SU1247428A1 - Wear-resistant foundry pig iron - Google Patents

Description

The invention relates to metallurgy, in particular, alloyed iron, working under conditions of abrasive wear under dynamic loads or elevated specific pressures, for example, replaceable parts of metallurgical and mining equipment, mold plates for the production of refractories, lining elements ball and ball-less ore-milling mills, etc.

The aim of the invention is to increase the viscosity of the inner layers of massive wear-resistant castings.

The invention is illustrated by examples.

The alloys are melted in an induction furnace with the main lining in the atmosphere of air, the contents of the components are given in Table 1 (the values of the concentrations of the components are rounded to the indicated signs).

The alloys were poured into a dry sandy-clay form with a diameter of 300 m and a height of 700–800 mm. Test specimens were cut from the axial portion of the casting perpendicular to its axis.

The test results (average for five samples) are shown in Table 2.

Nickel within the specified limits in the presence of the remaining alloy components stabilizes austenite in the casting layers lying at a depth of more than 100 mm from the surface of the heat sink, thereby increasing the viscosity of the material in these layers. This stabilization of austenite is not observed when the nickel content is below 1.5%. A decrease in the nickel content above 2.2% is impractical, since it does not lead to a further significant increase in the austenite resistance.

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Titan, within the specified limits, leads to: a decrease in the length of excess austenite dendrites and a crushing of austenitic chromocarbid eutectic colonies based on hexagonal carbide (Cr, Fe) C, which generally increases the viscosity of the alloy. The introduction of titanium into the alloy in an amount of less than 0.15% does not change the extent of excess dendrites; therefore, no decrease in the viscosity of the alloy is achieved. The addition of titanium to the alloy in an amount of more than 0.3% does not lead to further grinding of the eutectic colonies; therefore, it is inexpedient

The joint introduction of nickel and titanium in the specified ratio is most beneficial, since simultaneously with the stabilization of austenite of the inner layers of products, the extent of excessive austenite dendrites and the size of eutectic colonies decrease, resulting in a significant increase in viscosity of castings. depth (over 100 mm).

This makes it possible to broaden the limits of the silicon content compared to the prototype type.

From the data of Table 2, it follows that the viscosity of the proposed alloy, characterized by the magnitude of the impact strength in the layers of castings located at a depth of more than 100 mm from the heat sink surface, is 8–58% higher than the maximum for the prototype alloy, which allows It does not increase the service life of massive castings operating under abrasive conditions with dynamic loads or lower specific pressures.

I Prototype 1.8 1.00

P, 0 9,000.05 0.002 0.043 0.063

Editor M.Kelemes

Compiled by A. Osmantsev

Tehred G.GerberKorrektor V.Sinitska

Order 4082/27

urx, r 567 subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

, T a 6 l and c a 11

Table 2

Claims (1)

WEAR-RESISTANT CAST IRON, containing carbon, manganese, silicon, chromium, aluminum, calcium and iron, characterized in that, in order to increase the viscosity of the inner layers of the castings, it additionally contains nickel and titanium in the following ratio of components, May.%: Carbon 1, 8-2.5 Manganese 11.0-15.0 Silicon 1.0-2.2 Chromium 9.0-12.5 Aluminum 0.05-0.1 Calcium 0.002-0.005 Nickel 1,5-2,2 Titanium 0.15-0.3 Iron Rest No. M Bj