SU1585059A1 - Method and apparatus for bottom casting of steel - Google Patents

Abstract

The invention relates to ferrous metallurgy, in particular to methods of siphon casting of steel, and can be used for casting alloyed steels. The purpose of the invention is to improve the quality of the ingot surface. The method includes laying at the bottom of the molds before pouring steel carbon-containing organic material in an amount of 0.05-0.15 kg / t and placing heat-insulating and slag-forming mixture in combustible bags along the axis of symmetry of the cavity of the mold at the level of the upper end of the profitable extension. The device for implementing the method is further provided with a lid with a central opening for the release of hot gases and the spilling of the heat-insulating mixture after burning the bags and a lodgment for holding the bags. In this case, the lodgement is made in the form of a flat grid with vertical guides for fixing the packages, the lid is placed on the upper end of the profitable extension, and the packages with the mixture are placed on the lodgement in the form of a vertical stack. 1 hp f-ly, 3 ill.

Description

The invention relates to ferrous metallurgy, in particular to methods for siphon casting of steel and can be used for casting alloyed steels.

The purpose of the invention is to improve the quality of the ingot surface.

Figure 1 shows the device, general view; figure 2 - node I in figure 1; on fig.Z - section aa in figure 2.

The device contains a pallet 1 with siphon wiring 2 and an asterisk 3, molds 4 installed on it with profitable extensions 5 and center 6 for pouring steel, as well as metal covers 7 with a central hole 8 installed on profitable extensions (FIG. 3) to exit hot gases and spilling heat-insulating mixture and a lodgment 9 with packages 10, placed in the form of a vertical stack along the axis of the mold. At the bottom of the mold is laid carbon-containing organic material 11.

The implementation of the method and operation of the device is carried out as follows.

On the pallet 1 with the laid siphon wires 2 and an asterisk 3 install

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about

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mold 4 with profitable extensions 5 and center 6.

At the bottom of the molds, carbon containing organic material is laid, for example, dehydrated petrolatum, in an amount of 0.05-0.15 kg per ton of steel poured into the mold. Then, metal covers 7 with central apertures 8 and lodgments 9, made in the form of a flat grid with vertical guides, are installed on profitable extensions 5. On the crates 9 are placed in the form of a vertical stack of combustible bags with heat insulating shdakoobrazuyu mixture of the following composition: slag production of carbon-free ferrochrome 10-20%, ash CHP - base, graphite 3-4% (over 100%).

After that, the mold 4 is poured through the center 6 liquid steel.

During the first portions of the liquid steel entering the mold, the organic material 11 placed at its bottom burns out under conditions of oxygen deficiency with the formation of hot reducing gases and black carbon, which covers the walls of the mold with an even layer

from contact with liquid metal. At the same time, the recommended amount of combustible material (0.05-0.15 kg / t) ensures ignition and burning of bags 10 and spilling of the mixture from them when filling the mold with no more than 1/4 - 1/3 of its height, which contributes to obtaining high-quality surface ingots. A smaller amount (less than 0.05 kg / t) increases the time before the bags are burned out and the mixture is poured out, respectively, when the mold is filled by more than 1/3 of the height, which impairs the thermal insulation of the metal and the quality of the macrostructure of the ingot. The addition of combustible material in an amount exceeding 0.15 kg / t contributes to the early burning of packages with the heat-insulating mixture and its premature pouring onto the metal mirror with the formation of gross defects on the surface of the ingot due to the turning of particles of unmelted slag by a turbulent flow of metal. at a given height, the slag-forming and heat-insulating mixture on the metal mirror last well protects the smoothly rising

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metal from oxidation and intensive cooling, ultimately providing high quality ingot after hardening.

After the process of casting, crystallizing and cooling the ingots is completed, the latter are removed, the molds and the center removed from the pallet. The rigging is directed to preparation, and the ingots are rolled.

Then the cycle repeats.

Comparative analysis of the casting results data using the proposed method and the prototype (see table) showed that casting became the proposed method and using the proposed device significantly improves the surface quality of the ingots, helping to reduce scrap on surface defects and saving metal during grinding (blooms).

Claims (3)

1. A method of siphon casting steel, which includes introducing carbon-containing organic material and heat-insulating and slag-forming mixture into the mold cavity and pouring steel, characterized in that, in order to improve the quality of the ingot surface, carbon-containing organic material is laid at the bottom of the mold in the amount of 0, 05-0.15 kg / t of cast steel, and the heat-insulating and slag-forming mixture is placed in combustible packages along the axis of symmetry of the mold cavity at the level of the upper end of profitable extension , The packets are used to hold cover with a central opening for the exit of hot gases and the spilling of the heat-insulating and slag-forming mixture after burning the bags. 2. Method .1, characterized in that dehydrated petrolatum is used as carbon-containing organic material. 3. A device for siphon casting STESHES, containing a pallet with siphon leads and mounted on it a mold with a profitable extension and a center for pouring metal, as well as packages with heat insulating and slag-forming mixture, which is that it is equipped with a metal cap with a central a hole for the release of hot gases and spilling heat-insulating and slag-forming mixture after burning packages and cradles to hold the packages, while the cradle is made in the form of a flat grid 15850596 guides for fixing the packages, the cover is placed on the upper end of the profitable extension, and the packages with the heat insulating and slag-forming mixture - on the lodgment in the form of a vertical stack. Effect of casting parameters on surface quality of blooms Note, Quality Category I - cleaning up to 15% of the surface of blooms, Category II - 25%, Category III - more than 25% of the surface of blooms g  one 65058SI FIG.