SU1507523A1 - Arrangement for protecting metal jet by inert gas - Google Patents

Abstract

The invention relates to metallurgy, specifically to the casting and secondary treatment of liquid metal. The goal is to improve the quality of the metal by reducing its oxidation. The device contains a distribution manifold 1, a gas supply nozzle 2, an inner annular slotted nozzle 3 formed by walls 4 and 5, an outer nozzle 6 made tangentially to the inner nozzle 3 and located below the outlet ends of the nozzle 3 at a distance of 2.0 ... 6.0 of its width. The total cross-sectional area of the nozzles 6 is 0.1 ... 0.3 of the cross-sectional area of the nozzle 3. 2 Il.

Description

(21) 4318110 / 23-02

(22) 09/01/87

(46) 09/15/89. Bul P 34

(71) Institute of Ferrous Metallurgy

(72) V.V. Lissitsky, I.V.Murash, A.T. Lebed, V.F.Polkov, V.Ya.Minevich, L.M.Tatel, V.V.Klevakin, A.A. Deryugin and V.I. Burkov

(53) 621.746.27 (088.8)

(56) USSR author's certificate

K 229755, cl. B 22 D 7/12, 1967.

(54) DEVICE FOR PROTECTION OF METAL STRIP BY INERT GAS (57) The invention relates to metallurgy, specifically to the casting and external heating of liquid metal. The purpose of the invention is to improve the quality of the metal by reducing its oxidation. The device contains a distribution manifold 1, a gas supply nozzle 2, an inner annular slotted nozzle 3 formed by Stenches 4 and 5, an outer nozzle 6 made tangentially to the inner nozzle 3 and located below the output end of the nozzle 3 at a distance of 2.0-6, 0 its width. The total cross-sectional area of the nozzles 6 is 0.1-0.3 of the cross-sectional area of the nozzle 3. 2 ill. Q

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The invention relates to metallurgy, specifically to the casting and after-treatment of a liquid metal.

The purpose of the invention is to increase the metal's cage by reducing its oxidation.

Figure 1 shows the proposed device, a General view; Figure 2 - view A in figure 1 ..

The device contains a distribution manifold 1, a gas supply nozzle 2, an inner annular slot nozzle 3 formed by walls 4 and 5, an outer nozzle 6, performed tangentially to the inner nozzle 3 and located below the outlet end of the nozzle 3 at a distance (and ) 2.0 - 6.0 its pidrins. The total cross-sectional area of the nozzles 6 is 0.1-0.3 of the cross-sectional area of the nozzle 3. The device is mounted on a collector-holder 7 of a slide gate (not shown) and sealed with a refractory solution 8.

The device works as follows.

Before the metal is cast, an inert gas, such as argon, nitrogen, etc., is supplied to the device. The inlet manifold 1 enters IB through the nozzle 2 and exhausts from the inner annular slotted nozzle 3 in the form of a continuous annular jet. After

 The metal valve is protected by a jacket, with a ring of inert gas flow. In the process of outflow of gas through the nozzle 3 part of the inert gas enters

to the annular jet through the external tan-40 to a given inert gas flow rate, dosing potential nozzles 6 in the form of a transversely rotating flow drawn into the discharge zone of the root region of the annular jet, i.e. in the exit zone of this jet from the nozzle 3.

As a result of the interaction of the main (filler) and additional (swirling) oxidation jets, the potential of the protective jacket decreases dramatically due to a reduction in the intake of ambient air into the zone of greatest discharge created by the filler jet. The rotation of the additional flow creates a zone of reduced pressure inside it, which, when interacting with the direct flow, leads to their active fusion, averaging and an increase in the thickness as a whole.

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The location of the nozzles 6 and 3 at a distance (a) of 2.0 to 6.0 of the width of the nozzle 6 ensures the effective introduction of the swirling jet into the continuous flow into its root region, due to sufficient opening of the transverse flow and increasing the degree of filling of the root flow region of the direct flow. twisted.

Performing the specified distance less than the lower limit increases the intensity of the rotational movement in the direction of the flow of the jet stream as a result of the reflection of the swirling flow from the plane of the output end of the slotted nozzle. This leads to an increase in the disturbance in the contact zone of the continuous and swirling jet due to the increase in the flatness of the latter.

Performing the specified distance greater than the upper limit leads to an increase in the activity of interaction between the swirling flow and the flow line outside its root area due to the removal of the swirling flow from the discharge zone. This enhances the peripheral turbulization of the flow jet, which increases its contact with the surrounding atmosphere and impresses with inert hydrogenation with oxidizing components.

Making the total cross-sectional area of the nozzles 6 equal to 0.1-0.3 of the cross-sectional area of the annular slotted nozzle 3 provides the optimum ratio of direct and swirling flows during the scoop to form a 1tny shirt, which is almost devoid of oxidant suction from atmospheric oxygen. spheres to the main outflow zone

5 jets of inert gas. Moreover, the range of the total flow of the protective flow is not reduced and is practically maintained along the length of the jet of the metal to be cast in the bucket — mold or trowel area and in the continuous casting facilities of steel.

The fulfillment of the above ratio below the lower limit leads to a local interaction of the swirling flow with a side branch of the main flow, which is formed during the outflow from the slotted nozzle 3 into the expanding space, which causes unorganized outputs

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when they collide on outflows

from the nozzle 3, and leads to partial fy air saturation in the contact zone.

In addition, this leads to uneven filling of the root zone of the inert gas annular jet.

The fulfillment of the above ratio above the upper limit leads to an increase in the swirling flow and to the turbulence of the boundary part of the root zone of the flow jet, which enhances its peripheral turbulization and activates the interaction of the perimeter of the ring jet with the ambient air during its movement, and this reduces the inert potential of the protective jet and its long range

behind

Example. The flow rate of the inert gas to protect the metal jet during casting from the ladle is 60. With a distance between the glass of the sliding gate and the upper end of the set forth. At a peak or a receiving funnel of 0.2-0.3 m, the gas outflow rate from the inner annular slotted nozzle 3 is 50 to 70 m / s. The cross-sectional area of the annular slotted nozzle is 300 mm and the width is 0.4 mm. The total cross-sectional area of the outer nozzles 6 is 60 mm and their number is from one to

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6

The flow rate of the inert gas through the annular slit nozzle 3 is 40 m / g, and through the nozzles 6-20 m / h.

The proposed device improves the quality of the metal by increasing the reliability of the protection of cast steel by further reducing the oxidizing potential of the inert equipment | Lechs created around the metal jet. In addition, the device improves the surface quality of the ingot and finished metal products by reducing the oxygen content and non-metallic inclusions in the finished steel, as well as reduces the consumption of easily acidic elements and metal fragments and reduces the size of the headband.

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Claims (1)

Claims An apparatus for protecting a jet of metal with an inert gas, comprising a distribution manifold with an inlet 25 nozzle and inner nozzle and outer nozzles for supplying an inert gas, characterized in that it is intended to increase. the quality of the metal by reducing its oxidation, the outer nozzles are located tangentially to the inner annular nozzle and below its output end at a distance of 2.0 to 6.0 of its width, and the total area of the open-section section of the outer nozzles is 0.1-0, 3 cross-sectional areas of the inner annular nozzle. thirty 35 Type A fig.g