SU921671A1 - Apparatus for horisontal continuous casting - Google Patents

Description

(5) DEVICE FOR HORIZONTAL CONTINUOUS CASTING

I

The invention relates to metallurgy, and more specifically to the continuous casting of metals in horizontal installations.

A device for continuous casting of ingots, comprising a metal reservoir and a horizontal mold, is known. Between the vessel with the molten metal and the mold there is a refractory heat-insulating wall in which the sprue opening is made. The long and narrow gating hole corresponds in shape to the lower half of the inner wall of the mold 11.

However, the location of the sprue and its shape, corresponding to the configuration profile of the lower part of the mold, inevitably leads to its freezing and disruption of the process, especially during forced stops. In addition, the limits of the geometric parameters of the gate are not specified. Random selection of gate location

and its cross-section can also lead to disruption of the process and casting defects: freezing of the sprue, breakthrough of the hardened crust at the exit of the casting from the mold, tearing the crust inside the mold, the occurrence of heats, wets, etc. This is due to the presence of convective flows in the mold, the direction and distribution of which is determined by the location, shape and section of the hole through which the liquid metal enters from the metal reservoir into the mold cavity.

The fastening of the slab separating the taller receiver with the crystallizer cannot provide a tight joint, therefore bays, scuffs, rupture of the hardened crust are possible, which leads to defects in the surface of the casting and can cause the metal to break through at the outlet of the crystallizer.

The purpose of the invention is to create a directional, retarding developmental 33

tie natural convective flows, the supply of liquid metal into the cavity of the mold, ensuring the stability of the process and increase productivity.

To achieve this goal, in a device for continuous horizontal casting of blanks of a continuous section containing a metal reservoir, a water-cooled mold with a graphite liner, the uncooled color of which is connected to the metal receptacle, and a plug of low conductive material with a runner channel for the passage of liquid metal separating the metal receiver from the crystalline crystalline cavity. The gating channel has a flow area, its size is 0.02-0.07 of the transverse casting seed.

Moreover, the outlet of which is located at a distance from neither 1 forming a mold of 0.2-0, the height of the section of the casting, and its axis is inclined to the axis of extrusion at an angle of 10-30, with a larger section of the casting corresponding to a larger value angle of inclination, with several gating channels, the outlets are located in the same horizontal plane.

In addition, the plug is inserted into the protruding uncooled portion of the graphite liner and washed from all sides with liquid metal.

The drawing shows a diagram of the proposed device.

The device has a metal reservoir 1, a mold 2 with a water-cooled case and a graphite liner 3, plug 4 of. low thermal conductive material with a gating channel 5.

The device works as follows.

During the casting of the casting 6, the solidified crust during each cycle advances a certain distance in the mold 2 and the cavity 7 is filled with new portions of the liquid metal flowing from the metal receiver 1 into the cavity of the mold 2 through the gating channel 5 Experience in simulating heat and mass transfer between the liquid metal metal receiver and mold (experiments were conducted at the Department of Foundry production of ferrous and non-ferrous metals BPI), it was found that the least development teplokoveve714

tiviogo occurrence occurs when the exit hole of the gate channel is located at a distance from the lower generator of the mold, O, 2-0, A of the section height and when its axis is tilted at an angle U-ZO to the axis of extrusion.

Proceeding from the conditions of free expiration at each successive cycle

0 (without the occurrence of a vacuum in the cavity of the mold) and real speeds of casting on horizontal continuous casting plants, the optimum ratios of the cross sections of the sprue channel and the casting were determined.

The method of determining ratios is as follows. On the one hand, the metal consumption in the unit

0 time can be determined from the formula

 / where 0. - volumetric flow rate of liquid

metal per unit of time, cm Vc; V - - drawing speed,

cm / s (for the speed of drawing under the cyclic mode of drawing, the accepted speed of movement of the casting; in contrast to the speed of casting, is the average speed of movement of the casting taking into account the time of installation);

PTA casting cross section, cm From the other side

Qm RL, K.-

0 where i-f is the coefficient of metal consumption per unit of time;

FI „- section of the gating channel lk,„. 2

(sum of section ;; cm; с — acceleration of free fall, cm / sec;

H is the pressure of the liquid metal, which is defined as the difference between the upper levels in the metal receiver and the crystal, cm (Fig. 1).

Operating experience of continuous casting plants showed that the actual possible drawing speeds are in the range of 1.0–5 m / min (1.665, 33 cm / s). The coefficient of consumption is assumed to be 0.7.

The value of the head is assumed to be minimal, equal to 50 mm, since the further decrease in pressure is associated with the danger of obtaining an unfilled casting,

 cm / sec

V

-R

where do we have

ll one.

F

Lk o J 2 §805 °°

F P 33

, 07 LV. exel oh 7-2 -980

Therefore, the cross-section of the outlet should be 0.02-0.07 of the cross-section of the casting.

The dosing flow of molten metal into the mold cavity and the ability to determine the parameters of the gating channel for each size of the cast billet will ensure the stability of the process, will allow you to choose the optimal casting mode, which will significantly increase productivity. Installing the plug into the uncooled protruding portion of the graphite insert contributes to a tight fit, as it is pressed against the liner during the process as a result of the hydrostatic pressure of the liquid metal of the metal receiver. Such installation of the plug does not require additional fastening and avoids bays and the consequences associated with them. Production tests of the device under the conditions of the Kaunas Centrolit plant showed that the use of the proposed device allowed us to increase the casting speed by 1.5 times and, consequently, the installation capacity. For example, when casting a cast-iron cylindrical billet with a diameter of 100 mm, a lightweight winding plug was used with a gating channel of 015 mm (FI (- RPGL 002) tilted under

216716

an angle of 15 to the draw axis and located at a distance of 30 mm (0.3 height of the casting section) from the lower generator of the crystallizer, a casting speed of 0.9 m / min was reached (casting speed according to the old technology of 0.6 m / min), accordingly, the installation capacity increased by 1.5 times.

О In addition, there was no need to stop the drawing process at the time of topping up fresh portions of the metal into the metal receiver.

Claims (3)

1. A device for horizontal continuous casting, containing a metal reservoir, a water-cooled mold with a graphite liner, the uncooled portion of which is connected to the metal reservoir, and a plug of low heat conductive material with a sprue channel for the passage of liquid metal separating the metal reservoir from the cavity of the mold, characterized in that the purpose of ensuring the stability of the process and increasing the productivity of the installation, the gating channel has a flow area of 0.02-0.07 cross section Castings. 2. The device according to A.1. O tl and that the output frequency is (m, the opening of the gating channel is located at a distance of 0.2-0.4 of the cross-sectional height of the mold from the lower generator of the mold, and its axis is inclined to drawing axes at an angle of 10–30. 3. The device according to claim 1, about t l and that the plug with the outlet is inserted into the protruding uncooled part of the graphite liner. Sources of information taken into account in the examination 1. US Patent No. 3286309, cl. 22-57, 2, 1966.