JPS63242496A - Manufacture of flux cored wire for welding - Google Patents

Abstract

PURPOSE:To obtain a flux cored wire in small diameter and long size of good quality without any opening seam by executing the cold rolling of an intermediate stock obtd. by hot rolling a base pipe inserting a metal core pipe made by packing a flux. CONSTITUTION:The metal base pipe 2 and metal core pipe 3 are respectively prepd. in advance to insert the core pipe 3 packing a flux 5 into the base pipe 2. A starting stock 1 fixing the tip of the core pipe 3 to the tip of the base pipe 2 is then prepd. And, the base pipe 3 part of the starting stock 1 is hot rolled from the tip part to make an intermediate stock 6 and the intermediate stock 6 is then cold-rolled to obtain the aiming flux cored wire for welding. Said base pipe 2 should be of no opening seam like a seamless pipe, resistance welding pipe, etc., but the core pipe 3 may have an opening seam.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for manufacturing a flux-cored wire for welding, and in particular, a method for manufacturing a flux-cored wire for welding, in particular, a method in which a flux-filled metal sheath is closed in the circumferential direction (no open joints). The present invention relates to a method of manufacturing a flux-cored wire for welding.

(Prior Art) Welding flux-cored wires are widely used in automatic or semi-automatic arc welding. Flux-cored wire has a tubular metal jacket filled with powdery flux made of alloy components, deoxidizers, etc.

One method for producing flux-cored wire is to fill a U-shaped thin metal plate with flux, and then shape the U-shaped metal sheet into a 0-shape. (For example, JP-A No. 5
0-122439). In the flux-cored wire manufactured by this method, the seams between the thin plates remain as voids extending along the longitudinal direction of the wire. For this reason,
There are problems such as moisture and lubricant entering the flux, leakage of flux, and deterioration of wire feedability due to the anisotropy of the outer skin cross section.

As a solution to this problem, there is a flux-cored wire in which the joints are welded.

(For example, see Japanese Unexamined Patent Publication No. 109040/1983).

However, this flux-cored wire has a problem in that the flux deteriorates due to welding heat during welding.

Furthermore, JP-A-61-126994 discloses a method of preparing a starting material by filling holes in a steel ingot in advance with flux, and manufacturing a flux-cored wire by hot rolling and cold rolling this starting material. Disclosed.

Flux-cored wires manufactured in this manner do not have open seams and the manufacturing process does not involve welding, so the problems described above do not occur.

(Problems to be Solved by the Invention) However, in the manufacturing method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 61-1.26994, it is impossible to make uniform holes in the center of the cross section over the entire length of the steel ingot. ■ It is difficult to fill the holes in the steel ingot uniformly over the entire length, causing variations in the flux filling rate at the product stage. ■ Filling the holes in the steel ingot with flux Therefore, the range of adjustment of the filling rate is small, which is disadvantageous when manufacturing flux-cored wires with different filling rates. For these reasons, the conventional method described above was not satisfactory in terms of both production and product quality.

Therefore, the present invention aims to provide a method for producing a flux-cored wire that has no open joints and can produce a long, small-diameter flux-cored wire of good quality.

(Means for solving the problem) The method for manufacturing a flux-cored wire for welding of the present invention includes:
A starting material is prepared by manufacturing a metal main tube and six metal tubes in advance, inserting the six tubes into the mother tube, and fixing the tips of the six tubes to the tip of the mother tube. Then, the main pipe portion of the starting material is hot-rolled from the tip to produce an intermediate material, and then the intermediate material is cold-wire drawn.

The above-mentioned main pipe must be a seamless pipe, an electric resistance welded pipe, etc. without an open seam, but the 6 pipes may have an open seam.

6 tubes are filled with flux in advance. 6 When filling the tube with flux, a method is used that does not cause the flux to deteriorate due to heat. For example, the above-mentioned Japanese Patent Application Laid-Open No. 50-122
The method disclosed in Japanese Patent Publication No. 439 or Japanese Patent Publication No. 60-43239 can be used. 6 pipe is longer than the main pipe, and its outer diameter is smaller than the inner diameter of the main pipe. In other words, although the length of the 6 tubes may be slightly longer or shorter within the range permitted by manufacturing, it is actually the length of the main tube when the inner diameter becomes equal to the outer diameter of the 6 tubes after the main tube is rolled. is taken to be equal to The outer diameter of the main tube is about 25 to 120 mm, and the outer diameter of the six tubes is about 3.0 to 30 rntn.

To fix the tips of the six tubes to the tips of the main tube, welding or fixing fittings such as screws are used.

For hot rolling when making an intermediate material from a starting material, hot rolling using a normal stretch reducer or the like is used. For cold wire drawing of the intermediate material, cold wire drawing using ordinary rollers or dies is used.

A plurality of six tubes may be inserted into the main tube. In this case, in relation to the inner diameter of the main tube, the outer diameter of the six tubes must be the diameter of the circumcircle of a bundle of six tubes.

When a plurality of six tubes are inserted, the material of the outer skin of the six tubes, the cross-sectional shape of the six tubes, and the components of the flux filled into the heart tube may be different from each other.

(Function) The diameter of the main pipe is reduced by hot rolling of the starting material, but the outer diameter of the 6th pipe is smaller than the inner diameter of the main pipe, that is, the inner peripheral surface of the main pipe and the outer peripheral surface of the 6th pipe are Since there is a gap between them, only the main tube is rolled at first. The diameter of the main pipe is reduced and the main pipe is elongated by rolling, but since the 6th pipe is longer than the 6th pipe, when the inner peripheral surface of the main pipe and the outer peripheral surface of the 6th pipe are almost in contact with each other, The lengths of both tubes are approximately equal. After that, the main pipe and the six pipes are rolled together to form an intermediate material. In other words, the intermediate material is a composite pipe consisting of a main pipe and six pipes.

By cold drawing the intermediate material, the composite tube consisting of the main tube and six tubes is reduced in diameter and finished to its final size. As mentioned above, the flux filling process involves filling the main pipe with flux6.
Since it is only necessary to insert the tube with a gap, it is possible to easily and uniformly fill the entire length of the main tube with flux. Furthermore, by changing the cross-sectional dimensions of the six tubes, the flux filling rate can be adjusted over a wide range.

The main tube and the 6 tubes will become the outer sheath of the wire that will be inserted into the completed Franks. As mentioned above, since there is no open seam in the main tube, there is no open seam in the outer sheath of the flux-cored wire.

(Example Work) Fig. 1 shows an example of the present invention, and is a process diagram for manufacturing a flux-cored wire.

As shown in the drawing, a main tube and six tubes are manufactured in advance.

The main tube is an electric resistance welded tube and is manufactured by conventional methods.

That is, an oven pipe is made by forming a steel strip into an O-shape using a forming mill. Next, the edges of the open pipe are heated with a high-frequency current and pressed and joined with a squeeze roll to form a pipe. The pipe is finished into a regular shape with sipes. In this example, the material of the main pipe is mild steel, and the outer diameter is 90 mm, the wall thickness is 3 mm, and the length is 50111 mm.

The 6-tube is also manufactured by conventional methods, forming the strip into an O-shape in a forming mill. During molding, the U-shaped product is filled with flux through its opening. In this example, the material of the six tubes is mild steel, the outer diameter is 24.4+nm, the wall thickness is 3.2 mm, and the length is 171 m. Further, the flux is titania-based, and the filling rate is 12 tons.

FIG. 2 shows equipment for manufacturing intermediate materials from the main pipe and six pipes prepared as described above.

As shown in the drawing, the main tube 2 is placed on the conveying roller 24, and the six tubes 3 are unwound from the payout roll 21 and inserted into the main tube 2. At this time, the six tubes are straightened by the straightening roller 22 and fed into the main tube 2 by the feed roller 23. Next, the tip of the six tubes 3 is fixed to the tip of the main tube 2 by welding to prepare the starting material 1. FIG. 3(a) shows the starting material 1. In the figure, the main pipe 2 and the sixth pipe 3 are drawn concentrically, but in reality the sixth pipe 3 is in contact with the lower inner circumferential surface of the main pipe 2. Reference numeral 5 indicates a flux.

Next, the starting material 1 is continuously heated to 1050° C. in a heating furnace 25, and the main pipe portion is hot-rolled from the tip using a stretch reducer 26. FIG. 3(B) shows the intermediate material 6 during hot rolling at the time when the inner circumferential surface of the mother tube and the outer circumferential surface of the six tubes come into contact. At this time, the rolled main pipe 2
The outer diameter of a is 30rn [11], the inner diameter is 24.4 mm, the wall thickness is 2.8 mm, and the length is 171+n. therefore,
The inner diameter of the main tube 2 and the outer diameter of the six tubes 3 are equal, and the lengths of both tubes are also equal. FIG. 3(c) shows the intermediate material 8 that has been hot rolled. At this time, the outer diameter of the rolled intermediate material 8 is 13.8 mm.

As shown in FIG. 1, the intermediate material is plated after being drawn with a die and annealed. Then, the wire is drawn again using a die to be finished as a flux-cored wire. The finished flux-cored wire has an outer diameter of 1.6 mm and a length of about 53 km.

As mentioned above, since the main pipe is an electric resistance welded pipe, no open joints are formed in the outer sheath of the flux-cored wire.

(Example ■) In the above embodiment, only one six-tube was inserted into the main pipe, but in this example, three six-tubes were inserted as shown in FIG. 4. Flux filling rate into 6 tubes is 13.9
%. The manufacturing method in this case is exactly the same as that in the example, so its explanation will be omitted.

FIG. 4(a) shows the starting material 11. The dimensions of the main pipe 2 and the six pipes 3 are the same as those of the embodiment. however,
The length of 6 pipes 3 is 81 m.

FIG. 4(b) shows the intermediate material 16 during hot rolling at the time when the inner circumferential surface of the main tube and the circumscribed circle of the six bundled three-piece tubes come into contact. The main tube portion 2a of the intermediate member 16 has an outer diameter of 58 mm.
．． It has an inner diameter of 3 mm, an inner diameter of 52.5 m, a wall thickness of 2.9 mm, and a length of 81 m. The intermediate material 16 is subsequently hot rolled. FIG. 4(c) shows the intermediate material 18 that has been hot rolled. At this time, the outer diameter of the rolled intermediate material 18 is 13.8 m+n. Inside the intermediate member 18, there is no gap between the main tube 2b and the heart tube 3a, and the flux 5 is separated by a partition 3b formed by deforming the heart tube 3.

Next, the intermediate material I8 is sequentially drawn, annealed, plated, and re-drawn to be finished as a flux-cored wire. The outer diameter of the flux-cored wire is 1.6 mm and the length is about ti8 km.

In this example, the completed flux-cored wire has a cross-sectional shape whose interior is partitioned into three compartments by a heart tube. During welding, welding current also flows through the partitions of the heart tube, and arcs are generated from these areas as well.

Therefore, the flux at the center of the wire is also sufficiently melted by the heat generated by this arc.

(Effects of the Invention) According to the present invention, it is possible to easily manufacture a high-quality, thin-diameter, long flux-cored wire without open seams. Furthermore, the flux can be filled uniformly over the entire length of the wire, and the filling rate can be adjusted over a wide range.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 is a schematic diagram of a manufacturing process for a flux-cored wire, and FIG. 2 is a schematic diagram of equipment for manufacturing an intermediate material from a main tube and a core tube in the manufacturing process shown in FIG. 3 and 4 are cross-sectional views of the material during the manufacturing process, respectively. 1, lI-... Starting material, 2... Mother tube, 3... Heart tube,
5... Flux, 6.8.16.18... Intermediate material, 25-... Heating furnace, 26... Stretch reducer.

Claims (2)

[Claims] (1) In a method of manufacturing a flux-cored wire for welding by putting flux in advance into a metal tube that does not have an open seam and serving as an outer skin, and then hot-stretching and cold-stretching the metal tube, the metal main tube and A metal core tube that is longer than the mother tube, has an outer diameter smaller than the inner diameter of the mother tube, and is filled with flux is manufactured, and the heart tube is inserted into the mother tube, and the heart tube is inserted into the tip of the mother tube. A flux-cored wire for welding, characterized in that a starting material with a fixed tip is prepared, a main pipe portion of the starting material is hot rolled from the tip to create an intermediate material, and then the intermediate material is cold drawn. manufacturing method. (2) The method for manufacturing a welding flux-cored wire according to claim 1, wherein a plurality of heart tubes are inserted into the main tube.