Abstract

Content

• Introduction
• The purpose of research
• Conclusions

Modeling of processes of flowing steel through the casting channel of tundish slide gates of CCM

Introduction

In practice of the continuous casting of steel the main functional importance has the technology and equipment of dispensing of the metal flowing from the tundish into the mold. This technology tends to provide determinated specific consumption of steel (in accordance with the rate of extraction blanks), the most compact surface of the jet, as well as its protection from secondary oxidation. Most common in the modern МНЛЗ get the way of dispensing with the "lock-in-One" - "nonswirl nozzle", which provides high stability of the casting process.

However, this casting scheme has certain deficiencies, the essence of which is reduced to:

1. the possibility of mechanical failure or wear head stopper in the casting process;
2. to the sticking of the particles of alumina in contact with the surface of the stopper head-cup dispenser;

These limitations make the process of dosage more difficult and, consequently, lead to malfunction of the automatic maintenance of the metal in the mold. It should also should be kept in mind that the drive mechanism for moving the stopper-monoblock in the automatic control mode is sufficient inertia, which in turn limits the achievement of a high degree of accuracy of the system. This effect is most pronounced in the production of billets of small sections of high-speed casting.

An alternative solution, which is widespread in a number of metallurgical plants of the world, should be considered trehplitnogo use of slide gates installed in the bottom of the tundish. Dosing began at the expense of partial overlapping of the channel when the filling of the middle plate. At the same time made it possible to justify the industrial research a number of positive aspects of slide gates for continuous casting of billets.

In particular, the use of technology of casting through the therd plates slide gates provide wide opportunities for an integrated automatic control of the casting process.

As a rule, it includes an automatic start of the casting process, control and maintenance of metal in the mold, automatic regulation casting speed and the end of the casting process, including the time for gate overlap (for example, the replacement submersible glass), etc.

This achieves the functional stability of the CCM, including its high degree of readiness to adjust the mode of casting directly in the casting. In addition, the required precision in maintaining the level of metal in the mold also ensures quality of the workpiece surface, and integrated automation makes the decline in labor costs, assuming the casting "without human intervention." This dramatically reduces the number of breaches of the metal and the mold of overflows.

The purpose of research

The purpose of this researches is studying the characteristics of the movement patterns of the jet of metal in the bottling bucket and the intermediate channel assessment of the impact of various provisions of the average plate gate on the stability of the casting process as applied to casting for the CCM

Conclusions

The use of slide gates of three-plates dosing began flowing from the tundish of the CCM, in general, provides high stability and automation of the casting process. High accuracy in maintaining the level of metal in the mold also ensures quality of the workpiece, and a high degree of automation reduces the amount of labor costs, assuming the casting "without human intervention.

As the displacement of the middle plates of slide gates onto the holes in the top and bottom plates seen the emergence and development of the jet in a moving vortices and areas with a lower speed, which prevents the maintenance of the stability of the casting process. Favorable picture of the expiration of the metal from the tundish through a gate valve is mainly preserved by decreasing the value of open cross sectional area of the middle plate holes up to 0.9 of its nominal value. For more overlapping channels filling the holes are formed so-called "dead" zones in which material flow slows down and begins the formation of deposits that change the nature of the expiry of the flow and lead to premature replacement of slide gates.

With regard to conditions in the casting of the CCM «Electrostal» (section blank 125x125 mm and 135x135 mm), the recommended hole diameter of the inner sliding plates of 25-28 mm depending on the section blank and the speed of its exhaust. The probability of the process of tightening the inner cavity filling the channel with increasing the hole diameter is reduced to some extent.