SU789622A1 - Modifier - Google Patents

Description

The invention relates to metallurgy and foundry, to the issue of the manufacture of cages and their use for high-strength cast iron. Known modifier 1 for the following composition, wt.%; Magnesium Nickel Silicon Rare Earth Metals XYTICIA Carbon Manganese Copper Else. Iron However, the modifier does not provide for obtaining a high level of the co-mechanical properties of cast iron. The closest in technical terms to the proposed subject is cast iron 2 of its composition, Magnesium 5-10. Calcium 5-15. Rare earth metals2-10 Iron1-15 Nikel10-20

(54) MODIFIER 10g-20 Manganese 10-20 0.5-6 Carbon 3-15 Else Silicon However, a high content of calcium in the known composition of the modifier when used to modify the cast iron in the form results in the slagging of the modifier surface and the reaction The interaction of the metal modifier virtually ceases. The optimum content of the margin in the modifier for modification in the form is not more than 2, -4%, which is established experimentally. In addition, a modifier with a fraction size of not more than 10 mm must be used for modifying the mold. Copper and nickel in quantities of 10–20% impair the modifier comminution and contribute to the stabilization of the pearlite component of the metal matrix, which leads to a decrease in the plastic properties of the iron. Similarly behaves and manganese.

When using a known modifier in the microstructure of cast metal, the presence of stringent-free cementite is detected, which reduces the plastic properties and requires a heat treatment.

The purpose of the invention is to develop a modifier composition, mainly for obtaining high-strength cast iron by modifying cast iron in a mold, which provides an increase in the number of graphite inclusions and a reduction in their size, an increase in elastic-plastically} C.

The goal is achieved by the fact that the proposed modifier additionally contains aluminum and tungsten in the following ratio of components, wt.%:

Magnesium 5-10,0

Calcium0,2-2,4

РЗМ0,1-5,0

Barium0.5-3.0

Copper0,1-1,0

Nickel 0.1-3.0

Manganese 0.1-1.0

Carbon 0.2-2.0

Aluminum0,2-8,0

Tungsten0.01-2.8

Silicon45-70.0

Iron ElseAluminium in the composition of the modifier in the amount of 0.2-8% together with calcium, barium and rare-earth metals contributes to the grinding of graphite inclusions, which leads to the stabilization of the modification process.

Entering the modifier in a square increases the number of graphite inclusions and uniform distribution of all components in the modified iron in the cast state. The proposed method is illustrated by an example.

The cast iron is melted in a 30 kg induction furnace. The modification is carried out directly in the casting mold. The modifier with the size of the fractions up to 6 mm i.v. in the amount of 1% of the consumption of liquid iron for casting the mold. One wall of the chamber with the modifier is made of sheet of quartz glass, through which the modifier is observed to dissolve with a flowing stream of cast iron. Get the following chemical composition of the original cast iron, wt.%: 3,42-3,46 -carbon, 1,87-1,92 silicon, 0,23-0,28

manganese; 0.03 sulfur and 0.09 phosphorus. The melting of the original cast iron is carried out in a DSP-O electric arc furnace, 5. The pouring temperature is within 1400-1430 C .;

To study the structure and mechanical properties of modified cast iron, potting samples and castings with wall thicknesses from 5 to 40 mm are taken.

Table 1 shows the composition of complex modifiers; in table 2 the mechanical properties. and the structure of cast irons modified by the proposed and known compositions.

It should be noted that the mechanical properties of all cast iron modified with complex modifiers strongly depend on the composition of the original cast iron, especially its content of chromium, manganese, sulfur and phosphorus. The increase in their content in the original cast iron dramatically reduces the mechanical properties of the modified cast iron. Phosphorus and chromium are particularly negatively affected by plastic properties and impact strength.

The microstructure of cast iron modified with the proposed modifier in samples with a diameter of 30 mm is ferritic perlite with a content of 10-15% perlite, and the structure of cast iron is modified with a known modifier of pearlite-ferritic with a content of 10-18% ferrite. Checking the proposed composition of cast iron showed its effectiveness in the manufacture of cast iron with enhanced elastic-plastic properties. Thus, the elongation is increased by 7%, and the impact strength is 6 kgm / cm with a decrease in hardness of 80 NO. Obtaining high plastic properties in the cast state eliminates the heat treatment of castings.

The modification process proceeds calmly, without priroeffektu and smoke emission.

A preliminary calculation of the expected economic effect from the use of the modifier of the proposed composition shows that by increasing the number of graphite spheroids by 1 mm by 2 times, reducing their size by 1.5 times, increasing the relative elongation by 7% of impact strength per b kgm / cm and the elimination of heat treatment of castings, it will be 35-40 rubles. in the production of 1 ton of castings.

:Table 1

Famous

Known composition

6 — tensile strength; 5 — relative elongation; a — impact viscosity.

HB - hardness

Claims (2)

1. The patent of France 2152243, cl. C 22 C 35/00, 1972. 2. Authors certificate of the USSR 559990, cl. C 22 C 35/00, 1977.