RU2521915C1 - Conditioning agent - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to foundry and can be used for production of high-strength iron with globular graphite without structurally free cementite as-cast based on metalised pellets and steel wastes. Proposed agent contains components in the following ratio in wt. %: cerium - 7-10, lanthanum - 3.5-5.0, yttrium - 15-20, aluminium making the rest.

EFFECT: higher hardness and ductility.

1 ex, 1 tbl

Description

The invention relates to foundry and can be used to produce ductile iron with spherical graphite without structurally free cementite in a cast state based on metallized pellets and steel wastes.

Known modifier of the following composition, wt.%:

Magnesium 0.01-4.9 Rare earth metals 1-40 Aluminum 20-60 Barium 1-30 Calcium 5-30 Iron rest

(USSR author's certificate No. 428344, class C22C 35/00).

However, the disadvantages of this modifier are the instability of the modification effect caused by the high melting point (more than 1350 ° C) and smoke emission when introduced into molten iron.

Closest to the proposed technical essence and the achieved result is a modifier of the following composition, wt.%:

Rare earth metals 20-50 Yttrium 5-15 Aluminum rest

(USSR author's certificate No. 436882, class C22C 35/00).

However, the disadvantage of this modifier is that it contains a large amount of rare earth metals. When the content of rare-earth metals in the modifier is higher than 15%, spherical graphite disappears in the structure of cast iron and mechanical properties deteriorate.

The technical problem to be solved by the claimed invention is directed is to increase the strength and ductility of cast iron.

The problem is achieved in that the proposed modifier contains components in the following ratio, wt.%:

Cerium 7-10 Lanthanum 3,5-5,0 Yttrium 15-20 Aluminum rest

The optimal ratio of yttrium, cerium and lanthanum, respectively, is 2: 1: 0.5.

Method implementation examples

The modifier is introduced into molten iron, containing, wt.%: 3.0-3.6 carbon, 1.5-2.0 silicon, 0.5-1.0 manganese, 0.1-0.15 phosphorus, 0, 05-0.07 sulfur, by immersion in an amount of 1.0-1.25% by weight of liquid metal. The melting temperature of the modifier is 720-760 ° C. The modifier is well absorbed in cast iron. When it is introduced into liquid cast iron (at 1300-1600 ° C), the pyroeffect is not observed, the effect of producing spherical graphite is stable. On wedge samples bleached no.

The table shows the compositions of the proposed and known modifiers.

Table 1 No.
p / p The composition of the modifier, wt.%: Mechanical properties REM Y Al Tensile strength, kg / mm ² Relative extension, % Hardness HB Xie La one 7.0 3,5 15.0 74.5 54.2-59.3 4.0-4.3 260-270 2 8.5 4.25 17.5 69.75 60-64.4 4.4-5.2 280-310 3 10.0 5,0 20,0 65.0 59.4-64.0 4.1-5.0 280-310 four 28.0 15-20 rest 40.3-45.0 2.5-2.8 230-240

Claims (1)

A modifier containing rare earth metals (REM) and aluminum, characterized in that it contains cerium, latane and yttrium as a REM in the following ratio of components, wt.%:
Cerium 7-10 Lanthanum 3,5-5,0 Yttrium 15-20 Aluminum rest