JPS61159274A - Welding method - Google Patents

Abstract

PURPOSE:To improve the quality of the weld zone of thick plates by welding one pass with a sliding copper plate having a projecting shape to be fitted into a groove then welding the 2nd and subsequent passes by using a sliding copper plate having a recessed shape. CONSTITUTION:The projecting part 4 of the sliding copper plate 3 having the projecting shape is fitted into the groove 2 formed by butting members 1. A groove space part 5 remaining after the occupation of the part 4 is electrogas- welded by moving the plate 3. A stationary copper plate 6 on the rear side and the plate 3 are cooled with water during this welding. The plates 3, 6 are then removed and the groove space 5' between the sliding copper plate 3' having a recessed cross sectional shape and the 1st layer of deposited metal 7 is electrogas-welded while the plate 3' is moved. The quantity of heat input for the 1st pass is decreased by such method. The heat affected zone of the member is thus decreased and the quality of weld zone is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a welding method in electrogas welding that enables multilayer welding and reduces the amount of heat input per pass.

[Prior art 1] Conventionally, electrogas welding is performed by aligning the grooves of parts a to be welded together, placing a fixed copper plate on the back side of the grooves, and placing a sliding copper plate C on the front side, as shown in Fig. 3. Cooling water is sent to the fixed copper plate and moving copper plate C, and one pass welding is performed on one side while moving the sliding copper plate C in accordance with the welding speed.

[Problem to be solved by the invention 1 In general T reflex 1 hero gas welding, /fiT is performed with one pass on one side or one pass on both sides, so as the plate thickness increases, the groove cross-sectional area increases, making it difficult to reduce the welding current. If it is not made larger, it will be difficult to obtain a sound weld.

Therefore, the heat input when welding thick plates increases.

If impact performance (notch toughness value) is not required for a general M4m product, there is no particular problem even if the heat input is large, but if impact performance is required, especially if it is used at low temperatures, a large heat input may cause a problem. Since the impact performance of the weld heat affected zone cannot be ensured, welding with large heat input becomes impossible. The amount of heat input required depends on the material's quality and required performance, but at present, electrogas welding is usually used at a temperature of about -10°C. It is considered impossible for a structure that
The upper limit was a plate thickness of 111 m.

[Means for solving the problem] In order to solve the above-mentioned problems, the present invention uses a convex sliding copper plate that can be inserted in the welding area, and after welding at least one pass with a small amount of effort, weld the concave sliding copper plate. Welding was done using a sliding copper plate.

[Function] Since the convex part of the sliding copper plate fits into the groove, the space in the groove becomes smaller, and since this space is first electrogas welded, the amount of heat input in one pass is reduced. Decrease.

Multi-layer welding can be performed by sequentially welding using sliding copper plates with low height protrusions, and finally welding using a concave sliding copper plate.

Therefore, since the amount of heat input per pass can be reduced, high-quality electrogas welding of thick plates can be performed.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are diagrams showing an embodiment of the welding method of the present invention. The groove 2 is formed by fitting the convex portion 4 of the sliding copper plate 3 having a convex cross-sectional shape into the groove 2 formed by butting the members 1 together.
A part of the groove is occupied by the convex portion 4, and the remaining groove space 5 is electrogas welded while moving the sliding copper plate 3.

When welding the T reflex 1 to logarithmic welding, a fixed copper plate 6 is placed on the butt joint side of the member 1, and cooling water is supplied to the fixed copper plate 6 and the sliding copper plate 3.

Next, the fixed copper plate 6 and the sliding copper plate 3 having a convex shape are removed, and a sliding copper plate 3' having a concave cross-sectional shape is applied to the groove between the first layer welded metal 7 and the sliding copper plate 3'. Electrogas welding is performed while moving the sliding copper plate 3' through the space 5'.

Thereby, two-layer welding can be performed with two passes on one side, and the amount of heat input per pass can be reduced.

It should be noted that the welding method of the present invention is not limited to the above-mentioned embodiments, but can perform multi-pass welding on one or both sides by sequentially using convex sliding copper plates with lower convex parts. Of course, various modifications may be made without departing from the spirit of the present invention.

[Effects of the Invention 1 As described above, the welding method of the present invention exhibits various excellent effects as described below.

(T) Since electrogas welding is performed using a sliding copper plate shaped to fit into the groove, multilayer welding with two or more passes on one side is possible. Therefore, the amount of heat input per pass is reduced, the heat affected zone of the member is reduced, and the quality is improved.

<n) This makes it possible to weld three or more passes on both sides of a thick plate with a thickness of 40 mm or more. , It can also be applied to welding vertical joints of materials with limited heat input.

■ Since it is possible to weld only from one side, the number of setup steps can be reduced.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the welding state of the first layer in the welding method of the present invention, Fig. 2 is a diagram showing the welding state of the second layer in the welding method of the present invention, and Fig. 3 is a diagram showing the welding state of the second layer in the welding method of the present invention. It is a figure showing an example of a welding method. 1 is a member, 2 is a groove, 3.3' is a sliding copper plate, 4 is a convex part,
5.5' is a groove space, 6 is a fixed copper plate, and 7 is a welded metal. Patent application Hitoshikawajima-Harima City Industrial Co., Ltd. -〇-

Claims (1)

[Claims] 1) A welding method characterized by performing at least one pass of welding using a convex sliding copper plate that can fit into the groove, and then welding using a concave sliding copper plate.