JPS6044199A - Manufacturing method of flux-cored wire for welding - Google Patents

Abstract

PURPOSE:To produce a flux cored wire of which the seam does not gape with good production efficiency by joining straight steel pipes, supplying and filling a pellet-shaped flux into the steel pipe and reducing diametrically the pipe down to a desired diameter. CONSTITUTION:A steel pipe 1 is disposed from a container 3 to a flux filling position A then a pellet 2 is placed from a container 4 onto a pellet table 12. The pellet 2 is forced into the pipe 1 by a pellet pusher 5. Such pipe 1 is transferred by as much as the length of the pipe 1 by moving rollers 11. The pellet 2 is again supplied and filled in the pipe 1 and the pipe is similarly transferred. The flux cored steel pipe is manufactured by repeating such operation many times. Joining of the steel pipes to each other is accomplished by joining the steel pipes to each other in a welding position B. The size of the steel pipe is reduced by roller dies 8 after joining and the pipe is laminated into a coil shape by a coiler 9. A coil body 10 of the flux cored steel pipe is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a flux-cored wire for automatic and semi-automatic welding.

(Prior Art) Generally, a flux-cored wire for welding is a composite of a copper strip formed into a certain cross-sectional shape and filled with powdery flux consisting of a deoxidizing element, a slag-forming agent, etc.

This welding wire is used in a wide range of applications, from mild steel to low-alloy and high-alloy steel welding.

The conventional manufacturing method for flux-cored wire is to form a thin steel plate into a U-shape, fill it uniformly with powder-like welding flux whose composition has been adjusted in a specified manner, form it into a specified cross-sectional shape, and then stretch it. It is used for wire processing. Wires produced in this way have various drawbacks.

In other words, when a flux-cored wire is manufactured or made into a product, the joints tend to open, which hinders wire manufacturing. When welding is performed using this substance, it may increase the diffusible hydrogen in the weld metal or promote oxidation of the metal strip surface on the inner surface of the wire, increasing the total amount of oxygen in the weld metal. let me,
Degrades the mechanical performance of the deposited metal. In addition, for solid wires for welding, copper plating is applied to the wire surface for the purpose of preventing rust on the wire surface and improving conductivity during welding, but this plating is not applied to the wire that is inserted into the welding franks mentioned above. Not applicable to all. The reason for this is that the copper plating process is a wet method in which the object to be plated (wire) is immersed in a plating bath and plating is applied, which causes the inconvenience that the plating solution infiltrates into the wire through the seams.

On the other hand, flux-cored wires manufactured by completely filling flux into steel pipes such as welded pipes or seamless pipes in which the joints of the flux-cored wires are welded are manufactured using the above method, that is, by bending the steel strip. Compared to flux-cored wire manufactured by filling the inside with flux, the internal flux is protected from the outside air by a steel pipe with a completely closed surface, so even when filled with hygroscopic slack. The advantages of the above method include that it is easy to store for long periods of time without special considerations, and that surface treatments such as copper plating can be applied to the outer steel pipe to improve wire feedability and power supply during welding work. It eliminates the drawbacks and has excellent performance characteristics.

As a conventionally known method for filling a steel pipe with welding flux, there is a method disclosed in Japanese Patent Publication No. 45-30937. In this method, a bobbin with a fully wound steel pipe is fixedly placed on a table with the axis of the bobbin vertical, and after connecting the entire end of the steel pipe to a flux hopper, a vibrating table is vibrated to remove the C bobbin, that is, the steel pipe. Vibration is used to supply slack from the flux hopper into the steel pipe.

However, in this conventional method, the flux grains are filled into the steel pipe by bouncing and moving within the steel pipe due to the vibration of the steel pipe, so it takes a long time to fill only a predetermined amount of flux. However, it has the disadvantage of extremely poor productivity.

In addition, since this method fills the steel pipe with flux, the flux filling rate is adjusted by adjusting the cross-sectional dimensions of the steel pipe, that is, (steel pipe outer skin thickness)/(steel pipe diameter), so that the desired filling rate can be achieved. It is inconvenient and not a good idea to manufacture various types of steel pipes to suit the needs. Furthermore, it is necessary to wind the steel pipe around the bobbin in order to fill it with flux, which requires an extra step of winding the steel pipe, which is another drawback.

(Object of the Invention) The present invention has been made in order to solve the problems of the prior art described above, and provides a welding flux that does not open the seams in the longitudinal direction of the wires and can therefore be applied to all wires with various surface treatments. One of the objects of the present invention is to provide a method for manufacturing a welding flux-cored wire, and furthermore, to provide a method for manufacturing a welding flux-cored wire with good production efficiency, which enables supply and filling of welding flux into a steel pipe in a short time. An important purpose is to

(Structure of the Invention) The gist of the present invention is to achieve this object by repeating the operation of joining straight steel pipes of fixed length and the operation of supplying and filling pelleted flux into the steel nodules. The purpose is to make a slack-filled steel tube and reduce the total diameter of the flux-filled steel tube to a desired diameter.

In the present invention, the straight steel pipe to be subjected to flux filling is either a welded pipe such as an electric resistance welded pipe in which a copper strip is formed into a cylindrical shape and welded with a dowel, or a seamless pipe that does not have a joint by welding. Use all of them and choose according to the situation. The length of the pipe is, for example, 5 to 2 (1 m).

Furthermore, in the present invention, pelleted slack refers to the following items (■) or (■).

■ After dry mixing the flux raw materials in a predetermined ratio, add a binder (for example, water glass), wet mix for an appropriate time using a fret mill, etc., and extrude through the nozzle opening using a press to form pellets. Obtain a shaped flux lump. The shape of this pellet-like flux mass is preferably cylindrical to match the cross-sectional shape of the pipe, and the diameter of the cylinder is within a range of about 0.5 to 0.9 times the inner diameter of the pipe, so that the desired filling can be achieved in advance. It is determined based on the rate IC. Further, the length of the cylinder is suitably within a range of 2 to 5 times its diameter, considering the strength of the pellet itself and the insertion method. The strength of the pellets needs to be at least strong enough not to collapse during the process of feeding the pellets into the steel pipe, and weak enough to not easily collapse during the subsequent rolling process. The strength of such pellets is adjusted by the proportion of binder and degree of dryness.

■ After dry mixing the flux raw materials in a predetermined ratio, they are packed into bags to obtain pelleted flux. In this case, all materials for the bag should be selected that do not adversely affect the quality of the welding flux shear wire.

The method for inserting the pellet-like flux into the steel pipe is as follows: (1) Forcibly inserting the pellet-like flux into the steel pipe using a pushing device (first method)
(method in figure). (2) There is a method of inclining the steel pipe to an angle of repose greater than the angle of repose of the pellet-shaped flux and sliding the pellet-shaped flux into the steel pipe.

Supplying and filling the steel pipe with pellet-shaped flux in this manner has the advantage that a wide range of filling ratio designs can be achieved by adjusting the cross-sectional dimensions of the pellet-shaped flux.

The contents of the present invention will be explained in detail below based on specific examples.

FIG. 1 is a sectional view showing a specific example of the process of filling a hollow steel pipe with pellet-shaped flux (hereinafter referred to as pellets). A large number of hollow steel pipes 1 and pellets 2 before being filled with flux are each stored in a storage container 3.4, and are on standby so that they can be sequentially supplied to a flux filling position A immediately below. The steel pipe 1 is placed from the storage container 3 to the flux filling position A, and then the pellets 2 are placed one after another from the storage container 4 onto the pellet stand 12 at the filling position A. 2) Push it into the steel pipe until it is almost full.

A plug made of steel, vinyl, etc. is placed at the tip of the first steel pipe to prevent the supplied pellets from leaking from the steel pipe. When the first steel pipe is filled with pellets 1, this steel pipe is transferred by the length of the steel pipe by moving rollers 11 in order to place a new hollow steel pipe from the storage container 3 at the filling position A +/c. . Then, the pellets h'l are again supplied and filled into the steel pipe, and when the steel pipe is almost full of pellets, the pellets are transferred to the IC in the same manner as above. Repeat this operation many times to make a complete flux-filled steel vig. In the illustrated example, steel pipes filled with pellets are joined together at welding position B, but steel pipes filled with pellets and hollow steel pipes may be joined together. At this time, there are various welding methods for joining the same steel pipes, such as butt resistance welding, T-work G welding, etc., but TIG welding does not cause the back surface of the weld to show much on the inner surface of the pipe.
Preferably, this is done by welding. In the figure, 6 is a TIG welding electrode, and 7 is an outer surface deburring jig.

After filling the steel pipe with flux and joining the same steel pipes, the dimensions of the υ steel pipe are reduced using the roller die 8, the air inside the pipe is removed, and the flux is filled into all 31 parts of the pipe, and at the same time, the size of the pipe is reduced to a certain extent. Pack tightly. Subsequently, the steel pipes are coiled and stacked using a coiler 9 (indicated by dotted lines) to obtain a coil body 10 of flux-filled steel pipes to be used in the following process. Furthermore, the transfer roller 1
1 (the roller 11' is free), the roller die 8 and the coiler 9 are driven in conjunction with each other.

The flux-filled steel pipe thus obtained is then
The diameter is reduced to a desired diameter using a drawing die or roll rolling. During this process, annealing, plating, etc. are performed as necessary to obtain a flux-cored wire for welding as a product.

In the plating process, copper plating is mainly applied to the steel pipe for the purpose of preventing rust on its surface and improving conductivity during welding, but this point is similar to solid wire for welding.
As mentioned above, it is not possible to perform the plating process with wires having conventional seams. In addition, plating treatment is not limited to copper plating, but also other metals such as Mn, Zn, Ti, ldl, Ni,
It goes without saying that single metal plating of Cr or Sn, Sn/Cu alloy plating, double plating of Ni + Cr, etc. may be applied as long as the properties of the entire weld metal are not impaired.

(Example) Based on the specific example of the present invention shown in FIG. 1, a flux-cored wire for C02 gas arc welding was manufactured under the following conditions.

As a result, VC could be manufactured with good production efficiency, and the welding flux-cored wire thus obtained was of good quality. In other words, when welding was performed using this product wire, both wire feeding performance and welding workability were good.
The amount of diffusible hydrogen in the weld metal was low, and its mechanical properties were extremely good.

(Effects of the Invention) As described above, according to the present invention, it is possible to obtain a high-quality flux-cored wire for welding in which the mating portion in the longitudinal direction of the wire does not open, and the time required to fill the flux into the steel pipe is shortened. The industrial value of the present invention is extremely large because it can improve production efficiency.

[Brief explanation of the drawing]

FIG. 1 is an overall process diagram for explaining the method for producing flux-cored wire according to the present invention. 1'... Steel pipe, 2... Pellet, , 3...
・Pipe storage container, 4...-pellet storage container, 5
・・Pellet pushing device, 6・TIG welding electrode, 7
... Deburring jig 9, 8... Roller die, 9... Coiler, 10... Coil body, 11... Transfer roller,
12... Pellet stand.

Claims (1)

[Claims] By repeating the operation of joining straight steel pipes of fixed length and the operation of supplying and filling the flux-filled tube into the tube, the flux-filled steel tube is connected to the desired diameter of the entire flux-filled pipe. A method for producing a welding flank-filled choir characterized by reducing its diameter.