JPH0610792U - Ladle refining furnace lid structure - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a furnace lid structure of a ladle refining furnace in which cracks are less likely to occur even when exposed to a large heat load from high-temperature molten metal. [Structure] In the furnace lid of the ladle refining furnace, the lower portion of the furnace lid has a steel pipe structure, so that even if a large heat load from high-temperature molten metal is generated, a large thermal stress is not locally generated, , Cracks are also very unlikely to occur. Therefore, the frequency of replacing the furnace lid is extremely reduced, and the maintenance cost can be significantly reduced. Further, the steel pipe structure part of the lower part of the furnace lid also serves as the water supply header, so that only one water supply pipe from the fixed side is required and the overall structure becomes compact.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a furnace lid structure in a ladle refining furnace used for heating and refining molten metal.

[0002]

[Prior art]

 The furnace lid of the ladle refining furnace used for heating and refining the molten metal is located near the surface of the molten metal, so that the electrode surroundings are protected from the large heat load of the molten metal at high temperature. Except for this, water-cooled furnace lids are widely adopted. A representative example of a water-cooled furnace lid structure is introduced in "Recent Trends of LF Equipment / Electric Steelmaking Volume 60, No. 2, May 1989, Electric Steelmaking Research Society; page 198, Fig. 3". There is.

[0003]

[Problems to be solved by the device]

 However, each of these water-cooled furnace lids is a welded structure made of steel plate, a so-called jacket type. The welded part is exposed to the molten metal. When it is put into operation with such a structure, repeated thermal stress is intensively applied to the lower part, and cracks are generated and propagate at an early stage, leading to water leakage. Every time this water leak occurs, the furnace lid is replaced and repaired, so the replacement frequency is so high that it hinders operation. In addition, if water leakage becomes severe during operation, there is a risk of steam explosion.

Therefore, in the present invention, cracks and the like are unlikely to occur even when exposed to a large heat load from the surface of the molten metal at a high temperature, and therefore the frequency of replacement of the furnace lid is extremely low, and the furnace lid structure has a long life. For the purpose of providing.

[0005]

[Means for Solving the Problems]

 The present invention is to solve the above-mentioned problems, and is a furnace lid structure of a ladle refining furnace, characterized in that the lowermost portion of the furnace lid has a water-cooled steel pipe structure.

[0006]

[Action]

 By making the lower part of the furnace lid a steel tube structure, a large thermal stress is not locally generated even under a large heat load from the high-temperature molten metal, and therefore cracks are very unlikely to occur. The inventors of the present invention used a computer to compare the thermal stress under the same heat load between the conventional water-cooled jacket structure of the rectangular welded structure type and the steel pipe structure of the present invention. As a result, it was found that the thermal stress of the present invention was less than half that of the conventional type.

[0007]

【Example】

 FIG. 1 shows a sectional structure of a furnace lid according to the present invention. At the bottom of the furnace lid 1 is a lower pipe 2 having a steel pipe structure according to the present invention. Further, a water cooling panel 3 is arranged inside the furnace of the furnace lid 1. An upper pipe 4 is provided above the furnace lid 1, and a water-cooled small ceiling 5 is arranged on the upper pipe 4.

The operation is carried out in the following procedure. First, the ladle 7 is moved below the furnace lid 1 by a carriage (not shown), and the furnace lid 1 is lowered and placed on the ladle 7 by an elevator device (not shown). The electrode 6 gripped by a gripping device (not shown) descends through the opening of the water-cooled small ceiling 5 by a lifting device (not shown). After that, an arc is generated between the electrode 6 and the molten metal 8 to raise the temperature of the molten metal 8 and refine it.

Therefore, the furnace lid 1, especially the lower pipe 2 portion is exposed to a large heat load from the hot molten metal 8. The refractory 9 lined in the ladle 7 wears and falls off as the frequency of use increases, so the exposed area of the lower pipe 2 becomes wider and the molten metal on the lower pipe 2 becomes wider. The heat load from 8 increases.

The lower pipe 2 also serves as a water supply header, from which cooling water is supplied to each cooling unit via the water supply pipe 10. Therefore, only one water supply pipe from the fixed side to the furnace lid 1 is sufficient, the number of pipes is small, and the overall structure is compact. The lower pipe 2 is not limited to the circular shape shown in FIG. 1, but may be an integral type square pipe having rounded corners. An embodiment in this case is shown in FIG. Since the names and reference numerals in the figure are the same as those in FIG. 2, their explanations are omitted.

[0011]

[Effect of device]

 By making the lower part of the furnace lid a steel tube structure, a large thermal stress is not locally generated even under a large heat load from the high-temperature molten metal, and therefore cracks are very unlikely to occur. Therefore, the frequency of replacing the furnace lid will be extremely low, and the maintenance cost will be significantly reduced. In addition, there is no danger of steam explosion due to water leakage due to cracks, and you can operate with peace of mind. In addition, by using the lower pipe 2 as a water supply header, only one water supply pipe from the fixed side is required and the overall structure is compact.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of a furnace lid according to the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a furnace lid according to the present invention.

[Explanation of symbols]

 1 Furnace lid 2 Lower pipe 3 Water cooling panel 4 Upper pipe 5 Water cooling small ceiling 6 Electrode 7 Ladle 8 Molten metal 9 Refractory 10 Water supply pipe

Claims (1)

[Scope of utility model registration request] 1. A furnace lid structure for a ladle refining furnace, wherein the bottom of the furnace lid has a water-cooled steel pipe structure.