SU846075A1 - Method of producing continuous billets at metal continuous casting unit - Google Patents

Description

one

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

A known method for producing round billets at a continuous metal casting plant, comprising feeding liquid steel into a water-cooled mold, drawing an ingot with a liquid core, cooling the ingot until it is completely solidified, heating the ingot, deforming and cutting it into lengths 1.

The disadvantage of this method is the uneven development of the cast structure over the cross section of the ingot in the process of rolling between the mill rolls. The reason for this is the joint effect of temperature and reduction between the rolls having a small contact area with the ingot surface on the unevenness of deformation over the section of the ingot, because when the temperature is leveled, the metal is compressed most strongly (due to higher plasticity) in the surface zone of the ingot and it tends to move with greater speed than axial. With a total reduction of 2.3-3.0, the metal in the surface

the zone of the ingot is subjected to compressive stress, and in the axial zone, on the contrary, by tensile stress. Such an unfavorable stress-strain state circuit creates additional tensile stresses in the ingot, which precludes infusion of discontinuities and contributes to their development. Only individual voids and cracks, located one third of the ingot surface, are reduced and brewed. The axial porosity is preserved with almost no change. When such an ingot is cut to length, the porosity of the axial zone is opened at the ends of the workpieces and further, due to the oxidation of its surface during heating, causes the metal to separate in subsequent pressure treatment. The known method of manufacturing by continuous casting of metal does not completely solve the problem of obtaining high-quality preforms for the subsequent limit by pressure treatment.

The purpose of the invention is to improve the quality

Claims (2)

 ingots by providing a more uniform processing of the cast metal structure over the entire cross section of the ingot and reducing the anisotropy of the mechanical properties. This goal is achieved in that the ingot is heated with a temperature difference between the central and surface zones of the ingot within 150-200 ° C, and the ingot is deformed by successive twisting around its longitudinal axis, the angle of twisting being a 360 °. where a is the angle of twist, deg .; H is the length of the swirling area of the ingot, mm; D - the initial diameter of the ingot, mm. According to the proposed method, any ingot element undergoes the same deformation, and the metal volumes undergo uniform compression in both axial and radial directions, which contributes to the closure and welding of shrinkage defects in the ingot. The drawing shows a device that implements the proposed method. Liquid steel from the casting bucket 1 is fed to a water-cooled mold 2. Ingot 3, having a liquid core, is pulled out of the mold with 2 tons of leaning rolls 4 and passes through a zone of nozzle (secondary) water cooling 5, equipped with supporting rollers 6. After stretching rolls 4, the crystallized ingot 3 passes through the induction device 7 to level the temperature. The differential between the central and surface zones is within 150-200 ° C in order to bring the metal of the ingot into the same plastic state not Surface temperature of the ingot should be in the range of 900-950 °. Next, the ingot 3 after ovatively twisting around its longitudinal axis in a twisting machine 8. At the same time, the speed of reciprocating movement of the exciting and twisting devices in the twisting machine 8 changes in exact accordance with the speed of drawing the ingot 9 from the water-cooled crystallizer 2. The ingot 3 as it comes out of the twisting machine 8 enters the gas cutting machine 9, where it cuts into dimensional workpieces 10. The ends of the workpieces 10 have a dense macrostructure, without traces of any shrinkage origin. In the blanks obtained by a known method, in the process of their subsequent limit by pressure treatment, the structure is fully worked out and the high mechanical properties of the metal are achieved with a 3.0-3.5 fold decrease in the cross-sectional area, while in the blanks obtained by the proposed method, to achieve these goals, a reduction in the cross-sectional area of 1.3-1.5 times is sufficient. This allows not only to obtain high quality products, but also to increase equipment productivity by 15-20%. The economic effect from the introduction of the proposed invention may be more than 150 thousand rubles. The invention method for producing round billets on a continuous casting of metals, including the supply of liquid steel in a water-cooled mold, drawing an ingot with a liquid core, cooling the ingot until it is completely solidified, heating the ingot, deforming it and cutting to length, characterized in that In order to improve the quality of the workpieces, the ingot is heated with a temperature difference between the central and surface zones within 150–200 ° C, and the ingot is deformed by second twist about its longitudinal axis, the twist angle is equal to a value of 360 °. , where a is the value of the twist angle, degrees; H is the initial length of the ingot to be twisted, mm; D - the initial diameter of the ingot, mm. Sources of information taken into account in the examination 1. Sat. “Continuous Casting of Steel, 1974, 4, p. 51-52. Water