JPS6345917B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic butt welding method for L-shaped steel.

(Prior Art and Problems) As an automatic butt welding method for L-beam steel, the present inventors have developed a method in Japanese Patent Application Laid-Open No. 179585/1985, in which a vertical joint is electroslag welded without interrupting welding.
We proposed an automatic welding method for electroslag welding or submerged arc welding of downward joints, and also proposed a method for switching from vertical to downward welding in Japanese Patent Application Laid-Open No. 101289/1989.

However, in the switching method described in Japanese Patent Application No. 57-290569, although it is possible to accurately detect the weld metal surface and switch from vertical to downward welding, the probe for detecting the weld metal surface and the support for the probe Since the evacuation device is disposed above the welding section, the height of the entire welding device becomes large. Therefore, the range of application is limited where the space above the welding part is limited, such as butt welding of L-shaped longitudinal members within a double bottom structure in shipbuilding.

(Object of the Invention) The present invention was made in view of the above-mentioned problems, and provides an automatic butt welding method for L-shaped steel that expands the scope of application of the conventional method.

(Structure of the Invention) The present invention starts welding by feeding a welding wire to a welding start part through a welding torch to a groove formed by surrounding an L-shaped steel and this material, and supplies flux into the groove. After electroslag welding a vertical joint while forming a slag bath, the welding torch is moved horizontally without interrupting welding, and a downward joint is electroslag welded or submerged arc welded. In the method, detecting that the tip of the welding torch passes the upper end of the vertical joint,
After the welding torch stops rising, the weld metal accumulates and the wire protrusion length becomes shorter, and the welding current increases accordingly.It is detected that the welding current exceeds the preset current value, and the welding torch is leveled with the welding torch. L characterized by moving and welding a downward joint.
This is an automatic butt welding method for shaped steel.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a diagram for explaining the welding method according to the present invention, in which 1 is a base material, 2 is a welding torch, 3 and 4 are
is a drive roller for raising and lowering the welding torch 2, and 5 and 6 are guide rollers for the welding torch 2. welding torch 2
is covered with an insulating material over almost its entire length, and a metal ring 7 is partially attached to the middle part.

Numerals 8 and 9 are sliding metals that slide on the welding torch 2, and are connected to the welding torch 2 by lead wires 10 and 11, respectively.
It is connected to a control device (not shown) that controls the vertical movement and horizontal drive of the machine. 12 is a weld metal, and 13 is a slag bath that is deposited on top of the weld metal 12. 14 is a welding ammeter, and setting guideline 1
5, 16 and a pointer 17 indicating a current value, and has a structure that allows a detection signal to be taken out when the pointer 17 indicating the welding current value exceeds the set pointer 15, 16, respectively.

Welding progresses in the order of A, B, and C in the figure, and after reaching state C, the welding torch moves horizontally to weld the horizontal portion of the base metal 1. The indications of the welding ammeter 14 are respectively welding state A,
Corresponds to welding current B, and corresponds to welding state C.

In the above configuration, the method of the present invention will be explained according to the welding order. First, the wire 55 is fed to the welding start part through the welding torch 2, an arc is generated, and then flux is supplied into the groove, and the slag bath 13 is formed, and electroslag welding is started as shown in FIG. 1A. As the welding progresses, the welding torch 2 moves along the arrows 18 of the drive rollers 3 and 4.
Rotation in the direction causes it to be pulled upward. The rotation of the drive rollers 3 and 4 at this time is performed intermittently.

That is, when the weld metal 12 is filled into the groove and the molten metal level rises, the wire protrusion length becomes shorter, and when the pointer 17 of the ammeter exceeds the set pointer 15, the drive rollers 3 and 4 rotate, The wire protrusion length becomes longer, and as a result, when pointer 17 becomes lower than pointer 15, drive rollers 3 and 4 stop rotating.

In this way, the welding torch 2 is raised and vertical welding is performed while keeping the welding current set by the setting guideline 15, in other words, the wire protrusion length, constant.

As vertical welding progresses and reaches the state shown in FIG. The slides 8 and 9 are electrically connected, and a detection signal is sent to the control device (not shown) via the lead wires 10 and 11 to transmit the contact between the metal ring 7 and the slides 8 and 9. In response to the signal, the rotation of the drive rollers 3 and 4 is stopped, and even if the welding current pointer 17 exceeds the set pointer 15, the drive rollers 3 and 4 are controlled to continue in the stopped state.

In state B, welding continues while the welding torch 2 stops rising, and as the metal level rises, the wire protrusion length becomes shorter, the welding current value increases, and the pointer 17 eventually overlaps with the setting pointer 16. become,
The state shown in FIG. 1C is reached. When the current increases further and the pointer 17 exceeds the set pointer 16, the welding torch 2
is moved horizontally, and the horizontal members are welded.

The structure and operation of the present invention have been described above, and specific embodiments of the present invention will be described in more detail.

(Example) FIGS. 2 and 3 are perspective views showing embodiments of the present invention, and both show embodiments of the present invention in a hull bottom longitudinal.

Furthermore, FIGS. 4 and 5 show the arrangement of a contact type limit switch and a non-contact type limit switch for detecting the welding torch position used in the embodiment shown in FIG. It is a figure showing a relationship.

In Fig. 2, 1 and 1' are the bottom longitudinals to be welded, 19 is the end tab, and 20 is the copper material.
Backing material provided on the back side of base materials 1 and 1' (not shown)
It is installed in pairs and surrounding the groove.

The welding torch 2 is held between drive rollers 3, 4 and guide rollers 5, 6, and is provided to move up and down within the groove. It is rotatably supported around a shaft provided at right angles to.

On the other hand, the shaft of a torch elevating drive motor 22 attached to the base 21 is connected to the drive roller 3. Further, the base 21 is held by a vertical adjustment block 24 so as to be vertically movable via a connecting rod 23, and the base 21 can be adjusted vertically by turning a handle 34. Furthermore, the block 24 is
It is held in a frame 28 by a feed screw 26 and a guide rod 27 which are rotated by a horizontal drive motor 25.
is mounted on a clamp 29 and fixed to the base material 1 with a handle 30.

Furthermore, as shown in an enlarged view in FIG.
It is rotatably provided around shafts 32 and 33, and is covered with an insulating material over almost its entire length, except for a portion that slides into contact with the welding torch 2. 10,1
1 is a lead wire connecting the slides 8, 9 and the control device.

Although not shown in FIG. 2, in addition to the above configuration, the welding ammeter and the control device for controlling the motors 22 and 25 shown in FIG. 1 are included.

To describe the operation of the embodiment with the above configuration, the drive roller 3 is rotated by the lift drive motor 22, the welding torch 2 is raised, and vertical welding is performed.
When the slides 8 and 9 come into contact with the metal ring 7, the welding torch 2 stops rising. After that, as the metal level rises, the welding current increases and exceeds the set value.
The horizontal drive motor 25 rotates the feed screw 26 to horizontally move the welding torch 2 to perform downward welding.

In addition, although downward welding is performed by electroslag welding, the selection criteria for whether to perform submerged arc welding is determined by the plate thickness of the downward welding member, and the inventors have conducted various experiments and found that the plate thickness It was found that it is better to use electroslag welding for plates of 19 mm or more, and for base metals with a thickness of less than 19 mm, it is better to apply submerged arc welding. With either welding method, continuous welding was possible from vertical welding, and no defects occurred in the transition from vertical to downward welding.

Next, referring to FIG. 3, an example will be shown in which the method of the present invention is implemented using means different from the welding torch lifting means and horizontal moving means.

In the figure, reference numeral 35 denotes a holder that holds the welding torch 2, and the holder 35 is connected to a handle 38 via a connecting rod 36 to a vertical adjustment block 37.
The block 37 is held so that its vertical position can be adjusted by the operation of . And the support base 42 of the guide rod 41 is connected to the horizontal drive motor 4
3, the trolley 45 runs along the rail 44.
The rail 44 is fixed to a clamp 46, and is detachably attached to the base material 1 by a handle 47.

Furthermore, a position detection limit switch 4 for stopping the welding torch 2 from rising is mounted on the support base 42.
8 is provided. Although not shown, this embodiment also includes a control device for controlling the welding ammeter and motors 39 and 43 shown in FIG. 1.

The operation of this embodiment with the above configuration is the same as that of the above-mentioned embodiment as shown in FIG. The horizontal movement of the torch 2 is performed by running the cart 45 along the rails 44. Further, in the transition from vertical welding to downward welding, when the welding torch 2 rises and the vertical adjustment block 37 operates the limit switch 48, the welding torch 2 stops rising and the welding current further increases. This is done when it is detected that the set current has been exceeded.

Note that instead of the detection mechanism shown in FIG.
Similar effects can be obtained by using the non-contact type limit switch shown in the figure in the embodiment shown in FIG. In FIG. 5, numerals 49 and 50 are proximity switches, which have the function of detecting the metal ring 7 without contact. 51, 52 are lead wires, 5
Reference numerals 2 and 53 are mounting plates for proximity switches 49 and 50.

Next, welding conditions in the above-mentioned embodiment will be shown.

Base material: Mild steel scalene angle steel (L-shaped steel) Vertical member: Plate thickness 12 mm, length 350 mm Downward member: Plate thickness 17 mm, length 100 mm Welding material: Wire: Solid wire (φ1.6 mm) Flux: Fused flux (SiO ₂ −MnO
−CaO−MgO system) The same welding material was used for both vertical and downward welding.

Welding conditions: Vertical (electroslag welding): 380A
-38V, welding speed 8cm/min (average) Downward (submerged arc welding): 450A-40V, welding speed 12
cm/min In order to weld under the above welding conditions, the setting pointer 15 of the ammeter was set to 380A, and the setting pointer 16 was set to 450A, that is, after the welding torch 2 stopped rising,
When the current fluctuates from 380A to 450A and reaches the downward welding current, the horizontal drive motor 25 or 4
3 was activated.

As explained above, according to the method of the present invention,
It goes without saying that butt welding of composite members, especially L-beam steel as shown in the above example, can be performed continuously from vertical to downward, but it is also a simpler method compared to conventional techniques, and it is possible to It has an effect that can be easily applied even inside a large ship's hull.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of another embodiment of the invention, FIG. 3 is an explanatory diagram of still another embodiment of the invention, and FIGS. FIG. 5 is an explanatory diagram of the arrangement of the limit switch and the detection body in the embodiment of FIG. 2. 1, 1': Base material, 2: Welding torch, 3, 4: Drive roller, 5, 6: Guide roller, 7: Metal ring,
8, 9: Slide metal, 10, 11, 51, 52: Lead wire, 12: Weld metal, 13: Slag bath, 14:
Welding ammeter, 15, 16: Setting pointer, 17: Pointer, 18: Roller rotation direction, 19: End tab,
20: This material, 21: Base, 22, 39: Lifting drive motor, 23, 36: Connecting rod, 24, 37: Vertical adjustment block, 25, 43: Horizontal drive motor,
26: Horizontal drive feed screw, 27: Horizontal drive guide rod, 28: Frame, 29, 46: Clamp, 30,
47: Clamp handle, 31: Insulating plate, 32,
33: Axis, 34, 38: Vertical adjustment handle, 3
5: Holder, 40: Lifting drive feed screw, 41:
Guide rod for lifting/lowering drive, 42: Support stand, 44: Rail, 45: Dolly, 48: Limit switch, 4
9, 50: Proximity switch, 53, 54: Mounting plate, 55: Wire.

Claims (1)

[Claims] 1 Welding is started by feeding the welding wire to the welding start part through the welding torch into the groove originally formed surrounding the L-shaped steel, and while supplying flux into the groove to form a slag bath. In an automatic butt welding method for L-shaped steel, in which after electroslag welding a vertical joint, the welding torch is moved horizontally without interrupting welding, and a downward joint is electroslag welded or latent arc welded, the tip of the welding torch is After detecting that it has passed the upper end of the vertical joint and stopping the welding torch from rising, weld metal accumulates and the wire protrusion length becomes shorter, and the welding current increases accordingly, reaching the preset current. Detects that the value has been exceeded and moves the welding torch horizontally,
An automatic butt welding method for L-shaped steel, characterized by welding a downward joint.