KR100591293B1 - The method of inverse combined welding using electro gas welding and gas metal arc welding and copper shoe used therefor - Google Patents

Abstract

The present invention relates to a reverse bind welding method that can be used for vertical welding of a thick plate, the welding method comprising the steps of determining the maximum thickness of the welding strength does not lower than the required strength due to the increase in heat input even if EGW is applied; Applying EGW to a thickness t1 within the determined maximum thickness range; And applying the GMAW to the remaining thickness t2 from the thickness t1 to which the EGW is applied; Consists of including. In addition, in order to apply EGW only to a certain portion in the thickness direction of the base material, a sliding plate having irregularities matching the improved shape is used.

This welding method can prevent the strength deterioration due to the increase of heat input, reduce the width of improvement and the angle of improvement, thereby reducing the area of improvement while maintaining the advantages of EGW, which allows welding of the entire welding section in one pass. It is possible to reduce the heat input more than the conventional combine welding method, and the applicable thickness of the welding method is not limited, and in particular, it is possible to apply automatic vertical welding to a narrow improvement without special additional device.

Description

The method of inverse combined welding using electro gas welding and gas metal arc welding and copper shoe used therefor}

1 is a schematic diagram sequentially showing a reverse bind welding method according to the present invention;

Figure 2 is a plan view and a side cross-sectional view showing the implementation of the EGW in the welding portion using the sliding plate according to the present invention;

3 is a front perspective view and a rear perspective view of the sliding plate according to the present invention;

4 is a schematic plan view of a general GMAW welding method;

5 is a schematic plan and side cross-sectional view of a general EGW welding method;

Figure 6 is a cross-sectional view of the base material subjected to the conventional bind welding method,

7 is a cross-sectional view of the base material subjected to the reverse bind welding method according to the present invention.

<Description of Symbols for Main Parts of Drawings>

10,100 ---- substrate, 20,200 ---- welding torch,

21,210 ---- welding wire, 22,220 ---- protective gas,

30,300 ---- back side, 40,400 ----- front side,

50,500 ----- sliding plate, 51,510 ----- protective gas discharge,

52,520 ----- cooling part, 53,530 ----- protective gas supply pipe,

54,540 ----- Cooling fluid flow pipe, 550 -------- Supporting groove,

60,600 ----- backing material, 70,700 ----- molten pool,

800 -------- EGW weld, 900 -------- GMAW weld.

The present invention relates to a welding method that can be used for vertical welding of a thick plate, and more particularly, to perform a portion of the weld by welding the first part of the welding by performing the electrogas welding method and then the other part is welded by using a gas metal arc welding method It is about the combined welding method.

In general, in the case of welding a thick plate, Gas Meteal Arc Welding (hereinafter referred to as GMAW) and Electro Gas Welding (hereinafter referred to as EGW) are used.

As shown in FIG. 4, the GMAW supplies the welding wire 21, which is a consumable electrode, to the molten pool at a constant speed, while an arc is formed between the welding wire 21 and the base material 10 through a current. It is a welding method to generate | occur | produce and to weld using this arc. At this time, the arc is protected from the surrounding atmosphere by a shielding gas 22 supplied through a gas nozzle formed in an annular shape around the welding wire 21. This GMAW is more efficient than the general shielded metal arc welding method by the continuously supplied welding wire 21, and the welding speed is high and is applied to most of the shipbuilding process.

In the GMAW, as the thickness of the base material 10 becomes thicker, the number of welding passes increases to fill the weld. For example, welding of the 55 mm thickness base material 10 requires about 50 passes of welding. In addition, since the welding torch 20 is combined with the gas nozzle, the diameter of the welding torch 20 becomes larger than that of other welding methods, so that the welding torch 20 approaches and properly protects the arc with the protective gas 22. It is necessary to facilitate the access of the welding torch 20 by increasing the groove angle α. Therefore, the improvement angle (alpha) which is actually used applies the minimum 30 degree or more.

5 shows an EGW welding method, in which FIG. 5A is a plan view thereof, and FIG. 5B is a side cross-sectional view along the line B-B in FIG. 5A. The illustrated EGW welding method is a special type of GMAW, which is a welding method having the basic characteristics of GMAW, such as the use of consumable electrodes, the welding wire 21 and the protective gas 22, and welding using arc force. It is possible to weld the entire welded end surface of the base material 10, as shown in the molten pool 70 formed by continuously melting the welding wire 21, the rear surface portion 30 of the base material 10; Root gap) is blocked with a backing material (60) of a ceramic form and the front part 40 is welded by blocking with a sliding plate (50).

The sliding plate 50, which will be described in more detail below, has a protective gas discharge part 51 connected to the protective gas supply pipe 53 at an upper portion thereof, so that the protective gas 22 is discharged to the welding part so that the arc is ambient. The cooling part 52 is formed in the lower part and connected to the cooling fluid flow tube 54 to cool the welding part. Therefore, the sliding plate 50 has a function of blocking the front part of the welded part, and a function of cooling the discharged part of the protective gas to protect the arc from the ambient atmosphere.

This EGW has an excellent effect on the reduction of welding time and efficiency compared to the general GMAW. In addition, since the gas nozzle is separated from the welding torch 20 compared to the general GMAW, and the protective gas 22 is supplied through the protective gas discharge part 51 of the sliding plate 50, the welding torch 20 is small. Easy access to the weld cross section. Therefore, it is possible to use the improvement angle alpha smaller than 20 degrees, for example compared with general GMAW.

Such EGW has a disadvantage in that it is a very high productivity welding method in the vertical plate welding method, but when the plate thickness is increased to a predetermined thickness or more, the welding strength decreases due to an increase in the amount of heat input by welding.

Container ships currently being built at shipyards are becoming larger and larger, and the thicker parts of the hull (sheer strake, upper deck; upper deck, hatch coaming) have a thickness of 65 mm to 75 mm. It is going to come. Therefore, domestic and overseas shipyards are examining and testing the application of EGW in order to reduce the welding time, but as described above, due to the reduction of the welding strength due to heat generated by welding a wide welding cross section in one pass, the base material heat affected zone and welding The metal department is having difficulty securing the properties required by the Society.

Therefore, in order to reduce the heat input of EGW, it is inevitable to apply a welding method suitable for a base material and a material using GMAW as EGW. After the welding portion 900 was formed, the remaining portion was subjected to the EGW welding method (hereinafter referred to as "combined welding") to form the EGW welding portion 800. However, this combined welding method requires GMAW to be applied first, so that the improvement angle must be maintained at least 30 degrees. Therefore, the overall welding area is increased, and the surface gap is widened when EGW is applied to steel materials over 60mm thickness. There is a disadvantage in that it is difficult to secure the penetration, and this has a disadvantage in that the thickness is applicable.

The present invention was created to overcome the above disadvantages, and an object of the present invention is to perform the GMAW and EGW in a reverse bind method, that is, a method of performing the GMAW on the remaining thickness part after the EGW is first performed on the partial thickness of the welded part. It is to provide a reverse bind welding method to secure the weld strength and increase the productivity without changing the advantages of EGW, which can weld a weld in one pass.

Another object of the present invention is to provide a sliding plate suitable for the reverse bind welding method.

In the reverse bind welding method of the present invention for the above purpose is to determine the maximum thickness of the welding strength does not lower than the required strength due to the increase in heat input even if EGW is applied, and the EGW to a thickness within the determined maximum thickness range And applying GMAW to the remaining thickness from the thickness to which the EGW was applied.

In addition, determining the maximum thickness that the welding strength does not lower than the required strength even if the EGW is applied, the step of applying the EGW to any thickness of the specimen, measuring the strength of the specimen to which the EGW is applied, measured When the strength is smaller than the allowable strength compared to the allowable strength, the EGW application thickness is decreased, and when the strength is higher than the allowable strength, the EGW application thickness is increased so that the EGW is applied to the new specimen again and the EGW is applied according to the repeated results of the above steps. Determining the maximum thickness for the process.

In addition, the upper part is provided with a protective gas discharge part connected to the protective gas supply pipe, and the lower part has a cooling part connected with two cooling fluid flow pipes, each of which is an inlet and an outlet, so that when the EGW is applied, it blocks the front part of the welding part and discharges the protective gas. In the sliding plate which protects the arc from the ambient atmosphere and functions to cool the weld,

The protective gas discharge part and the cooling part were protruded to fit the improved shape of the welded part so that EGW was applied only to a certain part in the thickness direction of the base material.

In addition, the honeycomb (honey comb) is provided in the protective gas discharge unit to rectify the discharge of the protective gas.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a schematic diagram showing the reverse bind welding method according to the present invention in order, a portion of the base material is cut to show the welded portion. Before applying EGW, it is necessary to know the maximum thickness that the application does not reduce the weld strength due to the increase of heat input. To do this, perform EGW to a certain thickness using a material that can be used as a base material, measure the strength of the specimen, compare it with the required allowable strength, and apply the EGW if it does not meet the allowable strength. If the EGW is reduced and the allowable strength is exceeded, the EGW is applied to the new specimen again by increasing the thickness of applying the EGW, and the above steps are repeated to determine the maximum thickness of the EGW.

Of course, it is more preferable to implement not only one specific material but also various materials, and this maximum thickness can also be utilized in the manufacture of the sliding plate 500 as described below.

As described above, when the maximum thickness to which the EGW is to be applied is determined, the thickness of the maximum thickness within the range, that is, the EGW is performed up to t1 in FIG. 1A.

In this case, as shown in FIG. 3, a sliding plate 500 different from the conventional sliding plate 50 is used, and the overall structure of the sliding plate 500 is similarly protected to that of the conventional sliding plate 50. When the gas discharge part 510 is formed, the protective gas is discharged through the EGW to protect the arc generated between the welding wire and the base metal from the surrounding atmosphere, and the cooling part 520 is formed at the lower part of FIG. As described above, the molten pool 700 of the welded portion which is in contact with this can be cooled. To this end, as shown in FIG. 3, the protection gas discharge unit 510 is connected to the protection gas supply pipe 530 so that the protection gas is supplied to the protection gas discharge unit 510. In addition, the cooling unit 520 is connected to two cooling fluid flow pipes 540, each of which is an inlet and an outlet of the cooling fluid to the cooling unit, through which the cooling fluid circulates the cooling unit 520, as described above. The molten pool 700 is cooled. However, the sliding plate 500 according to the present invention, unlike the conventional sliding plate 50, as shown, the protective gas discharge portion 510 and the cooling unit 520 is projected to fit the improved shape of the weld Therefore, the sliding plate 500 can be inserted into the welded portion from the front portion 400 of the welded portion to the rear portion 300d direction up to a predetermined portion in the thickness direction of the base material, that is, the thickness t1. . This is well shown in Figure 2, Figure 2a is a plan view showing the implementation of the EGW using the sliding plate 500 according to the present invention and Figure 2b is a side cross-sectional view along the line A-A of Figure 2a. Therefore, as shown, using the sliding plate 500 according to the present invention, it is possible to apply EGW only to a part of the thickness t1 of the welded portion. Here, reference numeral 550 is used as a support groove to support the sliding plate to the EGW welder when applying EGW.

As described above, the maximum applicable thickness of the EGW may help determine the degree of protrusion of the protective gas discharge part 510 and the cooling part 520 of the sliding plate 500. In addition, by installing a honey comb on the protective gas discharge part 510 of the sliding plate 500 to rectify the discharge of the protective gas, the protective gas is stably and uniformly discharged, thereby causing vortex shedding and turbulence. This is preferable because it can prevent the atmosphere from entering the protective gas.

As shown in Fig. 1 and 2, the sliding plate 500 is inserted into the welding part to block the front part 400 of the welding part, and the back part 300 is provided with a backing material 600 as in the conventional method. After the film is closed, the EGW is subjected to the welding while raising the sliding plate 500 for cooling the molten pool 700 while discharging the protective gas 220 as in the conventional EGW, as shown in FIG. 1C. As a result, welding is performed by the EGW method only up to the thickness t1 to form the EGW welding part 800.

After the EGW up to the thickness t1 is completed, the sliding plate 500 and the backing material 600 installed for this purpose are removed as shown in FIG. 1C. The thickness t2 after the EGW is applied becomes wider as shown in FIG. 1D, thereby providing sufficient space for weaving the GMAW welding torch 200 to the left and right. .

Therefore, if the remaining thickness t2 is welded in several passes using the welding torch 200 for GMAW, as shown in FIG. 1E, a welding section to which the EGW is applied can be obtained up to the thickness t1 of the base material 100. The thickness t2 other than this can obtain a welded cross section to which GMAW is applied. This is indicated in the figure by the EGW weld 800 and the GMAW weld 900, and is shown in more detail in cross section in FIG.

As described above, FIG. 6 is a cross-sectional view of a conventional combine welding method, that is, a welding method in which GMAW is performed first and then EGW is performed. FIG. 7 is a cross-sectional view showing a reverse bind welding method according to the present invention. As can be seen from the comparison, the conventional combined welding method is performed with GMAW first, so that the angle of improvement becomes wider, and thus the applicable thickness of the combined welding method is restricted by this, but the reverse combine of the present invention In the case of the de-welding method, since the EGW which is not greatly influenced by the improvement angle is performed first, even a narrow improvement angle, for example, an improvement angle of about 20 degrees, can be sufficiently welded.

In addition, since the motion radius of the welding torch is sufficiently secured when the GMAW is applied after the EGW, if the EGW applicable thickness is sufficiently secured, the application thickness is not limited as in the combined welding method.

In addition, since EGW is preferentially applied in a small area of the welded part, the amount of heat input is further reduced as compared with the conventional combined welding method, and there is no need to worry about surface welding defects. Therefore, EGW is applied to shipbuilding steels to the extent that satisfies the standard value for shipbuilding steels to which the 1-pass EGW welding method cannot be applied, and the rest is applied to welding steels of 100mm thickness or more by applying general GMAW. Applicable

This reverse bind welding method is significantly improved welding efficiency compared to the general GMAW, and solves the heat input problem of the conventional bind welding method and the difficulty of applying to steel over 60mm thickness at the same time.

As described above, according to the present invention, by applying the EGW that is not significantly affected by the improvement angle first, and then, the reverse bind welding method is configured to apply the GMAW which does not have a relatively large amount of heat input than the EGW, so that the strength of the weld is increased due to the increased heat input amount. It is possible to prevent lower than the allowable strength, so that it is possible to weld a thicker thickness while securing a stable welded part strength, and it is possible to weld with a narrow angle of improvement, and the additional productivity improvement effect is not limited because the welding thickness is not limited. have. In addition, there is an effect that can be applied to the automatic vertical welding in a narrow improvement without a special additional device.

Claims (4)

Determining a maximum thickness at which welding strength is not lowered than a required strength due to an increase in heat input even when EGW is applied; Applying EGW to a thickness t1 within the determined maximum thickness range; And Applying GMAW from the thickness t1 to which the EGW is applied to the remaining thickness t2; Reverse bind welding method comprising a. The method of claim 1, wherein the determining of the maximum thickness of applying the EGW does not lower the required weld strength. Applying EGW to any thickness of the specimen; Measuring the strength of the specimen to which the EGW is applied; Applying the EGW to the new specimen by reducing the EGW application thickness when the measured strength is smaller than the allowable strength and increasing the EGW application thickness when the strength is higher than the allowable strength; And Determining a maximum thickness for EGW application according to the repeated execution result of the steps; Reverse bind welding method comprising a. The upper part is provided with a protective gas discharge part 510 to which the protective gas supply pipe 530 is connected, and the cooling part 520 to which two cooling fluid flow pipes 540 are respectively formed as an inlet and an outlet is formed in the lower part of the EGW. In the sliding plate 500, which functions to block the front part of the welded part and discharge the protective gas to protect the arc from the surrounding atmosphere and to cool the welded part, The sliding plate used in the reverse bind welding method in which the protective gas discharge part 510 and the cooling part 520 protrude to meet the improved shape of the welded part so that only EGW is applied to a predetermined portion in the thickness direction of the base material 100. 4. The sliding plate according to claim 3, wherein a honey comb is provided in the protective gas discharge part 510 to rectify the discharge of the protective gas.

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