JPS63254696A - Electrode holder of arc furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrode holder for an arc furnace in which a cooling passage is formed inside an electrode gripping part.

[Prior art] An arc furnace generates an arc between a 1-3 wood graphite electrode and a molten material such as scrap iron that is put into the furnace.The arc heat superheats and melts the material, refining and converting it into components. This is an electric furnace that adjusts the steel and taps it as an ingot.

The electrode of an arc furnace is supported by an electrode holder from the top of the furnace and suspended in the furnace, and its insertion length into the furnace is adjusted by an electrode lifting device. It is heated to a high temperature by radiant heat from the lid and flames erupting from the electrode insertion hole.

As a result, the electrical resistance at the electrode holder portion becomes thicker, resulting in increased power loss and problems such as deterioration of the grip strength of the electrode.

For this reason, a cooling water passage is formed inside the electrode gripping part, and by passing water, electricity is supplied while cooling the electrode gripping part.

However, the conventionally used electrode holder is
As shown in the drawings and FIG. 9, the main body 51 is made of cast steel, and has a structure in which a steel pipe 52 serving as a cooling passageway is surrounded by casting.

The electrode holder with this structure has been used for a relatively long time, and the current used during arcing is 30,00
It is often used below OA.

However, recently, with the advent of UHP furnaces, the current usage has approximately doubled, and it has been pointed out that the lifespan of electrode holders with conventional structures will be significantly shortened.

The following points are thought to be the causes of the decrease in life when the conventional electrode holder is applied to a UHP furnace or the like.

■Since the main body 51 of the electrode holder is made of copper Pf material, there are cavities and pinholes peculiar to M material, and the quality is not uniform.

■Since the steel pipe 52, which is a different material, is used in a cast-surrounded configuration, a gap is created between the steel casting of the main body 51 and the steel pipe 52, which serves as a cooling passageway, which significantly reduces the cooling effect. To be there.

■The thermal conductivity of the steel casting itself is low.

■As a result of the above, the electrode holder itself becomes vulnerable to sparks and cannot withstand long-term use in a high-temperature atmosphere.

Furthermore, in order to compensate for the insufficient cooling effect, conventional electrode holders are provided with a cooling ring 53 on the side of the furnace that directly receives heat, and water leakage accidents from this cooling ring 53 occur frequently, resulting in unexpected damage to the furnace body. It is not uncommon to be forced to do so.

[Problems to be Solved by the Invention] As mentioned above, the basic cause of the drawbacks of conventional electrode holders is that the entire electrode holder is made of steel casting, and furthermore, there is no meandering smooth passage inside the casting. Since it is difficult to form a water channel, the steel pipe 52 must be cast.

Therefore, the present invention eliminates the drawbacks of the conventional technology by using rolled copper material and forged copper material, which have excellent electrical and mechanical properties, as materials for the electrode holder. , was created with the aim of providing an electrode holder with many excellent advantages.

Means for Solving Problem E] The present invention provides an electrode holder for an arc furnace in which a cooling passage is formed inside the electrode gripping part, in which the electrode gripping side block is a structure of a rolled copper plate, and the power supply terminal side block is made of a rolled copper plate structure. The present invention relates to an electrode holder for an arc furnace, characterized in that the flock is a structure of forged copper material and/or rolled copper material, and the joint portion of both structures is welded with pure copper.

The basic structure of the present invention is shown in FIGS. 1 and 2, which are perspective views.

As shown in FIG. 1, the electrode holder of the present invention has an electrode grip side block 1 and a power terminal side block 2.
The former block 1 is a structure using a rolled copper plate as a material, and the latter block 2 is a structure using a copper forging material and/or a copper rolling material as a material.

Further, the electrode holding side block 1 has a cooling water passage 3 formed therein, so that water can be passed between the boats 4.5.

In the electrode holder of the present invention, as shown in FIG. 2, both blocks 1.2 are joined and pure copper welded to form a single body. That is, the part indicated by 6 in FIG. 2 is the joint, and the two blocks are welded with pure copper at the same part.

Note that the shapes of each block 1.2 in FIGS. 1 and 2 are merely examples, and do not limit the technical scope of the present invention.

In addition, the means for forming the cooling water passage 3 of the electrode grip side block 1 may be formed by forming a groove in one rolled copper plate and joining the other rolled copper plate by welding, or by forming a groove in the rolled copper plate. There is a method of constructing a meandering water passage by drilling a desired drill hole and plugging and closing it at a suitable place, but any method may be used as long as it uses a rolled copper plate.

[Operations] Before detailed explanation of the present invention, Table 1 shows a comparison of physical data of rolled copper materials, forged materials, pure copper welded materials, and copper cast materials. In addition, this data is based on Cu of rolled and forged copper materials.
It was obtained by setting the purity to 99.99%, and setting the normal Cu purity of the copper material used in conventional electrode holders to 99 to 99.5%.

As is clear from the table, rolled and forged copper materials have extremely superior properties in terms of electrical conductivity, thermal conductivity, tensile strength, elongation, and hardness compared to copper casting materials. .

The electrode holder of the present invention uses condition-rolled material and forged copper material for the electrode grip side block 1 and power terminal side block 2, respectively, and the joints of both flocks are welded with pure copper. It has the excellent physical properties shown.

That is, compared to an electrode holder made of copper Pf, it exhibits the following excellent characteristics.

■Since the electrical conductivity is approximately twice as high, power loss during arc furnace operation can be significantly reduced.

■Since the thermal conductivity is more than double, the cooling efficiency is high and temperature rise can be suppressed, so there is no increase in electrical resistance, and as a result, power loss can be reduced.

Further, by suppressing temperature rise, deterioration of the structure can be prevented.

■Due to its high mechanical strength, it is possible to design the electrode holder to be thinner, making it possible to reduce weight.

In addition, pure copper welding methods between both blocks 1 and 2 include welding in a reducing atmosphere while preheating each flock 1.2, and welding at room temperature using a special welding rod without preheating. There are means to do this, and any means can be applied to the present invention.

However, in order not to impair the properties of the material of each block, it is desirable to use the latter method that does not involve preheating. This is because a welding method that involves preheating may deteriorate the excellent mechanical properties such as hardness that the materials of both blocks 1.2 have.

[Example] Hereinafter, an example of the present invention will be described using FIGS. 3 to 7.

FIGS. 3 and 4 show parts of the electrode grip side block, both of which use condition-rolled material as a base material and bend the condition-rolled material into a U-shape.

Reference numeral 11 indicates an outer plate, and 12 indicates an inner plate serving as the electrode gripping side. After the inner plate 12 is bent, a meandering groove 13 is formed on its outer circumferential surface, which communicates with boats 14 and 15 formed on its side surface.

The electrode grip side block has an outer plate 11 joined to an inner plate 12 in which a groove 13 has been processed, and an inner circumferential surface 11a of the outer plate 11.
It is manufactured by welding pure copper to the outer peripheral surface of the inner plate 12 without preheating.

FIG. 5 shows the power terminal side flock 16, which consists of a joint part 17 with the electrode grip side flock and a terminal part 18. The terminal part 18 is attached to the joint part 17 by pure copper welding without preheating. There is.

Figure 6 is a perspective view of the completed electrode holder, in which the open end of the electrode grip side flock 19 manufactured above and the joint 17 of the power terminal side block 16 are joined together by pure copper welding without preheating. A predetermined portion 20 on the inner circumferential surface of the electrode holding block 19 is cut to match the diameter of the electrode to be used.

Note that 21.22 is a water supply pipe and a drain pipe attached to the boat 14.15.

The electrode holder thus completed is applied to an arc furnace as shown in FIG.

In the figure, there are 23 electrode holders according to this embodiment,
Attached to the support arm 24, the graphite electrode 2
5 is held suspended in the furnace 26.

Power is supplied from the cable 27 to the terminal portion 18 of the electrode holder 23 via the circuit breaker 28, the transformer 29 and the flexible cable 30, and the support arm 24 is connected to the motor 31.
The electrode 2 is operated by a lifting device 32 having a driving source.
5 into the furnace 26 is controlled.

Note that cooling water is supplied to the electrode holder 23 by a separately provided pump (not shown).

In the electrode holder 23 of this embodiment, the electrode gripping side flock 19 and the power terminal side block 16 are made of a rolled plate and a copper forging as base materials, respectively, and both blocks 19 and 16 are welded with pure copper without preheating. Since the electrode holder is integrated with the electrode holder, it has the excellent characteristics described in the [Operations] section compared to conventional cast electrode holders.

Furthermore, by forming the grooves 13 in the inner plate 12 by machining, the route of the cooling passage in the electrode holding block 19 can be set to have the highest cooling efficiency, and the inner wall surface can be It also has the advantage of being extremely smooth, allowing cooling water to flow at high speed. For example, it becomes possible to flow the cooling water at a flow rate of 2 m/sec or more, and the cooling efficiency of the electrode holder can be dramatically improved.

[Effects of the Invention] As a result of the above, the electrode holder of the present invention has the following effects compared to the conventional electrode holder made of cast steel.

■Since the mechanical strength is approximately 40% greater, the wall thickness can be made thinner and the weight of the product can be reduced. Therefore, the burden on the electrode lifting device can be reduced and the operation of the electrodes can be easily controlled.

■Since the electrical conductivity and thermal conductivity are approximately twice as high, the cooling efficiency is extremely high, and the temperature rise during operation and the accompanying rise in electrical resistance can be suppressed, preventing structural deterioration and reducing power loss. It will be reduced.

(2) Since deterioration of the structure can be prevented, the lifespan is more than twice as long, and since water leakage accidents due to sparks etc. do not occur, unexpected shutdown of the furnace body does not occur. Therefore, it becomes possible to improve the production efficiency of the arc furnace.

Furthermore, since the cooling efficiency is high as described above, there is no need to attach a cooling ring to the lower surface of the electrode holder, and there is no need for the furnace to stop due to water leakage from this cooling ring.

■There is no melting damage caused by sparks, etc., the service life is long, and there is no need for intermediate repairs, so repair costs can be reduced.Furthermore, manufacturing costs can be reduced by eliminating the need for a cooling ring.

Table 1 Copper casting material: Cu purity 99-99.5%

[Brief explanation of drawings]

Figures 1 and 2 show the basic configuration of the present invention, with Figure 1 being a perspective view of the electrode grip side block and the power terminal side block, and Figure 2 being a perspective view of the electrode holder of the present invention. be. Figures 3 to 7 show the embodiment, Figure 3 is a perspective view of the outer plate, Figure 4 is a perspective view of the inner plate, Figure 5 is a perspective view of the power terminal side block, and Figure 6 is the finished product. FIG. 7 is a perspective view of the electrode holder and a schematic configuration diagram of the arc furnace. FIGS. 8 and 9 are a plan view and a front view (main part cross-section) of a conventional electrode holder. 1... Electrode gripping side flock 2... Power terminal side block 3... Cooling water passage 4, 5... Port 6... Joint part, 1- Patent application agent Patent attorney Toshikazu Nagai, 'S',”. Figure 1

Claims (4)

[Claims] (1) In an electrode holder for an arc furnace that has a cooling passage inside the electrode gripping part, the electrode gripping side block is made of a rolled copper plate structure, and the power terminal side block is made of forged copper material or/and rolled copper material. An electrode holder for an arc furnace characterized in that the structure is made of pure copper welded at the joint of both structures. (2) Claim (1) in which the pure copper welding of the joint between the two structures is performed by a welding method that does not involve preheating means.
Electrode holder for arc furnace as described in Section 1. (3) The structure of the electrode holding block is made by bending one rolled copper plate and forming a groove for a water passage on its outer peripheral surface.
The electrode holder for an arc furnace according to claim 1 or 2, wherein another rolled copper plate is joined to the outer peripheral surface by pure copper welding. (4) The electrode holder for an arc furnace according to claim (3), wherein the copper rolled plates are welded to each other by welding means without preheating means.