RU2739358C2 - Crystallizer for production of continuously cast cylindrical workpieces from high alloys - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to continuous metal casting. Proposed crystallizer comprises case (3) with heat pipe arranged therein, condenser (11) communicated via steam lines (8) and condensate lines (18) with heat pipe to form closed evaporation-condensation circuit. Lengthwise ribs (7) are arranged in the space between pipes of the heat pipe along the perimeter. Inner surface of pipe between ribs is coated with porous coating (5). Condenser (11) is located outside the heat pipe housing, and there are two coils (12, 13) made of copper pipes, into which cold water is supplied. Condensate ducts (18) are combined into condensate collector (19) located at an angle α= 10–15° down to horizon. Single condensate line (20) adjoins lower part of condensate header. Hammered grate (9) is arranged in the upper part of heat pipe before inlet of steam pipelines.

EFFECT: higher reliability of cooling of crystallizer wall, exclusion of cracking of crust of formed billet due to uniform temperature distribution along perimeter and height of heat pipe, in contact with spilled melt.

1 cl, 1 dwg

Description

The invention relates to metallurgy, in particular to the design and cooling of the mold for producing continuously cast cylindrical billets from high-alloy steels and alloys.

Known crystallizer for producing continuous cylindrical billets [RF Patent No. 2651083. Crystallizer for producing continuous cylindrical billets / V.V. Stulov. 18.08.2018. Bul. No. 11], containing a housing with a heat pipe located in it, formed by pipes coaxially installed one into the other with the formation of a closed space for the coolant between them, a condenser connected by steam pipelines and condensate pipelines with a heat pipe to form a closed evaporation-condensing circuit, electric heating elements located in the lower part of the closed space between the pipes, and thermocouples connected to the automatic control system for the cooling of the mold, longitudinal ribs are made evenly along the perimeter in the closed space between the pipes coaxially installed in one another, the inner surface of the pipe of smaller diameter between the ribs is covered with a porous coating.

The disadvantages of the known crystallizer lie in the insufficient efficiency of the steam condenser and the heat pipe itself due to the lack of separation of the streams of the generated steam and the superheated liquid, as well as in the difficulty in supplying the melt to the crystallizer due to the location of the steam condenser at the top.

The inventive crystallizer is aimed at improving the efficiency of its operation when casting high-alloy steels and alloys.

The technical result obtained in the implementation of the inventive crystallizer consists in a higher reliability of its operation in transient modes associated with an increase in the casting rate of the melt, and, accordingly, with an increase in the density of the supplied heat flux, a more uniform temperature distribution around the perimeter and height of the heat pipe in contact with the poured melt, eliminating the likelihood of cracking the crust of the formed workpiece.

The inventive crystallizer is characterized by the following essential features.

Restrictive features: a housing with a heat pipe located in it, formed by pipes coaxially installed one into the other with the formation of a closed space between them for the coolant; a condenser connected by steam lines and condensate lines with a heat pipe to form a closed evaporative-condensation circuit; electrical heating elements located at the bottom of the enclosed space between the pipes; thermocouples connected to the automatic control system for cooling the mold; longitudinal ribs are made evenly along the perimeter in the closed space between the pipes coaxially installed in one another; the inner surface of the smaller diameter pipe between the ribs is covered with a porous coating.

Distinctive features: the steam condenser is located outside the heat pipe body; the condenser contains two coils made of copper pipes into which cold water is supplied; condensate pipelines are combined into a condensate collector located at an angle α = 10-15 ° downward to the horizon; a single condensate line adjacent to the bottom of the condensate collector; perforated grid in the upper part of the heat pipe in front of the entrance to the steam lines.

The causal relationship between the set of essential features of the claimed crystallizer and the achieved technical result is as follows.

The location of the steam condenser outside the heat pipe housing reduces the overall height of the mold and the height of the submerged nozzle for supplying the melt to the mold, thereby increasing the reliability of the metal casting process. The location in the condenser of two coils made of copper pipes, into which cold water is supplied, makes it possible to activate the process of condensation of water vapor on their surface.

Combining condensate lines into a condensate collector allows condensate to be collected from all condensate lines and redistributed into a single condensate line, which increases the level of returned condensate and, accordingly, the pressure of the liquid column pushed into the heat pipe.

The location of the condensate collector at an angle downward to the horizon allows the accumulation of liquid in the place where a single condensate pipeline adjoins it. As a result, there is no need to use several condensate pipelines cut into the bottom of the heat pipe.

Decreasing the angle of the condensate collector at an angle α <10 ° down to the horizon slows down the process of condensate flowing from the condensate pipelines into a single condensate pipe. As a result, the entire process of condensate return to the lower part of the crystallizer slows down and the normal mode of melt cooling is disrupted.

An increase in the angle of the condensate collector at an angle α> 15 ° downward to the horizon leads to an irrational increase in the collector perimeter and the length of the adjacent condensate pipelines, an increase in the dimensions and weight of the structure.

The presence of a single condensate line, adjacent to the lower part of the condensate collector, allows condensate to flow into the lower part of the crystallizer through one condensate line. As a result, the liquid level in one condensate line increases compared to several condensate lines and, as a result, the pressure for pushing the liquid into the lower part of the crystallizer increases. In addition, the total length of the condensate lines is reduced.

The location of a perforated grid in the upper part of the heat pipe in front of the entrance to the steam pipelines allows separation of the streams of steam and superheated liquid for its additional circulation in the heat pipe, and steam passing through the holes in the grid is directed to the condenser with a minimum amount of liquid. As a result, the efficiency of the steam condenser is significantly increased, that is, the amount of condensate formed per unit time, kg / s.

FIG. the external view of the mold for producing continuously cast cylindrical billets from high-alloyed alloys is shown.

The crystallizer for producing continuously cast cylindrical billets from high-alloyed alloys in Fig. consists of a pouring ladle 1 with a submerged nozzle 2, a body 3 with coaxially installed pipes of a smaller diameter 4 and a larger diameter 6, steam lines 8 with a perforated grate 9 with holes 10 installed in front of them, a steam condenser 11, with coils 12 placed in it and 13 with nozzles 14 and 15 for supplying cooling water, nozzles 16 and 17 for draining heated water, condensate lines 18 with a condensate collector 19 and a single condensate line 20 adjacent to it, forming a closed evaporative-condensation circuit of the heat pipe, electric heating elements 21, thermocouples 22 -25, connected to the automatic control system for the cooling of the crystallizer.

Previously, longitudinal ribs 7 are installed in the space between pipes 4 and 6, between which porous coatings 5 are fixed and a certain amount of coolant is poured. Electric heating elements 21 are turned on, which heat the coolant with pipes 4 and 6, longitudinal ribs 7, porous coatings 5 impregnated with the coolant. After reaching the set temperature, recorded according to the indications of the thermocouple 25, the mold is prepared for pouring the melt into it.

The operation of the crystallizer is carried out as follows. The electric heating elements 21 are turned off and the melt is poured from the pouring ladle 1 through the submerged nozzle 2 into the inside of the pipe 4, which leads to its further heating with the porous coating 5 and the heat carrier. When the porous coating 5 with the coolant is heated, steam is formed evenly along the height of the crystallizer, which, together with the boiling coolant, enters the space between pipes 4 and 6 and along the longitudinal ribs 7 then hits the perforated grid 9 and through the holes in it 10 enters through the steam lines 8 into the condenser 11. The coolant separated on the grate 9 from the steam flows down the walls of the pipe with a larger diameter 6 into the lower part of the crystallizer. The supply of cooling water through the pipes 14 and 15 into the coils 12 and 13 is switched on, which leads to the cooling of the steam and its condensation in the condenser 11. The heated cooling water comes out through the pipes 16 and 17. The condensate is collected through the condensate lines 18 into the collector 19 and then through a single condensate line 20 flows into the lower part of the space with pipes 4 and 6. The temperature of the water heated in the coils 12 and 13 of the condenser 11 is fixed according to the indications of thermocouples 23 and 24, which allows, at a known flow rate of cooling water to the crystallizer, to set the value of the heat flux removed from the poured melt.

Claims (1)

A crystallizer for producing continuously cast cylindrical billets from high-alloyed alloys, containing a housing with a heat pipe located in it, formed by pipes coaxially installed one into the other with the formation of a closed space for the coolant between them, a steam condenser connected by steam pipelines and condensate pipelines with a heat pipe to form a closed evaporative -condensing circuit, electric heating elements located in the lower part of the closed space between the pipes, thermocouples connected to the automatic control system for the cooling of the crystallizer, in the closed space between the pipes coaxially installed one into the other, longitudinal ribs are made evenly along the perimeter, the inner surface of the pipe of smaller diameter between ribs covered with a porous coating, characterized in that the steam condenser is located outside the heat pipe housing and there are two coils made of copper pipes into which There is cold water, the condensate pipelines are combined into a condensate collector located at an angle α = 10-15 ° down to the horizon, a single condensate pipeline is adjacent to the lower part of the condensate collector, and a perforated grid is located in the upper part of the heat pipe in front of the steam pipelines.

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