SU1208089A1 - Inoculant for malleable cast iron - Google Patents

Description

The invention relates to the metallurgy of alloys, namely to modifiers of liquid iron and can be used in the production of castings from ductile iron.

The purpose of the invention is to improve the mechanical properties of cast iron and reduce the duration of heat treatment.

The invention is illustrated by the following examples.

Example 1 Ferrosilicon and tellurium were ground to a powdery state and after mixing the components of the modifier with liquid glass, modifying cartridges were prepared. They took the shape of a mold that they were poured to solidify (5% liquid glass over 100% of the content of components in the modifier). To speed up the curing process, the modifying cartridges were dried in a drying cabinet at 200-300 seconds for 20 minutes. After that, they were installed in a mold to modify the cast iron.

The composition of the studied modifying mixtures is presented in Table 1,

080892

As follows from the above data, the presence in the modifier more than 25% of ferrosilicon and more than 75% of iron powder (example 6 and 5)

5 leads to the appearance in the structure of lamellar graphite, t, e, to gray cast iron, not white, and, accordingly, to a decrease in the mechanical characteristics of the cast iron, and the presence of

 O in the modifying cartridge more than 8% tellurium leads to an excessive increase in the amount of cementite in the structure and therefore to an increase in the duration of heat treatment.

 5 The presence in the modifier of less than 20% ferrosilicon (Example 4) leads to a decrease in the rate of graphitization. cast iron in the solid state and, accordingly, to an increase in the duration of heat treatment and a decrease in the mechanical properties of the iron, and the absence of less than 6% of tellurium in the modifier (example 5) leads to the appearance of gray iron in the structure, i.e. to the deterioration of the shape of graphite and the release of lamellar graphite in liquid iron and, accordingly, to a decrease in mechanical characteristics.

30 Liquid iron composition,%: C 2.4; Si 1.1; Mp 0.4; Cg 0.06; S 0.06, a melted duplex by the process of a cupola furnace - an electric arc furnace, was poured from a casting ladle. For J5 moms, in which modifying cartridges were put into a slag. In this case, prototypes were cast to determine the mechanical properties. 1 Below are the results of the modification, which are summarized in Table. 2

table 2

25

The structure and mechanical properties of the table. 2 were determined after carrying out heat treatment: heating to 960 ° C, holding at this temperature for 5 hours, cooling in air to 730 ° C, holding at this temperature

JQ temperature 5 hours and final air cooling,

Table 3 presents data on the duration of thermal heat treatment of cast irons, modified lime

., offers 1M formulations of modifiers.

Table 3

Claims (1)

MODIFIER FOR MOVIE CAST IRON containing tellurium, characterized in that, in order to improve the mechanical properties of cast iron and reduce the duration of heat treatment, it additionally contains ferrosilicon and iron in the following ratio of components, May.%: Tellurium Ferrosilicon Iron 6-8 20-25 The rest