EP3290532B1

EP3290532B1 - Converter furnace with bottom-blowing plug with improved workability

Info

Publication number: EP3290532B1
Application number: EP15910651.7A
Authority: EP
Inventors: Kunihiro Koide; Tomohiro Tsuda
Original assignee: TYK Corp
Current assignee: TYK Corp
Priority date: 2015-12-17
Filing date: 2015-12-17
Publication date: 2020-05-06
Anticipated expiration: 2035-12-17
Also published as: EP3290532A4; JP6563034B2; JPWO2017103959A1; CN107109502A; EP3290532A1; WO2017103959A1

Description

TECHNICAL FIELD

The present invention relates to a converter furnace. Specifically, it relates to a converter furnace comprising a bottom-blowing plug that is aimed at injecting a gas into a metallic molten metal in the converter furnace.

BACKGROUND ART

In converter furnaces, it has been heretofore carried out conventionally to inject a gas from a bottom-blowing plug, which is buried in the bottom portion of a converter furnace, in order to facilitate refining or stir molten steel, and the like.
The bottom portion of a converter furnace makes such a rough or simplified structure as illustrated in a vertical end-face diagram shown in Fig. 4. 10 designates an iron cladding of the bottom part of a furnace, and 20 designates a tuyere for injecting a gas. A permanent brick 9 is lined on the iron cladding 10 of the furnace-bottom part, and then a working brick 5 is laminated on this permanent brick 9. Moreover, the above-mentioned working brick 5 is available in such an instance that it makes a double-layer lining by a lower-layer brick 5b and an upper-layer brick 5a, as shown in Fig. 4; or in such another instance that it makes a one-layer lining by employing a long-length brick having a layer thickness to an extent of the upper and lower two layers. In the drawing, 6 designates a long-length integrated brick forming the tuyere, 7 designates a trunk portion of the furnace, and 8 designates a tapping port (see Patent Literature No. 1, for instance).
Patent Literature No. 2 discloses a converter furnace comprising a metal shell including a tuyere, a furnace-bottom refractory disposed inside the metal shell, and an injector for spouting oxygen gas to a metallic molten metal within the furnace. The injector has one end thereof inserted in the tuyere, which is held by a refractory ramming mixture disposed in the furnace-bottom refractory. The other end of the injector is provided with a bent coupling piece that is connected to a flexible hose.
Patent Literature No. 3 discloses a converter furnace as specified in the preamble of the claim. Other converter furnaces are known from Patent Literature Nos. 4 and 5.

Related Technical Literature

Patent Literature

Patent Literature No. 1: JP H05 70819 A
Patent Literature No. 2: BE 567 433 A
Patent Literature No. 3: JP S60 135512 A
Patent Literature No. 4: JP H03 24219 A
Patent Literature No. 5: EP 0 776 983 A1

SUMMARY OF THE INVENTION

Assignment to be Solved by the Invention

Since a refractory brick for converter furnace is exposed to high-temperature molten metals to be corroded, it needs to undergo relining regularly. When relining the converter-furnace bricks, it has been carried out to line bricks in the vertical direction and horizontal direction from a predetermined positon in the iron cladding; or, in a certain case, they are lined concentrically about the predetermined position serving as the center.
With regard to a bottom-blowing plug as well, the bottom-blowing plug is built in at a location, which is close to a position disposed, depending on the lining order of the refractory bricks, in the iron cladding, to let a gas supply conduit of the bottom-blowing plug pass through it.
There might possibly occur a case where such an inconvenience arises that the gas supply conduit of the bottom-blowing plug does not come into a hole for the gas-supply conduit in the iron cladding because of errors occurring at the time of lining and sticking the refractory bricks. In particular, when working with multiple plugs in the case where they are an interpolation (or inner-insertion) type bottom-blowing plug, respectively, the inconvenience might possibly arise so that the gas supply conduit of the bottom-blowing plugs does not come into the hole in the iron cladding because the hole in the iron cladding is small at the tuyere (see Fig. 4). If such is the case, the refractory bricks are exchanged for the other refractory bricks, or operations are done to adjust the position of the bottom-blowing plugs by scraping or grinding off some of the refractory bricks. However, such operations require a considerable time, so that such another inconvenience might possibly arise that the time for maintaining or repairing a converter furnace has become longer.
The present invention has been made in view of the above-mentioned problems. Hence, it is an assignment to the present invention to provide a converter furnace, which is tolerant towards errors occurring at the time of lining the furnace-bottom refractory.

Means for Solving the Assignment

A converter furnace according to the present invention, which is made to solve the assignment, comprises the features specified in the claim.
In the aforementioned converter furnace, it is possible to insert the gas supply conduit easily or readily into a hole in an iron cladding into which the gas supply conduit is to be inserted. As a result, it is possible to build in the bottom-blowing plug easily or readily into the furnace bottom.
Note that the bending/folding-free conduit needs to exhibit heat resistance, pressure resistance, and airtightness.

Effect of the Invention

It is possible to insert the gas supply conduit easily or readily into a hole, into which the gas supply conduit is to be inserted, in the iron cladding of the converter furnace.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a vertical cross-sectional diagram of a bottom-blowing plug according to an embodiment of the present invention;
Fig. 2 is a horizontal cross-sectional diagram of the bottom-blowing plug according to the embodiment of the present invention;
Fig. 3 is a partial end-face view diagram illustrating a modified embodiment of a bending/folding-free conduit outside the terms of the claim; and
Fig. 4 is a vertical cross-sectional diagram illustrating a rough or simplified structure of a converter furnace at the bottom.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in an embodiment according to the present invention, a bottom-blowing plug that is disposed in a furnace-bottom refractory for the bottom of a converter furnace, will be described concretely with reference to Figs. 1 and 2.
As illustrated in Fig. 1, a bottom-blowing plug according to the embodiment is constituted of a plug body 1 provided with multiple through bores 11, and a bending/folding-free conduit 2 installed to a downside of the plug body 1.
The plug body 1 is formed as a trapezoidal shape whose upper side is made smaller and lower side is made larger in the vertical cross section, and comprises a flat upper face 13, which faces opposite to a molten metal in the converter furnace, a lower face 12, and an outer peripheral face 14. As illustrated in Fig. 2, the outer peripheral face 14 of the plug body 1 includes two flat faces 14a, and curved faces (14b, 14c). The curved face 14b makes an arc of a circle whose center is a furnace-core center "O" of the converter furnace and which has a radius "R₀," whereas the curved face 14c makes an arc of another circle whose center is the furnace-core center "O" and which has a radius "R₁" (> "R₀").
A base 3, which forms a gas chamber 31, is attached onto the lower face 12 of the plug body 1. The gas chamber 31, to which the lower portion of the through bores 11 opens, is disposed in the downside of the plug body 1, and the bending/folding-free conduit 2 communicates with the gas chamber 31.
For a refractory material quality of the plug body 1, a long-service-life or highly-durable magnesia/carbonaceous material is desirable.
As illustrated in Fig. 2, the through bores 11 have a horizontal cross-sectional configuration formed as a circular shape, and are additionally disposed to elongate along the axial center line of the plug body 1. Moreover, the respective bores 11 open not only in the top face 13 of the plug body 11 but also in the bottom face 12, and accordingly make it possible to inject a gas into a molten metal. In the plug body 1 according to the present embodiment, 90 pieces of the through bores 11 are arranged at equal intervals on 5 pieces of imaginary concentric regular hexagons.
The gas chamber 31 is formed by plugging the cylinder-shaped base 3 at the downside with a disk 4. An installation port 41, which is arranged concentrically with the plug body 1, is disposed fixedly onto the disk 4 at the center. Note that 5 designates a metallic disk coming in contact with the lower face 12 of the plug body 1.
Onto the installation port 41, one of the opposite ends of the bending/folding-free conduit 2 is connected in series. The bending/folding-free conduit 2, which is made of metal, comprises a thin-thickness pipe 21, and a member 22 wound spirally around the pipe 21 on the outer periphery; and excels in the heat resistance, pressure resistance and airtightness. The spirally-wound member 22 operates to retain a circular cross section even when the thin-thickness pipe 21 bends.
In an example outside the terms of the claim, the bending/folding-free conduit 2 can also be a flexible hose 2A shown in Fig. 3. The flexible hose 2A is made by covering the outer periphery of a core tube 2A₁, which is made of stainless steel, with an over braid 2A₂, which is made of stainless steel. Note that 2A₃ designates an end connection made of stainless steel. The core tube 2A₁ is a kind of bellows, and the over braid 2A₂ is a fabric made of stainless-steel wire.
In the bottom-blowing plug according to the present embodiment, although all of the gas supply conduit 2, which communicates with the gas chamber 31, includes a bending/folding-free conduit, some of it can also include the bending/folding-free conduit partially.

Explanation on Reference Numerals

1:: Plug Body;
2:: Bending/folding-free Conduit;
2A:: Flexible Hose

Claims

A converter furnace (7) comprising: an iron cladding (10) whose furnace bottom includes a tuyere (20); a furnace-bottom refractory (6) disposed inside the iron cladding (10); and a bottom-blowing plug for spouting a gas to a metallic molten metal within the furnace (7),
the bottom-blowing plug including:
a plug body (1) disposed in the furnace-bottom refractory (6) and having: an upper face (13) facing opposite to the metallic molten metal, a lower face (12) positioned back to back with the upper face (13), and through bores (11) opening respectively in the upper face (13) and the lower face (12) for spouting the gas into the metallic molten metal; and

a gas supply conduit installed to a downside of the plug body (1) to supply the gas to the through bores (11),

wherein some or all of the gas supply conduit includes a bending/folding-free conduit,

characterized in that

the bending/folding-free conduit comprises a thin-thickness pipe (21) and a member (22) wound spirally around the thin-thickness pipe (21) on the outer periphery.