JPH0216844B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining the state of melting damage of a plate of a sliding nozzle device used for injection work in processes such as ingot making or continuous casting of molten metal (particularly molten steel). More specifically, in the work process of determining and replacing the life of the plate of the sliding nozzle device installed at the bottom of the ladle, in addition to the conventional qualitative judgment items, new quantitative items were added. It is intended to provide a determination method that incorporates the following factors into the determination and is useful for extending the life of the plate of a sliding nozzle device and reducing operating costs.

When injecting molten steel from a ladle that receives molten steel tapped from a steelmaking furnace such as a converter or electric furnace into a mold for ingot making or continuous casting, conventional methods are used to inject, control, and block the injection flow. Sliding nozzle devices have recently become widely used in place of stopper nozzle devices. This is because the sliding nozzle device can control and block the injection flow more reliably and easily than the conventional stopper nozzle device. Various types of sliding nozzle devices are already known, and a typical configuration thereof is as shown in FIG. That is, FIG. 1 is a cross-sectional view of a representative example of a known sliding nozzle device, in which the upper nozzle 5 penetrates through the ladle shell 4 and is buried in the lining brick 3 at the bottom of the ladle. The lower nozzle is obtained by fixing an upper plate 1 made of refractory brick material with a through hole 1a on the lower surface that matches the upper nozzle hole with a mounting bracket 6a, and holding the upper plate 1 on the lower surface with a mounting bracket 6b. 7 and a lower plate 2 made of refractory brick that can be horizontally slid by a piston cylinder 9 via a link mechanism 8 is provided so that its through hole matches the lower nozzle hole, and the lower surface of the lower plate 2 is attached to a mounting bracket 6a. It is slidably held by the mounting bracket 6c fixed to the lower plate 2, and the lower plate 2 is slid to connect the upper and lower nozzle holes to allow the flow of molten steel to flow (the figure shows a blocked state). This is what I did.

Upper plate 1 of this sliding nozzle device
The lower plate 2 and lower plate 2 are damaged by injection of molten steel, and must be replaced when the degree of damage reaches a predetermined limit. Conventionally, the lifespan of this plate was determined by observing from the bottom of the ladle (the bottom surface of the ladle). Condition of rough skin on the sliding surface of the top plate (B) Similarly, cracks (C) Status of hot water stopping at the end of injection (D) Condition of sparks blowing out and abnormal noises during nozzle cleaning (E) Condition of insertion of bare metal (B) Situation of sliding surface of used disposal plate This has been done based on qualitative judgments based on the current situation.

However, in such a method, it is difficult to make an objective and appropriate judgment because there are individual differences in judgment techniques. For this reason, premature replacement may lead to a rise in work costs, or replacement may be delayed, resulting in a steel leakage accident. Furthermore, there is no means to visually check the degree of erosion, especially for the lower plate 2, which poses a great risk of steel leakage accidents.

As described above, the conventional methods have various problems in determining the lifespan of plates, and it has been desired to realize an accurate method for determining the degree of erosion in order to extend the lifespan and reduce operating costs.

This invention was made to solve the above problems.

An embodiment of the present invention will be explained based on FIGS. 2 to 5. Each of these figures shows a side cross section of only the upper plate 1 (fixed) and lower plate 2 (sliding) of the sliding nozzle device at the bottom of the ladle which has been turned over.

After pouring the molten steel, turn the empty ladle on its side and set it in place so that the bottom of the ladle is almost vertical and the nozzle hole is facing horizontally. The through holes of the lower plate 2 are aligned with the through holes of the upper plate 1, the nozzles are fully opened, and the nozzles are cleaned using oxygen or the like. Next, as shown in FIG. 3, the lower plate 2 is slid and the sliding surface of the upper plate 1 is checked for metal removal, cracks, roughness, etc. This corresponds to the qualitative determination method described above.

Next, the smoke-generating substance A is inserted into the lower slide hole (the hole of the lower nozzle 7 or the through-hole 2a of the lower plate 2 in FIG. 1) by attaching it to the tip of a suitable long rod, and smoke is generated. As the smoke generating substance A, it is preferable to use a substance that ignites at a relatively low temperature and generates a large amount of smoke, such as polyvinyl chloride. At this time, the nozzle and plate of the sliding nozzle device are usually still in a red-hot state with residual heat from injection and nozzle cleaning, so smoke-producing substance A will spontaneously ignite and emit smoke due to the residual heat, but if it is not cooled, If the process progresses and spontaneous smoke generation is difficult to occur, an arbitrary igniter may be used to separately cause oxidation and smoke generation.

When the smoke-generating substance A starts to emit smoke, the flow direction of the emitted smoke is observed while gradually sliding the lower plate 2. When the melted parts of the sliding surfaces of upper plate 1 and lower plate 2 are in communication (state shown in Figure 3)
The smoke passes through the communication portion and flows in the direction B (inward of the upper plate 1) in the figure. As the lower plate 2 is gradually slid, as shown in Figure 4, when the communication between the melted parts of the sliding surfaces of the upper plate 1 and the lower plate 2 is cut off, the smoke flows in the direction B. This causes a reverse flow in the C direction (outward direction of the lower plate 2).

As described above, the method for determining the degree of plate erosion of the sliding nozzle device of the present invention is to observe the position where the flow direction of smoke generated from smoke substance A changes from direction B to direction C. This is to determine the state of loss. In other words, the shorter the sliding distance from the initial fully open state of the nozzle (the state shown in Fig. 2) to the state shown in Fig. 4, where smoke starts to flow backward in the C direction, the less the melting loss occurs. The longer the distance (D in FIG. 5) from the position shown in the figure to the end position of the stroke of the lower plate 2 (position in FIG. 5), the longer the remaining life of the plate.

Therefore, by measuring these distances, it is possible to quantitatively know the state of erosion and wear and tear of the plate and its remaining life. Note that E in Figure 5 is the total stroke length of the lower plate 2 (distance from the fully open position to the end of the stroke position, e.g. 210 mm)
It is.

In order to more accurately measure the remaining stroke length D, a stroke gauge as shown in FIGS. 6 and 7 may be used. FIG. 6 is a side view of the scale plate 10 of the stroke gauge.
The total length of 0 is equal to the total stroke length E.

FIG. 7 is a side view of the pointer 11 of the stroke gauge. The scale plate 10 shown in FIG. 6 is attached to the pot bottom iron skin 4 along the sliding direction of the lower plate 2, and the pointer 11 shown in FIG. If the pointer 11 is aligned with both ends of the scale plate 10 in the positions shown in FIGS. 2 and 5 of the plate 2, the position of the pointer 11 in the position shown in FIG. 4 can be read on the scale plate 10. Therefore, the remaining stroke amount D can be easily and accurately known.

As mentioned above, this invention inserts the smoke-generating substance A into the lower slide hole of the sliding nozzle device of an overturned ladle, and when the smoke-generating substance A starts emitting smoke, the lower plate is gradually moved to change the flow direction of the smoke. According to the present invention, the melting state or remaining life of the upper plate 1 and the lower plate 2 can be accurately and easily determined. An extension of plate life was achieved. This makes it possible to reduce work costs, and prevent steel leakage accidents by performing inspection and replacement while using the sliding nozzle device using a combination of qualitative and quantitative judgment items. This greatly improved work efficiency and safety.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a known sliding nozzle device. 2 to 5 are cross-sectional views of the plate of a sliding nozzle device for explaining an embodiment of the present invention. FIG. 2 shows the nozzle in a fully open state, FIG. FIG. 5 is a view showing the communication cut off state of the plate melted portion and the extreme end state of the lower plate stroke. FIG. 6 is a side view of the stroke gauge scale plate, and FIG. 7 is a side view of the stroke pointer plate. 1... Upper plate, 2... Lower plate, 5...
Upper nozzle, 7...Lower nozzle, 10...Scale plate, 1
1...Guidelines.

Claims (1)

[Claims] 1. A smoke-generating substance is inserted into the lower slide hole of a sliding nozzle device in an overturned ladle, and when the smoke-generating substance begins to emit smoke, the lower plate is gradually moved to change the flow direction of the smoke. A method for determining the degree of erosion of a plate of a sliding nozzle device, characterized in that the degree of erosion of a plate of a sliding nozzle device is determined by determining the degree of erosion of an upper plate and a lower plate. 2. Insert the smoke-generating substance into the lower slide hole of the sliding nozzle device of the overturned ladle, and when the smoke-generating substance starts to emit smoke, gradually move the lower plate, and the upper plate and lower plate will change due to the change in the flow direction of the smoke. Determining the degree of erosion of a plate of a sliding nozzle device, characterized in that the remaining stroke amount is measured by a pointer attached to a lower plate and a scale plate attached to a ladle shell. Law.