RU2463128C1 - Method of fabricating protectors - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Proposed method comprises heating metal chill mould, fitting filling core, poring melt in chill mould, curing and cooling metal in said mould and removing protector therefrom. Said metal chill mould is made up of heat tube with heating and cooling zone. Heating is performed to t₁=(1.2-1.5)t_boil, where t_boil is heat carrier boiling point. Forced cooling of chill mould is made after pouring melt in to t₂=(1.1-1.2)t_boil. Fitted filling core is heated together with chill mould.

EFFECT: higher efficiency of cooling, uniform structure of metal in moulded protector.

1 dwg

Description

The invention relates to foundry and metallurgical production, in particular to the production of cast protectors in cooled metal molds.

A known method of producing castings in a chill mold with a heat pipe [1. Patent No. 2276628 RU. A method of producing castings in a chill mold and a chill machine with a heat pipe for its implementation / V.V. Stulov, B.N. Maryin. Publ. 09/10/2006. Bull. Number 25. C.7], including the assembly of a chill mold with the installation of a rod made cooled in the form of a heat pipe with a heating and cooling zone, pouring metal into a chill mold, cooling the metal to a predetermined temperature, and removing the casting.

The disadvantage of this method [1] is the possibility of its effective use only for hollow castings.

A known method of producing cast protectors in metal molds [2. Kechin V.A. Theory and technology of cast tread materials. Vladimir: VlSU, 2004.181 s. See p.179], which includes heating the mold, installing a preheated embedded core, pouring the alloy into the mold heated to a certain temperature, holding the mold in the mold with cooling to a given temperature, removing the cast tread from the water-cooled mold.

The disadvantage of this method of producing treads [2] is the uneven cooling and crystallization of the alloy in a water-cooled mold, leading to the production of treads with a different grain structure. In addition, the use of water-cooled molds does not provide uniform heat removal along the length and width of the cooled wall due to the convective flow of water in the channel, which leads to the possibility of obtaining a different-grain structure of the protectors. The installation of a pre-heated embedded core in the mold increases the number of operations performed.

The inventive method is aimed at improving the efficiency of the process of producing protectors in a metal mold.

The technical result obtained by the implementation of the proposed method is

- improving the cooling efficiency of the metal in the metal mold;

- obtaining a more uniform and fine-grained metal structure in the cast tread.

The inventive method is characterized by the following essential features.

Limiting signs: heating of a metal mold; installation of the embedded rod; pouring the melt into the mold; aging of the metal in the mold with its cooling; removal of a protector from a mold.

Distinctive features: heating of a metal mold, made in the form of a heat pipe with a heating and cooling zone, is carried out to a temperature of t ₁ = (1.2-1.5) t _{instrumentation} , where t _{instrumentation} is the boiling point of the coolant in the mold; forced cooling of the mold is performed after pouring the melt until the mold temperature reaches t ₂ = (1.1-1.2) t _{instrumentation} ; heating of the installed embedded rod is carried out together with the mold.

A causal relationship between the totality of the essential features of the proposed method and the achieved technical result is as follows.

The implementation of the metal mold in the form of a heat pipe with a heating zone [3. Seeds M.G., Gershuni A.N., Zaripov V.K. Heat pipes with metal fiber capillary structures. K .: Vishka school. Head Publishing House, 1984. 215 pp.] Provides the possibility of uniform heating of the entire mold, which excludes the appearance in the cast metal of zones with different temperatures.

Heating the mold to a temperature of t ₁ <1.2 · t _{instrumentation} (where t _{instrumentation} is the boiling point of the coolant in the mold) does not allow uniform heating of the entire mold due to insufficient vapor pressure of the coolant.

Heating the mold to a temperature t ₁ > 1.5 · t _{instrumentation} leads to an inappropriate increase in the vapor pressure of the coolant in the structure and, as a result, increased requirements for manufacturing and structural strength.

Forced cooling of the mold after pouring the melt until the mold temperature reaches t ₂ <1.1 · t _{instrumentation} leads to the possibility of insufficient vapor pressure of the coolant in the structure and its uneven heating before subsequent pouring of the melt into it.

Forced cooling of the mold after pouring the melt until the mold temperature reaches t ₂ > 1.2 · t _{instrumentation} leads to the possibility of inappropriately high vapor pressure of the coolant in the structure during subsequent pouring of the melt into it.

The heating of the installed embedded rod together with the mold eliminates the need for its preliminary heating outside the structure.

The figure shows the appearance of the device for implementing the inventive method for producing cast protectors.

The device consists of a metal mold 1, made in the form of a heat pipe with a heating zone 2 and a cooling zone 3, a embedded rod 4, an installation table 5, a gas burner 6, a thermocouple 7 connected to an automatic process control system. The cooling zone 3 is made in the form of finned tubes 8.

The method is implemented as follows.

After the location of the mold 1 on the installation table 5 include a gas burner 6 with heating of the heating zone 2 of the mold and the embedded rod 4 to a predetermined temperature t ₁ = (1.2-1.5) t _{instrumentation} , where t _{instrumentation} is the boiling point of the coolant in the mold. When casting zinc alloys, a coolant is used in the design - a dauter with t _{instrumentation} = 300 ° C. Then t ₁ = 400 ° C, t ₂ = 350 ° C. After reaching the set temperature of the mold, fixed according to the readings of thermocouple 7, the melt is poured into the mold. Forced cooling of the finned tubes 8 of the cooling zone 3 of the mold 1 is carried out by air supplied from the compressor until the mold temperature reaches t ₂ = (1.1-1.2) t _{instrumentation} , fixed according to the readings of thermocouple 7. After this, the obtained tread is removed from the mold.

Claims (1)

A method for producing cast protectors, including heating a metal mold, installing a embedded rod, pouring the melt into the mold, holding the metal in the mold with cooling it and removing the tread from the mold, characterized in that the heating of the metal mold made in the form of a heat pipe with a heating and cooling zone is carried out to a temperature t ₁ = (1,2-1,5) t _{boiled, heated} where t - the coolant boiling temperature in the mold, after the melt is carried out forced cooling casting mold to reach a temperature zlozhnitsy t ₂ = (1,1-1,2) t _{was heated,} and the heating of the rod set is carried out together with the casting mold.