JPS58138577A - Spatter adhesion preventing method of welding torch nozzle, chip, jig, or the like - Google Patents

Abstract

PURPOSE:To prevent adhesion of spatter, by forming 2 layers consisting of a under coat layer being a binder, and a top coat consisting of powder of a solid lubricating agent, on the surface of a welding torch nozzle, etc. CONSTITUTION:Under coat of a binder consisting of an inorganic compound substance, an organic metallic compound and an organic polymer is performed to the surface of a welding torch nozzle, a chip, a jig, etc. subsequently, on this under coat, solid lubricating agent powder (for instance, boron nitride, graphite and molybdenum bisulfide) is top-coated. In this way, the solid lubricating agent of top coat is stuck to the under coat, and a spatter adhesion preventing effect is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of preventing hess batter from adhering to welding torch nozzles, tips, jigs, etc.

The purpose is to provide a method for imparting excellent spatter adhesion prevention properties to welding torch nozzles and the like.

Normally, when shielding gas is used in consumable electrode arc welding, droplet transfer forms vary depending on the selected welding conditions, and there are various forms from short-circuit transfer to spray transfer.

Among these, spatter is often generated in the case of short-circuit transfer and burr transfer, and even in argon gas shield or argon + carbon dioxide gas shield welding, which is said to generate relatively little spatter, these spatters are generated. During long welding operations, it accumulates on the tip of the contact tip and the gas discharge hole of the gas shield nozzle, obstructing the feeding of the consumable electrode wire and causing disturbances in current, voltage, etc. due to unstable feeding. .

Of course, if the amount of spatter deposited in the gas shield discharge hole becomes large enough to block the discharge hole, it will drastically reduce the shielding effect of the arc column and the molten pool, but the deposition is not so great.

However, the gas flow changes from laminar flow to turbulent flow, which reduces the shielding effect and causes air to be drawn in, reducing the quality of the weld. In particular, when the contact tip section or gas nozzle section is inserted into a narrow and deep groove and welded, the above-mentioned spatter may accumulate in the welding section due to the arc heat and the heat retained by the molten metal and weld metal. When welding, the arc that occurs between the welding wire and the material to be welded is normal, but if there is a potential difference between the torch body or the accumulated spatter and it comes into contact with the material to be welded, an abnormal arc will occur. This may cause problems such as

Even in the non-consumable electrode type arc welding method, the gas nozzle part or the contact tip part comes into contact with the welded material when it is at the same potential as the tungmetine electrode, such as in the joint mentioned above, due to the potential difference with the welded material. 7? ／ @
Live danger arises.

Furthermore, although robots and fully automatic welding have rapidly developed in recent years, spatter adhesion to the torch nozzle makes it necessary to stop welding midway through and clean the torch nozzle, which poses a major obstacle to the automation of welding lines. Ta.

Conventionally, attempts have been made to prevent the adhesion of spatter by applying various techniques to contact tips and gas nozzles.

In other words, the basic ideas of the solutions that have been tried so far have been to use intense cooling to keep the temperature of the contact tip as low as possible, or to use a material with high heat dissipation properties.

For example, there are many torches for welding where the part of the torch containing the contact tip is made of copper or its alloy, and is cooled from the inside and outside by water cooling, etc., but even so, when welding for a long period of time, spatter may be present at the tip of the contact tip or the wire. In addition to preferentially adhering to the area around the delivery hole, such a water-cooled torch is heavy and bulky, resulting in poor workability.

Furthermore, methods such as inserting a small nozzle into a narrow and deep groove are technically difficult to provide a sufficient cooling effect, resulting in phenomena such as even more severe spatter deposition.

Furthermore, for graphite, zinc fluoride, and tungsten disulfide, a method has been proposed in which the welding torch is coated with a mixture containing an aqueous solution of an inorganic binder; As a result, the original function of the solid lubricant powder is not fully demonstrated.

For example, JP-A-52-82'840 discloses a method for forming a welding torch retaining film using the layered crystal lattice Im-forming substance powder and an organic binder or an inorganic binder. 9! Examining the examples, it is found that the blending ratio of the binder to the layered crystal powder is approximately 15% or more, and in the most cases, as many as 50 binders are blended, and as a result, experiments by non-inventors etc. According to the authors, it was determined that this was by no means an excellent solution because the spatter was captured by the binder film, which could actually increase the amount of spatter attached.

This phenomenon is particularly noticeable in carbon dioxide welding, and in the case of automation, welding with a continuous arc time of 5 minutes or more is desired, but in most cases the above methods do not yield satisfactory results.

By the way, the present inventors have taken the above points into consideration and have decided to disperse the solid lubricant powder with a high-boiling point solvent and blend it with a binding agent such as a synthetic resin, colloidal silica, surfactant, or wax as in the past. Developed an extremely excellent spatter adhesion preventive agent that can temporarily adhere solid lubricant powder to torch nozzles, etc., without the use of solid lubricant powder, and filed a patent application on September 8, 1980 (Patent Application No. 141185-1985). did.

The product of this previous application exhibits an extremely excellent effect in continuous arc welding, and has extremely slow sputter deposition and maintains the limit of continuous arc time of 160 to 200 minutes, and conventional spatter adhesion prevention agents cannot. Continuous arc welding can now be performed for a longer period of time, which is 20 times longer than in the previous case where the continuous arc time could only be maintained for a limited time of 5 to 10 minutes.

However, as a result of subsequent research, it was found that the previous application did indeed have very good spatter adhesion prevention properties for continuous arc welding, but for intermittent arc welding, e.g. In arc welding such as "sand stopping", the force of spatter generation is strong at the moment of arc ignition (at the time of start-up), and because this occurs many times, the solid lubricant falls off rapidly and the spatter adhesion prevention effect tends to decrease. It turned out to be 1.

The present inventors have also demonstrated that FIJ
The present invention was achieved as a result of research aimed at developing a method for obtaining excellent spatter adhesion prevention effects even in the intermittent arc welding described above.

In other words, welding torch nozzles, tips, jigs, etc.
He came to invent a method for preventing spatter adhesion on welding torch nozzles, tips, and Jig J1, which is characterized in that the surface of the welding torch is undercoated with an adhesive and then overcoated with solid lubricant powder.

In the method of the present invention, a welding torch nozzle, etc. is first coated with a binder, and then a solid lubricant powder is overcoated on the coating layer of the binder, and the solid lubricant powder is bound to the torch nozzle, etc. by the adhesive force of the binder. Therefore, the solid lubricant, which is prone to spatter adhesion, is not exposed on the outer surface, and the entire surface is covered with solid lubricant powder, so spatter adhesion is significantly reduced, and at the same time, solid lubricant This prevents the powder from easily falling off, and as a whole it exhibits long-lasting and excellent sputter adhesion prevention properties.

The undercoat used in the present invention may be any material that has the function of solidifying the solid lubricant powder, and may be one or two selected from inorganic substances, organometallic compounds, and organic polymers.
It consists of more than one type of component, and examples of these components are as follows.

First, as inorganic substances, inorganic salts such as aluminum silicate, sodium silicate, aluminum phosphate, sodium borate, calcium borate, zeolite, bentonite, oxidized bow yarn, calcium oxide, titanium oxide, nickel oxide, oxidized Oxides such as molybdenum, metal powders and alloy powders such as copper powder, zinc powder, tin powder, brass powder, aluminum powder, and calcium heptadide,
Metal heptadides such as barium heptadide, nickel fluoride, manganese fluoride, and other inorganic fixing agents manufactured by Suzu Ikeya can be used.

Next, as organometallic compounds, organic boron compounds such as trimethyl borate, trioctyl borate, and trimethoxyboroxine, organosilicon compounds such as organochlorerane, organoalkoxysilane, alkylsilane, and polyorganopolysiloxane, and aluminum ethyl Organic aluminum compounds such as aluminum oxide, aluminum ethoxide, and methylaluminum dichloride, organic phosphorus compounds such as triethyl phosphate, triphenyl phosphate, and triphenite, as well as alkyl titanates, tetraalkoxy titanium polymers, and titanium. Various organometallic fixing agents such as organic titanium compounds such as acylate can be used.

Furthermore, as organic polymers, various synthetic resin vehicles such as acrylic resin, vinyl resin, polyester resin, epoxy resin, polyimide resin, fluorine resin M'i1, other natural resins, and oil-based resins are used. , surfactants bound with polyethylene glycol or polypropylene glycol, and other organic compounds can be used.

In addition, these fixing agents may be used alone or in combination of two or more.

It may be used by dispersing or dissolving it in a solvent, for example, in an amount of 5 to 60% by weight.

Examples of this application method include coating with a brush, a liquid dipping method, a fluid dipping method, a spraying method using a spray gun, and a method of filling an aerosol and spraying.

After drying and cooling as necessary, the undercoating process is completed.

Next, apply solid lubricant powder on top of this undercoat film! ! It is sipped.

This solid lubricant powder is a material with a layered crystal lattice structure in which the crystal structure is separated, such as powders of boron nitride, graphite, molybdenum disulfide, tungsten diMide, etc.
These may be used in combination as appropriate.

In such a solid lubricant powder, layered crystals are easily cleaved and exhibit lubricating properties.

In the present invention, it is preferable that the solid lubricant powder is dispersed in a solvent or water.

Further, the dispersion concentration of this solid lubricant powder is preferably in the range of about 15 to 40 degrees, and may be adjusted as appropriate to a concentration that is easy to apply.

Methods for applying the liquid mixture containing solid lubricant powder include brushing, spraying with a spray gun, and aerosol filling, but these methods may damage the adhesive layer, which is the bottom layer. Application by a spraying method is particularly preferable in order to avoid the above problems.

Alternatively, a method of inserting a nozzle coated with a solid lubricant into a container containing solid lubricant powder, or a method of filling solid lubricant powder with an aerosol and spraying it may also be used.

After this coating is completed, if necessary, air drying or heat drying is performed to complete the sputter layer prevention treatment according to the present invention.

As described above, according to the present invention, there is a coating layer made only of solid lubricant powder that exhibits lubricating properties on the outer surface of the torch nozzle, etc.
The adhesive that binds the solid lubricant and prevents it from falling off is located in the lower layer of the solid lubricant powder layer, and this lower layer is no longer directly bombarded by sputtering.

Therefore, the flying spatter always collides with the solid lubricant powder layer, and the solid lubricant separates or self-peeles to prevent spatter and skin contact, and the solid lubricant also damages the adhesive layer. Since the solid lubricant is firmly attached to the torch nozzle, etc., there is little chance of the solid lubricant falling off, and spatter adhesion is long-lasting not only in continuous arc welding but also in intermittent arc welding where start-up spatter occurs one after another. It exhibits preventive performance.

As explained above in detail, the present invention applies to torch nozzles, etc.
This is a method of forming two layers: 9 layers of undercoat as a fixing agent and 9 layers of topcoat consisting of solid lubricant powder that provides spatter adhesion prevention ability.

The adhesive undercoat layer solidifies the solid lubricant powder to maintain its ability to prevent spatter adhesion, and does not itself follow sputtering.

In addition, the solid lubricant powder exhibits excellent spatter adhesion prevention properties that are adhered to the surface.

Example 1: Disperse bentonite in water to a concentration of 10% by weight,
I brushed it on the torch nozzle and used it as an undercoat. After drying, fluorinated graphite dispersed in triclene at a concentration of 25 t% was sprayed with a spray gun for topcoating, and then dried. In other words, a torch nozzle having two coating layers was obtained by forming a film of bentonite as a solidifying agent in the lower layer and a film of graphite fluoride as a solid lubricant powder in the upper layer.

Using this torch nozzle, welding was performed under the following conditions and the degree of spatter adhesion to the nozzle was examined.

The degree of spatter adhesion was expressed as the cumulative arc time until spatter adhered to the nozzle tip and normal welding was no longer possible (until the nozzle diameter of 18 m+1 became 161 mm).

As comparative examples, two types were tested in the same way: one without treatment and one with only bentonite treatment.

Welding method Carbon dioxide gas semi-automatic welding conditions
Pa1 Welding current 800mm Arc voltage 80v Welding speed 400cm/min Wire diameter 1.2φ cod Gas flow rate 2017min Nozzle material Pure copper plating (inner diameter 1881)
Welding was repeated in a downward fillet welding cycle of 5 seconds arc and 1 second pause.

Table A shows the cumulative arc time results measured in the above tests.

Table A As shown in Table A, compared to comparative examples in which no treatment or only bentonite treatment was used, the embodiment of the present invention had an extremely long time, and all spatter was removed during this approximately 100 minutes. Normal welding was possible without this.

Example 2 A torch nozzle was prime coated with a 60% by weight ethanol solution of triethyl borate by brush coating.

Next, this torch nozzle was inserted into a container containing boron nitride powder to adhere the boron nitride powder to the undercoat layer and then dry it.

That is, triethyl borate was applied as a fixing agent to the lower layer, and boron nitride was applied as a solid lubricant powder to the upper layer, forming a two-layer coating.

Using the torch nozzle thus obtained, welding was performed under the following conditions and the cumulative arc time was measured in the same manner as in Example 1.

As comparative examples, a torch nozzle treated only with triethyl borate and a torch nozzle treated with a mixture of pocynitride and triethyl borate in a weight ratio of 5:10 were prepared and tested in the same manner.

Welding method Carbon dioxide robot welding Welding conditions Welding current 450A Arc voltage 467 Welding speed 450111/min Wire diameter 1.6φ Cod Gas flow rate 251/min Nozzle material Pure copper chrome plating C inner diameter 18f
f) Downward fillet welding Welding was repeated in a cycle of arc for 20 seconds and pause for 8 seconds.

Table B shows the cumulative arc time results measured in the above tests.

Table β As shown in the above table, even under these conditions where spatter generation is considered to be quite severe even during welding, the non-inventive examples obtained extremely excellent results.

In other words, compared to cases where only the adhesive is used alone, or when a mixture of 20% adhesive and solid lubricant is used to adhere the solid lubricant,
When these are made into a two-layer structure, the synergistic effect of each layer results in a continuous and excellent sputter adhesion prevention effect.

Claims (1)

[Claims] 1. A method for preventing spatter adhesion on welding torch nozzles, tips, jigs, etc., which comprises undercoating the surfaces of the welding torch nozzles, tips, jigs, etc. with an adhesive and then overcoating with solid lubricant powder. .