SU1458071A1 - Method of continuous casting - Google Patents

Abstract

This invention relates to the field of metallurgy, specifically to the continuous casting of metals. The aim of the invention is to increase the stability of the continuous casting process, improve the quality of the ingot by reducing cracking during local deformation of the ingot crust and increasing the accuracy of the geometric dimensions of the cross section of the ingots. Liquid metal 1 is served

Description

one

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

The aim of the invention is to increase the stability of the continuous casting process, improve the quality of the ingot by reducing the churning of the local deformation of the ingot crust and improving the accuracy of the geometric dimensions of the cross section of the ingots.

FIG. Figure 1 shows the setup for continuous casting of metal with preliminary deformation of the solid crust of the ingot at the place of its subsequent separation; in fig. 2 shows section A-A in FIG. one; in fig. 3 is a diagram of local heating of the outer layers of the shell immediately before the deformation zone; in fig. 4 is a diagram of the distribution of the temperature of the ingot crust over its thickness.

Liquid metal 1 (Fig. 1) is supplied to a water-cooled mold 2 of a rectangular cross section of a continuous casting machine (continuous casting machine). The forming crust 3 is drawn into the working space of the secondary cooling zone of the continuous casting machine formed by two rows of supporting rollers 4. In the area I of the secondary cooling zone, the ingot crust 3 is locally deformed by sequentially installed profiled rolls 5 at the sites of its subsequent longitudinal separation of the ingot into narrow billets.

Heating of the outer layers of the crust 3 (Fig. 3) of the ingot immediately before its reforming in the profiled rollers 5 is carried out, for example, with the aid of nozzle burners 6 installed above the surface area of the ingot in the zone of its subsequent longitudinal separation. Accelerated

cooling of the deformed crust after its profiling is ensured by placing water-air sprays 7 over the profiled section.

As a result of additional external heating of the moving shell, its temperature field directly in front of the deformation zone is described by a curve T (Fig. 4), which graphically reflects the process of unsteady interaction of two oppositely directed heat flows: from the liquid metal at the crust crystallization front and from the nozzle heaters

at the surface of the ingot.

In order to deform the crust of a steel ingot with a thickness of 20-40 mm, at which the profiling of the shell takes place in the best quality, it is necessary to heat its outer layers to the surface temperature T "(0.8-0.85). T" ,.

After profiling the ingot crust, the heat flux of external heating

reaches the crystallization front. At the same time, an increase in the temperature of the crust at the crust – liquid metal interface is accompanied by a slowing down of the ingot solidification process, which leads to its overheating and an increase in the danger of swelling of the finished section.

In order to level the thickness of the deformed ingot crust, the crystallization rate of the metal in the profiled section must be increased, which is achieved by local accelerated cooling of the ingot surface, for example, with water-air sprays 7 (Fig. 3).

Example. Spilled low angle

71

Before its deformation in the profiling rolls with subsequent accelerated cooling of the shell at the site of separation, the ingot shavings reduce the cracking by 3.5–5.0 times and reduce the depth of cracks on the surface of the workpieces by 2.5–4.0 times.

Claims (1)

Formula invention The method of continuous casting, including the supply of liquid metal to the cooling christandiser, continuous stretching from it and cooling parent steel 0.8 cn into ingots with separation of a two-phase billet and longitudinal separation of the billet into parts with preliminary deformation of the solid crust of the billet in place with cross-sectional dimensions i 300 X 1660 mm in a continuous casting machine using local deformation of the ingot crust in the secondary-cooling zone. The nozzle gas burners installed in front of the deforming protrusions of the chasers of successively installed pairs of rolls at a distance of 100 from the plane passing through the axes of each pair of rolls, heat the surface of the ingot crust to a temperature of 1210-1260 C. airless nozzles installed at a distance of up to mm mm behind the plane passing through the axes of each pair of rolls to a temperature of 990-890 ° C, which is 0.8-0.9 of the average temperature per meter cross section crust sla ba. The study of defects in separated blanks shows that the heating of the outer layers is 25 thirty 35 characterized in that, in order to increase the stability of the continuous casting process, improve the quality of the ingot by reducing the cracking during local deformation of the ingot crust and increasing the geometric dimensions of the cross section of the resulting ingots, deformation of the solid crust of the workpiece is carried out after local heating of the surface in the deformation zone to temperature T „(0.80-0.85) T„ „where T, is the solidus temperature of the metal being cast, followed by deformation by accelerated cooling of the surface STI deformed portion to a temperature T (0.8-0.9) T p, where the average surface temperature of an ingot cross section crust in place cooling. / t- /} Fi.2 0 five 0 five characterized in that, in order to increase the stability of the continuous casting process, improve the quality of the ingot by reducing the cracking during local deformation of the ingot crust and increasing the geometric dimensions of the cross section of the resulting ingots, deformation of the solid crust of the workpiece is carried out after local heating of the surface in the deformation zone to temperature T „(0.80-0.85) T„ „where T, is the solidus temperature of the cast metal, followed by deformation by accelerated cooling of the surface STI deformed portion to a temperature T (0.8-0.9) T p, where the average surface temperature of an ingot cross section crust in place cooling. L / fie.Z