SU143215A1 - Continuous metal casting mold - Google Patents

Description

Known molds used in continuous casting of metal, made with longitudinal waviness.

In continuous metal casting using belt type machines, it has been proposed to prevent external cracks from deforming the crust on the wide faces of the sheet ingot during the crystallization process. In this case, one of the two moving ribbons of the mold, between which the ingot was formed, was initially convex. As the ingot moved forward with the help of a mobile tape, its convexity gradually decreased and the deformation of the ingot was completed until it was completely fixed. However, belt-type machines for which this form of crystallizer was used are not practically used at present;

The most widely used machines for continuous casting of metal with a slip of the crust of the cooling metal relative to the walls of the mold.

When the sheet ingots are cast in an uninterrupted way, in the molds with a large wide-to narrow narrow ratio often longitudinal cracks form on the wide side of the ingot.

The proposed mold for continuous casting of metal with a slip of the crust, in order to eliminate the causes of the formation of longitudinal cracks in flat ingots, is made with a variable bulge or concavity along the height of the large faces of the walls of the mold.

FIG. 1 shows the first version of the proposed mold; in fig. 2 - his second option.

Spontaneous deflection of the edges of a sheet of continuous ingot in-inside can be observed when the supply of metal to the mold is stopped. At the same time, as the ingot crust thickens, it overcomes the hydrostatic pressure of the metal column and bends No. 1432152

with Eo-inward, whereby tensile stresses on the outer surface of the middle part of the wide faces of the ingot are reduced.

 A normally proceeding process of continuous stripping of thinning does not keep pace with the increase in pressure of the metal column. Therefore, the ingot faces do not bend in-in, and often, at the outlet of the Schuttler's rings, there are coarse longitudinal cracks.

Gakie treyatin, in particular, are observed when casting steel grade St-3 in the mold section of 640X150 mm.

In order to ensure that, in a normally flowing casting process, the bending of the edges of the sheet continuous ingot inwards, it is proposed to make a mold with a variable curvature of wide edges in height.

The first version of the mold is made with a profile of the upper section of the mold in the form of a rectangle. In Kiise, this profile is changed in such a way that the wide sides become more and more concave. At some distance from the top of the mold, this concavity reaches a maximum and does not change below (Fig. 1).

The second version of the mold is made with the profile of the upper section of the mold in the form of a figure with convex large sides. To the bottom, this bulge decreases, and, starting from a certain height, the profile becomes rectangular and changes further (Fig. 2).

When using a mold with a variable bulge or concavity of wide edges in height, the pressure of the ingot crust on the walls of the mold increases.

Calculations confirm that the pressure of the crust on the walls of the mold of the proposed profile, even with a relatively large deflection, will increase by only 6% compared with the mold of the usual profile, that is, with a constant curvature of the faces in height. Strengthening the ingot ingot from the mold will also increase by 6%, which is not significant to say about the increase in the number of transverse cracks on the ingot.

The manufacture of the mold of the proposed profile is possible either by casting or by machining. In the latter case, it is permissible to simplify the profile, which consists in the fact that the internal profile of the wide faces of the mold is a combination of a plane with a cylindrical surface intersecting at a certain angle. If this results in sharp edges, they should be rounded.

The subject is invented and

A mold for the continuous casting of metal into flat ingots on installations with a slip of the crust, characterized in that, in order to eliminate the causes of the formation of longitudinal cracks, the large faces of the walls of the mold are made with variable camber or concavity in height.

faz.l

fuz2