JP2012130931A - Electrode holder for butt welding machine of steel strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode holder for a butt welding machine of a steel strip, which prevents adhesion of sputter to electrode end faces without degrading the quality of steel strip surface.SOLUTION: The electrode holder for a butt welding machine of the steel strip includes a pair of electrodes that are provided on right and left sides in the butting direction of a welded material, and holders for supporting the electrodes. Furthermore, a double-layered coating material comprised of a primer layer made of a liquid curing type silicon modified acrylic resin and an upper layer made of a silicate ceramic coating material is applied onto the end faces on butting sides between the electrodes and the welded materials held by the holders.

Description

  The present invention relates to an electrode holder for a steel strip butt welder provided in a steel strip butt welder for connecting steel strips by welding.

For example, when processing such as pickling, annealing, and temper rolling is continuously performed on a steel strip manufactured by hot rolling, the steel strips are connected by welding to make the steel strip continuous. For such welding, a steel strip butt welder (also called a flash butt welder) is used because a welding material is not necessary.
In flash butt welding, the ends to be welded of the preceding steel strip and the following steel strip are cut by a cutting shear so that a parallel weld surface is obtained, and voltage is applied to a pair of upper and lower electrodes that clamp the steel strip ends. This is a welding method in which the ends of the steel strip after cutting are brought close to each other while applying heat, the contact local part is heated and melted by discharge, and then upset (pressure welding), and a large amount of spatter is scattered from the weld during discharge. . Since spatter is high-temperature iron powder (molten metal), when it adheres to the end face of the welding electrode, it is deposited on the electrode and grows in a lump on the end face of the electrode as welding is repeated. Since this lump is sandwiched between the electrode and the material to be welded to inhibit energization, or sandwiched between the electrodes to inhibit insulation, it adversely affects the welding quality. In addition, spatter lump falls on the steel strip and bites into the plate, thereby adversely affecting the appearance quality of the steel strip surface. Thus, the response to spatter generated in the discharge process is an important point in welding quality control.

  As a technique for preventing the welding of spatter to the welding electrode, there are a spatter adhesion preventing plate and a spatter adhesion preventive agent (for example, Patent Documents 1 and 2). In either case, a heat-resistant material is provided as a plate or film on the surface of the electrode to prevent spatter welding. As the heat-resistant substance, a resin or an inorganic material is used.

  As a spatter adhesion preventing agent, there is a type in which a liquid in which a heat-resistant resin is dissolved in a volatile solvent is applied by spray as a product that is generally sold and used as a product. However, they are intended to increase the life of parts such as arc welding nozzles and torches, or to prevent spatter adhesion to the base metal near the weld. For example, the electrodes of flash butt welders installed in pickling lines As such, it is not expected to be used for large areas. In addition, the spatter adhesion inhibitor of the type that forms a resin film by spray coating is insufficient in the durability and wear resistance of the resin film when used in a flash butt welder on the pickling line, and has been used in the past. Actual results show that the anti-adhesion effect disappears in about one week. When the effect disappears, it is necessary to reapply to the electrode surface. However, the inside of the online welding machine is narrow, and it is difficult to apply the inhibitor frequently without reducing the operation efficiency.

  In response to the above, a technique for applying an anti-spattering agent to an electrode in an online welding machine has been devised. For example, Patent Document 3 discloses a technique in which a spray device for a spatter adhesion preventing agent is provided on a cut shear and a spatter adhesion preventing liquid is automatically applied to an electrode at every welding. However, it is difficult to install such a device in an online welding machine due to space problems, and it is particularly difficult to install it later.

  In view of the above, the present inventors have devised the use of a method of applying machine oil to the electrode as an inhibitor that can be applied to the electrode at a high frequency and can obtain the effect of preventing spatter adhesion. However, when oil drops from the upper clamp electrode onto the plate surface, there is a problem in that quality incompatibility occurs.

  Also, in order to prevent the effects from disappearing in a short period of time, by applying an anti-grease agent made of heat-resistant resin sold for hand welders torches and nozzles to the electrodes, the resin can be applied rather than spraying liquid. A method of increasing the film thickness and ensuring durability can also be considered. However, the grease-like inhibitor liquefies the solvent at high temperature, so when applied to the upper clamp electrode, the spatter inhibitor drops on the plate surface and adversely affects the quality of the steel plate surface. There is a problem that can only be used for the side electrode.

Japanese Patent Publication No.51-40279 JP 2005-324217 A JP-A 61-27184

  In view of such circumstances, an object of the present invention is to provide an electrode holder for a steel strip butt welder that prevents spatter welding to an electrode end surface without deteriorating the quality of the steel strip surface.

  In order to solve the above-mentioned problems, the inventors have conducted extensive research and investigations. As a result, two layers of paint consisting of a primer layer made of a liquid-curable silicone-modified acrylic resin and an upper layer made of a silicate ceramic paint are used as an anti-sputtering electrode. By applying it to the end surface of the holder where the material to be welded abuts, the adhesion of the welding spatter to the electrode is prevented, while the coating itself peels off from the steel strip surface and the quality of the steel strip surface deteriorates due to dropping off of the material. I found it possible to prevent.

This invention is made | formed based on the above knowledge, The summary is as follows.
An electrode holder for a steel strip butt welder, having a pair of left and right electrodes provided in a direction in which the workpieces are to be abutted, and a holder for supporting the electrodes, wherein the electrodes and the materials to be welded abut each other. An electrode holder for a steel strip butt welder, characterized in that a primer layer made of a liquid curable silicone-modified acrylic resin and an upper layer made of a silicate ceramic paint are applied to the end face on the side.

  ADVANTAGE OF THE INVENTION According to this invention, the electrode holder for lap welding machines of the steel strip which prevents the sputter welding to an electrode end surface is obtained, without deteriorating the quality of a steel strip surface.

It is a figure which shows the electrode holder for butt-welding machines of the steel strip of this invention.

  FIG. 1 shows an electrode holder for a steel strip butt welder according to the present invention. According to FIG. 1, an electrode holder for a butt welder according to the present invention is a holder for supporting a pair of left and right electrodes 1, 1 'consisting of an upper electrode and a lower electrode provided in a direction in which the material to be welded abuts. 2 and 2 ', while applying a voltage to the pair of left and right electrodes 1 and 1' that clamp the steel strip end portions 3 and 3 'that are materials to be welded, the steel strip end portions 3 and 3' are connected to each other. The contact local part is heated and melted by electric discharge and then upset (pressure contact). At this time, two layers of a primer layer made of a liquid curable silicone-modified acrylic resin and an upper layer made of a silicate ceramic paint are formed on the end surfaces of the electrodes 1, 1 'and the holders 2, 2' on the side where the materials to be welded meet. The coating 4 is applied. In this way, the coating 4 is applied to the end surfaces of the electrodes 1 and 1 ′ and the holders 2 and 2 ′ as an anti-sputtering agent, thereby preventing the welding spatter from adhering to the electrodes and the steel strip surface of the coating itself. Prevents the deterioration of the quality of the steel strip surface due to peeling and flaking.

Furthermore, by using a two-layer paint consisting of a primer layer made of a liquid curable silicone-modified acrylic resin and an upper layer made of a silicate ceramic paint, the paint has heat resistance, insulating properties and high hardness.
Weld spatter scatters at a high temperature of 1600 ° C immediately after generation. By forming a film on the electrode surface with the heat-resistant paint of the present invention, it is possible to prevent the electrode and the sputter from being welded by the heat of the adhering spatter.
Since the coating material of the present invention has an insulating property, when applied to the electrode surface, it prevents the energized state during welding from changing and affecting the welding quality. In addition, it prevents the paint from melting due to the heat generated by the paint itself, and prevents dropping of the paint on the plate surface.
Since the coating material of the present invention has a high hardness, the coating material does not peel off or wear, and the coating material itself can be prevented from falling or biting on the plate surface, and the effect can be obtained over a long period of time.

In addition, it does not specifically limit about the coating method to the butt | matching surface of the to-be-welded material of the electrodes 1, 1 'and the holders 2, 2' of the said coating material. It is preferred that the primer layer is then semi-dried and then the upper layer is overcoated. This is because if the upper layer is overcoated after being completely dried, the primer layer paint may be peeled off together with the paint.
The thickness of the coating film is not particularly limited. Although it is preferable to apply as thin as possible from the viewpoint of manufacturing cost, it may be applied with a thickness that allows application without unevenness.

  Examples using an electrode holder for a steel strip butt welder installed in a pickling line are shown below.

  As a paint having heat resistance, insulation, and high hardness, a two-layer paint comprising a primer made of a liquid-curable silicone-modified acrylic resin and an upper layer of a silicate-based ceramic paint used for exteriors of building materials and civil engineering structures was used. Originally, this paint is a paint used on the outer wall and the like for the purpose of preventing rust, corrosion resistance, antifouling, and graffiti of building materials. Of the two-layer paints, the primer is, as the main agent, manufactured by Three Bond Co., Ltd., trade name: SL No. 100 main agent, 60 g, as a curing agent, manufactured by Three Bond Co., Ltd., trade name: SL No. 100 g hardener and 10 g are mixed, and 20 g of thinner (trade name: SL No. 103) manufactured by Three Bond Co., Ltd. is added as a diluent. The upper layer is manufactured by Three Bond Co., Ltd., trade name: SL No. 600 main agent, 100 g, as a curing agent, manufactured by Three Bond Co., Ltd., trade name: SL No. 600 hardener and 10 g were mixed, and 110 g of thinner (trade name: SL No. 303) manufactured by Three Bond Co., Ltd. was added as a diluent.

  Next, in the electrode holder for a steel strip butt welder shown in FIG. 1, the coating material was applied to the end surfaces of the electrodes 1, 1 'and the holders 2, 2' on the side where the materials to be welded face each other. First, the primer was applied so that the metal surface of the coated surface was completely covered, and when the paint was in a semi-dry state, the upper layer was then thick enough to obtain a uniform and smooth surface. It was applied and dried. On the other hand, a comparative example in which a general-purpose gear lubricant (mixed grease of mineral oil and water) is applied to the abutting surfaces of the workpieces of the electrodes 1, 1 'and the holders 2, 2', a comparative example in which nothing is applied Also prepared.

  While applying the voltage to the pair of electrodes 1 and 1 ′ for clamping the steel strip end portions 3 and 3 ′ of the preceding steel strip and the succeeding steel strip using the electrode holder for the steel strip butt welding machine composed of the above The steel strip end portions 3 and 3 'were brought close to each other, and the contact local portion was heated and melted by discharge, and then upset (pressure welding). And it investigated by the method shown below about the spatter adhesion prevention effect, the effect sustainability, the degree of dropping to the plate surface, and the ease of removal of adhering spatter.

Spatter adhesion prevention effect When spatter deposits can be visually confirmed on the end surface of the electrode and holder on the side to be welded, the spatter deposit is scraped off from the end surfaces of the electrode and holder. The number of scrapings was examined.

The paint was applied again when the paint peeled off from the end face of the effect sustaining electrode and the holder to be welded, and the number of times of application when the welding was performed 50 times was investigated.

Degree of drop on the plate surface The coil on which the paint or machine oil dropped on the steel plate surface was visually observable was used as the generation coil, and the number of generation coils per 100 coils was determined as the generation coil ratio.

Ease of removal of attached spatter When spatter was removed from the electrode or holder, in order to investigate the degree of ease of removal at this time, the tools used for removal and the removal method were investigated.

  The results obtained as described above are shown in Table 1.

From Table 1, the present invention example has the same spatter adhesion preventing effect as when machine oil is applied. Furthermore, it can be seen that the effect persistence is high because the paint does not fall off the plate surface, the paint does not peel off from the end surface of the electrode and the holder on the side where the material to be welded abuts. Moreover, even when spatter adheres to the steel plate surface, it can be wiped off with a cloth jig, and spatter removal is easy.
From the above results, spatter is deposited on the electrode and becomes a lump, which adversely affects the welding quality, the problem that the spatter deposited on the electrode is difficult to remove from the electrode and scrapes off using a jig is a physical burden on the operator, The problem that the duration of the effect is short with respect to the on-line use period of the electrode, and the problem that the protective agent applied to the electrode to prevent spatter adhesion falls on the steel plate surface are all solved.

1, 1 'electrode 2, 2' holder 3, 3 'steel strip edge 4 paint

Claims (1)

An electrode holder for a steel strip butt welder, comprising a pair of left and right electrodes provided in the butting direction of the workpiece, and a holder for supporting the electrodes,
A coating layer of two layers of a primer layer made of a liquid curable silicone-modified acrylic resin and an upper layer made of a silicate ceramic paint is applied to the end surface of the electrode and the holder on the side where the material to be welded abuts. Electrode holder for steel strip butt welders.

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