Active temperature feedback control of continuous casting

Abstract

The invention includes a system, method and machine readable program for dynamically controlling the casting of a material. Generally, the systems and methods described herein include an active control feedback system or aspects thereof including a temperature sensing device that is well-suited for the harsh environment of the interior of a caster such as a caster for casting metal. Temperature measurement can be accomplished either directly or indirectly. The system is configured to compare the measured temperature with an ideal casting temperature. The temperature sensing device is operably coupled to a cooling device that modulates a flow of coolant to dynamically cool the material being cast. In accordance with one embodiment of the invention, the cooling device includes a plurality of nozzles for delivering one or more cooling fluids to the material being cast.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority of U.S. Provisional Application Ser. No. 60 / 796,074 filed Apr. 28, 2006. This application is related to U.S. patent application Ser. No. 11 / 709,070 filed Feb. 21, 2007. Each of these applications is incorporated by reference herein in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to continuous casting machines and particularly to the control of the secondary cooling in the continuous casting machines where molten metal is molded into cast slabs, strands, billets and the like.[0004]2. Description of Related Art[0005]In a continuous casting machine (or “caster”) as depicted in FIG. 1, molten metal 1 is poured into a cooled copper faced mold 2 which controls the physical width and thickness of the finished product. Metal exits the mold 2 in the form of a strand or slab having a thin shell 3 of solidified metal with a core 4 of molten ...

AI Technical Summary

Benefits of technology

[0014]Generally, the system includes an active control feedback system or aspects thereof including a temperature sensing device that is well-suited for the harsh environment of the interior of a caster. Temperature measurement can be accomplished either by direct contact or non-contact methods. The system is configured to compare the measured temperature with a preferred casting temperature, such as an ideal casting temperature, at a particular point in the casting process. The temperature sensing device is operably coupled to a controller that controls a cooling device. The temperature sensing device may be provided with a purge gas line for removing debris from the area being measured. The cooling device, in turn, modulates a flow of coolant to dynamically cool the material being cast. In accordance with one embodiment of the invention, the cooling device includes a plurality of nozzles for delivering one or more cooling fluids to the material being cast. In accordance with a preferred embodiment of the invention, the nozzles deliver a spray comprising water and air. Dynamically delivering the coolant to the material in real time in response to temperature measurements of the material optimizes the efficiency of the casting system.

Problems solved by technology

Unfortunately because of the design of modern continuous casting machines, limited control of temperature is possible.

However, no successful attempts have been made to integrate that temperature to a predetermined curve such as an ideal curve, and imprecise cooling is the result.

Breakout is a major problem.

Breakout occurs when the thin shell of the strand of material breaks, allowing the still-molten metal inside the strand to spill out and foul the casting system, requiring an expensive shutdown.

Often, breakout is due to too high a withdrawal rate, as the shell has not had the time to solidify to the required thickness, or the metal is too hot, which means that final solidification takes place below the straightening rolls and the strand breaks due to stresses applied during straightening.

Either of these failures results in costly further processing, waste, or expensive and dangerous consequences to personnel and equipment.

While slab temperature is sometimes checked with a measuring device, this device is not integrated into the coolant control system.

The resulting lack of accurate temperature control during formation of the shell can affect the product quality because of the inability of the system to follow a preferred cooling rate.

However, such systems suffer from certain deficiencies.

An example of such a deficiency is the lack of temperature sensors that are suitable for the harsh environment inside of a caster, which tends to be extremely hot with very low visibility and high vibration.

Moreover, it has been recognized by others that the approach described in U.S. Pat. No. 4,073,332 is not practicable.

The state of the art still does not include a system for actively controlling continuous casting in a meaningful manner to truly maximize yield.

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