Dry coating composition and method for coating solid wire using same

Abstract

Disclosed are a dry coating composition and a method for coating a solid wire using same, the dry coating composition comprising: 50-95 wt % of polytetrafluoroethylene (PTFE); 5-30 wt % of wax; 40 wt % or less of at least one selected from the group consisting of molybdenum disulfide, talc, titanium oxide, and graphite; and 25 wt % or less of at least one selected from the group consisting of potassium stearate and sodium nitrite.

Description

Dry coating composition and coating method of solid wire using the same

[0001] The present invention relates to a dry coating composition and a method for coating a solid wire using the same.

[0002] MIG welding, a type of high-quality welding, uses wire. The wire is wound on a spool or stored in a pail pack. During welding, it passes through a feed roller and a welding torch cable, melted by the electric arc heat, and bonded to the base material. Therefore, ensuring excellent wire feedability, allowing the wire to pass smoothly from the wire feeder to the welding torch, is crucial for stable welding. Furthermore, recent welding efforts are increasingly focused on automation and high efficiency, necessitating more stable wire feed even at high feed speeds.

[0003] Typically, various wires, including wires for MIG welding, are gradually reduced in diameter as they pass through dies of various sizes from the initial raw wire to the final product, and are then drawn into the final product.

[0004] Factors affecting wire feedability in the wire drawing process include the drawing schedule based on the reduction ratio required to draw to the required diameter of the final product, the distribution of internal stress through adjustment of wire tensile strength or elongation deviations, and the straightness of the wire. Among these, the uniformity of the wire's internal stress distribution is an important factor to consider when determining wire feedability. It has been common to consider uniformity of internal stress distribution through adjustment of wire tensile strength or elongation deviations.

[0005] However, in the drawing process, as the wire is repeatedly drawn, the outer surface of the wire, that is, the surface that comes into contact with the die, becomes denser and harder than the center, and as the hardening is repeated, not only does the drawing of the wire become impossible, but the distribution of residual stress between the outer surface and the center of the wire becomes more uneven. Therefore, the simple adjustment of the drawing schedule according to the reduction rate and the management of the tensile strength of the drawn wire in the past have limitations in uniformly distributing the residual stress between the outer and inner surface of the final product wire.

[0006] In addition, the hardening of the wire surface due to continuous wire drawing causes wear of the die in contact with the wire and damages the surface of the drawing wire, which has a negative effect on the quality of the final product wire and ultimately acts as a factor in reducing the feedability of the wire during welding.

[0007] Therefore, to address surface hardening during the wire drawing process, a technology has been developed to treat the surface of solid wires for MIG welding by dispersing lubricants or coating agents in a wet solution. The highly volatile wet solution then evaporates, leaving residue on the wire surface that acts as a coating agent. Specifically, a lubricant containing alkali metal fatty acid salts such as stearic acid and oleic acid, along with substances such as molybdenum and graphite, has been developed. This lubricant, when applied to the wire, improves the wire's feedability.

[0008] However, if the lubricant as described above is used, the thickness of the lubricating film is formed thickly, which may result in defects in the welding results, such as increased fume generation and increased sputtering. In addition, even if coating using a solvent is performed as a wet coating, quality unevenness problems, such as reduced feedability, may occur due to the solvent remaining on the wire surface.

[0009] In particular, the wet coating method is carried out by spraying or dipping a wet liquid in which the coating material is dissolved using highly volatile organic solvents such as HCFC (Hydrochlorofluorocarbon) or IPA (Isopropyl alcohol). However, since organic solvents are used, the Clean Air Conservation Act (THC) must be complied with, and the facilities must be operated through periodic inspection and management, which requires high operating costs. In addition, there is a problem that separate facilities such as dust collection facilities must be built to solve various problems such as the risk of fire, harm to the human body, and environmental issues that may arise due to the volatilization of the solvent. Therefore, a new coating method that can minimize environmental pollution during the treatment of the solid wire surface is needed.

[0010] The present invention is intended to solve the problems revealed in the above-mentioned prior art, and one of the several objects of the present invention is to improve the arc characteristics and feedability of a solid wire coated using a dry coating composition.

[0011] Another object of the present invention is to provide a method for coating a solid wire, which enables a coating process to be performed with uniform coating quality and in an environmentally friendly manner by performing dry coating in powder form, rather than a wet coating method using a conventional solvent.

[0012] According to one aspect, a dry coating composition is provided, comprising: 50 to 95 wt% of polytetrafluoroethylene (PTFE); 5 to 30 wt% of wax; 40 wt% or less of at least one selected from the group consisting of molybdenum disulfide, talc, titanium oxide, and graphite; and 25 wt% or less of at least one selected from the group consisting of potassium stearate and sodium nitrite.

[0013] In one embodiment, the wax may be ethylene bis stearamide.

[0014] In one embodiment, the particle diameter of the PTFE may be 1 to 25 μm.

[0015] According to another aspect, a method for coating a solid wire is provided, comprising: (a) preparing the dry coating composition; and (b) applying the dry coating composition to the surface of the solid wire.

[0016] A solid wire coated with the dry coating composition of the present invention has the advantage of excellent arc characteristics and feedability during welding.

[0017] The coating method of the present invention has environmentally friendly and economical advantages compared to existing coating methods.

[0018] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the description of the invention or the composition described in the claims of this specification.

[0019] The following describes one aspect of this specification. However, the contents of this specification may be implemented in various different forms and are therefore not limited to the embodiments described herein.

[0020] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0021] When a range of numerical values ​​is stated herein, unless the specific range is otherwise specified, the values ​​have the precision of the significant figures provided according to the standard rules in chemistry for significant figures. For example, the number 10 includes the range of 5.0 to 14.9, and the number 10.0 includes the range of 9.50 to 10.49.

[0022] Dry coating composition

[0023] A dry coating composition according to one aspect of the present invention comprises: 50 to 95 wt% of PTFE (polytetrafluoroethylene); 5 to 30 wt% of wax; 40 wt% or less of at least one selected from the group consisting of molybdenum disulfide, talc, titanium oxide, and graphite; and 25 wt% or less of at least one selected from the group consisting of potassium stearate and sodium nitrite.

[0024] Here, dry coating means forming a coating layer by directly attaching a powder-state coating composition to the surface of a target material without adding a fluid such as an organic solvent or refrigerant.

[0025] PTFE (Polytetrafluoroethylene) is a polymer commonly known by its trade name Teflon, and is a type of fluorine resin with excellent heat resistance. PTFE lowers the coefficient of friction between the wire and the welding device, thereby improving the wire's feedability and enhancing moisture and tip wear resistance. Furthermore, the fluorine component contained in PTFE has excellent bonding strength with hydrogen, allowing hydrogen within the weld metal to be released during the formation of the weld metal, thereby also improving the weld wire's defect resistance.

[0026] The present inventors confirmed the excellent effect of PTFE and confirmed that when the PTFE is used as a base component of a coating composition to coat a wire, the arc characteristics and feedability of the wire can be improved, and thus completed the present invention.

[0027] In particular, the PTFE may be included in an amount of 50 to 95 wt%, preferably 55 to 90 wt%, and most preferably 60 to 85 wt%, based on 100 wt% of the total dry coating composition. When the weight % of PTFE in the dry coating composition satisfies the above range, the wire feedability, tip wear resistance, and defect resistance may be improved as the coating composition is coated on a solid wire.

[0028] For example, for 100 wt% of the total dry coating composition, PTFE 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, 65 wt%, 66 wt%, 67 wt%, 68 wt%, 69 wt%, 70 wt%, 71 wt%, 72 wt%, 73 wt%, 74 wt%, 75 wt%, 76 wt%, 77 wt%, 78 wt%, 79 wt%, 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, 85 wt%, 86 wt%, It can be 87 wt%, 88 wt%, 89 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, or a value between any two of these values. If the weight % of the PTFE exceeds the above range, the amount of fume generated during welding may increase, or the bead spreadability may deteriorate, thereby lowering the welding efficiency, and if it is below the above range, the feedability of the coated solid wire may deteriorate.

[0029] The particle diameter of the above PTFE may be 1 to 25 μm, and preferably 5 to 20 μm. Here, a particle diameter of 1 to 25 μm means that more than 90% by weight of the total PTFE particles have the above particle size distribution.

[0030] For example, the particle diameter of the PTFE may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm. If the particle diameter of the PTFE is less than the above range, the particle size may be too small compared to the surface roughness of the solid wire, so that the effect of reducing surface friction may be minimal, and if the particle diameter of the PTFE particle exceeds the above range, the PTFE particle may be coated too thickly on the surface of the solid wire, which may interfere with the current transmission with the contact tip during welding, so that the welding workability may deteriorate.

[0031] The wax acts as a lubricant and reduces internal friction when mixed with other solid particles of the dry coating composition, and when the dry coating composition is coated on a solid wire, reduces friction on the surface of the solid wire, thereby improving the feedability and arc characteristics of the wire.

[0032] In particular, the wax may be included in an amount of 5 to 30 wt%, preferably 10 to 25 wt%, and most preferably 15 to 20 wt%, based on 100 wt% of the total dry coating composition. When the weight % of the wax in the dry coating composition satisfies the above range, the coating composition can exhibit excellent applicability when coated on a solid wire, thereby enhancing resistance to rust.

[0033] For example, for 100 wt% of the total dry coating composition, the wax may be 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, or a value between any two of these values. If the weight % of the wax exceeds the above range, moisture resistance may decrease, resulting in deterioration of weld performance or an increase in lubricant residue, which may result in poor feedability. If it is below the above range, application properties may deteriorate, making it difficult to sufficiently secure resistance to rust and poor feedability.

[0034] The wax may be at least one selected from the group consisting of polyamide wax, polyethylene wax, and stearic acid metal salt wax, and preferably, the polyamide wax may be ethylene bis stearamide, but is not limited thereto. When ethylene bis stearamide is used as the wax, the coating composition may have excellent applicability and may have an excellent effect of reducing friction on the surface of the solid wire.

[0035] The above dry coating composition may further include at least one selected from the group consisting of molybdenum disulfide, talc, titanium oxide, and graphite. When the above dry coating composition further includes at least one selected from the group consisting of molybdenum disulfide, talc, titanium oxide, and graphite, the feedability of a solid wire coated using the coating composition may be further improved.

[0036] The above molybdenum disulfide has a pressure resistance of approximately 28000 kgf / cm 2As a lubricant, it has excellent extreme pressure resistance. In particular, it has excellent lubrication with a coefficient of friction of approximately 0.1 μ or less, and the minimum thickness required for one slip is only approximately 30 Å. At this thickness, 1 m 2 The amount required to cover the actual contact area is approximately 3 mm 3 (approximately 0.012 g). That is, even with a very small amount, the coating efficiency can be maximized. In addition, the lubricating effect of the molybdenum disulfide becomes more excellent when the friction surface and the sliding surface are parallel, and since the solid wire surface is oriented in the drawing direction, the friction surface and the sliding surface form a crystal orientation, so when the molybdenum disulfide is used as a coating composition, the feedability of the solid wire can be improved.

[0037] The above talc contains magnesium silicate as an additive called talc. The talc can also perform the function of improving the feedability of the wire by lowering the coefficient of friction.

[0038] The above titanium oxide is a material widely used as a photocatalyst, pigment, paint, food additive, etc., and can also be used as a lubricant. The above titanium oxide can also reduce friction within the coating composition and lower the coefficient of friction of the composition, thereby improving the feedability of the wire.

[0039] The above graphite is a solid carbon particle that can reduce the activation energy of the molybdenum element of the molybdenum disulfide by bonding with sulfur atoms (S), and can physically adsorb the molybdenum disulfide to increase adhesion during coating. Due to this stabilizing effect, when included in a coating composition, the feedability of the wire can be improved.

[0040] In particular, when the dry coating composition comprises 40 wt% or less of one selected from the group consisting of molybdenum disulfide, talc, titanium oxide, graphite, and combinations thereof, based on 100 wt% of the total dry coating composition, and the weight ratio of the molybdenum disulfide is 20 wt% or less, the weight ratio of the talc is 10 wt% or less, the weight ratio of the titanium oxide is 5 wt% or less, and the weight ratio of the graphite is 5 wt% or less, the feedability of a solid wire coated using the coating composition can be further improved.

[0041] Preferably, with respect to the total 100 wt% of the dry coating composition, the weight ratio of the molybdenum disulfide may be 2 to 15 wt%, the weight ratio of the talc may be 3 to 8 wt%, the weight ratio of the titanium oxide may be 1 to 5 wt%, and the weight ratio of the graphite may be 1 to 5 wt%, but is not limited thereto.

[0042] If the weight ratio of molybdenum disulfide exceeds the above range for 100% by weight of the entire dry coating composition, lubricant residue may remain inside the cable during welding, which may deteriorate the feedability and, accordingly, deteriorate the crack resistance.

[0043] If the weight ratio of the talc exceeds the above range for 100% by weight of the entire dry coating composition, lubricant residue may remain inside the cable during welding, which may deteriorate the welding performance, and thus, the arc characteristics may deteriorate.

[0044] If the weight ratio of the titanium oxide exceeds the above range for 100% by weight of the entire dry coating composition, lubricant residue may remain inside the cable during welding, which may deteriorate the feedability.

[0045] If the weight ratio of the graphite exceeds the above range for 100% by weight of the entire dry coating composition, lubricant residue may remain inside the cable during welding, which may deteriorate the welding performance, and welding may not occur normally as the amount of spatter increases, and the arc characteristics may become unstable.

[0046] The above dry coating composition may further include at least one selected from the group consisting of potassium stearate and sodium nitrite. When the above dry coating composition further includes at least one selected from the group consisting of potassium stearate and sodium nitrite, arc characteristics are improved, and thus stability can be secured during arc welding.

[0047] The above-mentioned potassium stearate is a fatty acid salt-based lubricant that has beneficial functions in improving wire freshness and controlling the amount of other additives attached. In particular, as a lubricant, it is excellent in reducing the coefficient of friction, and potassium, an alkali metal, has an arc-stabilizing effect, which can improve the arc characteristics of solid wires during coating.

[0048] The above sodium nitrite is a substance capable of adjusting the softening point and is an effective ingredient for high-speed dry surface coating. When the coating composition includes sodium nitrite, the coatability of the solid wire can be improved.

[0049] In particular, when the dry coating composition comprises 25% by weight or less of one selected from the group consisting of potassium stearate, sodium nitrite, and a combination thereof, with respect to the entire 100% by weight of the dry coating composition, and the weight ratio of the potassium stearate is 20% by weight or less and the weight ratio of the sodium nitrite is 5% by weight or less, stability during arc welding can be improved.

[0050] If the weight ratio of potassium stearate exceeds the above range for the entire 100% by weight of the dry coating composition, the arc length during welding may become longer, which may result in reduced bonding strength, insufficient penetration, and an increase in the amount of spatter may cause welding to not occur normally.

[0051] If the weight ratio of sodium nitrite exceeds the above range for 100% by weight of the entire dry coating composition, welding defects may occur due to moisture absorption, the arc length may become longer, the bonding strength may decrease, and a lack of penetration phenomenon may occur.

[0052] Coating method of solid wire

[0053] Below, a detailed description of a coating method for solid wire is provided. However, any details that overlap with the description of the dry coating composition described above will be omitted.

[0054] A method for coating a solid wire according to another aspect of the present invention comprises the steps of (a) preparing the dry coating composition; and (b) applying the dry coating composition to the surface of the solid wire.

[0055] In the past, the coating of the wire was performed by completely immersing the wire in a coating solution prepared by dissolving various components, such as lubricants, that can be included in the coating composition in a solvent such as IPA (isopropyl alcohol), drying it with hot air, and then volatilizing the solvent to perform the coating, or applying the coating to the welding wire using a sponge-shaped elastic body or a spray device.

[0056] This method is a wet coating method, and since it uses volatile solvents such as IPA or HCFC (hydrofluoric acid), there is a problem that the solvent may remain on the wire, which may cause unevenness in the coating, resulting in poor arc characteristics and deterioration of the feedability.

[0057] In addition, additional equipment such as dust collection equipment and heating equipment were required to volatilize the solvent remaining on the wire, and as volatile solvents remained within the factory, the risk of fire increased, environmental problems arose, and concerns about the health of workers deteriorated.

[0058] In order to solve these problems, the inventors of the present invention discovered that these problems can be solved by introducing a dry coating process in which the above-described coating composition is prepared by mixing it in a solid state such as a powder, and then coating is performed directly without a separate spraying process or wet process, thereby completing the present invention.

[0059] In particular, the coating method of the present invention has the advantage of significantly reducing the risk of fire, being an environmentally friendly process that does not require environmental regulations, and significantly reducing factors that pose a threat to the health of workers, since it does not use a volatile solvent containing alcohol for solid wire coating.

[0060] In addition, since there is no possibility of solvent residue, the unevenness due to coating is reduced, and thus the feedability and arc characteristics of the coated wire can be improved, it can be confirmed that the solid wire coating method of the present invention is an efficient and environmentally friendly process compared to the prior art, and the welding performance of the coated solid wire is also excellent.

[0061] The solid wire used in the above step (b) may be any one selected from the group consisting of a stainless steel solid wire such as STS 300 series or STS 400 series, a nickel alloy solid wire such as Inconel or Hastelloy, a mild steel solid wire, and a plated mild steel solid wire. Preferably, the solid wire may be a stainless steel solid wire or a nickel alloy solid wire, but is not limited thereto. When the solid wire is a stainless steel solid wire or a nickel alloy solid wire, there is an advantage in that excellent welding quality and cost-effectiveness can be secured when the coating method of the present invention is applied.

[0062] In the above solid wire coating method, first, the solid-state coating composition is placed in a coating box, and one selected from the group consisting of a rotating PCD, a non-rotating PCD, a ceramic tip, and a carbide tip is mounted on the coating box, and the coating composition is applied by passing the solid wire through it.

[0063] The above-mentioned rotary PCD, non-rotating PCD, ceramic tip, and carbide tip are hole-shaped machining tools that allow the wire to pass through the hole together with the coating agent, thereby uniformly coating the wire surface in all 360° directions. In particular, when the hole size is larger than the wire diameter, the coating amount on the wire surface can be optimized.

[0064] When applying the coating composition in the above step (b), the coating composition can be applied while processing the solid wire with a reduced surface area ratio, or can be applied without separate processing. If the coating composition is applied while processing with a reduced surface area ratio, the processing and coating are performed simultaneously without a separate post-processing process, which has the advantage that the solid wire can be used for welding together with the coating. In the case of applying without separate processing, if a wire that has already been reduced to the final product diameter in the drawing process is used, there is the advantage that the solid wire can be used for welding immediately after coating is completed in the same manner.

[0065] At this time, the roller and the coating box can be dust-collected to remove surrounding contamination sources due to fine particles generated during dry powder coating. By dust-collecting the roller and the coating box in the coating method, the possibility of the surface of the solid wire becoming contaminated can be significantly reduced, thereby making the quality of the solid wire coating more uniform. When the coating of the solid wire is uniform, the feedability and arc characteristics of the coated wire can be significantly improved.

[0066] Hereinafter, the embodiments of this specification will be described in more detail. However, the experimental results below represent only representative experimental results among the above embodiments, and the scope and content of this specification cannot be interpreted as being reduced or limited by the embodiments, etc. The effects of each of the various implementation examples of this specification that are not explicitly presented below will be specifically described in the relevant sections.

[0067] Example

[0068] Coating was performed on M-308L products (stainless steel solid wire) with a diameter of 1.2 mm using the coating compositions shown in Tables 1 and 2 below. Welding was performed under Ar+2% O2 conditions, which are welding gas conditions commonly used in MIG welding of stainless steel solid wire, and the weld quality was measured. The test conditions during welding are described in Table 3 below.

[0069] Classification (weight part) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 PTFE 70 70 9 56 56 0 60 55 55 60 60 Ethylene bis stearamide 20 20 52 0 10 20 25 20 520 Molybdenum disulfide 5 15 10 5 2 10 2 Potassium stearate 10 5 10 15 15 20 10 10 Talc 3 3 10 Titanium oxide 5 5 5 Graphite 2 3 Sodium nitrite 5

[0070] Classification (weight part) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 PTFE 40 50 55 55 55 55 50 60 55 Ethylene bis stearamide 25 5 10 10 40 Molybdenum disulfide 15 35 10 55 510 55 55 Potassium stearate 15 35 55 55 15 Talc 53 0 55 Titanium oxide 55 155 Graphite 55 52 55 Sodium nitrite 55 30 Calcium carbonate 25 Calcium stearate 20

[0071] Welding power supply cableWelding torch angle (°)Feeding rollerWelding current (A)Welding voltage (V)Stick-outWelding timeInverter (500A)3.5m, straight454rolls200~22024~2720mm3min

[0072]

[0073] Experimental examples 1-8

[0074] Experimental Example 1: Evaluation of the delivery system

[0075] To evaluate whether continuous welding is possible, the feedability was evaluated as “excellent” when the continuous welding time was 100 seconds or more, “good” when it was 80 seconds or more but less than 100 seconds, and “poor” when it was less than 80 seconds.

[0076] Experimental Example 2: Evaluation of Excessive Fume Generation

[0077] During welding, it was visually confirmed whether fume was generated in the form of vapor, and cases where it was generated excessively were marked and recorded.

[0078] Experimental Example 3: Evaluation of Excessive Slag Generation

[0079] The welding surface was observed to determine whether excessive slag was generated by non-metallic compounds during welding, and then recorded.

[0080] Experimental Example 4: Crack Resistance Evaluation

[0081] After welding, whether cracks were generated in the bead was evaluated, and whether cracks were generated at high temperatures thereafter was evaluated according to the JIS Z 3155 standard. If all standards were met, it was judged as “good”, and if any standards were not met, it was judged as “bad.”

[0082] Experimental Example 5: Evaluation of Residual Welding Debris

[0083] It was determined and recorded whether any substances such as slag generated during welding remained.

[0084] Experimental Example 6: Spatter Amount Evaluation

[0085] The ratio of the weight of the spattered weld metal to the weight of the total weld metal after welding is defined as the ratio of the spatter amount, and if the amount of spatter having a particle size of 1 mm or more exceeds 1.6% in the ratio (%) of the spatter amount, or if the ratio (%) of the total spatter amount exceeds 9%, the spatter amount is judged to be “excessive,” otherwise it is judged to be “normal.”

[0086] Experimental Example 7: Arc Stability Evaluation

[0087] In the above experimental example 5, if residue remained or the amount of spatter in the above experimental example 6 was excessive, the stability of the arc welding was considered to be low and was evaluated as “unstable”; otherwise, it was evaluated as “stable”.

[0088] Experimental Example 8: Evaluation of Defect Occurrence During Welding

[0089] It was determined and recorded whether common welding defects such as slag inclusion or porosity occurred after welding.

[0090] The evaluation results for the welding performance, excessive fume generation, excessive slag generation, crack resistance, residual dross, spatter amount, arc stability, and presence of defects during welding of the above experimental examples 1 to 8 are shown in Tables 4 and 5 below.

[0091] ClassificationExample 1Example 2Example 3Example 4Example 5Example 6Example 7Example 8Example 9Example 10SpeedinessExcellentExcellentGoodExcellentGoodGoodGoodGoodGoodExcellentExcellentFumeExcessiveGenerationXXXXXXXXXXExcellentGenerationSlagXXXXXXXXXXCrack ResistanceGoodGoodGoodGoodGoodGoodGoodGoodGoodGoodGoodResidualDrossXXXXXXXXXXSpatterAmountNormalNormalNormalNormalNormalNormalNormalArc StabilityStable ...

[0092]

[0093] Referring to Table 4 above, the solid wires coated with the compositions of Examples 1 to 10 exhibited excellent feedability during MIG welding, with no defects, no excessive slag and fume generation, and no residue remaining. In addition, the amount of spatter was within a normal range, and arc stability was maintained, confirming excellent arc characteristics during arc welding. In particular, in the case of Examples 1, 2, 4, 6, and 10, it was found that the feedability was further improved as the coating compositions included PTFE and wax in a specific content range.

[0094] ClassificationComparative Example 1Comparative Example 2Comparative Example 3Comparative Example 4Comparative Example 5Comparative Example 6Comparative Example 7Comparative Example 8Comparative Example 9Comparative Example 10Sending SpeedPoorGoodGoodGoodPoorGoodGoodGoodGoodGoodExcessiveFume GenerationXOXXXXXXXXExcessive Slag GenerationXOXXXXXXXXCrack ResistanceGoodGoodPoorGoodGoodGoodGoodGoodGoodGoodGoodResidualDrossXXXOOXOXXXSpatter AmountNormalNormalNormalExcessiveNormalNormalExcessiveExcessiveArc StabilityStableStableUnstableUnstableUnstableUnstableUnstableUnstablePresence of Welding DefectsXXXXXXXOXX

[0095]

[0096] Referring to Table 5 above, it can be seen that Comparative Example 1, in which the PTFE content of the coating composition is excessively low, has poor coating properties due to insufficient coating, and Comparative Example 2, in which the potassium stearate content is excessively high, has poor arc properties due to excessive generation of fume and slag.

[0097] In addition, it can be seen that Comparative Example 3, in which the content of molybdenum disulfide in the coating composition was excessively high, did not properly secure crack resistance at high and low temperatures. In Comparative Example 4, in which the content of titanium oxide was excessively high, it can be seen that residues of the coating composition remained, resulting in poor feedability. Similarly, in the case of Comparative Example 5, in which the content of talc was excessively high, residues easily remained, resulting in poor feedability and arc stability.

[0098] Comparative Example 6, in which the content of graphite in the coating composition is excessively high, shows poor feedability and poor arc stability as the amount of spatter increases. In Comparative Example 7, in which the content of wax is excessively high, lubricant residue remains, resulting in poor feedability and arc stability. In Comparative Example 8, in which the content of sodium nitrite is excessively high, it can be confirmed that defects occur during welding due to moisture absorption.

[0099] Finally, it can be confirmed that Comparative Examples 9 to 10, which used coating compositions that did not include wax, which is an essential component of the present invention, but additionally included other additives, also showed lower arc stability as the amount of spatter increased. Through these experimental results, it was confirmed that Comparative Examples 1 to 10 did not satisfy the content ratio of the components that the coating composition of the present invention satisfies, and thus the quality of the coated solid wire was lowered compared to Examples 1 to 10.

[0100] The description of this specification above is for illustrative purposes only, and those skilled in the art will readily appreciate that aspects of this specification can be readily modified into other specific forms without altering the technical concepts or essential features described herein. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0101] The scope of this specification is indicated by the claims set forth below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included within the scope of this specification.

Claims

1. PTFE (Polytetrafluoroethylene) 50-95 wt%; 5-30% by weight of wax; 40 wt% or less of at least one selected from the group consisting of molybdenum disulfide, talc, titanium oxide and graphite; and 25 wt% or less of at least one selected from the group consisting of potassium stearate and sodium nitrite; A dry coating composition comprising:

2. In paragraph 1, A dry coating composition wherein the wax is ethylene bis stearamide.

3. In paragraph 1, The above PTFE is a dry coating composition having a particle diameter of 1 to 25 μm. 4.(a) a step of preparing a dry coating composition according to any one of claims 1 to 3; and (b) a step of applying the dry coating composition to the surface of a solid wire; A method for coating a solid wire including: