RU2245213C1 - Ingot mold - Google Patents

Abstract

FIELD: manufacture of charge billets of refractory nickel alloys.

SUBSTANCE: ingot mold is in the form of tube with detachable plug. In open end of ingot mold funnel with hollow wall filled with easy-to-melt metal is placed. Insert is made of nickel alloy with refractoriness higher than that of billet metal and it is arranged in funnel. Discs-partitions are placed inside tube. Spacing between said discs corresponds to size of charge billets. Discs made of graphite or dense ceramics have central opening. In plug there are dead openings for receiving samples used for certification of charge billets. In funnel easy-to-melt metal prevents superheating of melt due to melting heat. At crystallization of billets funnel serves as hot top.

EFFECT: enhanced quality of measured billets, less irreversible losses of nickel alloys.

2 dwg

Description

The invention relates to the production of heat-resistant nickel alloys, in particular, to the manufacture of charge blanks intended for subsequent vacuum remelting with the aim of casting turbine parts.

Ceramic molds for the preparation of nickel alloys are known [1].

To extract the ingots, such molds are destroyed, and the ingots are cut into measured blanks. This increases the cost of production.

Reusable metal molds are also known. A detachable cast-iron mold (chill mold) does not provide the necessary quality of the surface of the ingot, it requires cutting the ingot into measured billets, which leads to significant irretrievable losses [2].

Closest to the claimed invention is a mold made of steel pipe with a plug at one of the ends [2]. This mold, adopted as a prototype, allows you to get ingots with a better surface than using cast iron molds, but does not eliminate the need to cut the ingot into billets. In this case, up to 2-3% of the expensive alloy is irretrievably lost, working time, abrasive wheels are spent. In addition, when cutting the upper parts of the ingot, an axial shell and loosens contaminated with abrasive material are opened, which requires the return of these sections of the ingot to re-melting with refining.

The task in the development of the proposed mold was to reduce the irretrievable losses of nickel alloys, improving the quality of dimensional blanks.

The problem is solved due to the fact that the pipe is equipped with non-metallic insertion disks with central holes for melt flow, installed in the pipe at distances from the plug and from each other, determined by a given size of the charge blanks; the mold is supplemented with a removable steel casting funnel mounted on the open end of the pipe, and the plug is made with blind holes for receiving samples for certification of charge blanks.

Insert discs made of dense ceramic or graphite. The funnel is made with an insert in contact with the melt being drained and made of a more refractory nickel-based alloy than the prepared charge stock.

The funnel is made with a hollow wall for filling with fusible metal.

The filling funnel is equipped with a filter with a central drain hole and, if necessary, a slit or foam-ceramic filter mounted above this insert.

The invention is illustrated by drawings, where figure 1 shows a longitudinal section of a mold, and figure 2 is a view along aa of figure 1.

The mold consists of a steel pipe 1 with a plug 2 at the lower end with blind holes for forming samples 3, ceramic or graphite disks 4 with central holes installed in the cavity of the pipe on graphite or ceramic pins 5, a pouring bowl 6 at the upper end of the pipe, made with cavity 7 for placing a cooling low-melting metal and with an insert 8 made of a nickel alloy, more refractory than the prepared alloy; a filter 9 with a central drain hole is placed in the cavity of the funnel. Also shown is the cover 10 and the pins 11, designed for ease of transportation of the mold hoist.

An overheated melt is poured into the assembled mold, fed to a vacuum melting and casting plant. The mold with the poured metal is extracted into the air, mounted on a press.

The low-melting metal (aluminum or its alloy with silicon) placed in the funnel cavity intensively selects heat from the melt due to its high thermal conductivity and high specific heat of transformation “solid-liquid”.

The insertion into the funnel of an insert made of a more refractory nickel-base alloy than the prepared charge stock protects it from erosion and excludes the enrichment of the alloy with iron, silicon and other components that make up the steel of which the funnel is made.

When a nickel alloy is cooled, crystallization occurs, including metal hardening in the funnel cavity. In this case, heat is released, which increases the efficiency of the funnel as a profitable extension.

the hardened ingot is squeezed out and its individual sections - measured billets - are beaten or cut.

The plug is used not only as a removable bottom, but also as a mold for obtaining samples intended for certification of ingot metal.

Instead of cutting from the ingots of the templates, cutting them into bars and machining the bars to the sizes specified by the metal testing methods, a metal that is close in geometry to the test sample hardens in a stub form. At the same time, metal losses and the time of preparation of samples for testing are significantly reduced.

The use of graphite and dense ceramic partition discs in the pipe, in addition to reducing metal losses when cutting the ingot into separate measured billets, allows due to the high thermal conductivity of the material of the partitions to reliably block the access of gases to axial loosening possible in the upper part of the ingot and prevent the formation of oxynitrides on their surfaces when removing the mold into the air.

Sources of information

1. Routing process "Remelting waste heat-resistant alloys in furnaces of the ISV series" No. 5911000346, OJSC "ZTL", St. Petersburg, 1996, 14 pp.

2. Kablov E.N. “Cast blades of gas turbine engines”. M., MISIS, 2001, p. 182.

Claims (1)

A mold in the form of a steel pipe with a detachable plug for producing charge blanks of nickel alloys, characterized in that a funnel with a hollow wall filled with low-melting metal and an insert in contact with the melt being molded and made of a more refractory nickel alloy is installed on the open end of the pipe than prepared billet billet, plug made with blind holes to obtain samples for certification of billet billets, and inside the pipe at equal distances from the plug and from each other Given the size of the billets, mounted disk partitions with central holes made of graphite or dense ceramics.

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