JP3388924B2 - Welding distortion reduction method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing welding distortion in welding a T-shaped structure without damaging a portion to be welded. About. [0002] Conventionally, in fillet welding in a T-shaped welded structure formed by combining a flat plate and an upright plate in a T-shape, a method of heating the back side of the flat plate prior to the fillet welding. There is. One example is shown in FIG. 2 (a) is a side view, and FIG. 2 (b) is a front view. In the figure, 1 is a flat plate, 2 is an upright plate, and this is combined with a T-shape and its fillet is welded to form a T-shaped structure. To form 3 is a consumable electrode welding torch for fillet welding, 4 is a TIG welding torch, 5 is a welding line on a flat plate material, 5 'is a welding line which is the target of the welding line 5 with the upright plate 2 interposed therebetween, 6 Is a weld bead. [0005] Reference numeral 7 denotes a line on the back side of the welding line 5 on the flat plate 2, and 7 ′ denotes a line on the back side of another welding line 5 ′. Reference numeral 8 denotes an arrow indicating the moving direction of the T-shaped structure composed of the flat plate 1 and the upright plate 2. Next, the welding operation according to the conventional method will be described. The consumable electrode welding torch 3 and the TIG welding torch 4 are fixed, and the T-shaped structure (the flat plate 1 and the upright plate 2) moves. First, in the TIG welding torch 4, the welding wire 5 is used.
An arc is generated between the electrode of the TIG welding torch 4 and the flat plate 1 along a line 7 corresponding to the back side of the flat plate.
The back surface of the flat plate is heated by the arc heat. The flat plate 1 is heated while moving. When the distance between the TIG welding torch 4 and the consumable electrode welding torch 3 is properly selected, as the distance from the TIG welding torch 4 increases, the back side of the flat plate 1 is reduced. Will be cooled and will be deformed in the shape of “H” toward the TIG welding torch. This is the same operation as the principle of linear heating. Thereafter, the flat plate 1 further moves,
Fillet welding is performed by the consumable electrode welding torch 3 along the welding line 5 of the flat plate 1. At this time, the welding heat input is applied to the front side of the flat plate 1. Therefore, the flat plate that has been deformed into the shape of “he” due to this heat input is “reverse”.
As a result, both deformations cancel each other, and the flat plate 1 becomes a flat panel without deformation after welding. Next, the same action is applied to the welding of another welding line 5 'and the heating of the line 7' on the back side of the flat plate 1 to complete the joint of the T-shaped structure. This effect enables welding with little welding distortion. However, the conventional fillet welding method as described above has the following disadvantages. (1) Since the back surface of the flat plate 1 is heated by the arc heat from the TIG welding, the surface of the heating portion may be melted, and the surface of the back surface of the flat plate 1 may be damaged. Therefore, after welding, the damaged portion must be repaired. (2) In the conventional method, since the heating area in the TIG welding is narrow, welding can be performed only separately for the welding of the welding lines 5 and 5 '. Therefore, the welding lines 5 and 5 'cannot be welded at the same time with the standing plate 2 interposed therebetween, resulting in a decrease in welding work. An object of the present invention is to provide a new fillet welding method which solves the above-mentioned disadvantages and reduces welding distortion. In order to achieve the above object, a method of reducing welding distortion according to the present invention is to provide a T-shaped joint for forming a T-shaped structure by combining a flat plate and a standing plate into a T-shape. In the fillet welding of the part, the T-shaped structure is moved to
The back surface side of the fillet weld in the flat plate of the serial T-type structure prior to the fillet weld is characterized in that heat is generated by <br/> RF heating using a high frequency induction coil. In the welding distortion reducing method of the present invention, prior to fillet welding of a T-shaped joint of a T-shaped structure, first, a high-frequency induction coil is used to remove the back side of the fillet weld of a flat plate material. Induction heating generates heat. As a result, the heated portion of the flat plate is cooled as it moves away from the high-frequency induction coil, and is deformed into a "H" shape toward the high-frequency induction coil. After that, the surface side of the flat plate that has moved is subjected to fillet welding by a consumable electrode welding torch, and the front side of the flat plate is heated by welding heat input, so that the flat plate will be deformed into a "reverse" shape. As a result, the deformation due to the high-frequency induction coil and the deformation due to the heat input from the welding cancel each other out, so that at the end of welding, the flat plate material becomes a flat panel and welding with little welding distortion can be performed. An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are configuration diagrams of one embodiment of the present invention, wherein FIG. 1A is a side view and FIG. 1B is a front view. In the figure, 1 is a flat plate, 2 is an upright plate,
This is combined with a T-shape and welded to form a T-shaped structure. Reference numeral 3 denotes a consumable electrode welding torch for welding one welding line 5 on the flat plate 1 and 3 'denotes a consumable electrode welding torch for welding another welding line 5' on the flat plate 1. . The welding torches 3, 3 'are arranged opposite to the target position with the upright plate 2 interposed therebetween. Reference numeral 6 denotes a weld bead, 7 and 7 'denote lines on the back side of the flat plate member 1, and 8 denotes a moving direction of the T-shaped structure. These are the same as those in FIG. It is. Reference numeral 10 denotes a high-frequency induction coil for generating heat on the back side of the flat plate 1, reference numeral 11 denotes a matching transformer, and reference numeral 12 denotes a high-frequency power supply. Next, the operation of one embodiment of the present invention will be described. The consumable electrode welding torches 3, 3 'and the high-frequency induction coil 10 are fixed, and the T-shaped structure (formed of the flat plate 1 and the upright plate 2) moves. First, prior to welding, the high-frequency induction coil 1
0 is used to generate heat on the back side of the flat plate 1. The high-frequency induction coil 10 is designed in advance so that the lines 7, 7 'on the back side of the flat plate of the welding wires 5, 5' generate maximum heat, and the matching transformer 11 matches the welding power source 12. Set aside. When power is input to the high frequency induction coil 10, the flat plate 1 itself generates heat by induction heating on the back side of the flat plate 1, and the front surface of the back surface of the flat plate 1 is mainly heated by the skin effect. Will be done. Thus, the consumable electrode welding torch 3, 3 '
When the distance between the T-shaped structure and the high-frequency induction coil 10 is properly selected, the portion where the back surface of the flat plate 1 is heated by the movement of the T-shaped structure in the direction of the arrow 8 cools as the distance from the high-frequency induction coil 10 increases. The flat plate material is deformed into the shape of “he” toward the ten side. Thereafter, the surface of the flat plate 1 is to be fillet welded by the consumable electrode welding torches 3, 3 '.
This time, since the surface side of the flat plate 1 is heated by the welding heat input, the flat plate material is going to be deformed into a “reverse” shape, and as a result, the deformation due to the high frequency induction coil 10 and the deformation due to the welding heat input are offset. Thus, at the end of welding, the flat plate becomes a flat panel and welding with little welding distortion can be performed. Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical concept of the present invention. Belongs to the technical scope of As described above, according to the present invention, the following effects can be obtained. (1) The rear surface of the flat plate is directly heated by using the high frequency induction coil, so that no damage is caused to the rear surface of the flat plate. Therefore, post-treatment such as rework after welding is not required, and a welded joint of a T-type welded structure with low welding distortion at low cost can be manufactured. (2) Since the back surface of the flat plate is directly heated by using the high frequency induction coil, the lines 7, 7 'can be heated simultaneously. Therefore, the welding can simultaneously weld the welding lines 3 and 3 'sandwiching the standing plate. Therefore, the working efficiency is twice as high as that of the conventional method, and highly efficient welding with little welding distortion can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a configuration of a first embodiment of the present invention, (a) is a side view, and (b) is a front view. FIGS. 2A and 2B show a configuration of a conventional method, in which FIG.
Is a front view. [Description of Signs] 1 Flat plate material 2 Standing plate material 3, 3 'Consumable electrode welding torch 5, 5' Welding line 6 Welding bead 7, 7 'Back side line of flat plate material 8 T-shaped structure moving direction 10 High frequency induction coil 11 matching transformer 12 high frequency power supply

Continuation of the front page (56) References JP-A-4-162978 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 31/00

Claims (1)

(57) [Claims] [Claim 1] Combining a flat plate and an upright plate into a T-shape,
In the fillet welding of the T-shaped joint when forming the T-shaped structure, the T-shaped structure is moved to move the T-shaped structure.
A method for reducing welding distortion, wherein the back side of the fillet weld of the flat plate is heated by high-frequency heating using a high- frequency induction coil prior to the fillet welding.