SU927860A1 - Cast iron composition - Google Patents

Description

The invention relates to metallurgy, in particular to finding cast iron used for the manufacture of parts for metallurgical equipment, such as blast furnace cooling plates.

Known cast iron 1 of the following composition

weight.%:;

Carbon3,2-4,0

Silicon0.8-1.2

Manganese1 - G, 5.

Aluminum1.2-1.5

IronErest

Cast iron has a high hardness (180NV) and wear resistance.

The disadvantage of this iron is that, when operating in conditions of elevated temperatures and corrosive environments, it is subject to significant growth and internal oxidation.

The closest to the proposed nq technical essence and the achieved result is cast iron of the following chemical composition, wt.%:

Carbon.2.2-3.7

Silicon0.5-3.0

Aluminum2-7

(54) CAST IRON

2

Manganese

0.8-3

Chromium

0.16-1.0

Titanium

0.1-1.0

Cast iron may contain phosphorus (0.1–0.8 wt.%) And SFU (0.05-0.2 wt.%) As impurities. This cast iron has the following mechanical properties:

Hardness (HB),

kg / mm 230-250

ten

Strength at

bending, 6gH3r., kg / mm 34.8-30.5

In sodium bicarbonate and ammonium chloride, parts from this cast iron have a durability of more than 9000 h 2.

15

The disadvantage of cast iron is its low resistance to corrosion and scaling resistance. This leads to additional stresses and irreversible deformations, changes in size and premature failure of castings that work under conditions of elevated temperatures, heat exchange, and aggressive stove atmosphere. 3 The invention chain is an increase in bone scale and growth resistance, which leads to an increase in the service life of castings. The goal is achieved by the fact that cast iron, containing carbon, silicon, manganese, aluminum, chromium, titanium and iron, additionally contains zinc in the following ratio of components, wt.%: 2.5-3.5 Carbon silicon 0.8-1 5 0.8-1.5 0.3-1.5 Manganese 1-3 Aluminum 0.2-1.2 0.02-0.5 0.02-1.0 Else Pr, and measure. The cast iron is produced in the MGP-102 quartz-lined furnace. Zinc is injected into the bottom of the heated Z1 pig zinc pig, followed by metal extrusion into the ladle and cast iron (casting temperature 1250-1260 ° C) for samples for testing the scaling resistance and high stability of the cast iron, as well as metallographic studies. For comparison, a known cast iron is smelted and examined. The table shows the composition of the alloys and the characteristics of their oxidation resistance and high stability.

With the introduction of zinc into the composition of cast iron, deep refining, alloying, reduction in the length and branching of graphite inclusions, which take on a compact vermicular form, occur. This leads to a decrease in the contact surface of graphite with marrice and, consequently, a decrease in the internal oxidation of cast iron, i.e. to increase the scaling resistance and high stability of cast iron. In addition, zinc, an element that enhances the thermodynamic activity of carbon, slows down the process of dissolving carbon of graphite in austenite of cast iron at elevated temperatures (above 723 ° C). This, in turn, increases the stability of cast iron.

As can be seen from the table, the values of the scaling resistance and the stability of the proposed

cast iron significantly exceed the same magnitude as the known. Higher operating characteristics (scaling resistance and high stability) allow to increase the service life of castings operating under heat exchange conditions and the oxidizing atmosphere of metallurgical furnaces by 1.5-1.7 times. The use of the proposed cast iron only for blast stoves cold stoves, because of the high cost of major repairs (about 5 million rubles) according to a preliminary calculation, it is possible to obtain an expected economic effect of 70-80 thousand rubles. per year on each blast furnace.

Claims (1)

Claims of pig iron, containing carbon, silicon, manganese, aluminum, chromium, titanium and iron, about tm 5 9278606 characterized by the fact that, in order to increase titanium 0.02-0.5, scaling and corrosion resistance, Zinc. 0.02-1.0 it additionally contains zinc in the following - Iron. The rest of the ratio of components, wt.%: Sources of information. Carbon 2.5-3.5 s taken into account in the examination of silicon 0.8-1.51. Author svndetelstvo USSR N «345226, Manganese 0.3-1.5kl. C 22 C 37/10, 1968. Aluminum 1.0-3.02. USSR author's certificate N 353996, Chrome 0,2-1,2kl. C 22 C 37/10, 1970.