SU1381166A1 - Pig iron modifying composition - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy, specifically to the modification of gray iron. The aim of the invention is to reduce the volume of shrinkage defects and increase the fluidity of the iron. The mixture for modifying the pig iron contains a ligature of the following composition, wt%: silicon 65-80; magnesium 0.8-2.7; calcium 0.6-4.2; aluminum 0.7-2.0; carbon 0.03-3.0, iron - the rest, as the base and antimony 10-50 wt.%. The use of the mixture reduces the volume of shrinkage defects by half and increases the fluidity of cast iron by one and a half times. Table I with b

Description

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The invention relates to ferrous metallurgy, specifically to the modification of gray iron.

The purpose of the invention is to reduce the volume of shrinkage defects and increase the fluidity of cast iron.

The proposed mixture for the modification of cast iron contains a ligature of the following composition, wt%: Silicon 65-80

Magnesium 0.8-2.7

Calcium. 0.6-4.2 Aluminium 0.7-2.0

Carbon0.03-3.0

IronErest

and additionally contains antimony in the following ratio of components, May.%:

Silicon Ligature -

- Magnesium - Calcium - Aluminum - Carbon - Iron. The basis of antimony10-50

The mixture for modifying the pig iron is introduced in an amount of 0.2-0.7% by weight of the liquid metal.

To study the effect of the modifying mixture, the composition cast iron is treated, wt%: C, 3.32; Si 2.5; Mp 0.8; Cg 0.14; Ni 0.04; S 0.04; P 0.06, which is melted in an ICT-0.16 induction furnace at 1400-1420 C. A 0.4% modifying mixture is introduced into the jet of liquid metal at the overflow from the furnace into the ladle.

Granulometric composition of the components of the mixture, mm:

Ligature Si - Mg - - Ca - Al - C - Fe2-10

Antimony Su2 (GOST

1089-73) 5-10

The modifying mixture is prepared by mechanical stirring. The compositions of modifying mixtures and ligatures, as well as the properties of cast iron are given in the table.

From the table it can be seen that the best options are mixtures 1-3. Modified cast iron 4 has a powder that is l-24% higher than cast iron modified by the proposed mixtures 1-3, Modified cubes of СЮ 5, have shrinkable defects by 1.88 times more, liquid-type - by 19% less than cast iron modified with mixtures 1-3. In addition, in the cast iron structure,

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five

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five

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five

five

Mixture 4 contains 10% free ferrite and therefore does not provide a pearlite structure. Cast iron modified with ligature 6 (prototype), as compared with cast iron modified with mixtures 1-3, has l-2.7 times more shrinkage defects, 5% less fluidity, a significant amount of free ferrite (22%).

In addition, the ligature 7 was made by fusing the ligature 6 (prototype) with metallic antimony (GOST 1089-73). Cast iron modified with this ligature has a 2.88 times greater volume of shrinkage defects, vl2% less fluidity and a significant amount of ferrite (18%) compared to cast iron modified mixtures 1-3,

Thus, the introduction of the mixture to modify antimony in an amount of more than 50% leads to a deterioration of the technological properties of the pig iron and the cost of the pig iron. Introduction to the composition of the modifying mixture of less than 10% antimony leads to an increase in the volume of shrinkage defects and a decrease in the fluidity of pig iron, as well as to the formation of a ferrite-pearlite structure in the iron instead of the required pearlitic one.

The proposed mixture can be used to modify cast iron of thin-walled, thick-walled and various castings, for example, ribbed cylinders.

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Claims (1)

Invention Formula The mixture for the modification of cast iron, containing a composition ligature, wt.%: Silicon 65-80 Magnesium 0.8-2.7 Calcium0,6-4,2 Aluminum 0.7-2.0 Carbon0.03-3.0 IronErest In order to reduce the volume of shrinkage defects and increase the fluidity of cast iron, it additionally contains antimony in the following ratio, wt.%: Antimony10-50 The specified ligature is Else 50 0.21 419 50 90 0.41 .342 ten 75 0.34 382 25 49 51 91 0.52 321 9 ) 100 0.87 283 , one, , TOO 0.92 341 0.20 420 0.20 420 22 18