JPH0377035B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a wire for gas shielded arc welding.

Conventional configurations and their problems Recently, the demand for improved welding performance has become stronger in the automobile and shipbuilding industries, and various improvements have been made to the gas shielded arc welding method in order to obtain faster and higher quality welds. It has been done. One of these improvements is to improve the shielding gas, replacing the conventional CO ₂ gas with Ar gas or Ar-CO ₂ mixed gas. Another improvement is the welding power source, which uses pulse control and inverter control to control the output waveform.

However, the basis of the welding arc phenomenon in consumable electrode arc welding is the arc discharge from the electrode wire and the melting phenomenon of the electrode wire itself, and therefore, improvements to the welding wire that have a decisive influence on this are as described above. This is more important than improving shielding gas and welding power sources.

Conventionally, gas shielded arc welding wire was the first
As shown in the figure, appropriate amounts of Si, Mn, and Ti were included as deoxidizers to allow the molten metal to perform an appropriate metallurgical action and to adjust the viscosity of the droplets and molten metal. In addition, in Fig. 1, 1 is Fe, Si,
This is an oxide of Mn and Ti. Figure 1 shows 0.8% Si in Fe.
FIG. 2 is a diagram showing the state of an alloy containing 1.6% Mn, 0.05% Ti, and an O ₂ amount of 50 to 200P.Pm. In order to improve the droplet transfer phenomenon, especially in pulsed arc welding and CO ₂ globule transfer welding, it is effective to include an appropriate amount of Ti and O ₂ in the wire to reduce viscosity and transfer the droplets as small particles. It turned out that there was.

However, all of these conventional improvement methods attempt to incorporate elements such as Si, Mn, Ti, and _O2 into the welding wire, and the process goes back to the steel-making process of the ingot, which is the raw material for the wire. This required research on the addition of elements. Therefore, the optimal amount of Ti for actual pulsed arc welding, O ₂
Obtaining the final product wire in quantity was a major manufacturing challenge. At the same time, the element-added wire has increased both raw material manufacturing cost and final product wire cost.

In order to improve this, in some cases, as shown in Fig. 2, a material 3 which is advantageous for arcing is applied to the surface of the wire 2.
The adhesion of these materials has been studied. For example, it has been reported that when a small amount of a metal with a low potential gradient, such as cesium, calcium, or potassium, is attached to the wire surface, the arc discharge phenomenon is stabilized and welding performance is improved.

However, with the method of directly attaching metal powder to the wire surface, when the welding wire is supplied with power from the power supply chip, its heat capacity is small, so it melts instantly and causes welding between the chip and the wire.
Wire feeding is momentarily stopped, leading to irregular feeding, and energization becomes unstable. For this reason, no matter how precisely the output waveform is controlled on the welding power source side, the actual arc phenomenon will be disordered and unstable. For this reason, it has been impractical to attach metal powder to the wire surface, even though it is easy to manufacture.

Purpose of the Invention The present invention was made in view of the current situation, and conventional problems include non-uniform transfer of droplets of wire, problems of wire welding to welding torches and chips, and problems of wire slipping in wire feeding devices and feed rollers. The purpose is to improve the shortcomings of

Structure of the Invention In order to achieve this object, the present invention provides that after the wire has been drawn into a thin wire, the wire is washed with hot water to remove the residual lubricant, and then the wire is drawn with a roller die or roller crimped. By repeating this process only once, the powdered or solid potassium carboxylic acid salt is fixed to the surface of the wire, and the amount of the fixed amount is 0.2 g or more and 10 g or less per 10 kg of wire, and the loosely attached copper and iron are 0.1g or less of metal powder per 10kg of wire.

Explanation of Examples Here, the powdered or solid potassium carboxylate salt was used because while liquid potassium stearate, potassium oleate, potassium palmitate, etc. dissolved in a solvent are advantageous for coating, stearic acid This is because potassium, potassium oleate, potassium palmitate, and the like have low solubility in solvents, so that an amount of potassium that is effective for arc discharge does not adhere to the metal surface.

That is, the method for attaching potassium stearate to the wire surface is to dissolve it in a solvent such as boiling water, ether, or alcohol, and apply it in liquid form to the wire surface as shown in Figure 3a.
A method of coating as shown in b is considered, and if this method is adopted, copper powder and iron powder will not adhere during the adhesion process, and it seems to be effective at first glance. Because potassium carboxylates such as potassium acid and potassium palmitate have low solubility in the above solvents,
In order to deposit potassium, which is effective for arc discharge, on the wire surface, a very large amount of liquid is applied, which causes other problems during welding, such as wire slipping at the wire feed roller. Therefore, in addition to fixing potassium carboxylate itself such as powdered or solid potassium stearate to the wire surface, it also suppresses free metal powders such as copper powder and iron powder that are inevitably generated during the fixing process to below a specified amount. This is the most effective way to achieve the intended purpose. In addition, in FIG. 3, 2 is a wire,
4 is carboxylic acid potassium salt.

Further, FIG. 4 shows a welding wire of the present invention in which a powdered or solid potassium carboxylate salt 5 is fixed to the wire 2.

In addition, other than potassium, cesium, calcium,
The reason for excluding sodium carboxylate is that it is expensive and does not have the same improvement effect as potassium, and it also has another drawback that the wire surface is susceptible to rust due to its high hygroscopicity.

Potassium stearate is a typical potassium carboxylate salt, and potassium oleate, potassium palmitate, etc. have similar properties, and industrially produced potassium stearate is usually , potassium oleate, potassium palmitate, etc.
In the present invention, these are collectively referred to as carboxylic acid potassium salts.

Next, the reason why the amount of potassium carboxylate attached to the wire surface was set to 0.2 g or more and 10 g or less is because, as shown in Figure 5, if the amount is less than 0.2 g, the amount of adhesion is too small and the degree of improvement in arc stability is reduced. This is because the amount of spatter generated, which is a measure of the degree of improvement, cannot be reduced. In addition, the reason for setting the value to be 10 g or less is that if too much is deposited, when carboxylic acids such as stearic acid are decomposed in the arc, the amount of diffusible hydrogen that enters the molten pool will increase as shown in Figure 6.
This is because it causes cracks in the weld and hydrogen embrittlement.

Next, the reason why loosely attached metal powders such as copper and iron are reduced to 0.1g or less per 10kg of wire is as follows.
When fixing potassium carboxylate powder or solid substances such as potassium stearate to the wire surface, mechanical fixing processes such as wire drawing with a die or roller crimping are usually performed. The copper plating and iron base of the 7th
This is because copper powder and iron powder are generated as shown in Figures a and b, and these loose metal powders 6 cause wire welding at the power supply chip. Of course, it is desirable that there be no free adhesion of metal powder, but it is unavoidable when mechanical bonding is performed, and it is necessary to accept certain tolerances when producing wire industrially. It is possible to reduce prices by improving productivity. This allowable value is 0.1 per 10 kg of wire from the experimental results shown in Figure 8.
g or less is desirable.

The wire manufacturing method of the present invention differs slightly between wires with copper plating and wires without plating, but basically involves dry powder wire drawing or roller crimping in the wire finishing process.

With conventional gas shielded arc welding wire,
In the case of copper-plated wire, a finishing process called skin-pass wire drawing is used in a liquid using a wet lubricant, but this method does not allow powdered or solid potassium stearate to firmly adhere to the wire surface. . For this reason, in the present invention, after the copper plating process, the wire is washed with hot water or chemically to sufficiently remove the chemicals attached during the plating process, and then the wire surface is dried with hot air to completely disperse the water, and then powdered stearic acid It was produced by dry wire drawing using a powdered lubricant containing potassium as the main component, and then applying rust preventive oil.

At this time, as a powder lubricant, in addition to industrial potassium stearate, potassium oleate,
Potassium salts such as potassium palmitate, sodium salts such as sodium oleate, sodium palmitate, and sodium stearate, extreme pressure additives and anti-friction agents such as graphite, sulfur, talc, and Zn-DTP are mixed appropriately. to adjust the particle size,
By adjusting the amount of powder drawn into the die and preventing die seizure under high pressure, the amount of potassium stearate attached to the wire surface can be reduced.
It is possible to control the amount between 0.2g and 10g, and reduce the amount of attached metal powder to 0.1g or less.
In addition to this, by using only one die, keeping the area reduction rate as low as 30% or less, and appropriately adjusting the wire drawing speed, potassium stearate, which does not contain metal powder, is applied to the wire surface. A specified amount can be fixed.

In addition, unplated wire without copper plating is washed with hot water immediately after the normal thin wire drawing to completely remove the dirty residual lubricant (containing a large amount of free metal powder). After that, it is preferable to carry out roller die wire drawing or roller pressure bonding only once to fix a specified amount of potassium stearate. Of course, in this case as well, the area reduction rate and wire drawing speed must be adjusted appropriately to ensure that the amount of potassium stearate fixed is within the specified amount, and the amount of free metal powder must be kept below the allowable value.

Furthermore, after completing this dry finishing wire drawing or roller crimping finishing process, if the rust preventive oil that is conventionally applied to the surface of the welding wire is further applied, the rust preventive performance during storage will be improved and the initial arc stability performance will be improved. This means that the improved performance of the wire of the present invention can be maintained for a long period of time without deteriorating the wire.

It is also possible to use roller crimping in the finishing process for copper-plated wire, and to use die dry wire drawing in the finishing process for non-plated wire, or to mix a powdered rust preventive into the powdered lubricant from the beginning.

Effects of the Invention As described above, according to the present invention, by fixing the metal salt of potassium, which is a metal advantageous for arc discharge, on the wire surface, the droplet transfer phenomenon during pulsed arc welding is made small and fine-grained. This makes it possible to significantly reduce the amount of spatter generated during welding. Pulsed arc welding is a welding method developed with the aim of reducing spatter during welding.
In order to prevent welding defects such as undercuts, the welding voltage is often lowered and used in an arc condition with short circuits.At this time, conventional wires in particular produce many spatters, but the wires of the present invention are used as shown in Figure 9. This is a significant reduction.

At the same time, due to the improved lubricity of the wire surface due to the adhesion of potassium stearate, the rate of fluctuation in wire feeding speed at the tip of the tip decreases as shown in Figure 10a and b, which improves arc stability. can.

In addition, Figures 10a and 10b are diagrams showing the fluctuations in wire feeding speed when 200A CO ₂ globular arc welding is performed using a 1.2mmφ wire, and Figure 10a is a diagram showing the fluctuation of the wire feeding speed when 200A CO 2 globular arc welding is performed using a 1.2mmφ wire. FIG. 10b shows the characteristics of the wire of the present invention. The wire of the present invention is
This is when potassium stearate is 5g/10Kg of wire and rust preventive oil is 1g/10Kg of wire.

i.e. carboxylic acid potassium salt wire 10Kg
The wire of the present invention, which is fixed at 0.2 g or more and 10 g or less, stabilizes the arc discharge phenomenon and smoothes wire feeding, so it can be used not only in pulsed arc welding, but also in globular arc welding using CO ₂ gas shielding. It is possible to dramatically improve the performance of consumable electrode arc welding, and to streamline production in the automobile and shipbuilding industries.

Furthermore, in the present invention, the amount of deposited metal powder such as copper and iron that is loosely attached is reduced per 10 kg of wire.
Since the weight is 0.1 g or less, it is possible to industrially mass-produce wires that are free from the risk of wire welding in the power supply chip, and the cost thereof can be reduced.

On the other hand, from a manufacturing perspective, compared to conventional wet finishing wire drawing, dry finishing wire drawing makes it easier to manage lubricants during the finishing process in the factory, and processes such as wet lubricant waste liquid treatment and pollution prevention. As a result, the equipment in the factory is less likely to get dirty, and the finished wire can be cleaned of dirt, improving product value and production yield.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional element-added wire.
Figure 2 is a schematic diagram of a conventional metal powder-coated wire, Figures 3a and b are schematic side views and front perspective views of a prototype wire coated with potassium carboxylate dissolved in a solvent, and Figure 4. a and b are side views and front perspective views schematically showing a wire to which powdered or solid potassium carboxylate of the present invention is fixed, and FIG. 5 shows the relationship between the amount of potassium carboxylate deposited and the amount of spatter generated. Figure 6 is a characteristic diagram showing the relationship between the amount of potassium carboxylate deposited and the amount of diffusible hydrogen in the weld metal, and Figure 7 is a side view schematically showing a prototype wire with free metal powder deposited. Front perspective view, Figure 8 shows the amount of metal powder adhering on the wire surface,
Figure 9 is a characteristic diagram showing the relationship between the number of chip welds per hour of arc welding, and the welding was performed under welding conditions commonly used in the automobile industry, that is, high-speed pulsed arc welding with a low welding voltage. Characteristic diagrams showing a comparison of spatter generation values between the conventional wire and the wire of the present invention. Figures 10a and b show the conventional wire and the wire of the present invention at 200A with a 1.2mmφ wire in a CO ₂ shielding gas atmosphere. FIG. 3 is a characteristic diagram showing a comparison of speed fluctuation rates during welding. 2...Wire, 5...Carboxylic acid potassium salt.

Claims (1)

[Claims] 1 After drawing the wire into a fine wire, the wire is washed with hot water to remove the residual lubricant, and then drawn with a roller die or roller crimped only once to form powder on the surface of the wire. Or fix solid potassium carboxylic acid salt and reduce the amount of fixation to 0.2 per 10 kg of wire.
0.1 g of loosely attached metal powder such as copper and iron per 10 kg of wire.
A method for manufacturing a gas-shielded arc welding wire having a wire of less than 10 g.