KR100895348B1 - Method of gas tungsten arc welding using by active flux - Google Patents

Abstract

The present invention relates to a gas tungsten arc welding method for butt joining a base material, according to the present invention, in the gas tungsten arc welding method for butt jointing a base material such as stainless steel pipes and fittings, stainless steel having a thickness of 3mm ~ 25mm Machining the base materials of steel pipes and fittings with V-type improvement and bevel-type improvement and attaching the base materials to each other so that the root spacing is 0mm, so that the work for maintaining the constant spacing (2mm ~ 4mm) of the two base materials can be omitted. It is easy to prepare for welding, and the active flux which increases penetration of the welding joint of the two base materials is applied to the improved surface of the welding joint. Therefore, when using gas tungsten arc welding, using one hand without using a welding rod Since welding is performed by the first floor, the welding work is quick and the worker can easily perform the first floor welding. It is possible.

Base material, active flux, weld bead, sealing weld bead, root spacing, root face, angle of improvement, face improvement

Description

Method of gas tungsten arc welding using by active flux}

1 is an exemplary view showing a gas tungsten arc welding step using the active flux according to the present invention.

2 is an exemplary view showing a sealing welding step according to the present invention.

Figure 3 is an exemplary view showing a base material having a V-shaped improved shape according to the present invention.

4 is an exemplary view showing a base material having an improved shape of a bevel type according to the present invention.

5 is an exemplary view showing another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: base material F: active flux

W: Welding Bead W1: Sealing Welding Bead

a: root interval b: root surface

c: angle of improvement d: degree of improvement

The present invention relates to a gas tungsten arc welding method for butt jointing of the base material, more specifically, to omit the preparatory work for maintaining the root spacing of the base material such as stainless steel at a constant interval, and when the base material is a tubular body, The present invention relates to a gas tungsten arc welding method using an active flux, which can easily form a superficial backside welding bead without being bound by eccentricity.

In general, in order to weld the base material of stainless steel and fittings such as flanges, elbows and tees, the ends of the base material to be welded are cut and processed at an angle of 25 degrees to 40 degrees, and then joined together to improve the shape of V. To form a shape, the base material is spaced 2mm ~ 4mm spacing is welded.

At this time, the area near the back side welded portion of the stainless steel is heated to a high temperature during welding to reduce corrosion resistance of the stainless steel by reacting with oxygen in the air, and thus purging the argon or nitrogen gas to suppress the oxidation reaction.

When the oxygen concentration is reduced to a predetermined content or less by the purging operation, first-layer welding is performed to form a back welding bead having excellent welding quality and beautiful welding appearance by using gas tungsten arc welding.

Meanwhile, after the first layer welding, various types of welding methods such as gas tungsten arc welding, fluxcored arc welding, gas metal arc welding, and submerged arc welding are applied according to the size and thickness of the steel pipe.

As described above, the first layer welding for forming the back welding bead on the base material of the stainless steel pipe and fittings according to the present invention is subjected to manual gas tungsten arc welding.

The gas tungsten arc welding is a very effective welding method for the first layer welding of stainless steel pipe due to low welding heat input, but has a disadvantage of low welding productivity due to the low welding speed and small welding amount, and also the back welding beads of molten metal during gas tungsten arc welding In order to form, the gap between the two base materials, that is, the welding preparation work, that is, the root spacing must be kept constant at 2mm to 4mm, so it takes a lot of effort and time to adjust the spacing, and also prevents molten metal from flowing between the root spacings. Since the welding worker must adjust the torch head and the rod insertion amount properly by using both hands, the welding worker requires very high welding skill and both hands should be used, which causes inconvenience of the musculoskeletal disorders such as wrist, shoulder, and waist. In addition, to fill the space between the root spacing The time to complete the weld was standing consuming.

On the other hand, the base material of the improved shape of the I-shaped non-improving process by the root spacing to 0mm, so that the two base materials to be directly bonded together without maintaining a constant interval, it is easy to prepare for welding.

In addition, when the root spacing is 0mm, the possibility of molten metal melted is small and the welding bead is formed by arc heat using only one hand to hold the torch head by using a desalination welding method without a welding rod. Compared with the welding posture, the welding posture is not required, and the high-tech welding work is not required, and the welding space is small because there is no root spacing and the angle of improvement.

However, due to the shallow penetration characteristics of the gas tungsten arc welding method, it is applied only to stainless steel welding of 3 mm or less in thickness, and in the case of a base material of 3 mm or more in thickness, a V-shaped improved shape having a root spacing of 2 mm to 4 mm is formed. Weld work is performed.

Thus, in order to eliminate the task of maintaining the two substrates to be welded at a predetermined interval, which is carried out by the conventional manual gas tungsten arc welding method, the welding distance is 0 mm and the welding is performed without the use of a welding rod. At the proper welding current and welding voltage, uniform backside welding beads can be formed.

However, in the case of manual welding, since the welding speed is not constant, the formation of the back welding bead is not uniform, so the manual gas tungsten arc welding method is difficult to apply.

In addition, even in the case of automatic welding with a constant welding speed, there are eccentricities in which stainless steel pipes and fittings are not completely concentric due to various factors such as manufacturing, cutting, transporting, and welding preparation work of stainless steel pipes and fittings. It is rugged and the size of the two welding base materials is not exactly the same, so even if they are joined together so that the root spacing is 0mm, there is a part where the root spacing is more than 0mm locally, and the improved joint shape such as overlapping of the two base materials due to eccentricity Since this is not constant, the welding quality is not constant.

On the other hand, [Table 1] shows the problem of V-shaped improved welded joints. When the root spacing exceeds 0 mm as shown in [Table 1], if there is no supply of the electrode, the arc heat of gas tungsten arc welding As a result of melting, or as shown in [Table 1] (B), when the base material having a thickness of 7.6mm and 16mm is melted by the arc heat, the amount of the base material is small so that the weld beads are concave. In order to form a convex backside welding bead, if a welding rod is supplied into the welding arc to increase the amount of melting, there is a problem in that the backside welding bead is not formed.

On the other hand, as shown in [Table 1] (c), if the root spacing is 0 mm or less, that is, when the ends of the two base materials overlap due to the eccentricity, the weld bead is not formed.

 Root Spacing> 0mm  Root Spacing = 0mm

(가) 용락 발생

(A) Melting out

(B) concave backside welding beads

(C) Back side weld bead not formed

Therefore, the welding of stainless steel pipes and fittings with a thickness of 3mm or more is V-improved, which requires work to maintain a constant gap between the two base materials and both hands must be used for inserting the welding rods. There is a problem that the welder required.

Accordingly, the present invention is to solve the conventional problems, the object of the gas tungsten arc welding method of butt jointing the base material such as stainless steel pipes and fittings, the thickness of 2 ~ 4mm two base materials of 2 ~ 4mm It is possible to form welding beads on the back of the upper layer without the preparation of welding to maintain at regular intervals, and by applying the active flux to increase the penetration of the weld joint of the two base materials on the improved surface of the weld joint, The present invention provides a gas tungsten arc welding method using an active flux that allows welding beads to be formed more quickly and easily.

In the gas tungsten arc welding method of the present invention for achieving the above object, the step of adhering the base material of the stainless steel pipe and fittings having a thickness of 3mm ~ 25mm to V-type or bevel-shaped improvement so that the root spacing is 0mm And applying an active flux that deepens the penetration during welding to the improved surface of the welded joint, and welding the welded joint to the first layer without using a welding rod. Hereinafter, the specific technical details will be described in more detail with reference to the accompanying drawings.

That is, Figure 1 shows the implementation step of the gas tungsten arc welding method according to the present invention, the present invention improves the base material 100 in the gas tungsten arc welding method for butt jointing the base material 100 Processing and adhering to each other such that the root spacing (a) is 0 mm; (S100) applying an active flux (F) to the improved surface (d) of the weld joint to increase penetration of the base material (100); (S120) performing a gas tungsten arc welding to the welded joint, but without the use of a welding rod 300 to perform a thorough welding; (S130) forming a superficial back surface welding bead (W) on the welded joint It consists of (S140).

In addition, the sealing step of the root spacing (a) of the base material 100 exceeds 0mm; (S110) further comprises.

On the other hand, the root surface (b) to omit the sealing welding bead construction work to prevent the formation of the molten and concave back welding bead that occurs when the root spacing (a) of the base material 100 exceeds 0mm It is a V-shaped improvement shape with 1 mm to 3 mm and an improvement angle (c) of 50 degrees to 80 degrees, or a bevel shape improvement shape with a root surface (b) of 0 mm to 2 mm and an improvement angle (c) of 20 to 40 degrees. .

In addition, after the active flux (F) is applied to the improved surface (d) of the welded joint to prevent the formation of molten and concave back welding beads generated when the root spacing (a) of the base material 100 exceeds 0mm Welding is performed while feeding the electrode 300 manually or automatically.

In the above, the base material 100 is made of stainless steel having a thickness of 3 mm to 25 mm, and may be implemented in other light alloys.

In addition, the constituents of the active flux (F) is an oxide or a combination of various compounds, such as titanium oxide, chromium oxide, silicon oxide, etc., the method of applying the active flux (F) is a brush, spray, flux It can be applied by various methods such as an attached tape.

In the reference numerals, reference numeral 200 denotes a torch head, and 300 denotes a welding rod.

Hereinafter, an embodiment of a gas tungsten arc welding method according to the present invention will be described in detail with reference to the accompanying drawings and tables.

That is, [Table 2] shows the change in the shape of the weld when uncoated and coated with the active flux (F), and the active flux (F) having the characteristics of increasing the penetration of the conventional gas tungsten arc welding and the present invention, the base material before welding ( After coating on the surface of 100), the penetration characteristics of the welded part were compared to show a cross-sectional photograph of the welded part.

As shown in [Table 2], the surface welding bead width and penetration depth of the conventional gas tungsten arc welding without applying the active flux F are 6.9 mm and 2.5 mm, respectively, and the active flux F is coated. After welding, the surface weld bead width and penetration depth were 5.6 mm and 4.2 mm, respectively, and the active flux F was applied. 1.7 mm increase. Therefore, when the active flux F is applied to the welding surface, welding is performed to deepen the penetration of the welding portion.

On the other hand, [Table 3] shows a cross-sectional photograph of the weld portion subjected to gas tungsten arc welding by applying the active flux (F) according to the present invention on the improved surface (d) of the V-type, the root spacing (a) is 0mm or more In this case, even if the active flux (F) is applied, melting occurs due to the arc heat of the gas tungsten arc welding or when the amount of the base material 100 melted by the arc heat is small, the phenomenon as shown in [Table 1] in which the weld beads are concave is formed. Will occur.

However, in order to increase the amount of melting during melting of the base material 100 due to arc heat to prevent the formation of melt or concave weld beads, the thickness of the root is 6mm and the root spacing (a) as in the embodiment of [Table 3] (a). The sealing weld bead W1 is formed for this 0.5 mm stainless steel.

At this time, the back welding bead is not formed and the sealing welding is a simple filling welding for the prevention of melting during the subsequent welding and the formation of the convex back welding bead, and a high level of technology is not required, and at a higher speed than the welding forming the back welding bead Welding is possible.

In addition, since only a portion where the root spacing a exceeds 0 mm is locally welded, the welding time for the sealing weld is not increased significantly.

In addition, the root spacing (a) is 0 mm in the photograph of Table 3 (a), because the root spacing (a) is lost by shrinkage after welding. As described above, after sealing welding is applied to a portion having a steel thickness of 4 mm and a root spacing (a) of 0 mm or more, gaseous tungsten arc welding is applied after applying an active flux (F) to increase the penetration of the weld on the sealing welding bead surface. The welded joint is shown as shown in the photograph of [Table 3] (b) and the weld bead (W) is formed well.

On the other hand, when the root spacing (a) is 0 mm or less, that is, the ends of the two base materials 100 overlap by eccentricity, the welding is performed under the welding conditions as shown in [Table 1], but in the [Table 1], the back welding bead W is In the embodiment of [Table 3] (C) in which the active flux F is applied while not being formed, a good backside welding bead W is formed.

Further, in the welded joint of V-shaped improved shape having a thickness of 3 mm or more, the portion where the root spacing a exceeds 0 mm is subjected to sealing welding, and then the active flux F is applied to the entire improved surface d of the welded joint. ) By applying a welding gas tungsten arc welding without inserting the electrode 300 to obtain a good back welding bead (W).

delete

Root Spacing> 0mm Root Spacing = 0mm

(가) 용접전 : 실링비드 용접사진

(나) 용접후 : 백비드 형성된 사진

(A) Before welding: Photo of sealing bead

(B) After welding: Photo of back bead formation

(C) Picture of back bead formed when there is step

On the other hand, [Table 4] shows the V-shaped or bevel-shaped improved shape and the cross-sectional shape of the welded joint to omit the construction work of the sealing weld bead (W1) according to the present invention, the root spacing (a) If the local area exceeds 0 mm, the root surface (b) is 1 mm to 3 mm and the angle of improvement (c) is 50 degrees to 80 degrees, or the root shape (b) for the purpose of forming a melt-resistant and concave back welding bead. It is preferable that the surface (b) is a bevel type improved shape having an angle of 0 mm to 2 mm and an improvement angle c of 20 degrees to 40 degrees.

As shown in FIG. 3, when the root shape b is an improved shape having a V shape of 2 mm, when the root spacing a is 0.5 mm, as shown in Table 4, no melting occurs and convex back welding. Bead (W) is formed, and when the root spacing (a) is 0.5mm or less it can be seen that no sealing welding is required.

In addition, as shown in FIG. 4, when the root surface is 0 mm, a bevel type improved shape, that is, one base material 100 is a V-shaped improved shape and one base material 100 is an I-shaped improved weld seam. When the root spacing (a) is 0.8mm, no melting occurs and convex back welding beads (W) are formed. Therefore, when the root spacing (a) is 0.8mm or less, sealing welding is not required.

(A) V improved shape

(B) Bevel improved shape

In addition, as shown in Figure 5 in another embodiment of the present invention, after the active flux (F) is applied to the improved surface (d) of the portion where the root spacing (a) exceeds 0mm, the electrode 300 is manually or automatically supplied It is also possible to prevent melting and to form a convex backside welding bead (W). In addition to stainless steel pipes and fittings can be applied to stainless steel sheet.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described embodiments, and the present invention is not limited to the above-described embodiments without departing from the gist of the present invention. Anyone can make various modifications as well as such changes are within the scope of the appended claims.

As described above, according to the present invention, in the gas tungsten arc welding method for butt welding base materials such as stainless steel pipes and fittings, the base metals of stainless steel pipes and fittings having a thickness of 3 mm to 25 mm are improved by V type improvement and bevel type improvement. It is possible to omit the work for maintaining the constant spacing (2mm ~ 4mm) of the two base materials by processing and bonding the base material to each other so that the root spacing is 0mm, as well as easy welding preparation work, the weld joint of the two base materials Since the active flux that increases the penetration of the metal is applied to the improved surface of the welded joint, the first-layer welding is performed by using one hand without the use of the electrode for the gas tungsten arc welding. It is possible to obtain effects such as welding.

Claims (5)

Step to improve the base material 100 and abut the root spacing (a) to be 0mm; (S100) Applying active flux (F) to the improved surface (d) of the weld joint to increase penetration of the base material (100); (S120) Performing gas tungsten arc welding on the welded joint, but not by using a welding rod 300; In the welding joint to form a first layer back welding bead (W); Gas tungsten arc welding method to butt-joint the base material 100 consisting of (S140), Sealing welding at a portion where the root spacing (a) of the base material (100) exceeds 0 mm; (S110) Gas tungsten arc welding method using an active flux comprising a. delete delete delete The method of claim 1, The base material 100 is a gas tungsten arc welding method using an active flux, characterized in that the stainless steel having a thickness of 7mm ~ 25mm.

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