SU1611973A1 - Cast iron rings of electric stoves - Google Patents

Abstract

The invention relates to metallurgy and can be used in the manufacture of electric hotplates. The purpose of the invention is to increase the stability and heat resistance. New cast iron contains, wt%: C 2.8-3.6

SI 3.01-4.0

MN 0.1-0.6

AL 0.002-0.02

CR 0.04-0.25

CU 0.4-0.25

MG 0,012-0,042

CA 0,001-0,006

REM 0.001-0.012

TI 0.01-0.10

N 0,003-0,02

FE the rest. Additional input into the composition of the proposed cast iron TI and N allows to increase the heat resistance by 1.24-1.51 times, as well as reduce casting growth by 1.28-3.6 times. 2 tab.

Description

also reduce the linear growth of 1.28-3.6 times, table 2.

The invention relates to metallurgy, in particular to the development of a composition of cast iron for the production of thin-walled electric hotplates.

The purpose of the invention is to increase the stability and heat resistance.

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

11E units of the content of the components are established, based on a favorable combination of structure and material properties.

When the carbon content is lower than the lower limit, the cast iron has an increased loading and hardness, and if the carbon content is above the upper limit, the formation of defects associated with the float of graphite is possible.

The silicon content range has been established, based on the need to produce a ferritic metal base, to create a surface protective film of silicon oxides and to increase the critical temperature of cig transformation. When the silicon content is less than G, 01 wt.%, A stable oxide film is not created, the content of pearlite in the structure of the metal base increases, the critical transformation temperature decreases.

When the silicon content is more than 4 wt.%, The ferrite is highly embrittled, which leads to cracks and conformational fights. In addition, the machinability is sharply deteriorated.

The upper limit of the manganese content is limited due to the fact that

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the higher its content, a significant increase in the amount of perlite is observed, the plastic properties of cast iron are improved.

Chromium, along with silicon, contributes to the formation of protective oxide films. The content of chromium and copper in the range of 0504-0.25 wt.% Stabilizes perlite occasionally, forming in the amount of 5-15 wt.% At the grain boundaries, and prevents the decomposition of such nepJiHTa when heated to subcritical and even critical temperatures. When the content of chromium and copper is less than 0.04 wt.%, Their stabilizing effect on perlite does not manifest itself, and with a content of more than 0.25 wt.% Of each of these elements, the hardness increases sharply and the cast iron becomes brittle.

In the specified range, aluminum contributes to graphitization of graphite and participates in the formation of a protective oxide film. When the aluminum content is above the upper limit, the porosity of the castings sharply increases.

When the content of r-shnni is less than the lower limit, a plasticized graft fg is formed in the structure of the cast iron, an increase in magnesium vEnarhne pred.ehp allows to obtain an optical amount (more than 50 wt.%) Vermiculum of graphite.

Calpium enhances the modifying effect of MagnI1I. Entering calcium of short-lived modifying agent in an amount of more than O5 006 wt.% Is undesirable because of the deterioration of the solubility of the modifier with a high calcium content j which negatively affects the quality of the modification.

Rare-earth metals, together with magnesium and calcium, enhance m: an odorizing effect, an increase in the content of rare-earth metals more than 0.012 enhances hardness and sharply increases the amount of spherical graphite in the structure.

Titanium in the amount of more than 0.01 wt. contributes to the formation of vermicular p-graphite. When titanium content exceeds 0.10 ka.%, Its modifying effect will dramatically increase, and lamellar graphite is formed in the cast iron structure,

Nitrogen helps to form vermicular graphite, crush the structure, increase the number of grains, and crush the inclusions of graphite.

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five

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five

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contribute to the production of high-density castings. When the nitrogen content exceeds the upper limit, the hardness increases, the plasticity decreases, and the risk of gas pockets in the iron increases sharply.

From cast iron of the proposed composition, rf 9 mm samples are cast, at which critical transformation temperatures and thermal fatigue resistance are determined during thermal cycling: heating by high frequency currents up to 550 ° C, water cooling.

The structure of the samples from the experimental compositions of cast iron and the test results are given in table. 1 and 2.

To obtain cast iron of the proposed composition, casting iron hoguns, pig iron, carbonaceous waste, steel, ferroalloys and ferrosilicon metals FS-45, FS-75, nitrated ferromanganese, ferrotitanium, ferrochrome, copper, aluminum are used. For smelting iron, the existing melting units are used, which ensure the temperature of the metal in the range of 1420–1500 ° C. hpHHHTfjyi in foundries with the introduction of ferroalloys and metals at various stages of smelting, with ferrochrome, nitrided ferroMapraHeirs , before it is filled with metal metal with overflows, A.PYUMINY is introduced as part of the SMG7KOZ complex modifier. The codification of cast iron to produce high strength cast iron with vermicular graphite is carried out in a casting ladle in an amount of 0.4-059% of the amount of liquid metal in the ladle or in a mold, E de smoldering the reaction chamber where it is placed. The amount of modifier depends on the amount of sulfur in the original iron. The fraction modifier SMGKOZ 5-10 ml.

As follows from Tables 1 and 2, the addition of Ti and N to cast iron in the composition of the proposed cast iron makes it possible to increase the heat resistance by 1.24-1.51 times and to reduce the linear growth by 1.28-3.6 times. F, formula invented and

Cast iron for electric hotplates containing carbon, silicon, manganese, aluminum, chromium, copper, magnesium.

calcium rare earth elements and iron, characterized in that, in order to increase the stability and heat resistance, it additionally contains titanium and nitrogen in the following ratio, wt.%:

Carbon2.8-3.6

Silicon3.01-4.0

Manganese.01-0.6

Chugu

The content of components, mas.g

Note SHG, VG, PG - respectively spherical, vermicular, lamellar graphite.

0

Aluminum

Chromium

Copper

Magnesium

Calcium

Rare earth

items

Titanium

Nitrogen

Iron

0,002-0,01

0.04-0.25

0.4-0.25

0,012-0,042

0.001-0.006

0.001-0.012 0.01-0.10 0.003-0.020 Else

Table I

Table 2

Claims (1)

Claim Cast iron for hot plates containing carbon, · silicon, manganese, aluminum, chromium, copper, magnesium, calcium, rare earth elements and iron, characterized in that, in order to increase the growth resistance and heat resistance, it additionally contains titanium and nitrogen in the following ratio of components , wt.%: Carbon 2.8-3.6 Silicon 3.01-4.0 Manganese 01-0.6 Aluminum 0.002-0, ΟΣ- Chromium Ο, 04-0.25 Copper 0.4-0.25 FROM Magnesium 0.012-0.042 J Calcium 0.001-0.006 Rare earth the elements 0.001-0.012 Titanium 0.01-0.10 10 Nitrogen 0.003-0.020 Iron Rest Table I Cast iron Component Content, May ί 1 ^Ti ϊ Vj Cr εξγξγ :: FROM Si Mp | REM I ] Sa i “ Famous 3.40 2.40 0.20 0.005 0.015 0.015 0.005 0.01 0.01 rest 3,55 2.71 S, 37 0,077 0,054 0.051 0.19 - - 0,032 0.53 _- ιι_ 3.70 3.05 0.50. 0.06 0, 10 ’ 0.06 0.40 - - 0.95 υ, ο Proposal be 1 2.80 3.01 0.10 0.001. 0.012 0.001 0.002 0.01 0.003 0.04 0.04 2 3.41 3.49 0.46 0.006 0,028 0.003 0.010 0,053 0.011 0.13 0.11 - 3 3.60 4.00 0.60 0.012 0,042 0.006 0.02 0, 10 0.02 0.25 0.25 Table 2 Cast iron The form graphite,% The metal base, ferrite (the rest is perlite),% Linear growth% Heat resistance of samples f 9 mm during thermal cycling (heating 550 ° C, water cooling), the number of cycles to failure Famous 30 vg + 70 PG 35 0.36 974 80 shg + 20 VG 65 0.44 1064 100 SHG fifty 0.58 1015 Offers gay 1 10 SH + 90 VG 85 0.28 1,324 2 35 shg + 70 VG 98 0, 18 1430 3 40 shg + 60 VG 95 0, 10 1612 Note. ШГ, ВГ, ПГ - spherical, vermicular, lamellar graphite, respectively.