WO2006080541A1

WO2006080541A1 - Welding wire

Info

Publication number: WO2006080541A1
Application number: PCT/JP2006/301602
Authority: WO
Inventors: Terumi Nakamura; Kazuo Hiraoka
Original assignee: National Institute For Materials Science
Priority date: 2005-01-27
Filing date: 2006-01-25
Publication date: 2006-08-03
Also published as: JP2006205205A

Abstract

A welding wire for use in an atmosphere of an inert gas having an active gas incorporated therein or in an atmosphere of an active gas, wherein a temperature distribution being non-uniform in the diameter direction is formed in the inside of the welding wire during welding by the melting point distribution being different in the diameter direction, or by at least any one of thermal conductivity, specific heat, electric resistance or density. The above welding wire can change the form of transfer of a molten metal drop, independent of the type of a shielding gas and electric current.

Description

Description Welding wire

【Technical field】

[0 0 0 1]

The present invention relates to a welding wire.

[Background]

[0 0 0 2]

In the conventional solid wire, the chemical composition is a uniform, in MIG / MAG welding small-current region (consumable electrode welding, high current C_〇 ₂ gas welding), the droplets become globular transfer.

At this time, the droplets are larger than the diameter of the welding wire, causing spatter when the droplets detach or when the droplets enter the molten pool, or cause a short circuit. Often causes.

[0 0 0 3]

In addition, when the current is increased, a transition from a certain critical current to the spray transfer form of small droplets occurs abruptly. In spray transfer, a long molten column is formed at the melting end of the welding wire, and the behavior of the molten column is unstable, causing arcing and short-circuiting. It becomes.

[0 0 0 4]

In order to improve these problems, it is necessary to appropriately change the droplet transfer mode.

[0 0 0 5]

However, with conventional welding wires, if the diameter of the material is constant, the droplet transfer of the welding wire is almost determined by the type and current of the shielding gas (see Non-Patent Document 1, for example). It was impossible to change.

[Non-Patent Document 1] Darnit Iordachescu et al., "Contributions to the Classification of the Metal Transfer in Arc Welding, IIW (2004) Doc. No. XII-1798-04 "

DISCLOSURE OF THE INVENTION

[Problems to be solved by the invention]

[0 0 06]

An object of the present invention is to provide a welding wire that can change the transition form of droplets without depending on the type and current of the shielding gas.

[Means for Solving the Problems]

[0 00 7]

In order to solve the above-mentioned problems, the present invention provides a welding wire used in an atmosphere in which an inert gas is mixed with an active gas or an active gas atmosphere. It is characterized in that a non-uniform temperature distribution in the radial direction is formed inside the welding wire during welding due to at least one of thermal conductivity, specific heat, electrical resistance or density.

[0 0 0 8]

The second aspect of the present invention is characterized in that, in the first feature, the melting point increases toward the center, or the welding temperature decreases toward the center.

[00 0 9]

The third aspect of the present invention is characterized in that, in the first feature, the melting point decreases toward the center, or the welding temperature increases toward the center.

【The invention's effect】

[0 0 1 0]

According to the first invention, the droplet transfer mode can be changed without depending on the type and current of the shielding gas, and spattering due to a short circuit or welding defects can be prevented. [0 0 1 1]

According to the second invention, the size of the droplet can be reduced, and the unstable behavior of the molten part at the end of the welding wire can be suppressed.

[0 0 1 2]

According to the third invention, the length of the molten column can be shortened, and the unstable behavior of the arc and the molten column can be suppressed.

[Brief description of the drawings]

[0 0 1 3]

FIG. 1 is a view showing a welding state of a conventional welding wire.

FIG. 2 is a view showing a welding state of the welding wire of Example 1.

FIG. 3 is a diagram showing the composition and melting point of the welding wire of Example 2 in comparison with the configuration.

FIG. 4 is a diagram showing the composition and melting point of the welding wire of Example 3 as well as its configuration.

FIG. 5 is a view showing a welding state of the welding wire of Example 3.

FIG. 6 is a view showing a welding state of a conventional welding wire.

7 is a diagram showing a state of performing a C 0 ₂ gas welding using a conventional welding wire.

8 is a diagram showing a the state of performing the C 0 ₂ gas welding using a welding wire of Example 3.

BEST MODE FOR CARRYING OUT THE INVENTION

[0 0 1 4]

In the present invention, in the welding wire, for example, a component having a low melting point is adopted in the outer peripheral portion, and a component having a high melting point is adopted in the central portion, or the temperature at the time of welding is lowered toward the central portion. it can. In such a welding wire, the droplet transfer mode can be changed from a globule transfer to a pseudo spray transfer, and an unmelted core is formed at the center of the melted part. Fluctuation of the melted part at the wire end can be suppressed. In addition, it is possible to reduce the size of droplets in the globule transfer.

In MIG / MAG welding, the droplet size is reduced, the spatter is reduced, and it is possible to change to a transfer mode such as spray transfer.

[00 1 5]

When MIG / MAG welding is performed at a higher current, the spray transition state with a long and elongated melt column has traditionally occurred, and the melt column shows unstable behavior due to the liquid column instability phenomenon. The arc is also unstable. As countermeasures at this time, it is effective to shorten the long-extending molten column or to control so that the molten column does not fluctuate in an unstable manner.

[00 1 6]

Therefore, in the present invention, the center portion of the welding wire can be a component having a low melting point, and the outer peripheral portion can be a component having a high melting point, or the temperature during welding can be increased toward the center portion. . By doing so, stable welding is possible and a stable penetration shape is obtained.

[00 1 7]

In order to form a non-uniform temperature distribution in the radial direction inside the welding wire during welding, it is only necessary to change at least one of thermal conductivity, specific heat, electrical resistance, or density. The composition of can be changed. For example, it is exemplified that materials having different compositions are arranged concentrically in the radial direction. The configuration of this welding wire is also common when the melting point distribution is varied in the radial direction.

[00 1 8]

The welding wire of the present invention is also effective as a filler material in laser welding and the like, improves the instability of the molten part, and ensures a stable amount of welding.

[Example 1]

[00 1 9]

The welding condition when the shielding gas was Ar + 20 C0 ₂ gas was compared with the conventional one. [0 0 2 0]

As shown in Fig. 1, in the high current range, the conventional welding wire has a spray transition in which the droplets are elongated, and the tip moves around in an unstable manner.

[0 0 2 1]

In contrast, a welding wire with a soft steel outer periphery and an incone with a lower melting point than the soft steel at the center shortens the molten column at the tip and causes unstable behavior of the molten column, as shown in Fig. 2. Is suppressed, and stable welding is possible.

[Example 2]

[0 0 2 2]

A low-alloy welding wire was prototyped. Fig. 3 shows the composition of the welding wire, comparing its composition and melting point. Table 1 shows the composition of the center and outer periphery of the welding wire. In Example 2, the melting point of the central part was lowered by about 100 from the outer peripheral part.

[0 0 2 3]

【table 1】

[0 0 2 4]

During welding, the molten column at the tip of the welding wire was shortened, and the unstable behavior of the molten column was suppressed, enabling stable welding.

[Example 3]

[0 0 2 5]

The melting point of the outer periphery of the welding wire was about 1400, and the melting point of the center was about 1500. Specifically, Inconel was used for the outer periphery and steel for the center. Figure 4 compares the composition of the welding wire with the melting point. FIG. Table 2 shows the composition of material A (steel) and material B (Inconel).

[0 0 2 6]

[Table 2]

[0 0 2 7]

In MAG welding in the low current region, the globule transition occurs, but as shown in Fig. 5, the formation of large droplets is suppressed. On the other hand, in the conventional welding wire, as shown in Fig. 6, droplets larger than the welding wire diameter are generated.

[0 0 2 8]

The droplet detachment time is 1 Z 2 of conventional welding wire, and stable droplet detachment is possible.

[0 0 2 9]

In addition, co ₂ gas welding was carried out to create massive droplets. With conventional welding wires, as shown in Fig. 7, massive droplets are formed. On the other hand, in the welding wire with the above material design, as shown in Fig. 8, the diameter immediately before the droplet separation is 1 Z 2 which is the droplet diameter of the conventional welding wire. . In this case as well, the droplet detachment time is one to two that of conventional welding wires, and stable droplet detachment is possible.

Claims

The scope of the claims

[Claim 1]

A welding wire used in an atmosphere in which an inert gas is mixed with an inert gas or in an active gas atmosphere, the melting point distribution being different in the radial direction, or at least one of thermal conductivity, specific heat, electrical resistance, or density The welding wire is characterized in that a non-uniform temperature distribution in the radial direction is formed inside the welding wire during welding.

[Claim 2]

The welding wire according to claim 1, wherein the melting point increases toward the center, or the temperature during welding decreases as it approaches the center.

[Claim 3]

The welding wire according to claim 1, wherein the melting point decreases toward the center, or the temperature at the time of welding increases toward the center.