JPS62151296A - Production of flux cored wire - Google Patents

Abstract

PURPOSE:To improve the packing work of a flux cored wire by packing a granular material into the hollow part of a steel pipe by maintaining the inner pressure of the steel pipe hollow part <= the specified pressure. CONSTITUTION:The hollow part of a hollow blank material 10 is subjected to a pressure reduction <=0.8 atomosphere via a pressure reducing chamber 3 by a vacuum pump. The flux 2 inside a hopper 15 is packed uniformly to the hollow part under the pressure reduction by opening the vacuum valve 7. There is a sheet cover 6 at the upper part of the hopper 5 which prevents the reduction of pressure decrease and performs the packing of the flux by the external pressure. By this composition the flux packing work can be performed at high packing speed which is not realized in the past and the flux packing in uniform composition is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a 7-lux cored wire for welding. In particular, the present invention relates to a method of filling a hollow portion with flux prior to hot rolling or cold wire drawing.

[Conventional technology]

Conventionally, in manufacturing flux-cored wires for welding, a typical example of a method for filling the inside of a tube with flux is the method disclosed in Japanese Patent Publication No. 30973/1983. The method is the third
As shown in the figure, a tube 1 wound into a coiled shape is filled with flux 2 while being vibrated.

This method has the disadvantage that the filling speed is extremely slow and that the flux composition tends to be uneven.In order to improve this problem, Japanese Patent Application Laid-Open No. 58-1
No. 54496 and Japanese Unexamined Patent Publication No. 59-35899 have been proposed. The former is characterized by applying rotational vibration to the coiled tube by inclining it, but is merely an extension of the technology of the aforementioned Japanese Patent Publication No. 45-30973. Flux is introduced by tilting the tube at an angle of 30 to 70 degrees, and for straight tubes by standing it up at an angle of 20 to 65 degrees, but the problem of uneven filling of powder and granules still remains, and the tube material There are various problems in maintaining the pipe at a high angle of inclination, such as restrictions on long pipes and the heavy and long equipment.

[Problem that the invention seeks to solve]

The known technique described in the above-mentioned publication, ie, the method of filling by utilizing the fluidity of flux or by allowing it to fall freely in the atmosphere.

The following problems still remain.

(1) Flux filling speed is low and filling work efficiency is poor.

(2) The powder and granules cannot be uniformly loaded, resulting in uneven flux composition.

The present invention aims to improve the drawbacks of the flux-cored wire manufacturing method and provide a highly efficient and uniform filling method.

[Means for solving problems]

The present invention is characterized in that, when filling the hollow portion of a steel pipe of a hollow material for flux-cored wire with powder, the internal pressure of the hollow portion is maintained at 0.8 atmospheres or less.

[Effect]

The present invention performs flux filling under reduced pressure, and (a) filling work can be performed most efficiently by using atmospheric pressure as external pressure; (b) flux is filled in a reduced pressure atmosphere. The principle is that by filling, air resistance is reduced equally regardless of whether the flux is powdered or granular, so that uniform flux loading is achieved.

FIG. 2 shows an example of a flux filling method under reduced pressure r.

A vacuum pump (not shown) is connected to a reduced pressure chamber 3, which is coupled to the hollow material 10 via a coupling connector 4. Flux surface seal 6
The flux charging hopper 5 is connected to the other end of the flux filling hollow member 10 via a coupling connector 4.

One end of the hollow member 10 to be filled with flux is closed in advance by drawing, fitting, welding, or the like to an extent that leakage of flux from the end surface is small.

Thereafter, the hollow member is communicated with the reduced pressure chamber 3, and the pressure in the hollow part is reduced.

The exhaust for reducing the pressure may be from both ends of the hollow member as shown in FIG. 2, or from only one side on the flux input side.

After reducing the pressure inside the hollow, the vacuum pulse 7 at the lower end of the flux hopper is opened and the flux is filled. At this time, since the powder and granular 7lux moves in the atmosphere under reduced pressure, there is less tendency for the powder and granules to separate due to air resistance, which is the case with conventional methods, and the flux composition is uniform. This makes it possible to load more easily.

In addition, the top surface of the flux hopper device is always exposed to external pressure due to atmospheric pressure by covering the surface of the flux with a flux cover sheet 6, such as a type of vinyl, to prevent a drop in the decompression state due to air entrainment during flux filling. However, the flux can be force-filled, and the flux loading efficiency is significantly improved.

The decompression operation and the flux filling may be performed simultaneously or independently. In either case, the larger the volume of the decompression chamber 3, the more efficient it will be.

FIG. 1 and Table 1 are examples showing the effect of reduced pressure on the efficiency of flux filling operations. A seamless steel pipe with an inner diameter of 7 mmφ is wound into a coil, and while it is kept in a horizontal position (no vibration or tilting is applied as in conventional methods), the inside of the pipe is filled with flux while being reduced to various pressures. This is what I did. The particle size of flux is approximately 0.0
It is 2-0.3 mm. The amount of flux input per unit time was used as a parameter indicating the efficiency of the filling operation, and this was expressed as the filling speed kg/hr.

Referring to the above-mentioned publication, which is disclosed as a prior art, it is about 50 kg/3 hr with the same pipe diameter, and this value is 0.8 in the filling method under reduced pressure of the present invention.
Corresponds to the internal pressure of atmospheric pressure. Therefore, in the present invention, the lower limit of the reduced pressure condition is set to 0.8 atm. It is clear from the data in FIG. 1 that increasing the degree of vacuum naturally contributes to improving the filling operation, and therefore there is no particular upper limit to the reduced pressure conditions.

Table 1 △ Same as or slightly better than the conventional method 0 Better than the conventional method It is a natural consequence that efficiency is further improved, and the present invention does not eliminate this.

〔Effect of the invention〕

As described above, the present invention (i) allows the pressure difference from atmospheric pressure to be used as external pressure during flux filling by reducing the pressure inside the hollow space, so that flux filling work can be performed at an unprecedentedly high filling speed. .

(ii) Due to the reduced pressure atmosphere inside the hollow tube, there is little separation of powdered and granular 7-lux, and flux filling with a uniform composition can be achieved.

(iii) Flux filling can be performed while the hollow material is lying on its side, and there is no need to construct large-scale equipment such as tilt holding equipment or vibration applying equipment.

[Brief explanation of drawings]

Fig. 1 is a graph showing the effect of hollow internal pressure reduction on flux filling efficiency, Fig. 2 is a system diagram showing the equipment configuration for implementing the present invention, and Fig. 3 is an explanatory diagram of the conventional vibratory filling method. . ■ Coiled steel pipe to be filled 2 Filling flux 3 Decompression chamber 4 Coupling connector 5 Flux hopper 6 Flux cover sheet 7 Valve 10・Hollow material for filling

Claims (1)

[Claims] 1. Hollow for flux-cored wire, characterized in that when filling the hollow part of the steel pipe of the hollow material for flux-cored wire with powder, the internal pressure of the hollow part is maintained at 0.8 atmospheres or less and the powder is filled. How to fill powder into material.