SU1425242A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the production of aluminum. The purpose of the invention is to increase the heat resistance in an anode gas at 1050 ° C and improve machinability. Cast iron contains, wt%: C 1.5-2.4; Si 4.5-6.0; MP 0.005-0.04; Cr 0.1-0.25; A1 1.1-2.5; Y is 0.04-0.1 and Fe is the rest. Increasing the content of Si and A1, as well as reducing the content of Mn in the iron of the proposed composition provides an increase in heat resistance of 1.47-2.15 times and improves workability by 1.09-1.21 times. 1 tab.

Description

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The invention relates to metallurgy, in particular to the development of a composition of cast iron for castings operating in an anode gas at high temperatures.

The purpose of the invention is to increase the resistance to heat in an anodic grz environment at 1050 ° C and to improve workability. The choice of the boundary limits of the components included in the proposed composition of cast iron, due to the following.

The lower limit of the carbon content is 1.5 wt.% And silicon, 4.5 wt.% Ensures the production of a ferritic-pearlitic structure with carbide inclusions not exceeding 1%. The upper limit for carbon at 2.4 wt.% And silicon for 6.0 wt.% Is associated with the formation of high-silicon ferrite, highly resistant to oxidation processes and high-temperature gaseous medium.

The lower limit on the manganese content is 0.005 wt.%, Chromium 0.1 wt.%, Aluminum 1.1 wt.% And yttria 0.04 wt.% Provides a significant increase in heat resistance in an aggressive gaseous environment at high temperatures with a minimum degree of doping.

A limiting chromium concentration of 0.25 w / v is established from the need to eliminate chill in the castings.

Increase yttri content

(0.1 wt.%) Does not give an increase in performance and is not economically feasible. When working with aluminum-containing cast irons, with an aluminum content of more than 2.5 wt.%, The tendency of the melt to film formation increases markedly, which leads to a decrease in the operating characteristics of the castings.

The smelting of cast irons of the known and proposed compositions is carried out in 60 kg of an acid fusion induction furnace. The technology for producing an alloy of the composition proposed consists in melting a low-manganese mixture — high-carbon metallized pellets;

neither in the melt of silicon ferroalloys (75 wt.% silicon), chromium (45 wt.% chromium), technical aluminum (98 wt.% aluminum) and modification in the ladle at 1450 ° C with metallic yttrium (99.5 wt.% yttrium) . The charge is calculated taking into account the absorption of silicon, chromium and aluminum at the level of 85-90%, yttrium - 45-50%. For tests for heat resistance in aggressive media, samples of cylindrical shape with a diameter of 0.015 mm and a length of 0.015 m are made and subjected to grinding. Heat resistance is estimated by the gravimetric method (kept at 1323 ° C for 75 hours). The workability of cast iron is indirectly judged by the durability of the tool used to process parts from cast iron of known and proposed compositions with the same processing conditions.

The chemical compositions of cast iron and a comparative analysis of their properties are given in the table.

As follows from the table, the cast iron of the proposed composition due to the selected ratio of components provides increased heat resistance in the environment of the anode gas

pr And 1050 ° C. 1.47-2.15 times, as well as improving the workability of 1.09-1.21 times.

Claims (1)

Invention Formula Cast iron containing carbon, silicon, manganese, chromium, aluminum, yttrium and iron, characterized in that, in order to increase the hydro resistance in the anode gas at 1050 ° C and improve the workability, it contains components in the following ratio, wt.%: Carbon 1.5-2.4 Silicon4,5-6,0 Manganese0.005-0.04 Chrome 0.1-0.25 Aluminum1.1-2.5 Yttrium0.04-0.1 IronErest