SU1539229A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the manufacture of molded parts of hydraulic equipment. The purpose of the invention is to increase the hydraulic density. New cast iron contains, wt%: C 2.5 - 3.3

SI 2.1 - 2.6

MN 0.005 - 0.04

MG 0.002 - 0.02

V 0.05 - 0.45

YT 0.06 - 0.15

CA 0,002 - 0,01

SB 0.05 - 0.12

CO 0.03 - 0.12

SN 0.002 - 0.12

TIN 0.005 - 0.08 and FE the rest. The addition of SB, CO, SN and nitrogen in the form of TIN to the composition of cast iron made it possible to increase the water density of cast iron by 1.3 - 1.35 times. 2 tab.

Description

The invention relates to metallurgy, in particular to the development of cast iron compositions for cast parts of hydraulic equipment.

The purpose of the invention is to increase the hydraulic density.

The choice of the boundary limits for the content of components in the iron of the proposed composition is due to the following.

The introduction of vanadium is due to its high chemical activity, the ability to increase the content of perlite in the structure, grind graphite, increase its shape factor and the density of cast iron, which provides a significant increase in hydrodensity. With vanadium concentration up to 0.05 wt.%, The increase in ring strength and tightness is insignificant, and at a concentration of more than 0.45 wt.%, chisel increases, the concentration of nonmetallic inclusions and carbides in the structure, which reduces tightness and toughness and does not provide an increment effect (increase in hydraulic density)

Yttrium has a bleaching and spheroidizing effect on the structure, refines the melt, helping to increase strength, density and tightness. When the yttrium concentration is up to 0.06 wt.%, Its effect on the structure, the properties of cast iron and hermeticity is insignificant, and with an increase in the bismuth concentration of 0.15 wt. - wear resistance.

Titanium nitride in an amount of 0.005-0.08 wt.% Crushed graphite and the structure increases the strength, hardness and tightness of cast iron. Their content

(L

with.

determined experimentally and limited to limits, above the upper of which nonmetallic inclusions appear at the grain boundaries and tightness decreases, and below the lower limit, the dispersion of the structure, hardness and hydraulic density are low.

Magnesium has a modifying effect, increases the content of perlite in the structure, dispersity and compactness of graphite, which contributes to an increase in density and germability. The effect of magnesium begins to manifest itself steadily from a concentration of 0.002 wt%, but with an increase in their concentration of more than 0.02 wt.%, Chillings increase, trash decreases. Calcium in the amount of 0.002-0.01 wt.% Cleans the grain boundaries and increases the tightness. When the content is more than 0.01 wt.% Calcium has a graphitizing effect and reduces the density and tightness of cast iron. At a calcium concentration of up to 0.002 wt.%, The concentration of non-metallic inclusions in the pig iron increases, the compactness of graphite decreases, the tightness and reliability of the hydraulic equipment components decrease.

The content of the main components (carbon 2.5-3.3 wt.%, Silicon 2.1-2.6 wt.% And manganese 0.005 ™ 0.04 wt.%), Taking into account the practice of producing hermetic castings from high-strength cast irons for details of hydraulic equipment and corresponds to the optimum concentration,

Metals from the group containing antimony, tin, cobalt in the mentioned amounts stabilize the structure and increase the content of pearlite, the density and tightness of cast iron, but at a concentration of more than 0, i 2 May, the concentration of carbides and their segregation increases, the elastic-plastic properties decrease. and tightness of cast iron in castings.

Cerium is excluded from the composition of the proposed cast iron, since it increases the content of vermicular graphite, which reduces the elastic-plastic properties, which contributes to a decrease in density and specific tightness.

The smelting of cast iron is carried out in open induction furnaces. With

0

five

0

five

0

five

0

hot-melt pig-iron ipluzkuch mot and mirovanny pellets, iron scrap, limit iron, return their own production. Melting technologies include melting of metalized pellets, pig iron and pig iron scrap, introducing a return of its own production, melt carburizing, introducing ferrosilicon, ferromanganese and liquefied silicon, microalloying with ferrovanadium, cobalt, antimony, tin, modifying the magnesium liquefied ferrovanadium, cobalt, antimony, tin; yttrium Fill up

d

Casting molds are produced with modified iron at 1380–1400 ° C.

Table 1 shows the chemical compositions of iron castings experienced melts. Table 2 presents the mechanical properties and water density of cast iron in castings.

The tests for hydraulic density were carried out on specially made samples cut from the central part of step-by-step process samples. The test samples were kept at a constant time of 15 s for the test samples. Determination of ring strength is made on pipe samples, mechanical properties on standard samples, 1 and wear resistance according to GOST 23.204-78.

As can be seen from table 2, the proposed cast iron, due to the additional input of antimony, tin, cobalt and nitrogen in the form of titanium nitrides, has an increased hydro-density of 1.3-1.35 times.

Claims (1)

Invention Formula Cast iron containing carbon, silicon, manganese, magnesium, vanadium, yttrium, calcium, nitrogen and iron, characterized in that, in order to increase hydrodensity, it additionally contains antimony, cobalt and tin, and nitrogen contains in the form of titanium nitrides in the following ratio components, wt.%: five Carbon Silicon Manganese Mary Vanadium Itgry Calcium Antimony 2.5-3.3 2.1-2.6 0.005-0.04 0.002-0.02 0.05-0.45 0.06-0.15 0.002-0.01 0.05-0.12 table 2 worthy I 230 880,910 "60 21 406 43P 432 400 520 540 535 1, 35 I, 48 I .57 I, 62 I, 30 1.56, 6B 1.64. 12.0 10.0 9.3 9.5 0.23 0.18 0.15 0.16