SU349238A1

SU349238A1 -

Info

Publication number: SU349238A1
Application number: SU1438559A
Authority: SU
Inventors: С. Е. Карликский В. М. Нисковских Е. Ю. Гельфенбейн; Г. Л. Химич
Priority date: 1970-06-18
Filing date: 1970-06-18
Publication date: 1974-05-05
Also published as: DE2117110A1; GB1332047A; FR2095323A1; US3729048A; FR2095323B1

Description

This invention relates to the field of metallurgy, in particular to the continuous casting of metals.

Installations for the continuous casting of metals are known, which contain a radial crystallizer and directing devices for the ingot in the secondary cooling zone, which includes successive arc sections with a radius equal to the radius of curvature of the crystallizer, curvilinear and rectilinear sections.

The disadvantage of such plants is “low quality ingot when casting at high speed.

In order to ensure high casting speeds and high-quality ingots, the arc section with the mold in the proposed installation is 0.2-0.4 in length, the total length of the secondary cooling zone, and the guides on the curvilinear section are set along a curve whose radius of curvature is directly proportional to the ratio the thickness of the sllt liquid phase at the maximal casting speed to the difference of the length of the curvilinear section and the current length of the arc of the curve, and the length of the curvilinear section is 1.3-1.8 times the radius of curvature of the cris allizatora on the angle between vertical) O n straight connecting the top portion kriBOLnneynogo with center of curvature of the mold.

The drawing shows the scheme of the proposed metal casting installation.

The installation contains a radial mold having a radius of curvature, which is intended for the primary cooling of the molten metal 2 and the formation of the crust 3 of the ingot 4. Then follows a secondary cooling zone where further ingot crystallization occurs. The secondary cooling zone includes an arc section 5 directly below the crystallizer, the radius of curvature of which is equal to the radius of the crystallizer core Rg, as a result of which the ingot is not deformed in this region. Length l

5 of the arc section 5, including the length of the crystallizer, is chosen so that the ingot is crystallized by 45-65% of its tolyline. In this case, the crust can resist simultaneous deformation from the action of ferrostatic pressure and the development of the ingot without the formation of internal defects.

The length at which the ingot acquires a crust of a given thickness of 1; s can be counted25

tan by the known ratio-: I

where and - tolln1: on the ingot shorter case;

/ (- constant of crystallization, cm / min 301/2;

showers, Ml min.

From experimental data it is known that in the secondary cooling zone the value of the constant crystallization fluctuates within

/ C 2.55-2.65

Taking the aforementioned ingot crystallization values at the end of the arc section and continuously crystallizing L and using the above ratio, we obtain

L, (0,2-OO, 4) /.

where LO is the total length of the secondary cooling zone.

On the curvilinear section 6, the ingot 4 should be smoothly straightened so that the deformation of the inner layers 7 of the ingot, which are close to the solid and liquid phase, is reduced, due to the uniform distribution of this deformation over the entire length of the curvilinear part.

According to the well-known relation, the total deformation of a strip with a thickness h during extension from radius R to radius c is defined by the expression:

h adPri uniform distribution of deformation and about the length of the curved section we have

-i- ,. cons,

where 5 is the current length of the arc curve, measured from its end or the same expression

.

where a is a constant curve.

According to the invention, willow should be replaced with h - liquid thickness instead of h: the ingot phase at the maximum casting speed, which is the current and curvilinear section. Expressing the current arc length of the curve through the full length L2 of the crochet-linear segment, we obtain the natural equation of the curve according to the invention:

R:. but

L, - S where O; - the current value of the arc length of the curve, o (read about its origin. On the edge of the arc and curvilinear part ii ho, R Ro, and 5 / O, then the constant paeiia

RoL,

where ho is the thickness of the liquid phase of the ingot at the beginning of the section,

L is the f-distance between the layers 7 of the ingot at the end of the segment.

bf 5i

Then / g, - / ig (1 -t) - t,

and the natural equation of the curve takes the form

L,

R (). -W-, L-, --Si

Benefits known. Ratio m ds

will get

one -

L., - y.oRo

1 in t 1-t

where Co is the angle between the vertical and the ir, connecting the beginning of the curved section with the HeHTpoiM curvature of the mold. The value of t is determined from the condition that the deformation rate of the ingot layers 7 is not more than the permissible value. From this condition, 2- -0.7. Then the length of the curved section will be: LZ (1.3; - 1.8) oo RO. The presence of internal temperature stresses in the ingot can lead to its distortion after leaving the secondary cooling zone devices. To prevent this, the ingot should be held for some time by guiding devices after straightening. From these conditions, the length of the spacing section 8 is determined as follows. by ratio

L, () / ie,

where he is the maximum thickness of an ingot molded at the facility.

The total length of the secondary cooling zone LI-f-L2 + LS should not be less than the length of the liquid phase in the slot at the maximum casting speed.

Subject invention

A metal continuous casting plant containing a radial mold and guide devices for the ingot in the secondary cooling zone, which includes successive arc sections with a radius

equal to the radius of curvature of the mold, curvilinear and rectilinear sections, characterized in that, in order to provide P1 high speeds for casting and obtaining high-quality ingots, the arc section with the mold is 0.2-0.4 in length and the length of the secondary cooling zone , and the guides on the curvilinear section are set along a curve, the radius of which is radius nponopH, Hoiia; iCH relative to

casting to the difference between the length of the curvilinear section and the current arc length of the curve, the length of the curvilinear section being 1.3-1.8 times the radius of curvature of the mold by the angle between the vertical and the straight line connecting the beginning of the curvilinear section with the center of curvature of the mold.