JPS6376811A - Service life lengthening method for metal-made furnace shell in converter barrel part - Google Patents

Abstract

PURPOSE:To lengthen the service life of a furnace shell by tightening the outer circumference of metal-made furnace shell in converter barrel part by metal- made reinforced ring and taking out the reinforced ring at the time of deformation of the reinforced ring at more than the prescribed limit. CONSTITUTION:The steel plate (JIS SM41) having excellent cracking resistance is used to the metal-made furnace shell 2 of converter 1 and the reinforced ring 4 made of the steel plate (JIS SM50) is fitted by bolts 5a and nuts 5b, in order to fasten the outer circumference of furnace shell 2 by the reinforced ring 4, so as to restrain the thermal deformation deformation. The converter 1 is used under this condition and when the reinforced ring 4 comes into contact with the inside of a trunnion ring 3 by gradual deformation of the furnace shell 2 and the reinforced ring 4, the reinforced ring 4 is taken out, to form a gap, between the furnace shell 2 and the trunnion ring 3. Further, the furnace shell 2 is continued to be used until such time as when the furnace shell 2 comes into contact with the inside of trunnion ring 3 by deformation of furnace shell 2. In this way, the service life of furnace shell 2 is lengthened to about two times that of conventional service life.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for suppressing thermal deformation of a metal shell of a converter for metal refining and extending the life of the shell.

<Prior art> The furnace shell (or shell) 2 of a converter for metal smelting is constantly exposed to high temperatures due to heat transfer from the inside of the furnace through the lining refractory 10, and bulgtng due to thermal deformation is avoided. The furnace shell 2 and trunnion ring 3 will be removed in 5 to 10 years.
makes contact with the inside of the At this time, there is a risk that the trunnion ring 3 will break due to the stress from the furnace shell 2 and the converter body will fall off, so the furnace shell must be renewed, which requires a large amount of cost.

In order to suppress such thermal deformation, measures such as (1) selection of a furnace shell material with excellent high-temperature strength and (2) reduction of thermal stress by air cooling the furnace shell 2 have been carried out.

However, the furnace shell is JIS 5B50. JISSM
Using high-strength steel such as 50 will make it difficult to deform, but on the other hand, there is a problem that cracks will easily form in the welded parts of the steel skin 2. Currently, the JIS standard is prioritized to prevent cracks.
It has become common to use steel material equivalent to 5M41. As for air cooling, it is difficult to blow a large amount of air uniformly over the entire surface of the furnace shell, so the cooling effect is not sufficient, and the thermal stress generated by localized cooling may encourage cracks, so the effect of extending the life of the furnace is not effective. In addition, water cooling pipes 9 were created by cutting a steel pipe in half and welding it to the steel shell to form a water channel in a part of the conical area, such as around the reactor mouth, as shown in Figure 4.
There are some cases where water cooling is applied locally, which has some effect in preventing thermal deformation, but there are no cases where the body is entirely water cooled. In the method of forming water channels by welding to the outer wall of the steel shell, it is difficult to uniformly cool the steel shell, and it is also difficult to water-cool the attachment parts of the support claws 6 and the support ring 7 to the steel shell 2. This is because a temperature difference occurs between the water-cooled part and the non-water-cooled part, making it easier for cracks to occur due to thermal stress. It is also possible to adopt a water-cooled jacket structure with a double inner and outer skin over the entire shell, but this would be complicated and increase the furnace weight by 20 to 30%, so the strength of the furnace body support structure including the trunnion ring would be reduced. 2) Equipment costs would be extremely high, it would be difficult to apply to existing converters, and full-scale water cooling would increase steelmaking costs due to increased heat loss to the cooling water of the reactor body. , difficult to employ.

<Problems to be Solved by the Invention> This invention solves the above-mentioned problems in selecting a material for the shell with excellent high-temperature strength, which is a conventional method for extending the life of the shell in the body of a converter, and in air-cooling the shell. This was done in order to overcome these drawbacks and to provide a method for extending the life of the steel shell that can be implemented industrially with simple reinforcement work.

Means for Solving the Problems〉 As a result of intensive research on how to extend the life of the metal shell of the converter body, the inventor discovered that the inside of the converter was made of steel plate (with excellent crack resistance).
We have learned that the life of a furnace can be extended by constructing the furnace shell with a steel plate with excellent deformation resistance (e.g. JISSM50a plate) on the outside, and based on this knowledge, we have come up with this invention. .

What is this invention? 8 Body metal furnace H2 of converter for molten metal refining
A metal reinforcing ring 4 is removably provided on the outer periphery of the furnace shell so as to tighten the furnace shell from the outside to suppress thermal deformation of the furnace shell 2. This is a method for extending the life of the metal shell of the converter body, in which the metal reinforcing ring 4 is removed after the metal reinforcing ring 4 has been deformed beyond a certain limit.

In this invention, the metal furnace shell of the converter has a double structure. In other words, the metal furnace shell is made of a metal material with emphasis on crack resistance, and a reinforcing ring made of a metal material with excellent deformation resistance is installed around the outer periphery of the main furnace shell to tighten the furnace shell. This suppresses thermal deformation. The reinforcing ring is configured to interconnect segments divided in the circumferential direction, for example, with bolts and pads, so as to form a body, and to be detachable from the furnace shell and the reinforcing ring. When the surrounding reinforcing ring gradually deforms and comes into contact with the inside of the trunnion ring,
The reinforcing ring is removed from the furnace shell to create a gap between the furnace shell 2 and the trunnion ring 3 again, and this gap gradually becomes smaller due to continued thermal deformation of the furnace shell until the furnace shell 2 comes into contact with the inside of the trunnion ring 3. (See Figure 5) Continue to use the furnace shell until this happens.

Function> The function of the present invention will be explained below according to the drawings.

Fig. 1 shows the structure of the reinforcing ring and the furnace shell that are directly used in carrying out this method invention.The outer periphery of the metal furnace shell 2 is equipped with a reinforcing ring 4 made of a high-strength material equivalent to JISSM50. is installed, so this reinforcing ring 4
This makes it possible to tighten the steel skin 2 equivalent to JIS 5M41 and suppress its thermal deformation.

Further, as shown in Fig. 3, the reinforcing ring 4 is divided into several segments υj in the circumferential direction, and is connected by bolts 5a and nuts 5b using the holes 8 of the trunnion ring 3. It has become. Therefore, even if the furnace shell 2 and the reinforcing ring 4 are deformed and come into contact with the trunnion ring 3, the reinforcing ring 4 can be removed from the furnace shell 2 by removing the bolts 5a and 5b. Converter operation can continue until 2 continues to deform and contacts trunnion ring 3.

<Example> In an 85Ton converter, reinforcement ring 4 with Jl +
are sequentially taken in between the support claws 6 distributed in the circumferential direction and between the trunnion ring 3 and the steel skin 2, and using the holes 8 of the trunnion ring 3, the bolts 5a and nuts 5 are inserted.
Connected with b. After about 5 years, the reinforcing ring 4 and trunnion ring 3 came into contact with each other due to the progress of thermal deformation, so after removing the reinforcing ring 4 in the reverse order, the drying operation could be continued for another 5 years. The lifespan of a conventional converter shell without a reinforcing ring was about 5 years, so the method of the present invention could extend the lifespan of the steel shell by about twice as much.

<Effects of the Invention> According to the method of the present invention, thermal deformation of the metal shell of the converter body can be suppressed, and its life can be extended from 5 to 10 years in the conventional case to 10 to 20 years. This allows for significant savings in renewal costs for metal furnace shells.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the converter with the reinforcing ring used in the present invention attached, Fig. 2 is a perspective view of the reinforcing ring used in the present invention, Fig. 3 is an assembled front view of the reinforcing ring, and Fig. 4 is an assembled front view of the reinforcing ring. The figure is a sectional view of a conventional converter, and FIG. 5 is an explanatory diagram of the state of contact between the deformed furnace shell and the trunnion ring. 1... Converter 6... Support claw 2... Furnace shell (iron shell) 7... Support ring 3... Trunnion ring 8... Trunnion ring hole 4... Reinforcement ring 9...・Water cooling pipe 5a...Bolt 1
0... Refractory 5b... Nasoto Fig. 1 1-m = Converter 2-m- Iron shell (furnace shell) 3--) Lanio/S/G 4-m- Reinforcement ring 5 a * 5 b---Bolt, nut 6---Support claw 7---Support ring 8---) Lanio/ring hole No. 2 Figure 3 Figure 4 Figure 9-11 Water cooling piping

Claims (1)

[Claims] On the outer periphery of the metal furnace shell (2) of the converter for molten metal refining,
A metal reinforcing ring (4) is removably provided to tighten the furnace shell from the outside to suppress thermal deformation of the furnace shell (2), and the metal reinforcement ring (2) and the metal reinforcement A method for extending the life of a metal shell of a converter body, comprising removing a metal reinforcing ring (4) after the ring (4) has deformed beyond a certain limit.