RU2002841C1 - Method for manufacturing charge for melting aluminum alloys and device for embodying it - Google Patents

Abstract

Usage: foundry, production of ligatures and other charge materials for the preparation of aluminum alloys and during in-mold modification. Essence — in order to increase the dissolution rate of charge materials, improve the mechanical properties of the alloy, casting and deformation are carried out in a relief water-cooled roll mold with the formation of protrusions and depressions on the surface of the charge with a ratio of the total surface area of the charge material to its volume from 20: 1 to 30: 1, in this case, the ratio of the depth of the depressions (height of the protrusions) to the size of the gap between the rollers should be ensured in the range from 3.3 to 2. 3 tables. 1 zlf, 2i

Description

The invention relates to non-ferrous metallurgy, in particular to methods for preparing a charge before melting, and can be used to obtain alloys and other charge materials for preparing, for example, aluminum alloys.

The state of the charge and the conditions for the preparation of charge materials have a significant effect on the structure and properties of aluminum alloys. This necessitates the preparation of the mixture before melting (V. Nikitin. The main laws of structural heredity in the charge-melt-casting system. Foundry, 1991, No. 4, p. 4-5).

A known method of preparing a charge for the preparation of aluminum alloys, including heating above a solidus temperature. melting and plastic deformation in a liquid-solid state 1.

The disadvantage of this method of producing a charge is that when it is used, having a smooth surface leads to a relatively low dissolution rate of the charge material when introduced into the melt, especially for refractory alloys such as aluminum-titanium, aluminum-zirconium, aluminum-titanium-boron. The coarse inclusions of primary intermetallic compounds in the structure, dissolving at a low speed in a liquid alloy at low technological temperatures and at a limited time for preparing the alloy, are often the reason for insufficient grinding of the structure or marriage of castings for intermetallic inclusions (Ligatures for the preparation of aluminum and magnesium alloys Napalkov V.M. et al. - M: Metallurgists, 1983, p. 160). This is due to the fact that dissolution proceeds along the charge-melt material boundary, and the contact area is determined by the total surface area of the charge additive. This drawback makes it difficult to use ligatures obtained by this method for extra-furnace modification (e.g., modification in ladle, mold).

In addition to the above, the productivity of this technological process of preparing a charge for preparing aluminum alloys is extremely low and not suitable for industrial use due to its long duration and laboriousness.

The aim of the invention is to increase the productivity of the process of producing the mixture and to improve the mechanical properties of the alloys.

This goal is achieved in that according to the method of preparing the charge for the preparation of aluminum alloys, including heating, melting and plastic deformation in a liquid-solid, the melt of the charge is poured and deformed in a roll mold with the formation of the surface of the charge in the form of protrusions and

0 troughs with a ratio of the total surface area of the charge to its volume, from 20: 1 to 30: 1, while the water-cooled rolls are made relief with a uniform alternation of protrusions and troughs with a ratio of the height of the protrusions to the gap between the rolls from 3.3 to 2, 0.

Using the proposed method for producing a charge for melting aluminum alloys and a device for its implementation provides the following advantages over the existing one:

- the implementation of casting, crystallization and deformation in one technological operation, which allows to increase

5 process performance;

-obtaining charge materials with a high degree of refinement and uniformity of the structure and a widely developed surface of the charge material, which

0 will allow the preparation of industrial alloys with enhanced and stable properties. In FIG. 1 shows the proposed roll mold, general view (hi is the thickness of the formed charge billet; h2 is the height of the protrusions (depressions); b3 is the thickness of the bridge); in FIG. 2 is a section along AA in FIG. 1.

Water-cooled roll mold consists of two rolls 1 wide

300-300 mm, with a relief surface, the configuration of which consists of protrusions and depressions, a mechanism for moving rolls and a drive mounted on a bed (not shown in the drawing).

5 The ratio of the height of the protrusions on the rolls to the size of the gap between the rolls is set in the range from 3.3 to 2.0. The surface topography parameters of the rolls correspond to the parameters of the charge stock.

0

The mold works as follows. The drive drives the embossed, water-cooled rolls 1. The melt of the charge is poured into the gap between the rolls5, which rotate to deform the liquid-solid phase 2 by rolling with an average degree of deformation of 40-75% with the formation of 3 protrusions and depressions on the surface of the charge billet.

The data on the topography of the charge stock are given in table. 1.

The method of producing the charge and the design of the roll crystallizer were tested on the example of producing aluminum-titanium alloys (5%) and remelting of the AK9ch alloy with their subsequent introduction as modifiers into the AMgblch and AK9ch alloys of GOST 1583-89, respectively.

Example 1. The technology for preparing the master alloy of aluminum - 5% titanium is as follows. A ligature based on aluminum with 5% titanium is poured from a temperature of 800-860 ° C and deformed in a roll water-cooled relief mold with an average degree of deformation of 40-75% with the formation of protrusions and depressions on the surface of the billet billet. Get a tape width of 300-500 mm The master alloy prepared by this method is introduced into the AMgblch alloy in the calculated amount.

The mechanical properties of the AMgblch alloy, prepared using the mixture obtained by the proposed and known methods for preparing the mixture — ligature AI — 5% Ti, are given in Table. 2.

Example 2. According to the proposed method receive remelting alloy AK9ch. In the furnace, the ingots of the AK9ch alloy are melted, overheated to a temperature of 700-710 ° C and subjected to processing as in Example 1. Then, the processed melt is introduced in an amount of 3% into the AK9ch alloy.

The mechanical properties of the alloy AK9ch prepared according to the known and proposed methods are given in table. 3.

Using the proposed method for producing charge materials and a device for its implementation provides, in comparison with the existing method, the following advantages:

-the ability to produce castings with enhanced and stable mechanical properties;

-increased productivity of the process of preparation of charge materials;

-decrease in the amount of ligature introduced into the melt;

-decrease in consumption of the amount of alloy for the manufacture of parts while maintaining their previous service properties.

(56) Copyright certificate of the USSR Ne 1135787, cl. C 22 C 1/02, 1985.

for the proposed method, the value of hi is accepted as the ligature thickness

Table 1

table 2

for the proposed method, the value of hi is accepted as the thickness of the treated portion of the charge.

Claims (2)

1. A method of producing a charge for melting aluminum alloys, comprising heating above solidus temperature, casting and plastic deformation in a liquid-solid state, characterized in that the casting and deformation are carried out in a roll mold with the formation of the charge surface in the form of protrusions and depressions with a ratio of the total area charge surface to its volume him equal to (20 - 30) -1, 2. A device for producing a charge for melting aluminum alloys, comprising a bed and a drive, characterized in that it is equipped with water-cooled rolls and a mechanism for moving them, the rolls being embossed with a uniform alternation of protrusions and depressions with a ratio of the height of the protrusions to the size of the gap between the rollers 3, 3 - 2.0. FIG. 7 FIG. 2