JPS60231599A - Wire for gas shielded arc welding - Google Patents

Abstract

PURPOSE:To reduce occurrence of spatter at the time of welding and stabilize arc by sticking proper quantity of powdery or solid halium salt of carboxylic acid such as kalium stearate etc. and controlling the quantity of adhesion of the metallic powder toless than prescribed quantity. CONSTITUTION:The wire for gas shielded arc welding is made by sticking powdery or solid kalium salt of carboxylic acid such as kalium stearate etc., 0.2- 10g per 10kg of wire, on the surface of the wire and making the quantity of metallic powder such as copper, iron etc. inevitably liberated and stuck at the time of sticking less than 0.1g per 10kg of wire. By making welding using this wire, the quantity of generation of spatter is reduced remarkably, deposition of welding tip and the wire is prevented, fluctuation of wire feed speed is prevented and stability of the arc can be improved. Above-mentioned wire can be obtained easily by dry drawing using a powdery lubricant mainly composed of kalium salt of carboxylic acid, or roller die drawing or sticking kalium salt of carboxylic acid by roller pressure welding.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a wire for gas shielded arc welding.

Conventional configurations and their problems Recently, demand for improved welding performance has become stronger in the automobile and shipbuilding industries, and improvements to gas-shielded arc welding methods are needed to obtain faster and higher quality welds. Various things have been done. One of these improvements is the improvement of the shielding gas, replacing the conventional C02 gas with Aγ gas or Ar
The solution is to switch to CO2 mixed gas. Another improvement is the improvement of the welding power source, which is an output waveform control method using pulse control or inverter control.

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 wires contain appropriate amounts of Si, Mn, and Ti as deoxidizers to allow the molten metal to perform an appropriate metallurgical action, and to reduce the viscosity of the droplets and molten metal, as shown in Figure 1. was making adjustments. In addition, in FIG. 1, 1 represents Fe and Si.

Mn, Ti oxides, Fig. 1 shows Si in Fe.
0.8%.

Mn 1.5%, Tio, o5%, 02 amount 50-2
00 is a diagram showing the state of an alloy containing P, P, and m.

In order to improve the droplet transfer phenomenon especially in pulsed arc welding and CO2 globule transfer welding, an appropriate amount of T is added to the wire.
It has been found that the inclusion of 1 and 02 is effective in reducing the viscosity and making the droplets transfer as small particles.

However, all of these conventional improvement methods attempt to incorporate elements such as 81, Ti, and 02 into the welding wire, and go back to the steelmaking 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.

Obtaining the final product wire in accordance with the amount of 02 was a major manufacturing difficulty. At the same time, element-added wires have high costs for both raw material production and final product wires.

In order to improve this problem, some research has been carried out on a trial basis, as shown in FIG. 2, to stick a substance 3 that is advantageous to the arc phenomenon on the surface of the wire 2. 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 tip, its heat capacity is small, so it melts instantaneously, causing welding between the tip and the wire, resulting in wire transfer. The supply stops momentarily, resulting in irregular supply and unstable energization. Unfortunately, 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 not been practical to stick metal powder on the wire surface, even though it is easy to manufacture.

Purpose of the Invention The present invention has been made in view of the current situation, and it addresses the problems of conventional wire droplet transfer non-uniformity, wire welding to the welding torch/tip, and wire slipping in the wire feeding device/feed roller. The purpose is to improve the shortcomings such as:

Structure of the Invention In order to achieve this object, the present invention provides the wire 10 with a powdered or solid carboxylic acid potassium salt on the wire surface! The wire 10 is fixed with a value of 0.2 f7 or more and 102 or less per 7, and metal powder such as copper and iron which is loosely attached to the wire 10 is set to 0.12 or less per 9.

Explanation of Examples Here, the powdered or solid carboxylic acid potassium salt was used because while liquid potassium stearate, potassium oleate, potassium palmitate, etc. dissolved in a solvent are advantageous for application, stearic acid This is because potassium, potassium oleate, potassium palmitate, etc., 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, as a method for adhering potassium stearate to the wire surface, it is dissolved in a solvent such as hot water, ether, alcohol, etc., and is applied in liquid form as shown in FIG. 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 at first glance it seems to be effective, but oleic substances such as potassium stearate Due to the low solubility of potassium carboxylates such as potassium acid and potassium palmitate in the above solvents, the amount of liquid applied is extremely large in order to attach potassium, which is effective for arc discharge, to the wire surface, which causes another problem during welding. For example, the wire slips on the wire feed roller and becomes untwisted. 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 and 4 is a carboxylic acid potassium salt.

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, carboxylates of cesium, calcium, and sodium other than potassium were excluded because, in addition to being expensive, potassium has no improvement effect, and has another disadvantage of being highly hygroscopic and prone to rusting on the wire surface. It is from.

Potassium stearate is a typical potassium carboxylic acid salt, and potassium oleate, potassium nocrumitate, etc. have similar properties. is usually mixed with potassium oleate, potassium palmitate, etc., and in the present invention, these are collectively referred to as carboxylic acid potassium salt.

Next, the reason why the amount of potassium carboxylate attached to the wire surface was set to 0.2 p or more and 102 or less is because, as shown in Fig. 5, if the amount is less than 0.2 y, the amount of adhesion is too small, resulting in poor arc stability. This is because the degree of improvement is small, and the amount of ivy generated as a measure of the degree of improvement does not decrease. Unfortunately, the reason for setting it below 102 is that if too much is deposited, when carboxylic acids such as stearic acid decompose in the arc, the amount of diffusible hydrogen that will enter the molten pool will increase as shown in Figure 6. This is because it causes cracking of the weld and hydrogen embrittlement.

Next, the reason why the free adhering metal powder such as copper and iron is reduced to 0.1 g or less per wire 10 is by fixing powder and solid substances of potassium carboxylate such as potassium stearate to the wire surface. In this case, mechanical fixing processes such as wire drawing with dies and roller crimping are usually performed, but at this time, the copper plating and iron base on the wire surface are inevitably scraped, resulting in copper powder as shown in Figure 7a and b. This is because these loose metal powders 6 cause wire welding at the power supply tip. Of course, it is desirable that this free adhesion of metal powder be free of defects, but it is unavoidable when mechanical bonding is performed, and a certain tolerance is allowed when producing wire industrially. This makes it possible to lower prices by improving productivity. Note that, based on the experimental results shown in FIG. 8, this tolerance value is desirably 0.12 or less for the wire 10.

The wire manufacturing method adopted to carry out the present invention differs slightly between copper-plated wire and non-plated wire, but basically it is a method of powder dry wire drawing or roller crimping in the wire finishing process. be.

In the case of conventional gas-shielded arc welding wire, in the case of copper-plated wire, a finishing process called skin bath wire drawing is used in a liquid using a wet lubricant. Potassium stearate cannot be firmly attached to the wire surface. Therefore, in the present invention, after the copper plating process, the wire is washed with hot water or chemically to sufficiently remove the chemicals that were attached during the plating process, and then the surface of the wire is dried with hot air to completely disperse the moisture.
After that, it was manufactured by dry wire drawing using a powder lubricant containing powdered potassium stearate as a main component, and then applying rust preventive oil.

At this time, as a powder lubricant, in addition to industrial potassium stearate, potassium oleate is used.

By appropriately mixing 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. By adjusting the particle size, adjusting the degree of powder drawing into the die, and preventing die burning under high pressure, the amount of potassium stearate attached to the wire surface is controlled to 0.22 or more and 10y or less. At the same time, it is possible to reduce the amount of metal powder adhesion to 0.12 or less. In addition, by limiting the number of dies to one, reducing the area reduction to a factor of 30 or less, and appropriately adjusting the wire drawing speed, potassium stearate containing no metal powder is applied to the wire surface. can be fixed to a specified amount.

In addition, for non-copper-plated wires, after the normal fine wire drawing is completed, they are washed with hot water to completely remove the dirty residual lubricant (containing a large amount of free metal powder) that had adhered to them. 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 (supported) deposited is within the specified amount, and that the amount of free metal powder is 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. In many cases, the improved performance of the wire of the present invention can be maintained for a long period of time without deteriorating the wire.

For copper-plated wire, roller crimping may be used in the finishing process, and for non-plated wire, die dry wire drawing may be used for the finishing process, or a powdered rust preventive agent may be mixed 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 surface9, the droplet transfer phenomenon during pulsed arc welding can be made small and fine. By doing so, the amount of spatter generated during welding can be significantly reduced. Pulse arc welding is a welding method that was originally developed with the aim of reducing spatter during welding, but there are some drawbacks to the welding process (blow balls).

In order to prevent welding defects such as undercuts, the welding voltage is often lowered and the arc condition is mixed with short circuits.At this time, conventional wires in particular generate a lot of spatter, but the wires of the present invention are used in Figure 9. has been significantly reduced.

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

In addition, in FIGS. 10a and 10b, a wire with a diameter of 1.2 mm is used, and 2
This is a diagram showing the fluctuation of wire feeding speed when performing 00A CO2 globular arc welding, and Figure 1o a
10 shows the characteristics of the conventional wire, and FIG. 10 shows the characteristics of the wire of the present invention. The wire of the present invention contains 52% potassium stearate.
/wire 1oKq, rust preventive oil 1y/wire 10 to 9
This is the case when

That is, the potassium carboxylate fixed wire of the present invention is
As a result of stabilizing the arc discharge phenomenon and smoothing wire feeding, it improves welding workability not only in pulsed arc welding, but also in globular arc welding using CO2 gas shielding, and revolutionizes the performance of consumable electrode arc welding. It is possible to increase production efficiency and promote production rationalization in the automobile and shipbuilding industries.

On the other hand, from a manufacturing perspective, compared to wet finishing wiredrawing in trenches, dry finishing wiredrawing makes it easier to manage lubricants during the finishing process in the factory, reducing wet lubricant waste disposal and pollution. Preventive treatment is no longer required, equipment in the factory is less likely to get dirty, and dirt can be removed from finishing wires, improving product value and production yield.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional element-added wire, Fig. 2 is a schematic diagram of a conventional metal powder-adhered wire, and Fig. 3 a, b.
Figure 4a is a schematic side view and front perspective view of a prototype wire coated with potassium carboxylate dissolved in a solvent;
b is a side view and front perspective view schematically showing a wire to which powdered or solid potassium carboxylate of the present invention is fixed, and FIG. 5 is a characteristic diagram showing 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 and front perspective view schematically showing a prototype wire with free metal powder deposited. Figure 8 is a characteristic diagram showing the relationship between the amount of metal powder deposited on the wire surface and the number of chip welds per hour of arc welding, and Figure 9 shows the relationship between the amount of metal powder deposited on the wire surface and the number of chip welds per hour. A characteristic diagram showing a comparison of the amount of spatter produced by a conventional wire and a wire of the present invention, which were welded at a lower welding voltage in pulsed ar welding. Regarding the wire of the invention, 1.2 mm φ in a CO27-rudo gas atmosphere.
FIG. 3 is a characteristic diagram showing a comparison of speed fluctuation rates during welding with a wire at 20oA. 2 Wire, 5. Carboxylic acid potassium salt. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 Figure 3" (b) Co-2 ('b) Figure 5 □] 71.21234567 B 910117 Melon I9 Ta-
°1-Eya Figure 7 ((L) (b)

Claims (1)

[Claims] Powdered or solid carboxylic acid potassium salt is fixed to the wire surface at a rate of 0.217 or more and 102 or less per wire 10, and loosely adhered metal powders such as copper and iron are fixed to the wire 10 at a rate of 012 or less per 2. Gas shielded arc welding wire.