CH650427A5 - Apparatus and process for starting the casting of the starting head during the continuous casting of metals - Google Patents

Description

The invention relates to a method for casting the start-up head during the continuous casting of metals with the aid of a radiation receiver arranged in a stationary manner which responds to the bath level in the continuous casting mold and which is connected in terms of control to an actuating device for the stopper closing the pan or intermediate vessel spout, and a device for carrying out the Procedure.

As is known, a start-up head is used for casting when continuously casting metals into the mold. A layer of cooling scrap is applied over the start-up head. After opening the steel supply from the tundish, the liquid steel in the mold rises. The bath height in the mold is carried out manually via direct closure control (stopper or slide) of the intermediate vessel as far as possible.

When a bath height in the mold is reached, which is generally approx. 100 mm below the upper copper edge of the mold, the start button, i.e. the bottom of the mold is pulled out of the mold using the cold strand. This process is also initiated by the operating personnel. At this moment, the starting process, i.e. the casting in the closed mold ends and the continuous casting begins. The steel is fed in the normal continuous casting process via a pouring level control. These pour level controls are based on mangetic, optical, thermal or radioactive radiation (DE-OS 2 757 052, DE-AS 1 458 181, DE-OS 2 736 227), the measurement being carried out at an angle to the direction of strand withdrawal.

All known devices are intended exclusively for the normal pouring process, whereby the operating personnel must always be used for starting.

The object of the invention is to provide a method and a device for starting up in the continuous casting of metals, with which manual initiation of the process is dispensed with, and thus an automated, but in particular reproducible casting process can be ensured.

To achieve this object, a method and a device are proposed according to the invention, as described in claims 1 and 2, respectively.

The method according to the invention effectively prevents damage that can occur when starting off manually, and moreover the casting can take place according to predetermined programs, e.g. linear or proportional.

The arrangement of a device according to the invention is shown schematically in the accompanying drawings. There 15 show: "

FIG. 1 shows the schematic representation of a device arrangement,

FIG. 2 shows a diagram of the illumination intensity / distance,

Figure 3 is a working diagram of lighting intensity / 20 distance / temperature / time.

As FIG. 1 shows, the arrangement according to the invention of a device consists of a radiation-sensitive element 1, 25 arranged outside the mold 3 at a defined distance from the mold and thus from the start head 2, the arrangement being such that a line of sight from the element 1 to the start head 2 R »exists; further known couplings between element 1 both for the feed control 4 from the tundish 5 and for the control 7 for moving the start head 2 out of the Ko-30 kille 3.

As shown in dash-dotted lines in FIG. 1, a lens system 11 can be arranged at a certain distance from the starting head 2 between the radiation-sensitive element 1 and the bath level. The radiation 35 is imaged onto the radiation-sensitive element 1, e.g. transmit a line scan camera. The size of the figure provides information about the distance of the bath level from the lens system and is used for the determination and evaluation for the start-up.

40 The strength of the energy source can be described with Stefan-Bolzmann's law, i.e.

E = er x F x T4

E = total energy emitted by a black body

45 F = surface of the radiating body

T = absolute temperature ct = radiation constant.

With a known radiation area, illumination area and known material constants, the energy arriving at the radiation-sensitive element per time or the temperature arising thereon can be represented as a function of its distance from the energy source.

When using the method according to the invention, the metal is passed from the tundish (5) via the immersion spout (6) onto the start-up head (2) into the mold (3), in a supply quantity per unit of time, which is carried out with the aid of the law the photometry can be determined. This law is described by the following equation:

60

e * 4

In this formula:

e = the illuminance (illuminance) I = the luminous intensity R = the distance

The light intensity I must be assumed to be constant when continuously casting a metal, since the casting temperature of the metal must be kept constant during continuous casting.

Due to the device arrangement according to the invention of a radiation-sensitive element (1) outside the mold (3), which is attached in a direct line of sight to the start-up head (2), the system is started up when the desired bath height is reached.

FIG. 2 shows the illuminance or radiation intensity arriving at the radiation-sensitive element (1) as a function of the distance between the element (1) and the bathroom mirror. The relationship becomes linear in the logarithmic representation. The diagram also shows the influence on the illuminance when adding casting powder to the bathroom surface. This influence is shown in FIG. 2 by curve b2. The curves at and a2 represent the relationship without the application of casting powder.

650 427

FIG. 3 shows a working diagram for the quantities of illumination intensity, distance, temperature and time. When preselecting a sprinkling time t1-target to tn-target and a time quantity program a, b, c, d, the distance from the radiation-sensitive element ( 1) be determined at every moment of the pouring process to the bathroom mirror. This distance is labeled “R” in the diagram. The distance between the radiation-sensitive element (1) and the wheel mirror can be preselected at the end of the casting process. This distance is designated in the diagram with «R ^ Soll» to «Rn-Soll». For a given material constant with regard to the radiation-sensitive element, a temperature “R” can be assigned to a distance.

If a lens system (11) is used, the distance measurement can be carried out later using an image size on the radiation-sensitive element (1) instead of an irradiation intensity.

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3 sheets of drawings

Claims (2)

650427 1. The method for casting on when continuously casting the start-up head of metals with the aid of a radiation receiver arranged in a stationary manner which responds to the bath level in the continuous casting mold and which is connected in a control-related manner to an actuating device for the stopper closing the pan or intermediate vessel pouring, characterized in that the radiation intensity ( s) perpendicular to the start-up head for determining the distance (R) of the bath level from the radiation receiver according to the formula where I is the constant light intensity, measured and, after reaching a predetermined bath level, the start-up head is lowered. 2. Device for performing the method according to claim 1 with a radiation receiver responsive to a radiation spectrum, characterized in that that the receiver (1) above the continuous casting mold (3) is arranged in a measuring position vertically above the start-up head (2).