JPH06315778A - Automatic welding method - Google Patents

Abstract

PURPOSE:To reduce reinforcement of weld more than necessity and to reduce the welding time and the grinding working time after welding by detecting slag bath electric potential of electroslag welding in the rail heads, detecting the molten metal height by the detected electric potential and stopping welding automatically. CONSTITUTION:The submerged arc welding method and the electroslag welding method or the gas shielded welding method, the submerged arc welding method and the electroslag welding method are used in combination as the automatic welding method of rails 1 and 2. At that time, an electrode 20 detects the slag bath electric potential and tungsten, etc., for instance, are used for this. The electrode 20 is insulated and set up on backing 7 or 8 via an electrode holder 21 and adjusted to the height to be inserted into slag bath at the position where welding is proceeded to attain the rail heads and molten metal exceeds the rail vertexs. Accordingly, when the slag bath electric potential becomes higher than the reference voltage, welding is stopped, hence the reinforcement of weld more than necessity can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rail automatic welding method.

[0002]

2. Description of the Related Art As field welding methods for rails, various automatic welding methods have been studied in place of the enclosed arc welding method and thermite welding method, and a technique disclosed in Japanese Patent Publication No. 4-57435 has also been proposed. This technology is an automatic rail welding method that uses both the latent arc welding method and the electroslag welding method. In the welding at the bottom of the rail, the first layer is backside welded by the latent arc welding method and the welding is interrupted. Without performing the bottom welding of the second and subsequent layers and the welding of the rail abdomen to the head by the electroslag welding method, the frame body placed on the rail bottom top surface and the top surface of the frame body are welded during the series of welding described above. This is an automatic welding method for rails that uses a placed metal to prevent slag and molten metal from flowing out and uses a welding power source with a constant voltage characteristic, a small diameter welding wire, and a molten flux.

[0003]

By the way, in the above-mentioned prior art, the slag and the extra portion surrounded by the metal for preventing the outflow of the molten metal are treated by a grinder or other method along the rail shape after welding is completed. Used and deleted. On the other hand, the extra height of the rail top is currently determined by the rising height of the torch. There is a problem that the extra height is not constant depending on the amount of slag bath and is in the range of 10 mm to 25 mm. . Further, there is a problem that the total construction time in the above-mentioned automatic welding method including the above-mentioned grinding work is prolonged. In order to shorten the total construction time, it is necessary not only to shorten the welding time but also to shorten the grinding work time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and the gist thereof is a latent arc welding method and an electroslag welding method, or a gas shield welding method and a latent arc welding method. In the automatic rail welding method that uses both the welding method and the electroslag welding method, a means for detecting the slag bath potential of the electroslag welding at the rail head is provided, and the molten metal height is detected by the detection potential. , An automatic welding method characterized by automatically stopping welding.

[0005]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the method of the present invention,
FIG. 2 is a diagram showing an example of a block diagram for detecting the slag bath potential. In FIG. 1, 1 and 2
Is a rail which is a member to be welded, and its end faces are installed in a butted state with a suitable groove interval. Reference numeral 3 denotes a backing material applied to the back surface of the bottom of the rail, which is used together with the copper plate 4 for forming the back bead. Frames 5 and 6 (not shown in the figure) are placed on the upper surface of the rail bottom, and are used as a pair before and after the rail, and are placed so as to surround the groove at the bottom of the rail. It is used to prevent the outflow of slag and molten metal. 7 and 8 are rail abdomen and head welding metal fittings, which are placed on the upper surfaces of the frame bodies 5 and 6,
It is installed slidably in the directions of arrows 9 and 10 by any driving means (not shown) such as a motor or a hydraulic drive mechanism as the welding progresses. 11 is a welding wire, 12
Is a torch for guiding the wire 11 into the groove and supplying electric power from the welding power source to the wire 11. Torch 1
Reference numeral 2 is held via a holder 17 and a connecting plate 18 on an oscillator 14 having a swing shaft that horizontally swings in the direction of arrow 13 and a carriage 16 that moves up and down in the direction of arrow 15. Reference numeral 19 is a guide rail of the truck 16.

The electrode 20 is for detecting the slag bath potential, and for example, Tengsten or the like is used. The electrode 20 is insulated and installed on the metal plate 7 or 8 via the electrode holder 21. When welding progresses and reaches the rail head, the molten metal exceeds the rail head top and is placed in the slag bath. It is adjusted to the height to be inserted.

In FIG. 2, the slag bath potential detected by the electrode 20 is compared with the voltage set by the reference voltage setting circuit 22 by the comparison circuit 23, and when the slag bath potential becomes higher than the reference voltage, the output signal of the comparison circuit 23. Then, the relay 24 operates. The contacts of the relay 24 are connected to a welding circuit (not shown) to stop welding.

[0008]

EXAMPLES Examples in which rails are automatically welded based on the above-described apparatus of the present invention will be described below. Welding power source: DC constant voltage characteristic power source, welding wire: 1.6 mmφ, solid wire, flux: fusion type flux, head welding current: 380 A, head welding voltage: 36 V, head torch rising speed: 1.5 cm / min , Head torch swing speed: 40 cm / min, Slag bath potential detection reference voltage: 1 V As a result of automatic welding, the extra head area is 5 mm to 10 mm
It was confirmed to be stable in the range.

[0009]

As described above, according to the present invention, excess rails can be reduced more than necessary in automatic rail welding, and the welding time as well as the grinding work time after welding can be shortened, resulting in high efficiency. Can provide a simple rail automatic welding method.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a method of the present invention.

FIG. 2 is a diagram showing an example of a block diagram for detecting a slag bath potential.

[Explanation of symbols]

 1, 2 Rails 3 Backing material 4 Copper plate 5,6 Frame plate 7,8 Die slip 9,10 Die slide direction 11 Welding wire 12 Torch 13 Torch slide direction 14 Oscillator 15 Bogie up / down direction 16 Bogie 17 Holder 18 Connection Plate 19 Guide rail 20 Electrode 21 Electrode holder 22 Reference voltage setting circuit 23 Comparison circuit 24 Relay

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Otoguro 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd. Technology Development Division

Claims (1)

[Claims] 1. A latent arc welding method and an electroslag welding method,
Or, in a rail automatic welding method performed by using the gas shield welding method, the latent arc welding method, and the electroslag welding method together, a means for detecting the slag bath potential of the electroslag welding at the rail head is provided, and the detected potential is used. An automatic welding method characterized by detecting the height of molten metal and automatically stopping welding.