JPS6123078B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lubricant and welding wire, which exhibits excellent lubricity and rust resistance particularly when wire-drawing metal materials, and also provides excellent lubrication by adhering to the surface of welding wire. The present invention relates to a lubricant that exhibits properties (feedability), electrical conductivity, etc., and a welding wire to which the lubricant is attached to the surface. In the following explanation, the lubrication performance of the lubricant will be the main issue, and specifically the lubricity (feedability) of the welding wire will be explained, but as is clear from the examples below, other characteristics are also considered. It is an excellent lubricant for wire drawing. Wires for automatic and semi-automatic welding have become extremely popular, mainly solid wires for carbon dioxide arc welding. However, flux-cored wire (hereinafter referred to as composite wire), which was also developed for carbon dioxide arc welding, has not become very popular despite its excellent workability and bead appearance. It has been pointed out that the reasons for this are not only the high price of the wire, but also the fact that the feedability of small-diameter wires is poorer than that of solid wires of the same diameter. In other words, the wire feedability is
It is extremely important to ensure good arc stability, bead appearance, and welding efficiency, and cannot be applied to automatic or semi-automatic welding unless feedability is satisfied. The reason why the feedability of the composite wire is poor is considered to be as follows. That is, the composite wire is
Generally, flux is filled in a thin-walled mild steel cylindrical casing of about 0.2 to 0.5 mm, so it is softer than solid wire, and since a seam is formed in the casing, it is fed under pressure with rollers. When feeding, the wire cross section tends to be deformed or buckled within the conduit tube, resulting in extremely large feeding resistance. For this reason, for large diameter composite wires of 2.4 mmφ and 3.2 mmφ, a knurled or geared feed roller is used. But 1.2mm
For small diameter wires such as φ and 1.6mmφ, dedicated knurled or geared feed rollers are not widely used, and flat rollers equivalent to solid wires are used, so it is necessary to attach a lubricating substance to the wire surface. This is intended to reduce feeding resistance. By the way, in the case of solid wires, one way to increase the lubricity of the wire surface is to apply copper plating to the wire surface and then apply a large amount of hydrogen-containing lubricant such as mineral oil, animal or vegetable oil, synthetic oil, or metal soap. This is commonly done. However, in the case of flux-cored wires, except for expensive seamless wires, these lubricants can penetrate through the seams and cause porosity and weld cracks due to hydrogen during welding. 300～
It is necessary to remove hydrogen generation sources as much as possible by baking at about 450°C. On the other hand, graphite, which has low hygroscopicity and does not have a hydrogen source, can be used as a lubricant.
Various techniques have been developed in which molybdenum disulfide, graphite fluoride, fluorocarbon oil, fluorocarbon resin, etc. are used alone or in combination of two or more types, but each has the following disadvantages. In other words, powders such as graphite, graphite fluoride, molybdenum disulfide, and fluororesin adhere to the wire surface in large quantities, which tends to deteriorate the mechanical properties of the deposit, and molybdenum disulfide and fluororesin have poor insulation properties. Since it is expensive, there is a risk of electrical conduction failure during welding. Regarding fluorine oil, it is stated in Japanese Patent Publication No. 48-34984 that it can be used as a lubricant for welding wires, but a satisfactory lubricating effect could not be obtained when applied to flux-cored wires. Furthermore, regarding lubricants containing graphite or molybdenum disulfide mixed with liquid fluororesin, or lubricants containing arc stabilizers, Japanese Patent Publications No. 50-38626, No. 51-4503,
It is disclosed in No. 51-43987, etc. However, since all of these lubricants are in the form of a base, it is difficult to make the amount of adhesion uniform, and the coating film tends to be too thick. In addition, when these lubricants are applied to wire drawing processing, they are applied to the wire surface in a die box, and then the coating film becomes thinner and more uniform as the surface is destroyed in the die, but liquid lubricants In comparison, sufficient drying cannot be expected, and the wettability to the wire surface is also not good, so there is a problem in wire drawability (die basic unit, etc.). Under the above-mentioned circumstances, the present inventors solved the problem of hydrogen intrusion into welding wire, especially composite wire.
We have been conducting intensive research with the aim of developing a lubricant that can significantly improve feedability without causing problems with electrical conductivity or weld metal. As a result, it was found that a lubricant that meets the above objectives can be obtained by specifying the types and proportions of the ingredients as shown below, and that this lubricant also has an excellent effect on improving the feeding performance of solid wires. Furthermore, it was confirmed that this lubricant was also excellent as a lubricant for wire drawing, and the present invention was finally completed. That is, the composition of the lubricant according to the present invention is that 0.1 to 10 parts by weight of a solid fluorine-based low polymerization degree compound having a molecular weight of 2,500 to 10,000 and belonging to an intermediate region between low molecules and polymers, generally called oligomers, in a solvent; The gist is that 0.1 to 20 parts by weight of graphite and/or molybdenum disulfide are blended and made into a suspension. The gist of the structure of the welding wire according to the present invention is that the lubricant is uniformly adhered to the surface of the wire. The structure and effects of the present invention will be explained below with reference to the types of constituent components of the lubricant and the basis for limiting the blending ratio. Not a thing,
Any suitable changes and implementations within the range that can comply with the spirit of the above and below are included in the scope of the technology of the present invention. The volatile solvent acts as a dispersion medium for fine powder dispersoids consisting of graphite and/or molybdenum disulfide and fluorine-based low polymerization degree compounds, and quick-drying solvents such as trichlorethylene and trichlorotrifluoroethane are used. be done. Since these agents quickly volatilize after being applied to welding wires, no harmful elements such as chlorine or hydrogen remain on the wire surface, and they can be applied to composite wires without any problems. If a slightly volatile solvent is used, it will take a long time to dry naturally after applying the lubricant, or a separate drying device will be required, which will reduce productivity, and the wire drawing process will not be carried out in a semi-dry state. If this is done, the lubricity deteriorates and problems such as die roughness occur. In addition, examples of fluorine-based low polymerization degree compounds (hereinafter abbreviated as fluorine-based compounds) include polyfluorinated olefin-based telomers represented by polytetrafluorinated ethylene telomers; Must be of a range. This is because, as will be made clear in the experimental examples below, satisfactory wire drawability and wire feedability cannot be obtained with liquid fluorine oils whose molecular weight is less than 2,500, e.g. 500 to 1,500;
Fluorine resin (manufactured by DuPont, USA, product name:
Teflon (etc.) has a large particle size and a high specific gravity, so it has poor dispersibility and cannot be uniformly adhered to the wire surface. Note that the fluorine compound having the above-mentioned preferred molecular weight range has not only excellent dispersibility as described above but also uniform adhesion to the wire surface.
When used alone, the lubricity is insufficient, and it is necessary to use it in combination with graphite and/or molybdenum disulfide to achieve the purpose. Moreover, in order to uniformly disperse these in a volatile solvent and obtain a stable suspension, the fluorine-based compound, graphite, and/or molybdenum disulfide must be used as fine powder, and the particle size is particularly small. A stable suspension can be reliably obtained by using fine powder of 3 μm or less. However, when preparing the powder simply for coating welding wires, it is desirable to use ultrafine powder of 1 μm or less in consideration of the electrical conductivity and the effect on the deposited metal. That is, when preparing for wire drawing, the dispersoids are uniformly spread over the wire surface during the wire drawing process, so as long as the stability of the suspension is maintained, dispersoids with a relatively large particle size are used. However, conductivity etc. are not inhibited. However, in the present invention, the blending ratio of the fluorine-based compound and graphite and/or molybdenum disulfide is
The latter was limited to 0.1 to 10 parts by weight, and the latter to 0.1 to 20 parts by weight, which were determined in consideration of application to welding wire. The lubricating thin film attached to the surface of the welding wire according to the present invention is made of a fluorine low polymerization degree compound with a molecular weight of at least 2,500 to 10,000, graphite and/or molybdenum disulfide in order to obtain good feedability and weldability. 0.001 to 0.1 per total wire weight
It is necessary to adjust the proportion by weight of the fluorine-based low polymerization degree compound with a molecular weight of 2,500 to 10,000 and graphite and/or molybdenum disulfide in this lubricating thin film, depending on the amount of the lubricant used on the wire surface. Since it is evenly attached, it is proportional to the original proportion. That is, since the weight ratio of the fluorine-based compound and graphite and/or molybdenum disulfide contained in the lubricating oil is the former (0.1 to 10) to the latter (0.1 to 20), the weight ratio of the two attached to the wire surface is The weight ratio is the former/latter=0.5 to 99 from the following formula. former/latter = (0.1~10)/(0.1~10)+(
0.1~20) /(0.1~20)/(0.1~10)+(0.1~
20) Taking the lower and upper limits of each range, the former/latter = 0.1/20.1 to 10/0.1 = 0.5 to 99 The amount of the lubricant thin film formed on the welding wire was set within the above range. If it is less than 0.001 part by weight based on the total weight of the wire, sufficient lubricity will not be obtained, whereas if it exceeds 0.1 part by weight, problems such as a decrease in the physical properties of the weld metal and electrical conductivity will occur. be. In addition, this lubricating thin film all has a molecular weight of 2500~
10,000 fluorine-based low polymerization degree compound and graphite and/or molybdenum disulfide, the ratio is 0.5 to 99.0, respectively, in the same way as the previous formula, compared to the proportion of the lubricant composition used excluding the volatilized solvent. Parts by weight, 1.0 to 99.5 parts by weight. That is, Figure 1 is a graph examining the relationship between the amount of solid fluorine compound (polytetrafluoroethylene telomer) added to the liquid lubricant and the feeding resistance of welding wire (the dashed line in the figure is Figures 2 and 3 also show the amount of fluorine-based compounds, the number of current fluctuations, and the amount of increase in carbon in the weld metal. This is a graph examining the relationship between The horizontal axis of the graph represents the amount blended into the volatile solvent, but in the explanation of the text, it is simply expressed as parts by weight. As is clear from these graphs, if the amount of the fluorine compound blended is less than 0.1 part by weight, the lubricating film becomes extremely thin, making it impossible to obtain sufficient feedability and drawability. on the other hand
If it exceeds 10 parts by weight, the number of current fluctuations will increase, and the arc will become unstable due to a decrease in current conductivity.
Moreover, carbon invades the weld metal, resulting in a decrease in mechanical properties. Note that FIG. 1 shows the effect of adding a fluorine-based compound alone, and in the case of a single blend, even if the blending ratio is increased, the feed resistance value cannot be lowered to 3.2 kg, which is the limit feed resistance value. Therefore, the wire feeding resistance and the number of current fluctuations were investigated by keeping the blending ratio of the fluorine compound constant at 0.1 parts by weight and changing the blending ratio of graphite or molybdenum disulfide, as shown in Figures 4 and 5. Further, FIG. 6 is a graph in which the relationship between graphite and molybdenum disulfide and the blending ratio of each of them alone was investigated in order to confirm the influence they have on the weld metal. As is clear from these results, if the blending ratio of graphite or molybdenum disulfide is less than 0.1 parts by weight, the above-mentioned limit feeding resistance value cannot be secured even if it is used in combination with a fluorine compound. 20 again
If the amount exceeds 1 part by weight, especially in the case of molybdenum disulfide, the insulating property is high, and together with the insulating property of the fluorine-based compound, poor current conduction becomes significant. Furthermore, if the amount exceeds 20 parts by weight, the amount of carbon or sulfur in the weld metal increases and the mechanical properties deteriorate. Note that it is preferable to use 10 parts by weight or less. The conditions and method for measuring the wire feeding resistance and the number of current fluctuations shown in Figures 1 to 6 above are as follows. [Welding wire] Composite wire for carbon dioxide arc welding (mild steel, 50Kg
(using titania-based flux for high-strength steel), wire diameter 1.6 mmφ [Lubricant] After removing the wire drawing lubricant from the surface of the wire drawn to 1.65 mmφ, a suspension liquid lubricant (solvent : trichlorotrifluoroethane,
Dispersoid: Polytetrafluoroethylene telomer (polytetrafluoroethylene telomer, graphite or molybdenum disulfide) with a molecular weight of 3500) is continuously dipped and coated, and skin-passed with a die to form a 1.6mm
Finish to φ. [Wire feeding resistance] Semi-automatic welding wire feeding device shown in Fig. 7 (1: torch, 2: 3m conduit tube,
3: 300mmφ loop to increase load, 4: Feeding motor, 5: Feeding roller, 6: Test wire,
7: Measure the feeding resistance of the wire when inching feeding with a feed motor voltage of 10V using a spool. The lower the measured value, the better the feeding performance, 1.6mm
In the case of a composite wire of φ, the resistance value must be 3.2 kg or less to avoid arc instability. On the other hand, solid wires of the same diameter have high rigidity, so sufficient feeding performance can be obtained even if the feeding resistance value is around 5 kg. [Number of current fluctuations] As a guide for current conductivity, welding is performed downward for 1 minute on a flat plate under the following conditions: welding current 300A, welding voltage 28V, welding speed 40cm/min, carbon dioxide gas 20/min, at 10A.
The above number of current fluctuations was measured, and the average value was determined by repeating the test 10 times. Note that the wire according to the present invention may be further treated with the lubricant of the present invention after being treated with another lubricant. For example, calcium, barium, lithium,
Consists of one or more lubricating substances such as magnesium and sodium metal soaps and one or more carrier agents such as calcium carbonate, barium carbonate, soda carbonate, lithium carbonate, lime, mica, titanium oxide, etc. Wire is drawn to a predetermined size using powdered lubricant, oil, liquid such as mineral oil, polybutene, or paste lubricant containing hydrogen, and after removing hydrogen by baking, the lubricant of the present invention is applied by dip coating or It can be applied by methods such as skin path drawing. The present invention is roughly constructed as described above, and its effects can be summarized as follows. (1) A volatile solvent is used as a dispersion medium, a fluorine-based low polymerization degree compound with a specific molecular weight is used as a dispersoid,
By using a specific amount of graphite and/or molybdenum disulfide, wire feeding resistance can be significantly reduced. Moreover, there is no fear of adversely affecting the arc stability or the mechanical properties of the deposited metal. (2) Therefore, not only ordinary solid wires and large-diameter composite wires, but also small-diameter composite wires can be applied to automatic or semi-automatic welding without any problem. (3) Since the lubricant of the present invention reduces not only wire feeding performance but also resistance during wire drawing, it can be effectively used as a lubricant for wire drawing of various wire rods. In particular, if this lubricant is applied before finishing wire drawing of composite wires, etc., it is possible to simultaneously suppress die wear and achieve uniformity of lubricant adhesion to the wire surface, resulting in high quality products with excellent feedability. Welding wire can be obtained. (4) This lubricant has good electrical conductivity and does not impede arc stability. Furthermore, since it also has a surface protection effect, welding wires with this adhered to the surface have good rust resistance, and deterioration during storage is prevented as much as possible. Next, an experimental example will be shown. Various lubricants shown in Table 1 were applied to the surface of a flux-cored wire for carbon dioxide arc welding with a diameter of 1.6 mm (mild steel casing: 50 kg for high-strength steel, flux: titania type), and the drawability of each wire was determined.
The feedability, conductivity during welding, increase in carbon and sulfur in the deposited metal, welding workability, and rust resistance of the wire itself were investigated. The results are shown in Table 2. However, the test method was as follows. [Wire drawing method] Continuous wire drawing machine, die schedule: 3.2φ → 1.6φ
(mm) Wire drawing speed: 200 m/min, 350 m/min, 450 m/min [Lubricant attachment method] When wire drawing is performed: When wire drawing is not performed by crimping at the time of flattening with each die: Finished drawing to 1.6 mmφ After the wire is drawn, the wire drawing lubricant is removed, and the lubricant of the present invention is dip-coated again. [Wire feeding resistance] and [Number of current fluctuations] Same as above [Welding conditions] Welding current: 320A, welding voltage: 30V, melting speed: 30
cm/min, power polarity: DC-RP, shielding gas: carbon dioxide 20/min, base material: JISSM-50A, thickness 19mm [Rust resistance test] Using a Ducycle weather tester, 35
℃・1 hour dry → 25℃・1 hour wet cycle
Repeat this for 24 hours and observe the state of rust on the wire surface.

【table】

【table】

[Table] From Tables 1 and 2, the following can be considered. (1) Conventional lime-calcium soap powder lubricant (No. 1) has good wire drawability and electrical conductivity, but has high wire feeding resistance, slightly unstable arc, and cannot be expected to have rust resistance. . Furthermore, in order to prevent deterioration of the physical properties of the weld metal, baging treatment after wire drawing is essential. (2) Although the molybdenum disulfide-graphite powder lubricant (No. 2) has good wire drawability, wire feedability, and electrical conductivity, it significantly degrades the quality of the weld metal and causes unstable arcing. It also has poor rust resistance. (3) Powder lubricant made of fluororesin (No. 3)
Although it has good wire drawability, wire feedability, and rust resistance, it has extremely poor current conductivity and poor arc start and arc stability, making it unusable. It also has a considerable adverse effect on the physical properties of the deposited metal. (4) Liquid lubricant made of fluorine oil (No. 4, 5)
cannot be applied before finishing wire drawing because it has poor wire drawability. Further, even when applied after finishing wire drawing, wire feeding performance is insufficient. (5) Fluorine oil-graphite-molybdenum disulfide paste lubricant (No. 6) has good wire feedability, welding workability, and rust resistance, but has poor wire drawability and conductivity, and Adversely affects the physical properties of weld metal. (6) Suspension lubricant (No. 7,
8) has insufficient wire drawability, and if applied before finishing wire drawing, satisfactory wire feeding performance cannot be obtained.
Welding workability and rust resistance are also insufficient. When applied after finishing wire drawing, excellent welding workability and rust resistance are exhibited, but wire feedability is still insufficient. (7) On the other hand, the lubricants (No. 9 to 15) that satisfy the requirements of the present invention are excellent in all of wire drawability, wire feedability, electrical conductivity, welding workability, and rust resistance, and are It does not reduce the physical properties of the metal.

[Brief explanation of the drawing]

Figures 1 to 6 are graphs showing the basis for limiting the blending ratio of fluorine-based compounds, graphite, and molybdenum disulfide;
FIG. 7 is a schematic diagram showing the apparatus used to measure wire feed resistance. 1...Torch, 2...Conduit tube, 3
...Loop, 4...Feed motor, 5...Feed roller, 6...Test wire.

Claims (1)

[Scope of Claims] 1. 0.1 to 10 parts by weight of a fluorine-based low polymerization degree compound having a molecular weight of 2,500 to 10,000 and 0.1 to 20 parts by weight of graphite and/or molybdenum disulfide are suspended in a volatile solvent. A lubricant characterized by being 2. The lubricant according to claim 1, wherein the volatile solvent is trichlorethylene and/or trichlorotrifluoroethane. 3. The lubricant according to claim 1 or 2, wherein the fluorine-based low polymerization degree compound is polytetrafluoroethylene telomer. 4 In claim 1, 2 or 3,
A lubricant in which a fluorine-based low polymerization degree compound, graphite and/or molybdenum disulfide are all fine powders of 3μ or less. 5. The lubricant according to claim 4, wherein the particle size of the fine powder is 1 μm or less. 6 In claims 1 to 4 or 5,
A lubricant for drawing metal wire. 7. The lubricant according to claim 6, wherein the metal wire is a welding wire. 8 A lubricating substance is attached to the surface of the welding wire in an amount of 0.001 to 0.1% based on the total weight of the wire, and the lubricating substance is at least 0.1 to 10 parts by weight of a fluorine-based low polymerization degree compound with a molecular weight of 2,500 to 10,000, graphite and/or Alternatively, a welding wire comprising 0.1 to 20 parts by weight of molybdenum disulfide. 9. The welding wire according to claim 8, wherein the weight composition ratio of the fluorine-based low polymerization degree compound and graphite and/or molybdenum disulfide is 0.5 to 99.0. 10 In claim 8 or 9, in the lubricating substance, a fluorine-based low polymerization degree compound of 0.5 to 99.0
Part by weight, graphite and/or molybdenum disulfide
Welding wire containing 1.0 to 99.5 parts by weight. 11. The wire according to claim 8, 9 or 10, wherein the fluorine-based low polymerization degree compound is polytetrafluoroethylene telomer. 12. The wire according to claims 8 to 10 or 11, wherein the fluorine-based low polymerization degree compound, graphite and/or molybdenum disulfide are all fine powders of 1 μm or less. 13. The wire according to claims 8 to 11 or 12, wherein the welding wire is a small diameter flux-cored wire.