JPH0518769U - Welding head for thick wall welding - Google Patents

Abstract

(57) [Summary] [Purpose] During welding, the contact between the shield cup and the surface of the thick pipe is accurately maintained, and continuous welding is possible without adjusting the protruding length of the electrode. [Structure] A welding torch 3 protruding from an end of an electrode 4 by a predetermined length and inserted into a circumferential joint narrow groove 2 of a thick pipe 1, and a shield cup supporting plate 5 fixed to a base of the welding torch 3.
Since the shield cup 7 supported by the shield cup support plate 5 via the spring 6 and the follower wheel 11 attached to the lower end edge of the shield cup 7 are provided, the lower end edge and the thickness of the shield cup 7 during welding are increased. The contact with the surface of the meat pipe 1 is accurately maintained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a welding head for welding thick pipes.

[0002]

[Prior Art]

 Conventionally, when performing narrow groove TIG welding of a butt peripheral joint of a thick-walled pipe, a shield cup 7 is used as shown in Fig. 2 (A) a longitudinal sectional view at the beginning of welding and (B) a longitudinal sectional view at the end of welding. The electrode 4 protruding from the tip of the attached welding torch 3 is inserted into the narrow groove 2 of the thick-walled pipe 1 to form the weld metal 12, and the welding is interrupted for each pass, and the protruding length of the electrode 4 is increased. The height is adjusted by one pass build-up height to eliminate the gap between the surface of the thick-walled pipe 1 and the shield cup 7 to secure the shielding property of the welded portion and improve the welding quality. There is a problem that can not be welded.

[0003]

[Problems to be solved by the device]

 The present invention has been proposed in view of such circumstances, and it is possible to accurately maintain the contact between the shield cup and the surface of the thick pipe during welding, and to perform continuous welding without adjusting the protruding length of the electrode. It is an object of the present invention to provide a welding head for welding thick-walled pipes that can be made possible.

[0004]

[Means for Solving the Problems]

 To this end, the present invention proposes a welding torch in which an electrode is projected from a tip by a certain length and is inserted into a circumferential joint groove of a thick pipe, a shield cup support plate fixed to the base of the welding torch, and the shield cup. It is characterized by comprising a shield cup supported by a support plate via a spring, and a model wheel attached to the edge of the shield cup.

[0005]

[Action]

 In the welding head for thick-walled pipe welding of the present invention, the arc length control is activated for each pass to raise the welding torch by one pass build-up height, and conversely a spring is activated to move the shield to the welding torch. Slide it down and press it against the surface of the thick pipe. As a result, the shield property of the welded portion can be accurately maintained without adjusting the protruding length of the electrode during welding, and continuous welding can be performed.

[0006]

【Example】

 An embodiment of the welding head for thick-walled pipe welding of the present invention will be described with reference to the drawings. Fig. 1 shows the welding head, Fig. 1 (A) is a longitudinal sectional view at the initial stage of welding, and Fig. 1 (B) is at the end of welding. FIG.

In FIG. 1, a welding torch 3 which is inserted into a narrow groove 2 of a peripheral joint of a thick-walled pipe 1 and which is to be welded has an electrode 4 projecting from a tip and fixed to a length suitable for welding. At the same time, the shield cup support plate 5 is fixed to the base portion. A shield cup 7 is supported by the shield cup supporting plate 5 via a spring 6, and the upper end of the shield cup 7 slidably contacts the outer periphery of the welding torch 3 and an O-ring 8 is interposed therebetween. Has been done. A shield gas nozzle 9 is connected to the upper side of the shield cup 7, and a gas lens 10 is housed inside the shield cup 7 slightly below the connecting position. A follower wheel 11 is attached to the lower edge of the shield cup 7.

In such a device, as the welding progresses from the initial welding state of FIG. 1 (A) to the final welding state of FIG. 1 (B), the arc length control is activated for each pass and the welding torch 3 is moved by one pass. When raised by the build-up height, the shield cup 7 is pressed downward by the elastic force of the spring 6, and the lower end edge of the shield cup 7 is always pressed against the surface of the thick pipe 1, thus maintaining the shielding property and keeping the same. Move by 11. Therefore, the shield property of the weld metal 12 of the narrow groove 2 can be accurately maintained without adjusting the protruding length of the electrode 4 during welding, and the narrow groove 2 circumferential joint welding can be continuously performed. You can

[0009]

[Effect of the device]

 In short, according to the present invention, the electrode protrudes from the tip by a certain length, and the welding torch is inserted into the groove of the circumferential joint of the thick-walled pipe, the shield cup support plate fixed to the base of the welding torch, and the shield cup. By providing a shield cup supported by a support plate via a spring and a model wheel attached to the edge of the shield cup, the contact between the shield cup and the thick-walled pipe surface during welding can be accurately performed. The present invention is extremely useful industrially, since a welding head for thick-walled pipe welding can be obtained which can be continuously held without adjusting the protruding length of the electrode.

[Brief description of drawings]

FIG. 1 shows an embodiment of a welding head for welding thick pipes according to the present invention. FIG. 1 (A) is a longitudinal sectional view at the initial stage of welding, and FIG. 1 (B).
[Fig. 4] is a vertical sectional view at the end of welding.

2A and 2B show a conventional welding head, in which FIG. 2A is a vertical sectional view at the beginning of welding, and FIG. 2B is a vertical sectional view at the end of welding.

[Explanation of symbols]

 1 Thick wall pipe 2 Narrow groove 3 Welding torch 4 Electrode 5 Shield cup support plate 6 Spring 7 Shield cup 8 O-ring 9 Shield gas nozzle 10 Gas lens 11 Follower 12 Weld metal

Claims (1)

[Scope of utility model registration request] 1. A welding torch in which an electrode is projected from a tip by a certain length and inserted into a circumferential joint groove of a thick pipe, a shield cup support plate fixed to a base portion of the welding torch, and the shield cup support plate. A welding head for welding thick-walled pipes, comprising: a shield cup supported by a spring on the inner side of the shield cup; and a model wheel attached to the edge of the shield cup.