SK1082016U1 - Method of casting molten metal with the use of an impact pad in the tundish - Google Patents

Abstract

Disclosed is a method of casting molten metal using an impact plate in a tundish in which liquid metal is fed to a tundish at which an impact plate with a spherical surface capturing an initial shock of current is optimized, the flow of liquid metal is optimized and the liquid metal is discharged from the tundish.

Description

The technical solution solves the method of continuous casting of molten metal using the impact plate with a spherical surface in the tundish.

BACKGROUND OF THE INVENTION

Medzipanva (MP) is usually a welded steel sheet with reinforcing ribs and is equipped with a refractory lining. In the tundish bottom, the outflow openings are walled. For tundish operations, they can affect the quality of the molten metal just before casting, so the development of tundish metallurgy is very important.

The intermediate tank fulfills several metallurgical functions such as a reservoir of liquid molten metal before casting and during the casting ladle replacement the molten metal transporter resp. steel for individual casting streams, minimizes casting stream spattering, decreases ferritic pressure of molten metal, homogenizes liquid metal chemically and thermally, separates liquid metal from slag, evaluates casting speed, monitors molten metal temperature, equalizes casting speeds, maintains steady constant flow molten metal, maintains a constant level in the crystallizer, decantes non-metallic inclusions, it is possible to apply the latest metallurgical operations such as. alloy. Flow control in MP adjusts retention time as well as dead volumes, minimizes the possibility of turbulent zones in the casting stream and the like. At present, an important goal is to use MP as a tool to inimatisate transition areas and dead volumes.

The resulting steel quality depends on the possibility of the lowest possible slag entrainment and maximum leaching of non-metallic inclusions, and therefore an optimum flow in the MP has to be achieved. The flow of liquid metal through the MP has a hydrodynamic nature, which includes a single-phase turbulent flow and a multi-phase flow when the retention time is divided, the number of inclusions increases depending on their movement, thermal energy shifts and swirling occurs at the beginning and end of casting. In order to achieve an optimum casting flow and thus a higher metal purity, it is important to ensure: a higher minimum and maximum retention time, a reduction in strong turbulence and dead zones, a poor coagulation in suitable turbulent zones and floating inclusions using active slags; an open (red) eye forming a well on the surface of the molten steel, causing air absorption. The residual metal and slag remaining in the MP must be mechanically removed before further casting, although this slag is recycled but its removal is laborious and prolongs the continuous casting time. Another problem is dead volumes which lead to heat losses and clumping at the outlet nodes and subsequently to sticking them. Therefore, the MP flow rate must be driven by optimal control of current directions and temperature gradients.

Special tundish accessories hitherto used are dams, partitions, impact plate, blocks for inert gas purging

Until now, a mechanical rectifier called "Anti-impact pad tundish" according to the Slovak patent no. 288043, which comprises a base plate with an upper impact surface surrounded by a side wall with bounded passages. The anti-impact pad is adapted to allow it to fall upon and deflect the incoming molten metal stream and allow the deflected stream to flow through the passages and the open top surface of the pad. The arcuate stepped portions surrounding the passages and / or the dam-like walls help to control the run-off. The separation and distribution of effluents facilitates the development of a countercurrent flow in the molten metal between the impact pad and the tundish outlet. However, the flow of liquid metal spreads down the tundish bottom to the outlet nodes, dead zones are formed in the upper corners of the MP.

The essence of the technical solution

These drawbacks are largely eliminated by the molten metal casting method using the impact plate in the tundish. The principle of the technical solution consists in that the liquid metal is fed into the tundish, on the bottom of which is placed an impact plate with a spherical surface, which consists of a refractory precast, resp. a prism with a quadrangular base and an upper convex base. The impact plate captures the initial impact of the current and prevents liquid metal from splashing, further dynamizing and optimizing the flow of liquid metal in terms of total volume. Upon reaching the desired level of liquid metal in the tundish, the discharge nodes are opened, the level of the liquid metal being constant and the amount of metal flowing equal to the amount of metal leaving the tundish through the discharge nodes to the next part of the ZPO.

The method of casting molten metal using the impact plate is also designed for a liquid metal casting mode with altered properties, i.e. when the next casting ladle has liquid metal with properties other than the previous one and therefore the MP must be emptied as much as possible before pouring the liquid metal. because

SK 108-2016 U1, the steel formed by the mixture of the first and subsequent ladles is not sold. The casting speed changes as the casting

a plate with a spherical surface that captures the initial impact of the current and eliminates the impact energy, the liquid metal is discharged in the total possible volume of MP through the outlet nodes and the submerged nozzle to the next part of the ZPO.

The advantage of the described method of molten metal casting using the impact plate is that by increasing the minimum and maximum retention time the short-circuit flow is eliminated even at low casting speed. into the metal volume and in practice will have a positive effect on the purity of the metal from the point of view of inclusions. In this manner of casting, the economic losses resulting from the non-sale of the steel of undetermined quality, which arise from insufficient tundish emptying, are reduced.

EXAMPLES

The liquid metal is poured from the ladle into a tundish on which a spherical surface impact plate is placed, which captures the initial impact of the current, prevents liquid metal from splashing, while dynamizing the flow of the liquid metal in terms of total volume and eliminating impact energy. Upon reaching the desired level of liquid tundish in the tundish, the discharge nodes are opened, wherein the liquid metal level is constant and the amount of metal flowing is equal to the amount of metal leaving the tundish through the discharge nodes to the next part of the ZPO.

The method of casting molten metal using the impact plate is also proposed for a liquid metal casting mode with altered properties, i.e. when the next casting ladle contains liquid metal with a content different from the previous one and therefore the MP must be emptied as much as possible before pouring the liquid metal. The casting speed varies as the ladle is replaced and therefore, at both lower and higher casting speeds, the innovated molten metal casting process using the impact plate extends the minimum and maximum retention time, which distinguishes it from the molten metal casting methods used hitherto. The liquid metal is fed into the tundish, at the bottom of which is an impact plate with a spherical surface, which captures the initial impact of the current and optimizes the flow of the liquid metal, the liquid metal is discharged in the total possible volume of MP through the spouts.

Industrial usability

The technical solution is industrially applicable in metallurgy, especially for the production of steel alloys, while allowing large steel mills to meet the requirements of small volumes of steel alloys efficiently and economically to use existing equipment.

Claims (2)

Method for casting molten metal using an impact plate, characterized in that before casting a impact plate with a spherical surface is placed on the bottom of the tundish, the liquid metal is poured into the tundish on the impact plate, the amount of cast metal in the tundish is adjusted equal to the amount of metal leaving the tundish through the discharge nodes to the next part of the continuous casting apparatus. 2. A method of casting molten metal using an impact plate, characterized in that before casting a impact plate with a spherical surface is placed on the bottom of the tundish, the liquid metal is poured into the tundish on the impact plate, the liquid metal being discharged from the tundish tundishes through spout nodes and an immersion nozzle to another part of the continuous casting machine.