SU593813A1 - Method of automatic control of ingot-cooling in continuous metal-casting plant - Google Patents

Description

The invention relates to the casting of metals and other materials, in particular to the continuous casting of metals by extrusion of the molten mass, by casting into tubular molds with open ends, and can be used in ingot cooling control systems in continuous casting installations of metal,

A known method for regulating the cooling of an ingot in continuous steel plants (UNCRM), is that the supply of cooling water to individual sections of the secondary cooling zone is reduced while reducing the casting speed flj.

There is also known a method for controlling the cooling of a reflector in continuous casting plants, which means that the supply of cooling water to individual sections and faces of the ingot in the secondary cooling zone is set depending on the varying casting speed 2.

In case of asymmetry of the heat sink from the ingot in the crystallizer, the resulting difference in the thickness of the symmetrical faces of the ingot and the difference in,

their surface temperatures do not in any way correspond to redistribution of cooling water along these edges in the cooling zone for the second time. As a result, the asymmetry of temperatures and thicknesses in the crystallizer continues to equalize in the secondary zone in the mold, which can lead to overcooling of individual faces of the ingot and, consequently, to the occurrence of unacceptable temperature stresses and internal defects in the ingot. This is due to the nature of the dependence of the yield strength on temperature, which, according to experimental data, has

ct

a-se

er, "

where T is the metal temperature}

1, S, C - empirical coefficients, derived from the brand of steel. It follows from the above dependence that the supercooling of individual faces of the ingot leads to an increase in the yield strength of the metal on the surface of these faces (i.e.

hardening of their shell), and, consequently, to the appearance of significant stretching of high stresses near the crystallization front, which can cause a discontinuity of the ingot ,, J

The aim of the invention is to increase the quality of the continuous ingot and the yield of metal from the installation. This is achieved by the fact that in a known method of automatically controlling the cooling of the ingot in the continuous casting plants of the metal, which consists in supplying cooling questions to individual sections and The grains of the ingot in the secondary cooling zone are set to depend on the varying casting speed, the measurement of the temperature difference and the flow rate of cooling water for each individual crystallization wall is introduced. Operations and rejecting products of these quantities (20 lov№ heat fluxes) from the calculated values for the same symmetric walls compensate these deviations corresponding increase (decrease) of the cooling water flow in the secondary cooling zone 25 spinning.

The selected law of compensation for deviations: heat flux is assumed in the form, pcc, e.a), l 1,2,3,4; , 2.in; cooling water flow rate on the I-th edge in p. -th section of the secondary cooling zone; pull rate; Qj-a is the specified (calculated) heat of water from the t -th wall of the crystallizer; U - the current heat sink from the I-th wall of the mold; 1, P ,, The proportional coefficients for p. -Th section of the secondary cooling zone; - the number of secondary cooling sections. The drawing shows a schematic diagram of a device that implements the proposed method. The device is considered to apply to a UNRS with a four-section zone of secondary cooling (the number of sections may be any). Two faces of the ingot are considered, the Upt-oyystvo contains regulators 1 of the flow rate of Vrda. for each section and faces of the ingot in the secondary cooling zone, to the input of which the control devices 2 are set for each section and the faces of the water flow.

The outputs of the setting devices 2 are connected to the output of the tachogenerator 3, which has a speed that is equal to the coupling and also outputs of the algebraic adders 4, which form the signal of deviations from the set value of the heat flux from the corresponding wall of the crystallizer; the signals from the sensors 6 temperature differences and flow meters 7 form the amount of heat flow from the corresponding steak of the mold.

The device works as follows.

Claims (2)

In stationary modes, the supply of water to individual shocks and secondary cooling granules. Is determined by the casting speed, i.e. signal from tachogenerator 3. When the heat flux deviates from any wall of the mold from a predetermined value, the signal from the output of the algebraic adder 4 passes to the setpoint 2 of the water flow regulator 1 corresponding to the face and changes the flow so as to compensate for the deviation of the heat flux from the corresponding wall crystallizer. Claims The method of automatically controlling the cooling of an ingot on a continuous metal casting plant consists in supplying cooling water to separate sections and faces of the ingot in the secondary cooling zone depending on the casting speed, characterized in that, in order to increase the yield of a suitable metal from the plant, in addition, the temperature difference and the flow rate of cooling water are measured individually for each wall of the mold and when the products of these quantities (heat fluxes) deviate for each face about tons of calculated values, which are the same for symmetrical walls, compensate for these deviations by varying the cooling water flow rates in the secondary cooling zone according to the corresponding facets in accordance with the formula ,,, () H 1,2,3,4; J, 2t; e Gj is the cooling water flow along the first face in the nth section of the secondary cooling; V- — drawing rate; - specified (calculated) heat sink from the t-th wall of the mold; talizer; Oh, is the current heatsink from the I-th wall of the crystallizer} Krj. pronouncing coefficients for the K-th section of the secondary cooling zone; W - the number of sections of the zone of the second chilled. Sources of information taken into account in the examination: 1. England patent number 737064, CP. 83/1 F, 1955. 2. Austrian patent number 188452, / cl. 31 B 8/02, 1956.