JPS58146809A - Melt-loss degree deciding method of plate of sliding nozzle device - Google Patents

Abstract

PURPOSE:To decide a melt-loss state of upper and lower plates exactly and easily, by inserting a fuming substance into a lower slide hole of a ladle which is made to fall down sidelong, and detecting a variation of the flowing direction of smoke in case when the lower plate is moved gradually. CONSTITUTION:An empty ladle is made to fall down sidelong, a fuming substance is inserted into a through-hole of a lower plate 2 and is fumed, the lower plate 2 is slide-moved from a full opened state that through-holes of the lower plate 2 and an upper plate 1 are matched, and a position where smoke changes its direction to an external direction C from an internal direction A, by which a melt-loss state of the plates 1, 2 is decided. In this way, the melt-loss state is decided exactly and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining the state of erosion 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). In more detail, in the process of determining the lifespan of the plate of the sliding nozzle device installed at the bottom of the ladle and replacing it, in addition to the conventional qualitative judgment items, there are new quantitative items. It is intended to provide a determination method that incorporates the following factors into the determination and can be useful in extending the life of the plate of the sliding nozzle device and reducing the amount of work required.

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 base the injection flow. Sliding nozzle devices have recently become widely used in place of stopper nozzle devices. This is because the sliding nozzle device allows injection flow control, foundation, etc. to be performed 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, the first
The figure is a cross-sectional view of a representative example of a known sliding nozzle device, in which an upper nozzle hole is formed on the lower surface of the upper nozzle 5 which penetrates the ladle steel skin 4 and is buried in the lining brick 3 at the bottom of the ladle. An upper plate 1 made of refractory brick material having a through hole 1a corresponding to the hole 1a is fixed by a mounting bracket 6a, and together with a lower nozzle/I/7 held on the lower surface of the upper plate 1 by a mounting bracket 6b. A lower plate 2 made of refractory brick material 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 a fixed mounting bracket 6C, 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 the vehicle stopped state). It is.

The upper plate (v-) 1 and the lower plate 2'' of this sliding nozzle device are eroded and damaged as molten steel is injected, and must be replaced when the degree of eroded damage reaches a predetermined limit, but conventionally, the life of these plates has been determined. A. Roughness of the sliding surface of the 4-plate when observed from the bottom of the pan (lower surface of the ladle) C. C. Stopping of hot water at the end of pouring D. Situation of sparks and abnormal noises during nozzle cleaning E. Metal This has been done based on qualitative judgments based on the condition of the sliding surface of the used disposal plate.

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 result in a rise in work costs, or
Delays in replacement may result in steel leakage accidents.

In particular, for the lower plate ◆2, there is no means to visually check the degree of erosion, and there is 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 operational costs.

This invention was made to solve the above problems.

The present invention will be explained in detail based on FIGS. 2 to 5. These figures each show 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, the lower plate 2 is slid as shown in the third panel, and the state of metal removal, cracks, roughness, etc. on the sliding surface of the upper plate 1 is checked. 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.

It is preferable to use a substance such as polyvinyl chloride which ignites at a relatively low temperature and generates a large amount of smoke as the smoke generating substance. 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-generating substance A will naturally ignite and emit smoke due to the residual heat, but if cooling progresses, However, if spontaneous smoke generation is difficult to occur, you may use any igniter to ignite and smoke separately.

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 the upper plate 1 and the lower plate 2 are in communication (the state shown in Figure 3), smoke passes through the communication part and moves in the direction B in the figure (inner part of the upper plate 1). direction). Gradually slide the lower plate 2 until the communication between the melted part of the sliding surface between the upper plate 1 and the lower plate 2 is cut off as shown in Figure 4, and the smoke will move in the direction B. It stops flowing and flows backward in the C direction (outward direction of the lower plate 2).

The method for determining the degree of erosion of the plate of the sliding nozzle device of the present invention is to determine the degree of erosion of the plate by observing the position where the flow direction of smoke generated from the introduction of smoke-generating substances changes from direction B to direction C, as described above. It is something to judge. In other words, the shorter the sliding distance from the initial nozzle fully open state (state !!I in Fig. 2) to the state shown in Fig. 4, where smoke begins to flow backwards in the C direction, the less the melting loss will be. The distance (D in FIG. 5) from the position in FIG. 4 to the end position of the stroke of the lower plate 2 (position in FIG. 5) is long (the remaining life of the culm plate is long. Therefore, By measuring these distances, it is possible to quantitatively know the state of erosion and remaining life of the plate.E in Figure 5 indicates the length of the entire stroke of the lower plate 2 from the fully open position to the maximum stroke. Distance to end position, e.g. 210
□ Shoulder M).

To more accurately measure the remaining stroke length D,
It is preferable to use a stroke gauge as shown in FIGS. 6 and 7. FIG. 6 is a side view of the scale plate 10 of the stroke gauge, the total length of the scale plate 10 being 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 at the positions of the lower plate 2 shown in FIGS. 2 and 5,
By reading the position of the pointer 11 at the position shown in FIG. 4 on the scale plate lo, the remaining stroke can be easily and accurately determined.

As described above, this invention inserts the smoke-generating substance A into the lower hole of the sliding nozzle device of an overturned ladle, and when the smoke-generating substance A begins to emit smoke, the lower plate is gradually moved to change the flow direction of the smoke. According to the present invention, the state of melting and damage of the upper plate and the lower plate is determined.

It was possible to accurately and easily grasp the state of erosion and remaining life of the plate 1 and the lower plate 2, and the life of the plates was extended. This makes it possible to reduce work costs, and to prevent steel leakage accidents by performing inspection and replacement while the sliding nozzle device is in use by combining qualitative and quantitative judgment items.
Work efficiency and safety have been greatly improved.

BRIEF DESCRIPTION OF THE 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 that explains the present invention in detail. FIG. 2 shows the nozzle fully open, FIG. Damaged part communication cut off state, 5th
The figures are diagrams showing the extreme end states of the lower plate stroke. Figure 6 is a side view of the stroke gauge scale plate.
ne4 Kasumi t7 no 1

Claims (1)

[Scope of Claims] 1. A smoke-generating substance is inserted into the lower slide hole of a sliding nozzle device of an overturned ladle, and when the smoke-generating substance begins to emit smoke, the lower plate F is gradually moved to prevent the smoke from flowing. A method for determining the degree of erosion of a sliding nozzle device, characterized in that the degree of erosion of an upper plate and a lower plate is determined based on a change in direction. 2. Insert the smoke-generating substance into the lower slide hole of the 7-pudding nozzle device in an overturned ladle, and when the smoke-generating substance starts to emit smoke, gradually move the lower plate, and as the flow direction of the smoke changes, the upper plate and lower Determining the degree of erosion of the plate of a sliding nozzle device, characterized by determining the erosion condition of the plate and measuring the remaining stroke amount using a pointer attached to the lower plate and a scale plate attached to the ladle shell. Law.