KR102094678B1 - Tube sheet automatic overlay welding device - Google Patents

Abstract

Tube sheet automatic overlay welding apparatus according to the present invention, the tube sheet automatic overlay welding apparatus for automatically welding the tube sheet, the main frame 100; A positioner 200 for fixing and supporting the tube sheet 210 to be welded; A welding part 300 for welding the tube sheet 210; A UP / DOWN frame 400 that is connected to the welding part 300 to adjust the welding position by moving the welding part 300; It is connected to the UP / DOWN frame 400 and includes a UP / DOWN motor unit 500 and a welding control unit 600 connected to and controlled by the welding unit 300 to move, and the welding unit 300 includes: It includes a welding torch that generates heat by discharging an electrode, and a Super-TIG feeding module that supplies a molten metal material to be a weld metal during welding, and the welding controller 600 increases the bead width with the base material to increase the welding speed. Includes an AVC (Auto Voltage Controller) that responds to the oscillation frequency so as to oscillate to increase productivity (welding speed) while avoiding excessive increase of the metal material, the metal material is a C-type filler, and the welding When welding with a device, the arc column applies a plasma stream in which plasma flows as a fluid from the upper electrode to the molten paper direction, and is perpendicular to the plasma stream. It is characterized in that the shape of the filler material is a concave plate shape.

Description

Tube sheet automatic overlay welding device}

The present invention relates to an automatic overlay welding device for a tube sheet that applies a super-TIG welding technique to improve the reliability and productivity of welding, and enables a simple worker to sequentially operate several welding processes that require high-functionality. .

In general, equipment or mechanical parts are worn due to wear, impact, erosion, or corrosion due to environmental influences, resulting in a large loss. In order to reduce this loss, a welding coating the surface of the material with abrasion or corrosion resistant material is called overlay welding. According to this definition, surface hardening by thermal spraying and heat treatment, that is, surface hardening methods such as carburizing, nitriding, and ion implantation are not included in overlay welding. The application of overlay welding to improve wear resistance ranges from very severe abrasive wear, such as rock grinding, to metal-to-metal contact wear, such as fine-tuning valves that do not allow wear of hundreds of a millimeter. Corrosion and high temperature oxidation have a great influence on the wear rate, so they are very important factors in material selection for overlay welding. Common installations are made of carbon steel, stainless steel or materials that lack wear resistance. Therefore, overlay welding is applied to parts where parts themselves are subject to severe wear or to repair parts that are damaged.

Mechanical equipment is the most productive when maintaining the original processing dimensions, and the quality of the product is excellent. Overlay welding improves the quality of production products, reduces maintenance intervals, and regenerates expensive parts at an affordable price by maintaining the life of these effective dimensions to the maximum. In particular, it is possible to significantly reduce production cost by reducing the storage of parts and reasonably managing spare storage parts.

Overlay welding is a method of coating a weld metal with excellent wear resistance, corrosion resistance, and heat resistance to a thickness of about 1 mm or more on a base material.

The bonding strength is higher than that of the base material because it is completely fused with the base material.

The welding speed is high, so the work efficiency is good and the thickness of the overlay layer is easy to control.

The overlay weld metal is excellent in quality because it undergoes metallurgical reaction in an inert gas atmosphere in the slag.

There is no limit to the size of the product to be overlaid.

Productivity is improved because downtime for maintenance can be reduced.

Even with a slightly higher load, efficiency increases.

Repair and maintenance costs are reduced by repairing damaged parts.

Wear and toughness are complementary because of the use of high toughness and low cost base materials.

On the other hand, the order trend of the tube sheet, which is a heat exchanger component, is increasing in order of the overlay welded tube sheet. The cost structure of the overlay welded tube sheet consists of a carbon steel base material, a processing cost of 30%, and an overlay welding cost of 70%.

In general, the diameter of the tube sheet for the most overlay welding is 1000 to 3000, and when the welding thickness is set to 3 mm, it is processed after welding to approximately 6 mm. In addition, when welding is performed, a welding layer thickness of 2 to 2.5 mm is formed, and a minimum of 3 welding is required to make a 6 mm height. The typical welding speed is 350 mm / min, and the diameter of the tube sheet takes over a week for 1000 to 3000. In order to solve this, the present invention is to develop a welding device by combining Super-TIG welding.

KR 20-0465353 Y1 KR 10-1356 240 B1 KR 10-0808914 B1 KR 10-2018-004626 A

Therefore, the present invention is to solve the above-mentioned problems, to reduce the welding cost of the overlay welded tube sheet, to provide a tube sheet automatic overlay welding device capable of 8Kg / hr welding that can be easily used by non-experienced people. have.

Tube sheet automatic overlay welding apparatus according to the present invention for achieving the above object is a tube sheet automatic overlay welding apparatus for automatically welding the tube sheet, the main frame 100; A positioner 200 for fixing and supporting the tube sheet 210 to be welded; A welding part 300 for welding the tube sheet 210; A UP / DOWN frame 400 that is connected to the welding part 300 to adjust the welding position by moving the welding part 300; It is connected to the UP / DOWN frame 400 and includes a UP / DOWN motor unit 500 and a welding control unit 600 connected to and controlled by the welding unit 300 to move, and the welding unit 300 includes: It includes a welding torch that generates heat by discharging an electrode, and a Super-TIG feeding module that supplies a molten metal material to be a weld metal during welding, and the welding controller 600 increases the bead width with the base material to increase the welding speed. Includes AVC (Auto Voltage Controller) that responds to the oscillation frequency so as to oscillate to increase productivity (welding speed) while avoiding excessive increase of the metal material, the metal material is a C-type filler, and the welding When welding with a device, the arc column applies a plasma stream in which plasma flows as a fluid from the upper electrode to the molten paper direction, and is perpendicular to the plasma stream. It is characterized in that the shape of the filler material is a concave plate shape.

The present invention has the effect of performing automatic overlay welding at the tube sheet overlay welding site. In addition, the existing manual overlay welding should be done by a skilled welder, but the present invention is effective even if it is not a skilled welder, but also by relatively simple training, thereby reducing welding costs. In addition, since it is efficient while applying the TIG technique, it is possible to secure a clean working environment, which is the advantage of the TIG, and to achieve relatively higher productivity and quality than SAW and MIG.

1 is an embodiment of a tube sheet automatic overlay welding apparatus according to the present invention.
FIG. 2 is a comparison diagram of a TIG arc and a SUPER-TIG arc to which the TIG arc and the plasma stream theory are applied.
Figure 3 is a method of calculating the dilution rate according to the penetration depth and the bead height of the base material during overlay welding by applying the present invention.
Figure 4 is an example showing a side banding test specimen welded by applying the present invention.
5 is a schematic diagram of an oscillation pitch during overlay welding according to the present invention.
6A is an example of a PLC program main screen of a tube sheet automatic overlay welding apparatus according to the present invention.
Figure 6b is an example of a manual operation screen of the PLC program Turn Table (positioner) of the tube sheet automatic overlay welding apparatus according to the present invention.
Figure 6c is an example of a manual operation screen of the PLC program oscillator of the tube sheet automatic overlay welding apparatus according to the present invention.
7 is a front view of a tube sheet automatic overlay welding apparatus according to the present invention.
8 is a plan view of a tube sheet automatic overlay welding apparatus according to the present invention.
9 is a side view of the tube sheet automatic overlay welding apparatus according to the present invention.

Hereinafter, with reference to the drawings according to an embodiment of the present invention, but for easier understanding of the present invention, the scope of the present invention is not limited by it.

When a part of the specification "includes" a certain component, this means that other components may be further included instead of excluding other components unless specifically stated otherwise. In addition, terms such as "... unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software. .

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. .

Prior to the description, a number of aspects and embodiments are described herein, and these are merely illustrative and not limiting.

After reading this specification, skilled artisans will appreciate that other aspects and embodiments are possible without departing from the scope of the invention.

Before addressing the details of the embodiments described below, some terms will be defined or clarified.

Arc welding refers to welding using arc (spark, heat generated during discharge). Generally, it is divided according to the electricity supply method and whether the electrode rods are consumable or non-consumable. There are AC type and DC type in the electricity supply method, and the DC type has a more constant voltage supply than the AC type, so welding characteristics are better.

GTAW is an abbreviation of Gas Tungsten Arc Welding. Welding is a method that melts and bonds each material with arc and heat generated between them by passing current and voltage between electrodes (welding rod, base material). GTAW welding uses tungsten as an electrode. Ar gas is mainly used as a protective gas.

SAW is a method of arc welding, which provides a granulated solvent instead of a coated flux to cover the welding area.

MIG is a method of arc welding, also called GMAW welding, and unlike SMAW, where the coating coated on the welding rod melts to produce an inert gas, sprays an inert gas such as argon, helium carbon dioxide, or mixed gas directly to the welding area. By creating an inert atmosphere that prevents chemical changes in the welded part, unlike SMAW, there is no slag caused by the coating material, and since there is no restriction on the electrode shape by the coating material, unlike SMAW, which can only use a straight electrode, the electrode can be continuously supplied. It is characterized by being able to.

TIG is a sub-class of arc welding and is also called GTAW or WIG. Unlike other methods, the electrode is made of tungsten with a very high melting point, so only the arc is generated, and a wire is supplied to the arc to weld it, which corresponds to the non-consumable electrode method.

Super-TIG refers to welding in which the productivity is significantly improved by changing the filler shape to C type in GTAW to absorb heat better.

A filler is also called a filler metal (a filler material) and refers to any material used to join two metals during welding or soldering. It is classified according to the characteristics of use (mainly coating material, protective gas, etc.), and is also classified according to the chemical composition of the weld metal.

Next, a detailed description will be given of a tube sheet automatic overlay welding apparatus according to the present invention with reference to the drawings.

1 is an embodiment of a tube sheet automatic overlay welding apparatus according to the present invention, FIG. 2 is a comparison view of a TIG arc and a SUPER-TIG arc to which a conventional technique is applied to a TIG arc and plasma stream theory, and FIG. When the overlay is welded by applying the present invention, the dilution rate calculation method according to the penetration depth and the bead height of the base material is shown, and FIG. 4 is an example showing a side banding test specimen welded by applying the present invention, and FIG. 5 is an overlay according to the present invention Schematic diagram of the oscillation pitch during welding, FIG. 6A is an example of the PLC program main screen of the tube sheet automatic overlay welding apparatus according to the present invention, and FIG. 6B is a PLC program of the tube sheet automatic overlay welding apparatus according to the present invention Turn Table ( Positioner) is an example of a manual operation screen, Figure 6c is the number of PLC program oscillator of the tube sheet automatic overlay welding apparatus according to the present invention An example of an operation screen, FIG. 7 is a front view of a tube sheet automatic overlay welding device according to the present invention, FIG. 8 is a plan view of a tube sheet automatic overlay welding device according to the present invention, and FIG. 9 is a tube sheet automatic according to the present invention It is a side view of an overlay welding apparatus.

1 to 9 will be described with respect to the tube sheet automatic overlay welding apparatus according to the present invention.

Briefly explaining the structure of the inventor tube sheet automatic overlay welding device, the main frame 100, the positioner (Turn Table, 200), the tube sheet 210, the welding part 300, the UP / DOWN frame 400, It can be divided into UP / DOWN motor part 500 and welding control part 600.

The present invention enables welding at a welding speed of 8 kg / hr by applying super-TIG welding with eco-friendly high productivity. It is possible to intelligently oscillate to prevent fusion defects with the base material, which may occur most frequently in the process of producing by overlay welding a large surface of the tube sheet, especially fusion defects occurring in the toe portion of the bead overlap.

Precise welding is possible by changing the position of the welding torch by controlling the ball screw + servo motor of the welding holder from changing the position of the welding torch by sliding the existing cantilever beam, and moving the welding torch vertically and horizontally by entering the welding production design data. It is possible to weld after controlling it. In addition, AVC (Auto Voltage Controller) that reacts precisely according to the oscillation frequency is applied.

In addition, in order to achieve a welding speed (production speed) of 8 kg / hr, a C-Filler with a width of 1 mm and a thickness of 1 mm is precisely fed, using a concentric circle system that reduces the penetration of the base material and prevents defects in the bead overlap.

A plasma stream that can be applied to the present invention will be described with reference to FIG. 2. In turn, it shows an example of Super-TIG arc from the viewpoint of the existing TIG arc, the viewpoint of the TIG arc by the plasma stream theory, and the viewpoint of the plasma stream theory.

In the past, the arc was regarded as a plasma column, and thin and round wires were supplied, and thin wires with a specific surface area were adopted.

If the plasma stream theory is applied, the arc column is modeled with an arc physics characteristic of a plasma stream in which plasma flows as a fluid from the upper tungsten electrode to the molten paper direction, establishing a theoretical system. We developed a Super-TIG welding technology that dramatically improved productivity by devising and applying the shape of the filler material in a concave plate shape to be perpendicular to the stream.

Referring to FIG. 2, it can be seen that the TIG Arc Plasma Stream has the highest amount of heat input to the filler material when it collides in the normal direction to the surface of the filler material. Plasma stream can be received in the normal direction rather than a circular wire shape, and since a C-type filler material having a large specific surface area capable of receiving the input heat is used, the welding speed is fast, so that an effect of improving productivity can be obtained.

Next, referring to FIG. 3, the portion where the overlay welding of the tube sheet is performed in a high-temperature corrosion-resistant environment for a dilution rate of 5% or less, after the overlay welding, the content of Fe is limited to within 5%, and the content of Fe is diluted with the base material It is determined by the rate. The dilution rate of the base material is determined according to the following formula according to the penetration depth and the bead height of the base material during overlay welding.

Next, in order to achieve the maximum deviation of the weld bead height (quality) within 3 mm, the difference between the height of the valley and the height of the weld bead is the deviation of the weld bead height and the maximum value is small, which is a very important factor in cost reduction since the cutting amount decreases. Therefore, it is possible to reduce the dilution rate while reducing the maximum deviation by adjusting the oscillation technology and the current ratio.

Next, in order to achieve 0Ea / m2 of surface pores, in TIG welding, since the molten paper is still and the bubbles in the liquid are difficult to escape to the outside, the surface of the base material is kept clean and the C-Filler surface is clean so that bubbles do not occur from the beginning. Therefore, a management standard is established to suppress the generation of pores, and oxide removal of the surface beads of the first layer is performed. To this end, physical force is periodically applied to the molten paper by a low-frequency pulse so that bubbles inside the liquid can easily escape to the outside.

Next, referring to FIG. 4, in order to achieve within 3 mm of the crack in the welding specimen side banding test, if there is a fusion defect between the base material and the overlay welding layer, or if slag mixing or pores occur, cracking may occur in the side banding test. Therefore, it is possible to thoroughly prevent such cracks and finally pass the side banding test.

Tube sheet automatic overlay welding device of the present invention, the tube sheet automatic overlay welding device for automatically welding the tube sheet, the main frame 100; A positioner 200 for fixing and supporting the tube sheet 210 to be welded; A welding part 300 for welding the tube sheet 210; A UP / DOWN frame 400 that is connected to the welding part 300 to adjust the welding position by moving the welding part 300; A UP / DOWN motor unit 500 connected to the UP / DOWN frame 400 to allow movement; It characterized in that it comprises a welding control unit 600 for controlling the connection with the welding unit 300.

The positioner 200 is connected to the welding control unit 600, so that it can be rotated to adjust the welding position. As shown in Figure 6b, the positioner 200 can be operated by the welding control unit 600.

Next, the welding unit 300, a welding torch to generate heat by discharging the electrode; It includes a Super-TIG feeding module that supplies molten metal material to be a weld metal during welding.

According to the welding method, the electrode rods should have one end sharply closed when DC welding is to be performed, and rounded ends in the case of AC welding.

The electrode bar is characterized in that it consists of any one of tungsten, tungsten containing 1% to 2% thorium weight, and tungsten containing 0.8% to 2.2% lanthanum weight.

In more detail, when thorium is included, the arc is stable and consumes less electrodes, so it is used for direct current positive polarity, and is mainly suitable for welding steel, stainless, and copper alloys. When the electrode contains celium, it is a low current electrode rod, which is particularly widely used in precision molds.

When lanthanum is included, it is used for welding various molds such as iron, stainless steel, and aluminum, and exhibits particularly excellent performance on aluminum.

The electrode rod containing zirconium uses AC high frequency and is a high current electrode, which has a longer life than pure tungsten electrode, is more suitable for AC welding, and shows excellent performance in aluminum welding. Therefore, the user will be able to apply and use materials suitable for them.

Next, to explain the electrode rod in more detail, the concentration of the arc changes depending on the processing of the tip of the tungsten electrode. If it is as wide as 45 to 60 degrees at the processing angle, the arc is concentrated narrowly, and when it is pointed at about 20 to 30 degrees, the arc is generated broadly. Also, depending on the material, there is a difference in the concentration of the arc. For example, in the case of a thorium tungsten electrode rod, it is known that if the processing angle is about 30 degrees, the concentration of arc is similar to that of a cerium tungsten electrode rod, which is 45 degrees. This means that the thorium side has a higher concentration, but the arc start has a better cerium side. Therefore, the user should use an electrode electrode suitable for a more material in carrying out the present invention.

Next, the welding control unit 600 increases the bead width with the base material to avoid oscillation of the welding speed and increase the productivity (welding speed) so as to oscillate to increase the productivity, AVC (Auto responding to the oscillation frequency) Voltage Controller).

Referring to FIG. 5, to explain the oscillation, the overlay oscillation pitch means the torch oscillation and the repeating distance of the trajectory of the trajectory according to the welding progress.

The predetermined predetermined values (1%, 0.8%, 20-30 degrees, 45-60 degrees) described above are described to help the understanding of the present invention, which may vary depending on the operator's settings, It is natural that the above-described numerical values are not limited to the present invention.

Although described above with reference to the drawings according to embodiments of the present invention, those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above.

100: main frame
200: positioner
210: tube sheet
300: weld
400: UP / DOWN frame
500: UP / DOWN motor part
600: welding control unit

Claims (6)

A tube sheet automatic overlay welding device for automatically welding tube sheets,
Main frame 100;
A positioner 200 for fixing and supporting the tube sheet 210 to be welded;
A welding part 300 for welding the tube sheet 210;
A UP / DOWN frame 400 that is connected to the welding part 300 to adjust the welding position by moving the welding part 300;
The UP / DOWN motor unit 500 is connected to the UP / DOWN frame 400 so as to be movable.
It includes a welding control unit 600 to control the connection with the welding unit 300,
The welding part 300, a welding torch to generate heat by discharging the electrode rod and
Includes a Super-TIG feeding module that supplies molten metal material to be a weld metal during welding,
The welding control unit 600 increases the bead width with the base material to avoid oscillation of the welding speed while increasing the productivity (welding speed) so as to oscillate, AVC (Auto Voltage Controller) responding to the oscillation frequency ),
The metal material is a C-type filler,
When welding with the welding device, the arc column applies a plasma stream showing a flow of fluid as a fluid in the direction of the molten metal from the upper electrode and makes the filler material shape into a concave plate shape so as to be perpendicular to the plasma stream. The content of Fe after welding is determined by the dilution rate of the base material, and the dilution rate of the base material is determined by the following Equation 1 and Equation 2 according to the penetration depth and the bead height of the base material during overlay welding.
The electrode 310 is a tube sheet automatic overlay welding device, characterized in that one end is sharply closed in the case of direct current welding, and rounded in the case of alternating current welding according to the method of welding.
(Equation 1)

(Equation 2)

The method according to claim 1,
The positioner 200 is connected to the welding control unit 600, characterized in that it is possible to rotate to adjust the welding position, automatic tube sheet overlay welding device.
delete delete The method according to claim 1,
The electrode bar is tungsten, thorium weight 1% to 2% of the tungsten containing, lanthanum weight of 0.8% to 2.2% of the tungsten contained in the tube sheet automatic overlay welding device comprising one.
delete

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