SU1266891A1 - Cast iron - Google Patents

Abstract

The invention relates to the field of production of ferrous metals used to produce castings that work in friction pairs at high speed and high hydraulic pressures. The aim of the invention is to increase the mechanical, anti-friction properties and water density of iron castings. The proposed cast iron contains, wt%: carbon 2,83, 5; silicon 1.8-2.7; manganese 0.5G, 2; copper 0.2-0.7; phosphorus 0.1-0.2; magnesium 0.03-0.05; barium 0.1-0.3; indium 0.05-0.1; iron else. with 2 tabl .®

Description

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o - The invention relates to the production of ferrous metals used to produce pipes, sleeves, blocks and other castings, which work as anti-friction in friction pairs and high hydraulic pressure, and can be used in metallurgical shipbuilding and other industrial sectors. The aim of the invention is to increase the mechanical, anti-friction properties and water density of cast iron. Note The iron head was produced from fresh charge materials in an induction furnace with a capacity of 25 kg in a crucible with an acidic quartz foot. When the temperature of the cast iron poured the bench type ingots. . The chemical composition of the proposed and well-known iron is given in table 1. The choice of the quantitative ratio of the elements is made, based on the following considerations. The carbon content ranges from 2.8-3.5%, which facilitates the process of obtaining metal in cupola furnaces, and the casting properties of the cast iron are not. Increasing the carbon content above the upper limit is impractical, but since it adversely affects the mechanical properties of cast iron, silicon is contained in an amount of 1.8-2.7%. The silicon content above 2.7% causes fragility even with the usual content of manganese and phosphorus. When reducing the content. silicon below 1.8% in thin castings may be the release of graphite in the form of lamellar, in addition, the area of increased shrinking shells increases, which has a negative effect on hydrodensity. Manganese has the opposite effect on the structure of cast iron. silicon, reducing the amount of ferrite and increasing the amount of pearlite, in connection with which it is increased, and decreases e. Therefore, to obtain high ductility, the manganese content should not be lower than 0.5%, which eliminates heat treatment. As manganese increases, the pig iron decreases. The manganese content above 1.2% leads to an increase in the quantity of perlite and an increase in the cold break ratio. Phosphorus has a very significant effect on the structure and properties of cast iron, the image of the PV and lowering the elongation and impact strength, so its content should not exceed 0.2%, and in thick-walled castings, where liquation is widely developed, the content should be 0.1% that contributes to the preservation of fine-grained structure. Copper should be in the amount of 0.20, 7%. If the copper content is higher than 0.7%, lamellar graphite is formed, and as copper decreases below 0.2%, the strength of the iron does not increase. The introduction of magnesium in this ratio (0.03-0.05) has a positive effect as a spheroidizer, if it is less magnesium, then graphite crystallizes into a spherical shape only partially, as a result of which the mechanical properties of the iron decrease. A higher content of magnesium (more than 0.05%) leads first to the formation of cementite in the raw structure, and then to overmodification (formation of lamellar graphite). A lower magnesium content (less than 0.03%) does not lead to graphite in a spherical shape, which negatively affects the anti-friction properties. The introduction of indium in the amount of indium in the amount of 0.05-0.1% and barium in the amount of 0.1-0.3% with a low melting temperature helps to obtain the required spherical shape of graphite and fine grain size, improves the plastic properties of the iron, which is due to the distribution of these elements within the grains. In addition, these elements contribute to the strengthening of grain boundaries, since all oxides are displaced inside the grains. However, indium and barium are deoxidizing, injected. Which improves the quality of the metal, helps to increase the density of castings, especially in thin sections, such products as hydraulic blocks. Reducing the content of elements less than the lower limit does not provide all of the above qualities of high-strength and anti-friction cast iron. Increasing the content of these elements above the upper limit dramatically reduces

the elastic properties of cast iron due to the release of oxides, indie and barium at the grain boundaries.

Samples were prepared from the obtained ingots to study the mechanical 5 antifriction properties of cast iron. In addition, whether the samples were made for water density.

Tests for breaking the samples were carried out on a machine of the P-5 brand, and on impact by the machine KM-30. The antifriction properties of cast iron were determined on the MI-1 friction machine according to the roller scheme - a partial liner with a constant speed of a slip w of V 0.45 m / s.

In Table 2, according to the test results, the mechanical, anti-friction properties and water density of the proposed alloy are given in comparison with the well-known .20

As can be seen from the table, the cast iron of the proposed composition has high kexaHH4ecKHMH, anti-friction properties and water density.

In addition, the pre-fusion alloy showed high performance during rigorous tests on the stands in the Eistema hydraulic pumps and hydraulic motors.

made from the proposed composition of cast iron, amounted to 32,000 h at suitable pressures of up to 400 atm and casting speeds of up to 15 m / s.

Thus, the proposed alloy mechanical, anti-friction properties, wear resistance and water density exceeds the known cast iron.

Claims (1)

Formula invented and Cast iron containing carbon, silicon, manganese, copper, phosphorus, magnesium and iron, in which, in order to increase the mechanical anti-friction properties and hydrodensity, it additionally contains barium and indium in the following ratio, wt.%: Carbon 2.8-3.5 Silicon1.8-2.7 Manganese 0.5-1.2 Copper0,2-0,7 Phosphorus 0.1-0.2 Magnesium. 0.03-0.05 Barium0,1-0,3  Indium0.05-0.1 table 2