JPH023672B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a gravity welding method and device for welding downward butt portions while swinging a welding rod, and provides a method and device for highly efficient arc welding with fewer welding defects by simple means. The purpose is to provide The conventional gravity welding method, for example,
As shown in the figure, one or more welding rods 2 are attached to a gravity welding machine 1, and a groove 5 is welded without swinging. In this case, the welding rod used is a welding rod whose core wire 3 is coated with a coating material 4 as shown in FIG. 2a. Recently, as shown in Fig. 2b, using a welding rod 2' in which a plurality of welding rods are arranged and tied together with a wire 6, etc., the root of the groove is melted with the lower welding rod, and the bead is flattened with the upper rod. There is also a known product that aims to have the effect of Therefore, this method also discloses that a balance weight is provided on the slider so that the axis of the welding rod has eccentricity characteristics according to the groove spacing, especially in irregular grooves where the groove spacing varies. ing. However, in downward butt welding, in order to efficiently weld irregular grooves with different groove spacing without welding defects, a single rod is insufficient in the amount of weld deposited, and the groove walls are insufficiently fused and fused. There are drawbacks such as the occurrence of defects, and even if multiple welding rods are used as shown in Figure 2b, and welding is performed while changing the axis according to the groove spacing using a balance weight, the amount of welding increases. However, in areas where the gap is wide, the arc still cannot melt the walls on both sides of the groove completely and evenly, resulting in poor fusion, and the weld metal may be offset to the groove. However, there is a need for an improvement in the tendency to form a so-called uneven thickness bead. Furthermore, in the method of bundling and using a plurality of welding rods, it is necessary to scrape off the coating material at the mating portions of the respective welding rods, and it is also necessary to combine and bind them together. In addition, wires and the like as binding materials pose difficulties in transportation and construction, and from this point of view, improvements are also desired. The present invention advantageously solves all of these difficulties, and has developed a method and device that can perform welding with simple means, without welding defects, and with high efficiency.The main points of this invention are: 1. A gravity welding method characterized in that a welding rod coated with a coating material on a plurality of core wires that touch along the lower core wire is swung around the axis of the lower core wire while welding the downward butt part, 2. In a gravity welding device, a mechanism is installed on the slider attached to the slide bar to rotate the welding rod holder around the lower core axis of the welding rod via an overload absorption mechanism using an eccentric cam linked to the motor shaft. This is a gravity welding device characterized by being provided with a welding rod swinging device. In the present invention, as shown in FIG. 3, the welding rod used has a plurality of core wires 3, 3' attached to the core shaft of each core wire by an appropriate method, for example, by welding the ends. The welding rod A is made by bringing the welding rods into contact with each other and uniformly coating the circumferential surface with a required amount of coating material 4. In particular, it is possible to ensure and easily distribute the required coating material on the surface. , has the conditions to effectively achieve the original characteristics of a deformed welding rod, is easy to manufacture, and exhibits excellent operation and effect without any problems during transportation and construction. Accordingly, in the present invention, downward butt welding is performed while such a welding rod is oscillated about the lower core axis, but the oscillation is adjusted as appropriate depending on the range of the groove angle. It is a matter of choice. In other words, the method of rotating the welding rod using a balance weight as disclosed in JP-A No. 57-130775 allows the welding rod to be tilted to closely follow the fluctuations in the groove spacing, but the welding rod is not actively oscillated. However, the welding of the groove into the left and right walls is not uniform, and one side always melts well while the other side not only suffers from poor fusion, but also has the disadvantage of forming the unevenly thickened bead described above. On the other hand, in welding according to the method of the present invention, a small motor swings the welding rod from side to side at high speed around the lower core shaft of the welding rod, which has multiple core wires that are in contact with each other along the shaft center coated with a coating material. , it is possible to reliably and evenly melt the left and right walls of the groove, effectively preventing fusion defects. Additionally, the molten metal is evenly distributed over the groove, resulting in a flat weld bead. Therefore, the next pass of welding can be performed satisfactorily, and overall defect-free welding can be performed with high efficiency. Next, the present invention will be explained in detail based on an example device. Fig. 4 shows an example of a gravity-type downward welding machine, in which a slider B that descends by gravity is attached to a slide bar 7 whose one end is supported by a leg 6, and the welding machine installed on this slider B. Holder 8
Attach welding rod A to the groove 5 for downward butt.
It is used for welding. Therefore, the device of the present invention has the fifth slider B on this slider B.
The welding rod A, which has a plurality of core wires that are in contact with each other along the axis and are coated with a coating material, is swung within a predetermined angle range as shown by the arrow around the lower core wire 3', an example of which is shown in the figure. It is equipped with a moving mechanism. In the figure, 9 is a swing motor, 10 is an eccentric cam that is linked to the motor shaft, and 11 is a leaf spring that clamps the cam 10. This leaf spring 11 is attached to a metal fitting 16 that is integrally connected to the shaft 12. installed.
Further, the shaft 12 is supported by a bearing 15 and can rotate around its axis. Furthermore, the holder 8 that holds the welding rod A is such that the centerline of the core wire 3' of the welding rod A is aligned with the axis 1.
It is installed so that it coincides with the axis of 2. In addition, the leaf spring 11 protects the motor by deflecting when an overload is applied to the swinging of the welding rod A due to the opening condition of the bevel. It can sufficiently cope with abnormal fluctuations and can easily and fully achieve the desired purpose. Regarding this embodiment, when the swinging motor 9 is rotated in a certain direction, the welding rod A swings as shown by an arrow 14 about the lower core wire 3' as shown in FIG. To explain this aspect with reference to FIG. 7, when the welding rod A is set in the groove 5 as shown in FIG. 6, the welding rod A swings relative to the groove 5 as shown in FIG. Welding is performed while completely melting the wall 13. As a result, sufficient penetration is obtained,
The surface of the weld bead becomes smooth, and welding defects are significantly less likely to occur.Moreover, since multiple core wires are used at the same time, welding can be performed with high efficiency. The effects of the present invention will be illustrated below with specific examples. Table 1 shows the dimensions and chemical composition of the test steel, and Table 2 shows the chemical composition and mechanical properties of the test welding rod. A conventional welding method for comparison is a gravity welding method in which a single coated welding rod is fixedly held as shown in FIG. FIG. 8 shows a groove to which the conventional method was applied, and FIG. 9 shows a groove to which the method of the present invention was applied. These dimensions and angles are as follows. θ ₁ : 60°, θ ₂ : 50°, t ₁ : 9mm, t ₂ : 25mm, t ₃ : 50
mm, B: 50 mm, G ₁ : 8 mm, G ₂ : 10 to 15 mm. Next, Table 3 shows the welding conditions for welding these grooves. FIG. 10 shows a lamination method using a conventional welding method. A is for a plate thickness of 25 mm, and b is for a plate thickness of 50 mm. FIG. 11 shows the welding lamination method according to the present invention. Table 4 shows the results of various tests performed on the welded joints obtained by the above method.

【table】

【table】

【table】

【table】 [Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an aspect of the conventional gravity welding method, and Fig. 2 is an explanatory diagram of a conventional welding rod, where a is a case in which there is one core wire, and b is an example in which two welding rods are combined. shows. Fig. 3 is an explanatory diagram showing an example of a welding rod used in the present invention, Fig. 4 is an explanatory diagram showing an example of a gravity welding machine used in the method of the present invention, and Fig. 5 is an explanatory diagram showing an example of a gravity welding machine used in the method of the present invention. An explanatory diagram showing one example of a welding rod swinging mechanism to be provided, FIGS. 6 and 7 are explanatory diagrams of an embodiment of the method of the present invention, and FIGS. 8a and b are groove shape diagrams used in a conventional welding method. Figures 9a and b are diagrams showing an example of the groove shape used in the welding method of the present invention, Figures 10a and b are diagrams showing the lamination method in the conventional welding method, and Figures 11a,
b is a diagram showing an example of a lamination method in the welding method of the present invention. 1: Gravity welding machine, 2: Welding rod, 3, 3': Core wire, 4: Covering agent, 5: Bevel, 6: Wire, 7: Slide bar, 8: Welding rod holder, 9: Swing motor , 10: Eccentric cam, 11: Leaf spring, 12: Swing transmission shaft, 13: Groove wall, 14: Swing direction, 1
5: Bearing, 16: Metal fittings.

Claims (1)

[Scope of Claims] 1. Welding the downward abutting portion while swinging a welding rod in which a plurality of core wires that are in contact along the axis are coated with a coating agent around the axis of the lower core wire. A gravity welding method characterized by: 2 In a gravity welding device, a coating material is applied to a slider attached to a slide bar through an overload absorption mechanism by an eccentric cam that is linked to a motor shaft, and to multiple core wires that touch the welding rod holder along its axis. A gravity type welding device characterized by being provided with a welding rod swinging device having a mechanism for rotating the welding rod around the lower core axis of the welding rod.