range 873-1273 K at a specific pressure of 10-50 MPa.

In the range of 2.2–4.0% of aluminum, an increased resistance to an increase in the volume of iron appears, mainly due to the complete elimination in the structure of the graphite phase. Up to 2.2% aluminum is a strong graphitizer, the amount of carbides is small and the wear resistance falls.

Increasing the amount of aluminum above 4% in cast iron results in increased brittleness and drastically reduces the wear resistance of cast iron at elevated temperatures under thermal cycling conditions. Maintaining a high carbon content in cast iron, contributing to hardness and wear resistance, is possible only if the nature of the interaction changes in the range of aluminum concentration of 2.2–4.0%.

Tests of cast iron for wear with an aluminum content of more than 4% show a weight loss of the sample from the proposed cast iron of 10 kg / m per 1000 m path. Such a sharp deterioration in the properties of the iron 5 is associated with the deterioration of its structure due to the manifestation of a re-graphitizing ability. When the aluminum content is less than 2.2%

0

0

five

0

intensive sticking of the material in contact with the iron (steel 35) n with an increase in the duration of the test of the sample, its engraving loses its original shape.

An increase in the carbon content of over 3.6% leads to the appearance of large acute-angular carbides in the cast iron structure, which contributes to a sharp increase in the adhesion of the counterbody material to the tool from the proposed cast iron. A carbon content of less than 3.1% significantly reduces wear resistance at elevated temperatures and specific pressures.

Wear resistance tests were carried out on a specially designed installation. The sample rotation speed of 2.3 m / s. The temperature of the counterbody made of steel 35 varies from 873 to

1.5 1.85 26

1.3 2.4 23

1.1 2.55 24

1.4 2.2 26

1.5, 9 25

2.2 0.05 Else

4.0 0.08 Else

3.2 0.15 Else

2.2 0.1 0.- talted

2.0 0.15 Else

3.4 1.1 2.1 .24 4.2 0.1 Else

734

1273 K, the specific pressure of the sample on the counterbody is 10-50 MPa. The weight loss of the sample is determined by weighing on an analytical balance with an accuracy of four decimal places.

The proposed cast iron is melted in an induction furnace with a neutral lining of high-alumina material, l

The initial charge materials are foundry coke-iron castings L2, LZ, steel scrap, ferrochrome and

the ferromanganese is introduced with a solid filling, and the ferroboron and aluminum are introduced into the liquid metal before release. The pouring temperature of cast iron is 1673 + 10 K. The temperature of the liquidus hurray is 1533, the solidus temperature is 1418 K.

1073 1.4 1273 0.9

3.8

1.7

1.5

3.9

2.0

0.8

3.4 (sticking)

Nalipanie

-

5.8 (deformed) 3,4 (deformation)

10.2

Editor M.Blanar

Compiled by G. Dudik Tehred V. Kadar

Order 2104/19

Circulation 567Subscribe

LOWERED by the USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

Table continuation

CorrectorE.Sirohman

Claims (1)

WEAR-RESISTANT CAST IRON containing carbon, silicon, manganese, chromium, aluminum and iron, characterized in that, in order to increase wear resistance at 873 1273 K and specific pressure 10 50 MPa, it additionally contains boron in the following ratio of components, mas’L: Carbon 3.1-3.6 Silicon 1.1-1.5 Manganese 1.85-2.55 Chromium  23.0-26.0 Aluminum 2.2-4.0 Boron 0.05-0.15 Iron Rest §