SU1759937A1 - Cast iron modifier - Google Patents

Abstract

Use - modification of high-chromium wear-resistant cast iron. The essence of the invention: additional input to the mixture of lead and vanadium in the following ratio, wt.%: Aluminum 3-24, lead 0.6-2.1; vanadium 3-30; silicocalcium else When using the proposed composition of the mixture for the modification, reducing the cost of modifying the cast iron while maintaining the level of its mechanical properties. 1 tab.

Description

The invention relates to foundry production, in particular to the modification of high-chromium wear-resistant cast iron.

At present, complex modifiers consisting of chemically active, surface-active, carbide-forming elements and silicon-containing substances are beginning to be used in the practice of foundry production.

Ba, Ca, Al, Ce, Sr, La and other elements that form stable compounds with oxygen and sulfur in solution are used as chemically active elements. Wide and the range of surfactants: Bi, Se, Te, Pb, Sb. The carbide-forming elements provide compounds with carbon that are stable at the temperatures of the molten cast iron. This is W, V, NB, Cr, Mo. Ti etc. Silicon-containing additives that are part of complex modifiers, as a rule, are made on the basis of ferrosilicon or silicocalcium

by dissolving Ba, Si and other elements close to them.

A common drawback of the listed analogs is that there is no clear system for the selection of components. A large number of compositions in which there are no representatives of separate groups and vice versa without the justified need for the composition introduces several representatives of one group, which complicates the manufacture of the modifier without increasing its effectiveness.

The closest to the proposed one describes the composition of the complex modifier in a positive solution (according to Application No. 4482748 / 31-02, prototype), where a complex modifier was proposed, including 3-24 AI, 3-30 V; 0.6-2.1 Bi and SiCa the rest. The known modifier makes it possible to reduce the depth of transcrystallization in castings up to 2.5 mm and, as a result, significantly increase mechanical x (L

WITH

Nj

sl y che

00

VI

Characteristics and especially impact viscosity. This modifier has significant drawbacks. The main ones are the deficiency of Bl and B and the sufficiently wide strip of residual herbal crystalline structure on the surface of castings.

The aim of the invention is to reduce the cost of the modifier, achieved by replacing BI and B with other less deficient elements,

This goal is achieved due to the fact that a complex modifier containing a chemically active, surface-active, carbide-forming element and a silicon-containing additive contains lead as a surface-active element, and vanadium as a carbide-forming element in the following ratio of components, wt.%

AI3-24

V3-30

Pb, 0.6-2.1

Silikokaltsy Else

Comparative analysis with the prototype allows us to conclude that the claimed composition of the modifier differs from that known by the introduction of new surface-active and carbide-forming elements.

The claimed modifier is cheaper by eliminating the deficient B and B.

To investigate the effectiveness of the modifying action of the modifier, in

whose composition included Pb and V, a series of experiments was carried out, during which the iron of the ICh270Kh18 brand was smelted in a silith furnace, heated to 1450 ° C, after which V + AI + PB were introduced into it first, and then separate 15 C SiCa . The value of the additive was 0.3% by weight of the metal. The modifier was introduced in the form of a mixture of crushed 75% FeV, pieces of aluminum and lead, and

also crushed 30% SICa. A part of the metal was poured into quartz ampoules of 22 mm to obtain samples for determining the transcrystallization depth (A), and the rest of the melt was used for casting

standard samples for the determination of toughness (CS).

It follows from the table that a feedback is observed between the depth of transcrystallization and toughness than already

the transcrystallization zone, the higher the viscosity. Experiments have shown that V and RV are full-fledged substitutes for B and B, and their cost is an order of magnitude lower.

Claims (1)

Claims for the modification of cast iron containing aluminum and silicocalcium, characterized in that, in order to reduce the cost while maintaining the level of the mechanical properties of cast iron, it additionally contains lead and vanadium in the following ratio of components, wt.%: Aluminum - 3.0 - 24.0; lead - 0.6-2.1; vanadium - 3.0-30.0; silicocalcium - the rest.