JPS5841691A - Flux-cored wire for welding and its production - Google Patents

Abstract

PURPOSE:To obtain a good welded state in a flux-cored wire for welding for which a long-sized pipe welded and joined at a seam is used by regulating the shapes of weld beads formed on the inside surface of the pipe. CONSTITUTION:A covered pipe 2 has weld beads 4 formed in the production stage of pipe by welding of an electric welded pipe in the longitudinal direction on the inside surface thereof. If a flux-cored wire for welding having the section wherein the ratio h/t between the height (h) of the beads 4 on the inside surface of the pipe and the inside thickness (t) of the pipe is <=0.5 and that the ratio a/A between the sectional area (a) of the beads on the inside surface of the pipe and the sectional area of the pipe inside is <=0.04 is produced, a good welded state is provided. Said wire is produced by packing a flux in the electric welded pipe having a section where the relation h'/t'=0.04-0.4 between the height h' of the beads on the inside surface of the pipe and the wall thickness t' of the pipe and the relation a'/A'=0.001-0.03 between the sectional area a' of the beads on the inside surface of the pipe and the sectional area A' of the pipe inside. Thus, the wire is drawn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides automatic and semi-white RF
The present invention relates to a wire with a wire for connecting to a TJ+W+ river and a method for manufacturing the same.

Currently, flux-cored wire for welding has a composite structure in which a metal band is 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 for a wide range of welding purposes before welding steel, low alloy steel, and high alloy steel.

Conventional 41L method for making flux-cored wire Bonito 1. After forming a strip of steel plate into a tJ shape, uniformly fill the powder and granular welding wire with a predetermined hk adjustment.
- The wire is drawn into a wire formed into a predetermined cross-sectional shape.

Wires produced by this conventional method have drawbacks. In other words, when manufacturing a flux-cored wire or when it is made into a finished product, the joints 1 and 1 are likely to open, which poses a problem in wire manufacture, and also causes the following undesirable problems when welding using this wire. was occurring.

(1) 11ill of moisture on the outer surface of the wire from the opening!
Organic substances such as lubricants used during the manufacturing process' PV enters the flux and when welding is performed using it, it may increase the diffusible hydrogen in the weld metal and cause damage to the inner surface of the wire and the surface of the metal strip. This accelerates the oxidation of the weld metal and increases the amount of oxygen in the weld metal, resulting in a total deterioration of the mechanical performance of the weld metal.

(2) Opening: Reflux leaks to the outside of the wire, causing wear on the feed roller that is part of the wire feed device rt of the welding machine.

(3) Although the wire cross-sectional shape 1 is originally ideal as a tributary circle, the cross-sectional shape due to the opening [] has an adverse effect on the deformed I7 wire feedability.

In addition, in solid wire 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. F11 cannot be applied. The reason for this is that the plating process is a wet method in which the object to be plated (flux-filled wire) is immersed in a plating bath to perform plating, which causes the inconvenience that the plating liquid enters the inside of the wire through the seam. One way to solve this problem is to weld the joints of the cladding tubes before or in parallel with flux filling.
It is being proposed. For example, in the technique described in the Japanese Patent Application Publication No. 45-30937-R, the parts were joined by welding.

1. Coil the tokushaku tube to an appropriate diameter and open the tube.
7 lux from part k4 using vibration into the pipe II
i- <fulfillment>.

Purpose of the present invention V1 By regulating the shape of the inner weld bead formed on the inner surface of the tube in a welding flux shear wire manufactured using long tubes that have been welded together as described above. Th
It is to provide e.

The gist of the present invention is a flux-cored wire for welding in which the hI pipe is a welded joint pipe, in which h71 = 0.5 between the pipe inner bead height 11 and the pipe wall thickness 1.
and the relationship between the tube inner bead cross-sectional area 2I and the inner tube cross-sectional area A [a/h≦004! The flux-cored wire for welding having the characteristic h, the manufacturing method θ of the pot, and the distance between the tube inner bead height 11 and the tube wall thickness t', h'/,..., n, o 4~ 04, and the tube inner bead cross-sectional area a' and the tube inner cross-sectional area A'
A method for manufacturing a flux-cored wire for welding, characterized by filling an electric resistance welded tube with a cross section having a relationship of "/1>t" of 0.001 to 0.03 with flux and drawing the wire. .

The contents of the present invention will be explained in detail below. FIG. 1(a) is a cross-sectional view of a welding flux-cored wire 1 whose cladding tube 2 is a welded joint tube, and the cladding tube 2 is densely filled with welding flux 3.

The cladding tube 2 has a weld bead 4 formed in the longitudinal direction of its inner surface during tube manufacturing by electric resistance welding tube welding. The weld bead 4H
Although it is desirable that the product does not have it, it is necessary during manufacturing, and even if an attempt is made to remove it, it will be difficult, so it is inevitably formed in the product state as shown in Figure 1 1). . Then, the ratio +1/l of the height 11 of this pipe inner weld bead 4 and the wall thickness τ1″ is 0.
5 or less, and the cross-sectional area of the tube inner bead (Fig. 1 (b)
) The inventors of the present invention have confirmed through experiments that a welding flux-cored wire having a cross section in which the ratio d/a of a to the pipe cross-sectional area A is 004 or less exhibits the best welding condition. That is, the ratio h7. For wires with a cross-section of more than 0.5 and a lump of more than 0.04', the cross-sectional shape of the wire will be asymmetrical due to the bead on the inner surface of the tube, resulting in a biased and asymmetric current density even during welding. Therefore, the arc is not stable and full welding becomes impossible. In addition, the wire becomes stiff due to the plastic bending caused by the wire, and when the wire is fed, it becomes hard and does not lead to a good welding condition.

Next, a specific example of the method for manufacturing a flux-cored wire of the present invention is shown in FIG.
It is a diagram showing the state of pipe production in b), with dimensions 37.5X21.
+1l11 hoop 4'5 is formed into a cylindrical shape by bending it in an outward direction at right angles to the hand direction, so that both side edges of the hoop face each other, and the opposite side edges are squeeze rolls by, for example, high-frequency induction welding. Weld by applying pressure according to step 7. At this time, both edges of the cylindrical hoop are heated and melted by the high-frequency induced current, and the squeeze roll 7
As shown in FIG. 4(a), as shown in FIG. .8 is formed.

The weld bead 7 on the outer surface can be removed relatively easily by cutting with a cutting tool, but it is difficult to remove the weld bead 8 on the inner surface V
[It was extremely difficult, and the inner bead 8 shown in Fig. 4(b) was left in place, and the tube was sent to the following process as an electric resistance welded tube with an outer diameter of 12.7 m and a wall thickness of 2 fIIm. In particular, electric resistance welded pipe 1c+' during pipe manufacturing in the manufacture of flux-cored wire for welding,
//'It is a thin tube with a diameter of 16 mm or more, and it is almost impossible to remove the inner bead with the current technology.

After the above-mentioned 3111 tube (a), it is annealed (b), and then the tube is drawn and wound in an aligned manner (e→), and the force is applied to the 3111 tube (a), which is wound in an aligned manner on a slightly reduced drum.

With this 1" section, the outer diameter of the V1 electroponic tube is 12.7 to 1.
It is reduced to 0.7 mm and moved on to the next flux filling).

At this time, the resistance welded tube (Fig. 2 ())
Assuming that (the ratio 1 between the HfH inner bead height 11' and the tube wall thickness t' is 0.04 to 0 mm, and the ratio between the tube inner bead cross-sectional area a' and the tube inner cross-sectional area A' is 1) I is 0.001
~0.03, and the welding and pressurizing conditions h: are determined in the pipe making process (a) so as to satisfy this condition.

This condition is not only necessary to obtain the flux-cored wire for welding of the present invention, but also a condition for unfavorable treatment in the subsequent steps (7 lux filling step), that is, the above ratio 11. /, , is less than 0.04, a'
If /AI is less than 0.001, the mechanical strength of the di-joint part of the ERW pipe will be poor, and the wire drawing process after filling with flux (7) will be poor.
In (4→, (g), (IJ)), the welded part is likely to break and the internal flux may leak out, which is a problem. To explain further, for ERW pipe welding: I, a good weld joint r1, welding conditions, i.e. heating power, frequency, welding speed, pressurizing force, etc., 4- material of the pipe to be welded, 1 optimum value according to dimensions. As a guide for determining whether the weld 1 mating part is good or bad, the inventors of the present application focused on the weld bead shape of the V1 welder, and determined that the weld bead was determined as follows. It was confirmed that if the dimensions were above, the welded joint would be good without any fusion failure. In other words, if the weld bead formed on the inner surface of the ERW tube before filling with flux satisfies the above dimensions, it can be used as a good ERW tube for the following process; The parts are poorly fused, the mechanical strength is poor, and the joints will break in the following steps.

Also, when the ratio I+/11 exceeds 0.4 and ak exceeds 0.03, the inner bead becomes less than 7 lux, making it difficult to achieve a uniform filling rate. , unable to provide products of good quality. The above h' + 1' e a' w A' is shown in Figure 1 (
1)), (C).

It is a symbol equivalent to 1, a, A.

In the flux filling process), the powder flux obtained by measuring the fusix original 4'A in advance in a separate process, performing wet mixing, drying, firing, etc., was wound around a drano using the above-mentioned tube-pulled aligned winding. This is the process of filling ERW tubes with 7 lux.The drum with the tube wound thereon is placed on a vibrating table with the axis of the drum vertical, and the free end of the tube wound on the drum is placed on the drum. ``over the two-part flange'' of the 1. A predetermined amount of flux is filled into the electric resistance welded tube, that is, the cladding tube, by vibration while connected to the flux container.

The flux-filled cladding tube 1 is subsequently drawn to bring its outer diameter closer to the desired final value.

Outer diameter 10.11111 to 5011II1 with wire drawing (A)
After reducing the size to 1, an intermediate annealing was performed to remove stress by annealing (H) to J11, followed by wire drawing (G) to an outer diameter of 5011II
+ to 2. i tnm.

Then, it is sent to the plating process C-chin, where copper plating is applied to the surface of the cladding tube, and then the outer diameter of the cladding tube is reduced from 21 mm to 12 mm f+4 final diameter 1 with one force. The cross-sectional shape of the cladding tube (Fig. 4 (IJ')) satisfies the condition fr- of the present invention mentioned in 17 above. It is loaded into a roll or bale pack to become a flux-cored wire for welding as a product.

In addition, in the above-mentioned plating treatment (copper plating is applied to the broken Φ pipe to prevent rust on its surface and improve conductivity during welding), it is not limited to copper plating, but other Mn, Zn
, Ti, AJ3. Ni, Cr, Sn)q
+Single metal plating, Sn +Cu alloy plating, Ni
-1- Double layering of Cr, etc. may be applied within a range that does not impair the properties of the weld metal. In this respect, the present invention is similar to a solid wire for welding, and as described above, the plating process cannot be performed with a wire having a conventional seam.

Further, the numerical values of the tube outer diameter, wall thickness, etc. in the above 1-1 body example are merely examples, and may be appropriately set to optimal values in accordance with the equipment, hoop material dimensions, and desired product dimensions.

Next, the effects of the present invention will be explained based on examples 1.
Table 1 V [Test ERW pipe before flux filling: (as (
Flats 1 and 2 are examples of the present invention, /163 is a comparative example) Each product is 500 K after being prepared and subjected to a prescribed process.
This table shows the cross-sectional shapes of the test ERW pipes and products, and the welding results obtained by the manufacturing engineer and the product in the case of 9. Several of the cross-sectional areas of the inward bead height in the pipe show average values.

(Both Jl and trial electric resistance welded tube V1 were made of mild steel. [7. The manufacturing process from the electric resistance welded tube to the finished product was in accordance with the manufacturing process flowchart shown in Figure 2. In other words, the wire drawing schedule was In this example, the outer diameter of the ERW pipe is 10.7 m, which is 1? in the figure.
, l (1, Otmm), and the desired outer diameter of the cladding tube is 1.
．． In step 2, an intermediate annealing process and a plating process were performed, followed by wire drawing. In addition, the filling flux is titania-based for all of /161 to /I, and the product's 7 lux fill rate (filling flux weight 16°/wire weight x 100
)II target value was set to 122%.

As shown in the table, the manufacturing results showed that the wire drawing condition was good for both the invention examples A61 and 2, O': and II example 163. In addition, we made a prototype of an ERW tube with a -1 method of the pipe inner bead that did not meet the specified value (7) The strength of the welded joint was insufficient, and breakage was observed during the wire drawing process, resulting in the product not being made into a product. Also, the flux charging state is /16
1.2 All wires were good and had a uniform filling rate, but in /16:(, the size of the 1711 bead in the pipe was larger than the specified value, so there was a noticeable variation in the flux filling rate. Ta.

Table 1 Next, we investigated the welding conditions of the product welding flux-cored wires manufactured as described above and corresponding to 6, /ff; The results showed that the wire of 161 had good arc stability and wire feedability.
The wire No. 2 has somewhat good arc stability and wire feeding performance, and is slightly inferior to the wire I61 in IL performance, but within the allowable range, and the wire feeding motor of No. 63 is unstable and the wire feeding performance is poor. The sex was also bad.

Table 2 Figure 5 shows the welding current and wire feedability to judge the arc stability when welding was carried out using the /161.2.3 wire under the conditions shown in Table 2. 3 is a graph recording fluctuations in armature current of a feed motor. As is clear from this, the present invention (91j/761
The wire V [, welding and armature current are both stable, arc stability and wire feedability are good, and AC3
The wire of /163 was fairly good, and the wire of /163 [welding and armature current constantly fluctuated, arc stability +/1 and wire feedability were poor.

According to the present invention, the size of the bead on the inner surface of the ERW tube before flux filling is regulated within a predetermined range, so that the manufacturing condition is improved, and the 1
1) The flux-cored wire used for melting the product 11. Control 5
This regulation improves welding conditions, especially arc stability, and wire feedability, and is of great value to the industry.

[Brief explanation of the drawing]

Figure 1 shows a cross-sectional view of a flux-cored wire for welding in which the cladding tube is a welded joint pipe, and Figure 2 shows a cross-sectional view of a flux-cored wire for welding according to the present invention. Manufacturing 21: Flowchart of culm, Figure 3 14 Shows the state of pipe formation by ERW pipe welding, and is a perspective view, Figure 4 (a) is a sectional view of the ERW pipe immediately after pipe production, (11) shows the pipe FIG. 5 is a cross-sectional view of the electric resistance welded tube with the outer surface bead removed, and is a graph showing the welding current and the armature current of the wire feed motor during welding of the wires of the present invention and the comparative example. . 1: Flux-cored wire for welding 2: Cladding tube 3: Flux for welding ・1: Weld bead 6 on the inner surface of the tube
: ERW pipe No. 2 Fig. ii'4r (outside [-1'2.7mmψ, I"l/jJ-
2m mφ) Su L 4! . 'Flash alignment η°J left (outer diameter 12.7-10.7mmφ)
7inkzu icJ pseudo L=---1--<\)
■；

Claims (2)

[Claims] (1) Is the cladding pipe welded? t, the relationship between the tube inner bead height h and the tube wall 17t is 11/1≦0.5, and the relationship between the tube inner bead cross-sectional area JI and the inner tube cross-sectional area A. A flux-cored wire for welding, characterized in that it has a cross-section with a relationship of a/A≦0ρ4. (2) Between the pipe inner bead height 11' and the pipe wall thickness t'
71' ” 0.0 /1 to 04, and between the pipe inner bead cross-sectional area a' and the pipe inner cross-sectional area A' -0,
1. A method for manufacturing a flux-cored wire for welding, characterized in that an electric resistance welded tube having a cross section having a relationship of 0.001 to 0.03 is filled with 7 lux and drawn.