RU639189C - Device for delivering metal into crystallizer - Google Patents

Description

 The invention relates to metallurgy, specifically to the continuous casting of metals and alloys.

 A device is known for supplying metal to a crystallizer made in the form of a refractory deep-sea glass with side outlet openings, the axes of which are located at an angle to the horizontal.

 The known device provides effective protection of the melt from secondary oxidation and improves the casting conditions. In the case of equal distances from the glass to the walls of the mold in the direction of all the holes, the known device allows to obtain minimal development of unevenness of the solidification front and the turbulence of the meniscus of the metal in the mold, which makes it possible to cast at the maximum allowable speeds and a satisfactory quality of the workpieces.

 However, the practice of continuous casting is often confronted with cases where the jet must be fed at different distances to the walls of the mold. Such cases are most typical for casting metals and alloys into billets of rectangular cross section - metal feed by three and a large number of inclined jets, etc. The use of a known device for these conditions leads to the fact that the jets of metal enter the hardening shell at different heights from the meniscus and with different intensities, which leads to a significant development of uneven solidification front and turbulence of the meniscus of the metal in the mold. As a result, it is necessary to reduce the casting speed, and cast billets are characterized in some cases by low quality.

 The purpose of the invention is to increase the reliability of the casting process and the quality of the workpieces.

 This is achieved by the fact that the device contains side holes of different diameters, and the reduced diameter of the larger hole is 1.1-2.5 times greater than the diameter of the smaller hole, and the angle of inclination of the smaller hole is 1.2-2.7 times greater than the angle of inclination of the larger hole .

 Figure 1 shows a General view of the device; figure 2 is a view of figure 1.

The device 1 consists of an intermediate bucket 2 with a stopper 3 and a deep-sea refractory cup 4 installed in the bucket 2 with outlet holes 5, the axes of which are inclined at an angle α ₂ and holes 6, whose axes are inclined at an angle α ₁ to the horizontal plane. The diameters of holes 5 are denoted by d ₂ , holes 6 - by d ₁ , and d _{1 is} greater than d ₂ 1.1-2.5 times, and the angle α _{2 is} greater than the angle α ₁ 1.2-2.7 times.

;

= где α_1,2,3...n - угол наклона оси 1,2,3...n выходного отверстия к горизонтальной плоскости;
l_1,2,3,....n - горизонтальная проекция отрезка прямой от оси стакана до стенки кристаллизатора по оси 1,2,3...n отверстия;
d_1,2,3...n - диаметр 1,2,3....n отверстия.The values of the angles and diameters of the holes are determined from the following relationships:

;

= where α _{1,2,3 ... n} is the angle of inclination of the axis 1,2,3 ... n of the outlet to the horizontal plane;
l _{1,2,3, .... n} - horizontal projection of a straight line from the axis of the glass to the mold wall along the axis 1,2,3 ... n of the hole;
d _{1,2,3 ... n} - diameter 1,2,3 .... n of the hole.

= B где W^х _ось - скорость потока на оси струи, м/с;

- безразмерная длина струи, в калибрах.The indicated relations are obtained on the basis of a study of the laws governing the distribution of a cylindrical jet in the cramped space of the liquid phase of a continuous ingot. Such a study, performed by the method of hydraulic modeling, gives the following dependence of the flow velocity on the jet axis on its length
(W $\genfrac{}{}{0ex}{}{\text{x}}{\text{about}}$ _smiling )

= B where W ^x _axis is the flow velocity on the axis of the jet, m / s;

- dimensionless jet length, in calibers.

Here x is the dimensional length of the jet;
d is the jet diameter, m;
A and B are constants.

.We represent this dependence in the form
(W $\genfrac{}{}{0ex}{}{\text{x}}{\text{about}}$ _c ) ^A = B

.

,
Аналогично для струи диаметром d₂, истекающей из стакана на расстояние х₂ до встречи с оболочкой сляба, скорость потока составит в месте встречи

^.
Из условия равенства скоростей потоков W

=W

на оси струй y различных мест оболочки сляба получаем

=

.In accordance with it, the flow velocity on the axis of the jet with a diameter of d ₁ from the glass, spaced x ₁ from the crystallizer wall, will be at the junction of the jet with the slab shell
(W $\genfrac{}{}{0ex}{}{\text{x}}{\text{about}}$ _c ) ^A = B

,
Similarly, for a jet with a diameter of d ₂ flowing out of the glass at a distance of x ₂ before meeting the slab shell, the flow velocity will be at the meeting point

^.
From the condition of equality of flow rates W

= W

on the axis of jets y of different places of the slab shell

=

.

 By imposing on the last equality the condition for the jets to meet with the slab shell at the same height, taking into account possible variations in the angle of inclination; and jet diameter, we obtain the above relations, where the variations are taken into account by coefficients of 0.8-1.2 and 0.9-1.1, respectively, for the first and second relations.

The device operates as follows. From the intermediate ladle 2, metal 9 enters the cup 4, the metal consumption is regulated by the stopper 3, and then through two holes 5 and two holes 6, respectively, to wide B = 2l ₁ and narrow A = 2l ₂ faces of the hardened crust 7 of the workpiece with jets of diameter d ₂ and d ₁ at angles α ₂ and α ₁ at the same height H from the meniscus 8 of metal 9 in the mold 10 with the same intensity.

 The device 1 is preferably used together with the coating of the meniscus 8 of the metal 9 in the mold 10 with a layer of slag 11.

 An example of a specific implementation of the device, not excluding other embodiments. Steel is fed through an elongated immersion nozzle with a diameter of a conducting channel of 70 mm into a mold with a cross section of 230 x 290 mm. The glass has four outlet openings in the form of slots 80 mm high, tilted down.

The proposed glass is made with holes of different diameters. Moreover, from the side of the near faces (230 mm in size), the thickness of the gap is 15 mm (reduced diameter 27 mm) and its axis is inclined at an angle of 30 ^o to the horizontal; from the far edges (290 mm in size), the thickness of the slit is 20 mm (reduced diameter 32 mm) and the inclination of its axis is 25 ^o .

Claims (1)

 DEVICE FOR CONDUCTING METAL TO CRYSTALIZER, made in the form of a refractory deaf glass with side outlet openings, the axes of which are located at an angle to the horizontal, characterized in that, in order to improve the reliability of the casting process and the quality of the workpieces, the refractory glass contains side holes of different diameters, moreover the reduced diameter of the larger hole is 1.1-2.5 times the diameter of the smaller hole, and the angle of inclination of the smaller hole is 1.2-2.7 times the angle of inclination of the larger hole.

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