SU1763505A1 - Cast iron - Google Patents

Abstract

This invention relates to metallurgy, in particular to compositions of high-strength gray alloyed iron. SUMMARY OF THE INVENTION: Cast iron contains carbon, silicon, manganese, chromium, nickel, vanadium, cobalt, titanium, and iron. New is the addition of gallium and germanium to cast iron in the following ratio of components, May. %: carbon 2.5-4.5; silicon 1.5-3.6; manganese 0.3-1.5; chromium 0.4-3.2; Nickel 0.3-1.1; vanadium 0.01-0.05; cobalt 0.01-0.2; titanium 0.05-0.5; gallium 0.0005-0.005; germanium 0.0005-0.001; iron - the rest. The use of cast iron makes it possible to improve the service properties of cast iron: 0 257-288 MPa, heat resistance (number of thermal cracks, pcs) 21-25. cl

Description

This invention relates to metallurgy, in particular to compositions of high-strength gray alloyed iron.

Known cast iron 1, the following chemical composition, May. %:

Carbon

Silicon

Manganese

Chromium

Nickel

Vanadium

Molybdenum

2.5-4.0

0.5-2.6

no more than 1.0

0.15-1.5

0.25-2.0

0.1-0.4

0.25-2.0

0.15-0.5

0.25-2.0

Rest

Boron

Copper

Iron

The disadvantage of this iron is not enough high wear resistance and strength, as well as its high cost, which significantly narrows the scope of its use.

The closest in technical essence and the achieved result is cast iron 2, containing, May. %:

Carbon3.0-3.4

Silicon1.0-1.2

Manganese0.4-0.8

Chrome 7.5-9.5

Molybdenum 0.6-0.8

Nickel0,2-0,4

Vanadium2.0-2.4

Tungsten 0.6-0.8

Cobalt1,6-3,0

Titanium0.08-0.15

IronErest

The disadvantage of this cast iron is its low strength and heat resistance, which

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ABOUT

from the next

reduces the operational properties of castings.

The aim of the invention is to increase the strength and heat resistance of cast iron.

This goal is achieved by the fact that the known iron containing carbon, silicon, manganese, chromium, nickel, vanadium, cobalt, titanium and iron, according to the invention, additionally contains gallium and germanium in the following ratio of components, May. %:

Carbon2,5-4,5

Silicon1.5-3.6

Manganese 0.3-1.5

Chrom0.4-3.2

Nickel0.2-1.1

Vanadium 0.01-0.05

Cobalt 0.01-0.2

Titan0.05-0.5

Gallium0,0005-0,005

Germanium0,0005-0,001

IronErest

The choice of limits for the content of elements in the proposed iron is associated with the features of their influence on the crystallization process. The chromium content in the claimed limits provides crystallization, in contrast to the prototype cast iron, in a stable pattern without isolation of free cementite, which increases the heat resistance of the cast iron.

The limits of the content of vanadium and titanium were chosen taking into account their joint influence with chromium on the formation of complex carbides in the cast iron structure, which contribute to the strengthening and enhancement of the proposed properties. An increase in the content of vanadium and titanium above the upper limit leads to the bleaching of pig iron and a decrease in the claimed properties.

The limits of nickel and cobalt content in the iron are due to their joint effect with the carbide-forming elements on the iron structure. The claimed limits for nickel and cobalt provide effective resistance to the whitening effect of chromium, vanadium and titanium with their content at the upper limit. The introduction of cast iron into the claimed limits of gallium and germanium, which exhibit donor properties when interacting with other components, helps to neutralize the negative effect of carbide stabilizing elements on the heat resistance of cast iron. In addition, these elements contribute to obtaining a uniform structure in the iron without structurally free cementite, which increases the strength properties. When the content of gallium and germanium is lower than the proposed lower limit, their effect on the claimed properties decreases sharply, and when the content of these elements is higher

of the upper limit, they contribute to the release of free ferrite in the iron structure, which reduces the strength and heat resistance of the iron.

5 Comparative analysis of the claimed

technical solution with the prototype showed that the composition of the pig iron differs from the known introduction of new components, namely gallium and germanium. In this way,

0 the claimed technical solution meets the criterion of novelty.

In the process of researching the claimed technical solution for the scientific, technical and patent literature has not been identified.

5 sources containing together the features that distinguish this technical solution from the prototype. The introduction of gallium iron into the composition is known. The use of gallium in the well-known solution made it possible to increase purity and improve the workability of the iron. However, the use of this element in combination with other components in a known composition does not provide it with the properties that they exhibit.

5 in the claimed solution, namely the increase in strength and heat resistance. Thus, the introduction of cast iron, gallium and germanium, allows us to conclude that the proposed technical solution meets the criterion

0 significant differences.

Example, For experimental verification of the claimed composition, 6 compositions of cast irons were smelted (see table). The cast iron was smelted into 200 kg of an induction furnace.

5 After the iron was melted in the furnace and the melt was overheated to a temperature of 1400 ° C, cylindrical billets with a diameter of 50 mm and a length of 400 mm were poured into earth forms. From these blanks, samples were made to test for strength in accordance with GOST 1497-73. Heat resistance was determined by counting thermal cracks on samples with a diameter of 15 mm and a height of 15 mm after a series of

5,100 thermal cycles carried out according to the mode: heating to 800 ° C, holding for 15 minutes and cooling in water.

As follows from the data obtained, the retention of the ingredients in the proposed

0 (2-4) provides the cast iron with an increase in tensile strength of more than 1.6 times and heat resistance by more than 1.4 times as compared with the prototype cast iron. When the content of ingredients in the pig iron is lower than the lower limit (5) and above the upper (6), there is a sharp decrease in the strength and heat resistance.

The study of the properties of the proposed cast iron showed that when the content of ingredients in the proposed limits it is characterized

Claims (1)

Claim Cast iron containing carbon, silicon, manganese, chromium, nickel, titanium, vanadium, cobalt and iron, characterized in that, in order to increase strength and heat resistance, it additionally contains gallium and germanium in the following ratio of components, May. %: Carbon 2.5-4.5 Silicon 1,5-3,6 5 Manganese 0.3-1.5 Chromium 0.4-3.2 Nickel 0.2-1.1 Titanium 0.05-0.5 Vanadium 0.01-0.05 10 Cobalt 0.01-0.2 Gallium 0.0005-0.005 Germanium 0.0005-0.001 Iron Rest Example Number Cast iron The content of components in cast iron "wt.% Tensile Strength, NPa Heat resistance (number of terms, cracks), pcs FROM Si Np St N1 Ti V With Sa Ge Fe. According to the prototype 3.2 0.6 8.5 0.3 0.12 2.2 2.2 - - rest 156 36 2 Offered All items on NP 2,5 1,5 O.z oh 4 0.2 0.05 0.01 0.01 0,0005 0,0005 rest 257 22 3 All items are average 3.5 2,5 1,0 1.8 0.6 0.25 0,03 0.1 0.002 0,0005 • rest 28V 21 4 All items on 8P 4.5 3.6 1.5 3.2 1,1 0.5 0.05 O. ² 0.005 0.001 rest 261 25 5 All items below NP 2,4 1.4 0.2 0.3 oh 1 0.02 0.005 0.005 0,0003 0,0003 rest 162 45 6 All items above OHL 4.6 3,7 1.6 3.4 1.2 0.6 0,07 0.25 0.006 0.002 rest 14? 41