JPS6045995B2 - Composite wire for electrogas arc welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite wire for electrogas arc welding, and is aimed at solving the problems caused by conventional composite wires.

In conventional electrogas arc welding using a composite wire, for example, as shown in FIG.
When welding is carried out under the shielding gas 6 by feeding the wire 7 into the groove formed by the grooves 5 and 5, a slag layer 3 is formed between the heated surface of the weld metal 2 and the front and back copper pads 4 and 5. is formed. The physical properties of the formed slag have a great influence on the heat shape, slag peeling, and sliding properties of the copper abutment. Conventionally, electrogas arc welding generally requires 24 or 3
．． Welding is performed using a large diameter wire of 2-2 and a heat input of 100KJ/cwt or more, but recently welding with a heat input of 100KJ/cwt or less is being performed using a small diameter wire of 2- or less. began to take place. Several problems have become recognized in high-efficiency, low-heat welding. The first is the frequent occurrence of slag jamming, and the occurrence of horizontal cracks due to this jamming. Second, the heat is thin and does not fit well with the groove. Third, slag peeling becomes difficult. The present invention has been made to solve these problems, and by specifying the flux components in the composite wire, the above-mentioned drawbacks can be prevented, and the necessary mechanical strength and toughness can be improved. It is satisfying. That is, the composite wire according to the present invention is a composite wire for electrogas arc welding consisting of a steel jacket and a flux containing metal powder filled therein, in which the flux is at least 0.1 to 1% based on the total weight of the wire. .0
%Lj2CO3, 0.3≦SlO2/Ll2CO3≦
15 SlO2, 0.05≦Af2O3/SlO2≦
0.5 Ae2O3, 0.2≦NaF+Na2c2O
4≦0.5, one or two types of NaF or Na2c2O4, 0.05≦CacO3+BacO3≦0.5
It is characterized by containing one or two types of CacO3 or BacO3, and furthermore, the total weight of the slag-forming substances including the above substances is 0.5 to 3%, and the metal powder is 10 to 30%. This is a composite wire for electrogas arc welding. The reason why the composite wire for electrogas arc welding according to the present invention has the above structure will be explained in detail below.

In the present invention, the metal powder contained in the flux is:
It refers to iron powder, iron alloy powder, etc., and can contain alloy additive components as necessary.

Next, Li2CO3 itself has a low melting point of 618°C and is a highly fluid and good arc stabilizing substance, but it also prevents the slag entrapment defect that often occurs in electrogas arc welding and produces a good bead. Through many experiments, we learned that it is a substance that forms shapes.

When Ll2CO3 is added in a range of 0.1 to 1.0%, a good bead shape without slag entrapment is formed regardless of the welding conditions and the shape of the copper abutment. However, if it exceeds 1%, excessive slag will be formed directly under the arc, making the arc unstable and at the same time significantly increasing welding fume.
．． If it is less than 1%, no effect can be expected. SlO2 is added to increase the fluidity of the slag and improve the compatibility between the molten metal and the groove.

Especially when added in the presence of Lj2CO3, the slag is of good quality. It becomes glassy and forms a bead with sufficient melting. That is, this Li2CO3 acts as a flux for SiO2. However, if SiO2 is added in excess of Li2CO3, a high quality glass with sufficient melted SiO2 cannot be formed. In this case, the range in which good glass quality is formed is 0.3≦SlO2/Li2CO3≦1.
This is the range shown by 5. If it is less than 0.3, the effect of SiO2 addition is small.

If it exceeds 1.5, the bead shape will become irregular.

Ae2O3 is added to improve slag removal.

Glassy slag containing a large amount of SiO2 usually makes it difficult to peel the slag off. Therefore, we searched for a substance that would be effective in improving slag peeling and found that Af2O3 was effective. However, contrary to SiO2, Af2O3 increases the viscosity of the slag and reduces its fluidity, so if it is added in a large amount compared to the amount of SlO2, the effect of SiO2 on slag fluidity is lost. Therefore, the amount of SlO2 added is 0.05≦Ae2O
3/SjO2≦0.5. 0.05
Otherwise, slag peeling will not be improved.

When it exceeds 0.5, the fluidity of the slag decreases, the sliding of the copper plate becomes poor, the arc becomes unstable, and the bead shape becomes thin.

NaF and Na2C2O4 are added to make the arc more stable.

When NaF and Na2C2O4 are added, the droplets become finer,
An extremely stable arc is maintained. If the total amount is less than 0.2%, no effect can be expected, and if it exceeds 0.5%, welding fumes will increase significantly and the working environment will become worse. Cac
O3 and BacO3 are added as gas generating agents to shield the welding atmosphere.

In the electrogas arc welding method, CO2, Ar-CO
Since the shielding gas such as 2 is sent through the sliding copper fitting, it does not require a large amount of gas generating agent, but it supports gas shielding and prevents defects due to insufficient shielding in places with poor working environments such as outdoors. Added for the purpose of The total is 0.
If it is less than 0.5%, the shielding effect cannot be expected. 0.5
%, spatter increases and welding workability deteriorates.

Next, the total amount of slag-forming substances, including the above substances, in the flux is specified to be in the range of 0.5 to 3.0%, which is because steel plates with a thickness of 9 to 401 WL, which are commonly used, are prepared with an excess or deficiency of slag. This is to ensure that the welding is done in good condition without any damage.

Some substances such as slag forming agents, arc stabilizers, and gas generating agents are scattered as welding fumes and gases, but most of them form slag, so electrogas welding involves welding within a groove surrounded by a copper dowel. In this method, it is necessary to adjust the optimum amount of slag. Therefore, as a result of examining various plate thicknesses, groove shapes, and copper pads, we found that even if the slag amount is the smallest on the thick plate side, if it is less than 0.5%, slag will be insufficient and the bead appearance will be poor. 3 even on the thin plate side where the amount of slag is the highest
%, the slag becomes excessive and the arc becomes unstable. For this reason, it is limited to a range of 0.5 to 30%.
Basically, it is best to design the lower limit range for thick plates and the upper limit range for thin plates. Furthermore, the addition of components other than those listed above is not excluded; for example, CaF, which has been conventionally used as a stable slag forming agent.
2, TiO2, MnO2, etc., are also included in the present invention within the above specified range.

Furthermore, SiO2 and Ae2O3 can be added not only as single oxides but also as composite oxides such as potassium silicate, sodium silicate, potassium feldspar, and mica.
The essential components of a composite wire have been described above in terms of bead shape, weld defects, and welding workability, but the weld metal itself must satisfy the required mechanical performance.

The mechanical performance of weld metal is determined by the alloy components contained in the metal powder in the flux.

Normally, in composite wires, the steel outer sheath is made of mild steel, so metal powder containing an alloy component is added to ensure a certain level of strength and toughness. These metal powders include Fe-Si, Fe
-Mn, Fe-MO, Fe-Ti, Fe-B, Fe-A
Iron alloy powders such as e.g., single metal powders such as Si, Mn, Ti, Al, and Ni, and alloy powders such as Af-Mg and Ni-Mg are appropriately selected and added depending on the application. In addition, we have improved the melting rate and lowered the heat input, improving toughness. Optional iron powder is added to improve efficiency. Next, the reason why the total amount of metal powder 8 including the above-mentioned components in the flux is specified to be in the range of 10 to 30% is to enable welding in a stable arc condition. If it is less than 10%, the area of the copper sheath will inevitably be larger than the area of flux on the cross section of the wire, resulting in larger droplets and increased spatter, resulting in poor workability.

On the other hand, if it exceeds 30%, the steel outer skin area will become smaller.
The steel jacket melts too quickly, and the arc length fluctuates too much, making the arc unstable. 10 to 3 due to such reasons
Limited to 0% range. The manufacturing procedure for the wire of the present invention is to fill a copper sheath with a flux of a predetermined composition while forming it, and then draw and sinter the wire to obtain a product.

Next, the effects of the present invention will be illustrated in more detail with reference to Examples.

Wire diameter 16 made of slag-forming substances shown in the upper row of Table 1
A sequential O-shaped composite wire was manufactured.

Steel outer skin: C: 0.06%, Si: 0.1%, Mn: 0
．． A 4% mild steel material was used. Further, the metal powder components added to the flux are as shown in Table 2. Next, using these wires, a welding test was conducted under the welding conditions shown in Table 3 using 50k9/W & 2nd class high tensile strength steel with the groove shape shown in Figures 2 and 3 as the material to be welded. .

The results are shown in the lower part of Table 1.

The wire of the present invention was the only wire with a stable arc, no slag entanglement, good bead appearance, and good slag peeling.

[Brief explanation of the drawing]

Figure 1 is a diagram of the principle of electrogas welding, Figures 2 and 3
The figure is a diagram showing the groove shape used in the example. 1...Base metal, 2...Weld metal, 3...Slag layer,
4...Front side sliding copper butt, 5...Back copper butt, 6...
・Shield gas, 7...Welding wire, t: plate thickness.

Claims (1)

[Claims] 1. In a composite wire for electrogas arc welding consisting of a steel sheath and a flux containing metal powder filled in it, the flux is at least 0% relative to the total weight of the wire.
．． 1-1.0% Li_2CO_3, 0.3≦SiO_
2/Li_2CO_3≦1.5 SiO_20.05
≦Al_2O_3/SiO_2≦0.5 Al_2O
_3, 02≦NaF+Na_2C_2O_4≦0.5 or one or two of Na_2C_2O_4
It contains one or two types of CaCO_3 or BaCO_3 such that 0.05≦CaCO_3+BaCO_3≦0.5, and the total weight of the slag-forming substance including the above substances is 0.5 to 3%, and the metal powder is A composite wire for electrogas arc welding, characterized in that the content is 10 to 30%.