SU1379079A1 - Method of secondary cooling of unequal octahedral continuously cast ingots of alloyed steel - Google Patents

Abstract

The invention relates to the field of metallurgy, and more specifically to continuous multi-casting of unequal alloy steel billets. The aim of the invention is to improve the quality of the ingots. This goal is achieved by the fact that in the secondary cooling area of 0.1 .., 0.3 depths of the liquid well, following the area with the same cooling rate of all faces of the workpiece, only narrow faces facing each other in ingots adjacent to each other are sprayed streams with intensity O, 01 ... O, 03 l / kg, which avoids local supercooling of these faces and prevents the formation of cold quenching cracks.

Description

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The invention relates to metallurgy, and more specifically, to continuous casting of steel alloy blanks, mainly in multi-stream installations.

The purpose of the invention is to improve the quality of ingots.

The goal is achieved by eliminating the local supercooling of narrow faces of ingots of neighboring streams facing each other, which leads to quenching cracks in the production of ingots from alloyed steels.

Example. Octagonal ingots with a section of 270 370 mm are cast on a three-strand vertical machine for continuous casting of billets of steel grade 5HNM.

The height of the nozzle cooling zone of all faces of the ingots is 700 mm (the area adjacent to the mold), the length of the nozzle cooling zone of only narrow and inclined edges is 1400 mm (the area following the area adjacent to the crystallizer).

Working casting speed 0.4 m / min.

Nozzle cooling mode: total specific water flow rate of 0.06 L / kg stly; specific consumption of water for wide grni 0.01 l / kg of steel; specific consumption of water on external narrow and inclined sides of 0.025 l / kg of steel; the extent of the subsequent nozzle cooling zone of the narrow faces of ingots of adjacent streams facing each other is 1,400 mm; cooling intensity of narrow faces of ingots facing each other, 0.02 L / kg of steel.

When casting by the proposed method, under the crystallizer, the surface temperature of the ingot is equal to 1080-P60 s, in the zone of impact of the nozzles 780-940 ° C, after the zone of nozzle cooling 720-810 C.

Cooling the faces of the ingots facing each other, on the site next to the site with the same

cooling intensity over a depth of more than 0.3 the depth of the liquid well, with an intensity of 0.03 L / kg of steel, leads to overcooling of the ingots, and, ultimately, to the formation of internal cracks. The cooling of the faces of the ingots facing each other, in the area following the section with the same cooling intensity in height, with an depth of more than 0.3 depth of the hole, with an intensity of less than 0.01 l / kg of steel, does not practically exclude the radiating effect of the faces of the ingots facing to each other, i.e. their mutual warming up, which leads to the formation of quenching cracks.

The method allows to improve the quality of continuous ingots due to

Claims (1)

elimination of scrap blanks for cold quenching cracks. Invention Formula Method of secondary cooling of non-sided octahedral continuously cast ingots of alloyed steel, mainly during multi-casting, including nozzle cooling of the ingot surface under the mold at a length O, 01 ... O, 05 depth of the liquid phase with the ratio of water flow to narrow and inclined faces to water flow to wide faces, equal to 1.5 ... 3.0, and additional cooling only narrow faces, characterized in that, in order to improve the quality of the ingots, additional cooling of the narrow faces is carried out over a length of 0.1 ... 0.3 of the depth of the liquid phase with the cooling intensity of facing each other faces of the ingots from the neighboring streams equal to 0.01 ... 0.03 l / kg.