RU1796339C - Method of continuous billet casting - Google Patents

Abstract

The method includes feeding metal and a moving mold and drawing the workpiece, the mold making plane-parallel motion, in which its points move along identical closed paths with a revolution frequency of 0.5-50 Hz around axes parallel to the drawing axis of the workpiece.

Description

The invention relates to metallurgy and can be used in the manufacture of continuously cast billets.

The purpose of the invention is to increase the productivity of the process and the quality of the workpiece.

The lower limit of the frequency of revolution of the mold points around the axes is 0.5 Hz and is determined on the basis of the minimum drawing speed of the workpiece when freezing its crust is at the minimum (permissible) speed. Reducing the lower limit of the frequency is unacceptable, as a breakthrough of liquid metal at the exit of the mold can occur. The upper limit of the frequency of revolution of the mold points around the axes is determined to be 50 Hz and is selected based on the maximum drawing speed of the workpiece, the maximum rotation speed of electric motors that communicate the motion to the mold. Increasing the upper frequency limit is not advisable, since it will require a significant complication of technological equipment.

The method is carried out as follows.

Liquid metal is fed into the preheated metal detector with its further frenzy into the mold moving plane-parallel with the metal detector. The metal solidifies at the end of the preform, where there is a transverse groove of a dovetail, and from this solidified metal along the cooled walls of the mold, a crust of a continuous preform is formed.

The plane-parallel movement of the mold creates a continuously changing gap between the formed crust of the preform and the cooled walls of the mold. The liquid metal enters into this gap in small portions and quickly solidifies on the previously formed crust. Thus, intense freezing of the crust of the continuously cast billet occurs. Then, the workpiece with the metal hardened at its end together with the crust is pulled at a constant speed not exceeding the rate of rise of the metal crust in the direction opposite to that of the workpiece. (The rate of rise of the crust depends on the brand of poured

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metal and the speed of plane-parallel motion of the mold. This speed is determined experimentally in each case). Thus, a continuously cast ingot with a liquid core comes out of the mold, with further movement of the ingot through the secondary cooling zone and the area in front of the liquid cutting mechanism, the core of the ingot solidifies and the billet formed from the continuous cast is cut by the cutting mechanism into pieces of measured length, which are sent further according to technological process of enterprise production. The method can be implemented on a horizontal continuous casting machine. The exit of the mold is closed with a seed (more precisely, with a hinged link on its front part), which is sealed with asbestos on the mold walls. A burner is introduced from above into the opening of the cover of the metal detector and the lining of the metal detector is heated to a temperature of about 1200-1250 ° C. They include cooling the mold: water is supplied to the mold water jacket under a pressure of 0.3-0.6 MPa. Next, a plane-parallel motion is reported to the mold with the metal detector, in which its points move along the same path m -. Circumference m (radius 1-5 mm) at a speed of 30 rpm (i.e., frequency 0.5 Hz). Then a liquid metal (for example, steel 35; HS) is fed into the metal receiver, the temperature of which is 1595 .., 1615 ° C: From the metal receiver, the liquid metal enters the crystallizer, where it hardens in the dovetail and

the remaining surface at the end of the seed. From the solidified metal along the cooled walls of the mold, a crust of a continuously cast billet is formed. Then

a workpiece with hardened at its end -. together with the crust (hardened along the walls of the mold), they are pulled out at a speed of 1-3 m / min. Thus, continuously extruding from the mold

an ingot with a liquid core, which, upon further movement through the secondary cooling zone and the section in front of the cutting mechanism, completely hardens, and by means of the cutting mechanism, the continuously cast billet formed is cut into pieces of measured length. The proposed technical solution allows to increase the production productivity of continuously cast billets for

due to the intensification of peel freezing

workpieces by quick cooling small

servings of liquid metal entering

continuously varying clearance between

hardened crust and a cooled crystallizer wall during its plane-parallel motion. In addition, the proposed method provides continuous casting with good surface quality (without clamps,

breaks, flows, cracks). The fine-grained structure of the workpiece is the result of circular motions of the liquid metal in the mold, which leads to a more uniform decrease in temperature over

the entire volume of the liquid metal, and further ensures the solidification of the liquid core of the continuously cast ingot with many crystallization centers.

Claims (1)

SUMMARY OF THE INVENTION A method for continuously casting preforms, comprising supplying metal to a mold, imparting movement to the walls of the mold and drawing the blank from the mold, characterized in that that, in order to increase the productivity of the process and the quality of the workpiece, the crystallizer walls are informed of plane-parallel movement along closed paths with a frequency of 0.5-5.0 Hz around axes parallel to the axis of drawing of the workpiece.