JPS5921713B2 - Rail welding method using electroslag welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a consumable guided electroslag welding method and apparatus.

This welding is an automatic welding process performed in a vertical or near-vertical position using one-bath technology, and once started, is completed without interruption. This consumable guided welding method uses heat generated by passing an electric current through molten flux, and the conductive flux is a flux that responds to the current passed between the electrode wire and the joint to be welded. It is kept in a heated molten state by the resistance it has.

The consumable electrode wire is directed to the bottom of the joint by a consumable guide tube, which also carries the welding current until the consumable electrode wire passes through the guide tube. The consumable guide tube dissolves just above the surface of the flux pond. The electrode wire is fed into a molten flux pond and melts therein. The cavity formed by the material being applied and the retaining hardware applied to each side thereof contains a molten flux pool and molten weld metal.

The molten flux pool floats on top of the molten weld metal, protecting it from the outside air. The molten electrode wire and molten construction material metal collect in the cavity below the flux pond, form molten weld metal, and solidify to join the pieces to be welded. Since the tip of the metal to be welded is contained in a cavity below the construction material, welding can be started at a constant temperature and also ensure melting of the construction materials to be joined. .

The invention is applicable to all consumable guided welding operations, but is primarily intended for use in welding long railway rails.

The present invention relates to a method for longitudinally welding a rail having a head and a bottom with a lower hardness than the head by electroslag welding using a consumable electrode. According to the invention, (a) one or more capsules containing cold gold material and closed to prevent loss of said alloy material are attached to the consumable electrode guide tube, and (b) between the rails to be welded. A guide is placed in the welding area to position the capsule in position on the top of the rail to be welded, and (6) heat from the alloy flux pool forces the alloy material from the capsule into the alloy flux pool between the rails. This welds the rails with a weld metal having a hardness approximately equal to that of the top surface of the rail to be welded.As it is primarily applied to welding railway rails, this application will be described below.

Since the composition of the weld metal is different from that of the rail, it tends to be less hard (softer material) when joining the rails, especially in the head region of the rail.

Therefore, it is desirable that the weld metal joining the head portion of the rail be harder than the rail itself so as to provide resistance to abrasion. In the past, this desired property was either lacking or the process was done in a relatively variable manner, with the operator manually adding additives to the weld metal pool, but with the present invention, this process no longer requires There is no need to rely on the skill of others. A consumable container having a predetermined size and location suitable to hold the desired amount of metal added by welding is provided in the consumable guide, with one or more additional consumable containers being secured to said guide. or formed within. The depletion guide according to the invention can therefore be pre-designed for any special welding, and once the correct guide has been selected,
The additive material held in the consumable container is automatically delivered to the location required for welding. When welding railway rails, the holding fittings routinely allow the molten flux to extend beyond the tip of the rail joint, so that the weld metal melts and flows beyond the head of the rail at the end of the weld. It will stretch slightly.

Both the beginning part and the last part are removed to the desired specifications by flame cleaning. The top surface of the rail head is then polished to provide a continuously smooth surface. The form of the retainer typically consists of four water-cooled copper brackets, each forming a separate portion of the total retainer.

These sections extend from below the base of the rail, around the sides, and beyond the top so as to form a mold for all of the weld metal. The four fittings are held in a tight configuration throughout the welding process by external steel clamping devices. In preparation for welding, both ends of the rail are cut horizontally into squares using a mechanical saw or flame cutting method.

After the initial preparation of both ends of the rail and preparation of the equipment, the welding process begins.

Next, the consumable electrode wire is automatically fed by setting the required wire feeding speed, welding current and voltage.
This method is performed more or less automatically. When necessary during the welding process, the operator can change these settings by adjusting the controls on the device.

Alternatively, the welding process may be determined in advance, and the parameters may be automatically changed using a time adjustment device. The total amount of flux required is predetermined and added at the start of the welding, and then the amount of flux is determined either in the form of a covering attached to the outer surface of the guide tube or by a timing device operating the metering inlet. Added automatically.

Alternatively, the operator may manually add as much as necessary. The invention will now be described in detail with reference to the accompanying drawings, in which examples are shown.

The accompanying drawing is a side view of a consumable guide with multiple tubes according to the invention when used for butt welding of railway rails. The illustrated destruction guide consists of three cold-drawn, jointless or similar mild steel tubes 1, with an outer diameter of, for example, 8 m! ×Inner diameter is 3wm, length is approximately 37cm. The composition of the tube 1 may be of the SlO/10 type (carbon 0.08/0.13, manganese 0.30/0.60). The guide tubes 1 are closely held at their distal ends by the safety plate 2, so that they are held together and aligned in one plane. This allows the tube 1 to operate without jamming between the inner part of the holding fitting and the ends of the rail. The safety plate 2 is riveted or spot welded to the guide tube 1 so that it is held firmly and stably during assembly and welding processes. The safety plate 2 also has the same potential across the three guide tubes 1 and facilitates the passage of the three electrode wires into the guide tubes 1, allowing them to be connected to a specially designed wire feeding device. Send to head.

The central guide tube 1 is straight and the two outer guide tubes 1 are sloped outwards at the bottom in order to adapt the shape of the rail cut and the holding fittings. The distance between the centers of the guide tubes 1 varies depending on the size of the rail to be welded. Since the hardness of the welded metal is particularly lower than that of the top surface of the rail head, several methods are required to increase the hardness of the weld metal to a value similar to that of the rail.

This results in uniform abrasion even though the degree of operation varies. In accordance with the present invention, a method of imparting a specific hardness to the top surface of the rail head is accomplished by melting the hardening agent with a rising molten flux pool.

The flux pond automatically consumes the electrode wire fed into it and, in particular, the erasing guide with hardener capsules 3 installed therein. Since the capsule 3 made of mild steel is installed in this way, when the shape of the guide tube 1 is installed in the correct position between the ends of the rail, the base or lower part of the capsule 3 will be located in the head 4 of the rail. Top 1 of the horizontal plane passing through the top surface
2 to 15 mrn (%/7 to %l'). A hardening agent such as FeMn (iron manganese) is contained in the four capsules 3. The capsule will melt due to reflected heat from the rising molten flux pool, where the molten flux pool is approximately 6 to 8 of capsule 3.
It's 7m below. The capsule 3 continues to melt and weld the hardening agent until the welding is completed. This method provides a uniform hardness value distribution from the top surface down to the last section of approximately 6 to 12 wrm. The four capsules 3 have a respective guide tube 1 on each side of one of the two outer guide tubes 1.
The three guide tubes 1 and the four capsules 3 are all aligned in one plane. The amount of FeMn required to give a particular hardness varies from approximately 10 to 307 depending on the size of the rail, the chemical analysis of the rail material, the thermal diffusivity of the retaining hardware, and the proportion of Mn in the FeMn. Ru.

The capsule 3 is filled with a specific amount of FeMn, sealed to prevent losses and attached in place in the guide tube 1 by means of rivets or spot welds. A consumable part of the type consisting of a guide tube 1 and an attached capsule 3 is used to direct the electrode wire to the welding area and deposit the weld metal at a uniform and controlled rate and at a predetermined time and place. It is integrated into one piece to automatically give the appropriate hardness. The metal capsule 3 can be replaced by another suitable container.

[Brief explanation of the drawing]

The accompanying drawing is a side view of a consumable guide in an embodiment of the present invention. 1... Guide tube, 2... Safety plate, 3... Capsule, 4... Rail head.

Claims (1)

[Claims] 1. A method of longitudinally welding a rail having a head and a bottom having a hardness lower than the head by an electroslag welding method using a consumable electrode, the method comprising: (a) containing an alloy material; (b) placing the guide 1 in the welding area between the rails to be welded, the top surface of the rails being welded; (c) supplying alloy material from the capsule 3 to the alloy flux pond between the rails by means of heat from the alloy flux pond, thereby causing the welding of the rails to be welded; A method of welding rails with weld metal that has a hardness approximately equal to that of the top surface.