JPH1024389A - Wire for pulse mag welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire for welding having a reduce spatter generating quantity and capable of welding with good bead shape in the pulse MAG welding as gas shield arc welding method with using pulse power source. SOLUTION: This wire for pulse MAG welding has a composition consisting of, by weight, <=0.15% C, 0.10-0.60% Si, 1.0-2.0% Mn, <=0.020% S, further, two kinds or more among Ni, Cr, Zr, which are 0.01-0.20% Ni, 0.01-0.20 Cr, 0.001-0.10% Zr as well as 0.03-0.30% the total quantity, and the balance essentially Fe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse MAG welding wire, and more particularly, to a welding wire capable of performing welding with a small amount of spatter and a good bead shape.

[0002]

2. Description of the Related Art Gas shielded arc welding is widely used in combination with a robot because it enables highly efficient welding and is easy to automate.
Among these gas shielded arc weldings, MAG welding using a gas in which an inert gas such as Ar is mixed with CO ₂ as a shielding gas can perform welding with less spatter than welding using only CO ₂ gas. is there. However, even in this mag welding, when the welding current is low, the generation of spatter cannot be sufficiently suppressed.

On the other hand, a pulse power source is used as a welding power source,
A pulse mag welding method in which a high current and a low current are alternately flowed in a pulse shape has been proposed. In this pulse mag welding method, spatter can be reduced even under a low welding current.

As shown in FIG. 2, in this pulse mag welding, the formation and transfer of the droplet 102 is ensured in one cycle of high current and low current.
It is desirable that the droplets 102 move toward the base material 104 at the time of low current. As long as this is ensured, the generation of spatter is suppressed and the shape of the bead becomes good. However, in this case, droplet 1 at high current
In order to reliably form droplets 02 and transfer the droplet 102 at a low current, it is necessary to set and maintain the peak holding time Tp at a high current at an appropriate Tp.

However, this Tp varies depending on the composition of the welding wire and other conditions. Unless the Tp is properly set and maintained, the transfer of one droplet to one droplet cannot be ensured and the Tp is generated at a high current. Even if the dropped droplet 102 has a low current, it does not detach from the wire 100 and continues to grow until the next high current, and at the next high current or after that, the droplet 1
02 moves to the base material 104 side. In this case, since the size of the droplet 102 becomes large, the droplet 102 comes into contact with the base material 104 to generate spatter, and There is a problem that the bead shape is deteriorated.

[0006]

The invention of the present application has been made to solve such a problem. Thus, the invention of the present application provides the composition of the pulse mag welding wire in terms of% by weight: C: ≤ 0.15%, Si: 0.10 to 0.60%, M
n: 1.0 to 2.0%, S: ≦ 0.020%, and two or more of Ni, Cr, Zr
1 to 0.20%, Cr: 0.01 to 0.20%, Zr:
0.001 to 0.10% and the total amount is 0.03
０．３0.30%, and the balance is substantially Fe.

[0007]

As described above, in pulse mag welding, whether or not Tp at the time of a high current is optimally set is a factor that affects the quality of welding. Therefore, if the range of the appropriate Tp is narrow, it is difficult to adjust the holding time at the time of high current during welding to the appropriate Tp, and the welding conditions are likely to deviate from the optimum conditions. And the bead shape becomes worse. Conversely, if the range of the appropriate Tp is wide, it is easy to maintain the optimum welding conditions even if the welding conditions vary to some extent, and thus it is possible to perform welding satisfactorily.

FIGS. 3A and 3B show this in detail. FIG. 3A shows the case where the appropriate Tp range is narrow, and FIG. 3B shows the case where the appropriate Tp range is wide. . As shown in the figure, the amount of spatter increases sharply when the actual welding Tp is slightly different from the appropriate Tp, whereas when the range of the appropriate Tp is wide ((b)). It can be seen that even if the actual welding Tp is slightly different from the proper Tp, the amount of spatter does not increase so much.

The present inventor focused on the peak holding time Tp at the time of the high current and studied the composition of the welding wire.
When two or more kinds of r and Zr are contained in the above range, it has been found that a proper range of Tp can be widened, and the present invention has been completed. That is, according to the present invention, as shown in the conceptual diagram of FIG.
It is possible to reliably transfer the droplet from the wire to the base material in each cycle.

That is, according to the present invention, the setting of welding conditions is facilitated, the generation of spatter can be suppressed well, and the occurrence of arc breakage, humping bead, etc. due to a long arc length can be effectively prevented. Suppression can be suppressed and the bead shape can be made favorable.

Next, the reasons for limiting each chemical component in the welding wire of the present invention will be described in detail. C: ≦ 0.15% C enhances the strength of the weld metal, but if it exceeds 0.15%, the workability to the wire deteriorates. Therefore, in the present invention, the upper limit of C is set to 0.15%.

Si: 0.10 to 0.60% When the content of Si is less than 0.10%, deoxidation becomes insufficient and defects such as pits and blowholes occur in the weld metal. On the other hand, if the ratio exceeds 0.60%, under appropriate pulse conditions of one droplet per pulse, the droplets grow too large, and large spatters are likely to occur. Therefore, in the present invention, Si is set to 0.1
0 to 0.60%. A more desirable amount of this Si is 0.20 to 0.40%.

Mn: 1.0 to 2.0% If the Mn content is less than 1.0%, the droplets grow too large under proper pulse conditions to produce one droplet per pulse and large spatters are likely to occur. . On the other hand, if it is more than 2.0%, the strength of the weld metal increases, and the workability to the wire deteriorates.
Therefore, in the present invention, Mn is set to 1.0 to 2.0%.
A more desirable amount of this Mn is 1.3 to 1.5%.

S: ≦ 0.020% If S exceeds 0.020%, the surface tension of the droplet becomes low, the droplet is not stably formed in a spherical shape, and the spatter increases. Therefore, in the present invention, S is set to 0.020% or less. S
Is more preferably 0.010% or less.

Ni: 0.01 to 0.20% Cr: 0.01 to 0.20% Zr: 0.001 to 0.10% and 0.03 to 0.30% in total of two or more kinds. By containing two or more elements within the above range, and by making the total amount 0.03 to 0.30% at that time, it is possible to widen the appropriate range of Tp with less spatter. However, excessive addition causes spatter to occur frequently. On the other hand, if the addition amount is small, a sufficient effect for widening the appropriate range of Tp cannot be obtained. Therefore, in the present invention, the contents of Ni, Cr, and Zr are set to the above ranges.

[0016]

Next, embodiments of the present invention will be described in detail. Table 1
The pulse mag welding was carried out under the following welding conditions using welding wires of various compositions shown in FIG. <Welding conditions> Base material SPC plate thickness 3.2 mm Shielding gas Ar + 20% CO ₂ welding method Downward bead-on-plate welding Tip base material distance 15 mm Peak current value 460 A Peak current holding time 0.9, 1.1, 1.3 , 1.5, 1.7 ms Wire feeding speed 7.0 m / min Arc voltage 23 V Welding speed 150 cm / min The proper peak current holding time was measured, and the amount of spatter generated was measured. The results are shown in Table 1. Note that the appropriate peak current holding time is 0.5
It was determined from 0 g / min or less to the time when the amount of sputtering was the least. In addition, the value of the spatter amount in the table is indicated by the smallest sputter amount value.

[0017]

[Table 1]

FIG. 1 shows NO. 5, NO. 1
4, NO. 23 shows the relationship between the peak current holding time and the spatter amount. From the results of Table 1 and FIG. 1, in the case of the welding wire according to the example of the present invention, the range of the appropriate peak current holding time is wide, The conditions are easy to set, the amount of spatter generated is small, and in particular, NO. 1 to N
O. It can be seen that a more desirable result is obtained for the sample of No. 5. In the case of the welding wire of the present invention, the bead shape was also good.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be implemented in variously modified forms without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a peak current holding time and a sputtering amount obtained in an example of the present invention.

FIG. 2 is a diagram showing the relationship between the formation of droplets and the transfer of droplets in pulsed mag welding in relation to an applied current.

FIG. 3 is an explanatory diagram illustrating an advantage of widening a range of a proper peak current holding time in pulse mag welding.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 welding wire 102 droplet 104 base metal

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C22C 38/58 C22C 38/58

Claims (1)

[Claims] C: ≦ 0.15% Si: 0.10 to 0.60% Mn: 1.0 to 2.0% S: ≦ 0.020% by weight%, and Ni, Cr, Zr: 0.01 to 0.20% Cr: 0.01 to 0.20% Zr: 0.001 to 0.10% and the total amount is 0.03 to 0.3%. A pulse MAG welding wire, wherein the wire is contained in a range of 30% and the balance is substantially made of Fe.