SU1447915A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the production of parts subjected to mechanical loading and corrosive wear. The purpose of the invention is to increase the flexural strength, corrosion-mechanical wear resistance in a heat-treated condition. New cast iron contains, wt%: C 1.8-2.2; Si 2.8-4.6; Mp 0.2-0.8; Cr 16-21; Mo 0.5-1.5; V 1.1-2.3; B or Ti 0.02-0.2; Nb (C, N) 0.1-0.3; Fe rest. The addition of V, Mg, Te, and LH (C, N) to the composition of the cast iron provides an increase (εK 1.16-1.24 times and a crush-and-mechanical wear resistance 1.13-1.23 times. 2 tab.

Description

4ib 4; H

one

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The invention relates to metallurgy, in particular to the development of the composition of cast iron for castings operating under impact abrasive conditions.

The purpose of the invention is to increase the flexural strength, corrosion and mechanical wear resistance in the heat-treated state.

The selection of boundary limits for the content of | Q and no components in the cast iron composition is as follows.

Additional introduction of vanadium in the amount of 1.10-2.3 wt.% Provides an increase in corrosion resistance, hardness, impact resistance, microhardness, strength and stability of mechanical properties, which provides a substantial increase in resistance to impact loads and 20 corrosion-mechanical wear resistance. When its concentration is up to 1, fO wt.%, The corrosion-mechanical resistance is insufficient, and when the concentration of vanadium is more than 2.3% by weight, 25 the resistance to wear and corrosion-mechanical wear resistance is reduced.

Niobium carbonitrides in the amount of 0.1-0.3 wt. % Are an effective modifying additive that increases the microhardness of the matrix, which grinds it, which contributes to an increase in the resistance of corrosion-mechanical wear. At their concentration up to 0% by weight, its effect on the microhardness of the matrix and the resistance of cast iron to corrosion and mechanical wear is insignificant, and with an increase in the content of niobium carbonitrides more than 0.3% by weight

40 increases the number of non-metallic

inclusions along grain boundaries; impact resistance and mechanical properties and resistance to corrosion and mechanical wear and operational properties are reduced.

The carbon content in nugun within the range of 1.8–2.2%, together with manganese in the amount of 0.2–0.8%, provides cast iron with the ability to withstand shock loads and corrosion and mechanical wear and is adopted taking into account the production practice white wear-resistant cast iron.

The introduction of molybdenum into the solid solution within the specified limits effectively increases corrosion resistance, the content of martensite and in the structure. Kasbid - corrosion-mechanical

45

Q

0 5

0

0

0

five

five

3-2

wear resistance. With a molybdenum content of up to 0.5%, the microhardness of the matrix and the corrosion-mechanical wear resistance are insufficient. With an increase in the molybdenum content of more than 1.5%, the shock resistance and stability of the performance properties decrease, which is due to its insufficient solubility in chromic martensite and the formation of stable austenite. Improving the chromium content above the specified limit in the presence of a component from the group containing boron and titanium reduces the characteristics of impact destruction and resistance to corrosion and mechanical wear. When the chromium concentration is up to 16%, the microhardness of the matrix and corrosion-mechanical wear are insufficient. The components from the group containing boron and titanium increase the dispersion and microhardness of the matrix and the wear resistance of cast iron at a concentration of more than 0.02%, but at a concentration of more than 2%, the impact resistance and stability of corrosion-mechanical wear resistance decrease significantly due to an increase in the content of non-metallic inclusions.

Magnesium increases the microhardness of the matrix, the spheroidization of non-metallic inclusions, and the resistance of cast iron to corrosion-mechanical wear. Its modifying and microalloying effect begins to manifest itself at a concentration of 0.02%, but at a magnesium concentration of more than 0.1%, the pyroelectric effect is enhanced, the structure homogeneity, microhardness and resistance to corrosion and mechanical wear deteriorate. the introduction of tellurium; 3 koliches; 0.01-0.05% increases. mikrtv & matrix and corrosion-mechanical wear resistance. When the concentration of tellurium is up to 0.01%, the corrosion-mechanical wear resistance is insufficient, and with an increase in its content of more than 0.05%, the shock resistance and stability of the mechanical properties decrease.

The silicon content below 2.8% at the accepted concentration of the alloying components does not affect the corrosion-mechanical wear resistance, and an increase in the concentration of silicon more than 4.6% leads to a strong embrittlement of the alloy, a consequence of which

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durability and impact resistance.

PRI meri Experienced smelting of the known and proposed cast irons is carried out in induction furnaces with basic lining. At the end of melting, vanadium is added to the furnace, and the cast iron is modified by niobium carbonitride, magnesium ligature and tellurium by means of internal modification. Melting is carried out in dry liquid glass forms at 1470-1510 ° C.

In tab. 1 shows the composition of the cast iron experienced bottoms.

The study of the mechanical and operational properties of cast iron and the structure is carried out after heat treatment according to the mode: heating up to 1050 t10 ° C with a PP-EO rate of C / h, holding for 1 h, quenching and tempering at 220 ° C for 2 h,

In tab. Table 2 shows the results of a study of the microstructure, the microhardness of the matrix, and the mechanical properties of the iron.

As follows from the table. 2, the additional introduction of vanadium, magnesium, tellurium, and niobium carbonitrides;

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 an increase of 6 1.16-1.24 times and a corrosion-mechanical wear resistance of 1.13-1.23 times.

Claims (1)

Invention Formula Cast iron containing carbon, silicon, manganese, chromium, molybdenum, boron or titanium and iron, characterized in that, in order to increase the flexural strength, corrosion-mechanical wear resistance in the heat-treated state, it additionally contains vanadium, magnesium, tellurium and niobium carbonitrides in the following ratio, wt.%: 0 five Carbon Silicon Manganese Chromium Molybdenum Boron or titanium Vanadium Magnesium Tellurium Carbonitrides niobium Iron 1.8-2.2 2.8-4.6 0.2-0.8 16-21.0 0.5-1.5 0.02-0.2 1.1-2.3 0.02-0.1 0,, 05 0.1-0.3 Else Tv t Os g «abov T a P. l and. C in 2