RU2004598C1 - Chute for discharge and modification of cast iron - Google Patents

Abstract

Usage: ferrous metallurgy and foundry, more specifically, to devices for metallurgical processing of alloys. SUMMARY OF THE INVENTION The gutter is additionally equipped with a removable, mounted on top of the main gutter, pallet, lined with a layer of plastic refractory material, for example chamotte paste. placed in a plastic refractory layer with the formation of a ribbed convex-concave profile of the pallet 1 zp.f-ly, 2 silt.

Description

The invention relates to ferrous metallurgy, and more particularly, to devices for metallurgical processing of liquid metal to modify it, as well as for refining, deoxidation, alloying and carburization of cast iron.

A trough of a melting unit, for example a cupola, which consists of a body and a lining, is known. Cast iron is modified by feeding a modifier from above into a stream of metal flowing down the trough. The disadvantage of this method is the metallurgical additives float onto the metal surface and the degree of absorption of additives is low (40 -50%) and high consumption of modifier.

The closest in technical essence to the claimed is the trough of the melting unit, which consists of a metal casing, a lining and an attachment to the casing. The supply of the modifier is carried out under the stream of metal flowing down the gutter using a screw device. This allows to increase the degree of assimilation of the modifier up to 55-65% due to the fact that the modifier is introduced deep into the metal. However, the possibility of the additives floating up onto the metal surface in the bucket and leaving them in the slag in this device is not eliminated, since there are no additional measures to intensify the process of dissolving the additives on the segment of the auger-gutter-ladle path. It is most advisable to dissolve the additives in the metal before the jet enters the bucket, however, the known trough does not provide this.

The aim of the invention is to increase the degree of assimilation of the modifier and reduce its consumption

This goal is achieved in that the chute for draining and modifying cast iron, consisting of a metal body, a lining and an attachment unit to the casing of the unit, is additionally equipped with a removable pallet mounted on top of the main chute, lined with a layer of plastic refractory material, while the surface of the pallet is at a depth the flowing metal layer is lined with modifier pieces placed in a plastic refractory layer to form a ribbed convex-concave profile of the pallet. The pallet can be lined with a layer of fireclay paste. The supply of the gutter with a removable, mounted on top of the main gutter, a pallet lined with a layer of plastic refractory material allows two technological operations: the discharge of metal and its modification. Moreover

if modification is not required, the pallet is not used. Various metallurgical additives can be lined in the layer of plastic refractory material of the pallet: modifying, deoxidizing, refining, alloying, carburizing, desulfurizing, dephosphorizing and others. Facing the surface of the pallet to the depth of the flowing metal with modifier pieces placed in a plastic refractory layer allows automatic modification or other metallurgical processing of the metal when draining the metal.

5 Metal processing is carried out by reacting a stream of metal with pieces of modifier placed in the lining of the pallet. When interacting with chunks of a modifier, the metal leaches small particles of material from the chunks (i.e., erosion of chunks is observed), which then, due to their microscopic size, quickly dissolve in the flowing stream of metal. This allows the particles to completely dissolve.

5 modifiers in the metal stream until it enters the bucket. This eliminates the possibility of particles floating in the bucket and leaving them in the slag, which can significantly increase the degree of assimilation of the modifier, and consequently reduce the consumption

modifier.

The formation of a ribbed convex-concave profile of the pan allows to intensify the dissolution process

5 modifiers in a stream of metal. This is because the modifier pieces form a complex, irregular, ribbed, convex-concave profile of the pallet. In connection with this, a stream of metal when draining along

0 the gutter is turbulized, intensively mixed, actively reacts with a modifier. In this case, diffusion processes proceed intensively, which contributes to an increase in the degree of assimilation of the modifier.

5 together, all the distinguishing features provide an intensification of the modification process with a high degree of assimilation of the modifier and a reduction in the consumption of the modifier. When using the pallet many times, all 100% of the modifier is used for its intended purpose.

Figure 1 shows a groove, a longitudinal section; figure 2 - section aa in fig. 1,

5 The gutter consists of a housing 1, a lining 2, an attachment unit 3 to the casing of the melting unit. On top of the main trough, a pallet 4 is mounted, lined with refractory plastic mass (fireclay) 5. Modifier pieces 6 are embedded in the lining of the pallet 6

the size in diameter is 30-70 mm. The pieces are joined together, the protruding parts of the pieces are 15–20 mm high. The pieces form a complex, uneven, ribbed, convex-concave surface of the pallet. The modifier pieces are lined with only that surface of the pallet that is filled with liquid metal when draining.

The pallet has loops 7 for transportation, and the main groove has a stop 8 for fixing the pallet in the working position.

The gutter can work either with a pallet (if modification is required) or without a pallet (if no modification is required). The pallet is interchangeable; if necessary, it can be replaced with a new one or dismantled.

The device operates as follows. Before smelting, 2-5 interchangeable trays are prepared depending on the volume of the metal to be smelted and the need to obtain modified cast iron. The preparation consists in applying a flat refractory plastic fireclay paste with a thickness of 30-40 mm to the pallet and lining this layer with modifier pieces. The lining is made by pressing pieces into the refractory layer. Then, the lining of the pallet and modifier is dried with a gas burner,

During melting, the pan is mounted on the main channel. The installation of the pallet is carried out if a modification of cast iron is required, i.e. production of high grades of cast iron (SCh20, SCh25, SChZO, etc.). The pan can be used repeatedly.

When cast iron is released, a metal stream when it flows over the surface of a pallet reacts with pieces of a modifier. In the process of reactions, the dissolution of the modifier is intense, with greater speed. The degree of assimilation of the modifier increases to 82-85%, which is 20-27% more than that of the prototype. In this case, the consumption of the modifier per 1 ton of cast iron is accordingly reduced (from 5 kg / t to 4-4.2 kg / t for the modifier - 75% ferrosilicon).

The device allows the modifier to be introduced deep into the jet in the form of the smallest particles resulting from the erosion of the modifier pieces by the flowing stream of cast iron. Particles, due to their microscopic size, are heated intensively in the metal to provide a modifying effect and a high degree of assimilation of the reagents.

The interaction of the metal stream with the modifier takes place over a very developed surface of the modifier pieces along a rather long path (the cupola grooves are usually 2-3 m long). This leads to an increase in the time and contact area of the reacting phases, which leads to the intensification of diffusion processes, and therefore to an increase in the degree of assimilation of the reagents.

The ingress of individual pieces of the modifier into the stream is excluded, since the pieces are firmly lined in the pallet. This eliminates the ingress of pieces into the bucket, their floating to the surface and leaving in the slag, which also helps to increase the degree of assimilation of the modifier and reduce its consumption.

The device dissolves the modifier in the metal before the jet enters the bucket. Turbulization and intensive mixing of the metal stream due to the uneven, ribbed, convex-concave surface of the pallet due to the presence of protruding pieces of the modifier also contribute to an increase in the degree of assimilation and intensification of the dissolution of the modifier. In a turbulent, bubbling metal stream, diffusion processes intensify.

(56) Vozdvizhensky V.M., Grachev V.A., et al. Foundry alloys and their melting technologists in mechanical engineering. M.: Mechanical Engineering, 1934, p. 284.

USSR copyright certificate No. 1315482, cl. C 21 C 7/064, 1986.

Claims (2)

1. DRAIN FOR DRAINING AND MODIFICATION OF IRON, consisting of a metal casing, lining and attachment unit to the casing of the unit, characterized in that, in order to increase the degree of assimilation of the modifier and reduce its consumption, it is additionally equipped mounted on top of the main channel an interchangeable pallet lined with a layer of plastic refractory material, while the surface of the pallet is lined with modifier pieces placed in a plastic refractory layer to the depth of the flowing metal layer to form a ribbed convex-concave profile of the pallet. 2. A chute according to claim 1, characterized in that the pallet is lined with a layer of fireclay paste. Figure 2