JPH0237829B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a welding twisted wire made by twisting a plurality of wires made of stainless steel and a nickel-based alloy, and which has particularly good feedability and straightness, and The present invention relates to a twisted wire that can obtain a sound welded part without porosity defects such as blowholes. [Prior art] The twisted wire for welding is, for example,
As disclosed in No. 117255 and No. 57-31494, it is made by twisting multiple wires into one, and even if the wire is moved straight, the welding arc will naturally move around the axis of the wire. Even when applied to narrow gap welding, penetration into the sides of the groove progresses uniformly and reliably, resulting in higher welding efficiency and superior quality welded joints compared to ordinary solid wire. can. Therefore, this type of twisted wire is rapidly becoming popular mainly for automatic welding such as TIG or MIG, and the wire material is also applicable not only to carbon steel but also to stainless steel, nickel-based alloys, etc. It's starting to happen. [Problems to be Solved by the Invention] By the way, twisted wires are manufactured by bundling a plurality of small diameter wires and giving appropriate twists using a wire twisting machine. A considerable amount of lubricating oil used in the process is attached to the wire surface, and this burns or decomposes due to the welding heat, generating a large amount of gas and causing pore defects such as blowholes. It is desirable to sufficiently remove lubricating oil by degreasing or the like. On the other hand, wires made of stainless steel or nickel-based alloys themselves have good corrosion resistance, so there is no need for copper plating like carbon steel wires.
It will be commercialized as a bare wire. Therefore, surface scratches created during wire drawing remain on the surface of the product wire, resulting in higher surface roughness than copper-plated wire. Therefore, the feeding resistance of wires made of stainless steel or nickel-based alloys is larger than that of copper-plated wires, and if the lubricating oil on the surface is removed to prevent the occurrence of pore defects, the feeding resistance will be higher than that of copper-plated wires. It tends to be larger than a fixed wire. In particular, twisted wires are made by twisting multiple strands of wire together as mentioned above, so they have poor straightness compared to normal solid wires, and furthermore, by being twisted, spiral grooves are formed on the surface. Therefore, the connection resistance becomes even larger. In addition, as the wire feeding speed is increased to meet the recent demand for improved welding efficiency, the feeding resistance increases at an accelerating rate, which not only reduces the straightness of the stranded wire but also causes damage to the feeding line. In some cases, the wire may buckle and become unable to feed. Under these circumstances, the present invention is aimed at a welding twisted wire made by twisting a plurality of wires made of stainless steel or nickel-based alloy, and which provides excellent wire feeding even when the wire feeding speed is increased. The present invention aims to provide a twisted wire that not only ensures feedability and straightness, but also allows a sound welded joint free of pore defects and the like to be obtained. [Means for Solving the Problems] The present invention provides a welding twisted wire made by twisting a plurality of wires made of stainless steel or nickel-based alloy, the wire having a tensile strength of 90 to 190.
Kg・f/mm ² , and the diameter (d) of the wires to be twisted
The gist lies in that the twisted pitch (pt) satisfies the relationship [15d≦pt≦45d] and that the amount of lubricant deposited is suppressed to 20 ppm or less. [Function] The chemical composition of the strands constituting the twisted wire according to the present invention is TIG of stainless steel or nickel-based alloy.
It is not different from solid wire used for welding, MIG welding, etc., and stainless steel is JIS Z.
3321 and AWS A5.9, and nickel-based alloys refer to nickel and nickel alloys as specified in AWS A5.14. All recognized stainless steels and nickel-based alloys in the art can be used in the present invention. On the other hand, the cross-sectional shape of the twisted wires made of metal as described above is not essentially the same as the cross-sectional shape of the twisted wires made of carbon steel, etc.
As shown in Figures A to C, the strands 1a have approximately the same cross-sectional shape,
1b,... in the cross section, each strand 1a, 1
The wires are bundled and twisted so that the lines connecting the centers P of b, ... form a regular polygon, and during welding, the arc is evenly distributed in the circumferential direction around the axis O of the twisted wires. It is designed to expand. Figure 2 A~
C is a cross-sectional view showing a twisted wire according to the present invention, in which a core wire ₁₀ is arranged in the center, and a line connecting the centers P of a plurality of wires 1a, 1b, . They are bundled and twisted around the core wire ₁₀ to form a polygon. FIG. 3 is a partial side view of the above-mentioned twisted wire, and the twisted pitch (pt) refers to the pitch of the twisted spiral of the wires 1a, 1b, . . . to be twisted. When applying such twisted wires to automatic welding equipment such as TIG welding and MIG welding, the most important issues are the straightness and feeding stability of the wires. However, as mentioned above, the twisted wire is made by twisting the thin metal wires 1a, 1b, . It also has the disadvantage of being prone to buckling when it encounters resistance, and has poor straightness and feedability compared to ordinary solid wire. In particular, when using uncopper-plated strands such as stainless steel or nickel-based alloys, the feeding resistance becomes even greater due to the high surface roughness of the strands as described above, resulting in poor straightness and feeding. Feedability deteriorates further. On the other hand, lubricating oil used in the wire drawing process and twisting process to obtain strands has the effect of improving the slippage on the surface of the twisted wire and increasing feedability, but on the other hand, it burns or decomposes due to welding heat. This causes gasification and causes pore defects such as blowholes. Therefore, in order to obtain a sound welded joint free of pore defects, it is necessary to minimize the amount of lubricant deposited. By the way, Figure 4 shows
Y308 series (JIS Z 3321) wire (diameter 0.53mm)
The subject is a twisted wire (diameter 1.6 mm) made by bundling and twisting seven wires to have the cross-sectional shape shown in Figure 2A.
This figure shows the results of an experiment investigating the influence of the amount of lubricating oil (oil) on the number of blowholes. However, the experimental conditions were as follows, and the number of blowholes generated in a bead with a length of 250 mm was determined by the naked eye. <Welding conditions> Welding current: 250A, DC-RP Welding voltage: 28V Welding speed: 30cm/min Shielding gas: Ar + 2% O ₂ , 25/min As is clear from Figure 4, sound welding with no porosity defects. In order to secure the metal, the amount of lubricant attached must be kept below 20ppm. However, in the case of twisted wires made of wires made of stainless steel or nickel-based alloys, if the amount of lubricant deposited is kept to such a low level, straightness and feedability will deteriorate significantly due to the reasons mentioned above. The original characteristics of the twisted wire cannot be fully utilized. Therefore, we conducted various studies to improve the feeding and straightness of twisted wires, and found that the twisting pitch (pt) could be adjusted appropriately to meet the above conditions according to the diameter (d) of the strands. For example, reduce the amount of lubricant
It has been found that even when the amount is kept below 20 ppm, straightness and feedability can be improved to a satisfactory degree. By the way, Figure 5 shows the wire feed when the twisted wire shown in Figure 2A was made using seven Y308 wires with a diameter of 0.53 mm, and the twisted pitch (pt) was varied. This shows the supply resistance. The diameter of the twisted wire is 1.6 mm, the tensile strength is 110 to 120 Kg・f/mm ² , and the amount of lubricating oil is 6
~10 ppm, and the feeding resistance was measured by the following method. <Method for Measuring Feeding Resistance> As schematically shown in FIG. is 3000 mm, and a feeding path with 150 mm radius bends is formed at three locations along the way.
The load applied to the wire feeding motor when each twisted wire was fed from the wire reel 2 was measured as the feeding resistance. As is clear from Figure 5, feeding resistance can be minimized by setting the twisting pitch (pt) within the range of 15d to 45d relative to the diameter (d) of the wires to be twisted. can be kept to a minimum. The reason why the feeding resistance changes significantly depending on the twist pitch can be considered as follows. In other words, if the twist pitch is too large relative to the diameter of the strands, the outer diameter of the stranded wires tends to be uneven, and the intersection angle between the helical direction of the strands to be twisted and the feeding direction becomes large. It is thought that the friction with the inner surface of the conduit cable increases and the feeding resistance increases. On the other hand, if the twisting pitch is too small, the mutual binding force due to twisting will be reduced and the strands will come apart when bent, which will distort the cross-sectional shape of the twisted wire and cause the outer diameter to become uneven. , it is thought that as a result of the decrease in the rigidity of the wire as a whole, the feeding resistance also increases.
In any case, if the twist pitch is set within the range of (15d to 45d) relative to the diameter of the strands, sufficient rigidity is guaranteed for the twisted wires, and sufficient binding force between the strands is ensured. A value that is guaranteed is guaranteed, and feeding resistance can be minimized. Further, as the feeding resistance is reduced, phenomena such as bending or buckling during feeding do not occur, so that the straightness of the twisted wire is improved. If an attempt is made to increase the wire feeding speed in order to improve welding efficiency, the feeding resistance will increase at an accelerated rate in proportion to the wire feeding speed. If the strength of the twisted wires themselves in the axial direction is insufficient, the wires may buckle within the conduit cable, making it impossible to feed them. Therefore, we thought that it was necessary to find out the strength in the axial direction that would not cause buckling even when the feeding resistance became considerably high, so we conducted an experiment and obtained the results shown in FIG. 7. In other words, Fig. 6 shows the values of the tensile strength and wire feeding resistance of the twisted wires extracted from the data of the examples described later, and in order to reduce the feeding resistance, it is necessary to It can be seen that the tensile strength of the material should be 90Kg·f/mm ² or more. However, if the tensile strength becomes excessive, the flexibility of bending along the feeding path within the conduit cable will decrease, feeding resistance will increase, the wear and tear of the conduit tube will become significant, and furthermore, the wires will be damaged. When twisting, the wires may break, making the twisting operation difficult. Therefore, in order to avoid these problems, the tensile strength of the twisted wire should be increased to 190 kg.
It is necessary to suppress f/ ^mm2 or less. The tensile strength of the stranded wire is determined by [tensile load of the stranded wire/cross-sectional area of the stranded wire].
This is substantially the same as the tensile strength of the strands. [Example] Example 1 C: 0.04% (weight %: same below), Si: 0.39%,
Mn: 1.50%, Ni: 9.87%, Cr: 19.82%, P:
The target was stainless steel with a chemical composition of 0.021%, S: 0.005%, balance Fe and unavoidable impurities. Various twisted wires having the cross-sectional shape shown in Figure A and having different tensile strength and twisting pitch were prepared, and their performance as welding materials was investigated. The results are shown in Table 1. In Table 1, the feeding resistance of the twisted wires was measured according to the method shown in Fig. 6, and the straightness was measured as shown in Fig. 8 when each wire was fed by the method shown in Fig. 6. A test wire W was made to protrude by 25 mm from the contact tip 6 at the end, and judgment was made based on the magnitude of the deviation width (x) of the tip of the wire W from the feeding center.

[Table] From Table 1, we can think of the following. Wires Nos. 1 and 3 are comparative examples in which the tensile strength of the twisted wires is insufficient, the feeding resistance is large, the straightness of the wires is poor, and the bead shape is extremely poor. Wire No. 2 is a comparative example in which the tensile strength of the strands is too high, and the strands break during the twisting process, making it difficult to manufacture the twisted wire itself. Wire Nos. 14 and 15 are comparative examples in which the twist pitch exceeds the specified range, and the wires tend to come apart due to insufficient binding force between the strands, making it impossible to feed them. Wires No. 16 and 17 are comparative examples in which the twist pitch is too short. In No. 16, the tensile strength of the strands is lower, so twisting is possible, but the outer diameter tends to be uneven and feeding is difficult. The resistance is large and the straightness is also poor. Also No.
With 17, the tensile strength of the wire is too high, making it difficult to twist in small pitches and causing wire breakage. On the other hand, wires No. 4 to 13 are examples that meet the specified requirements of the present invention, and have good twisting workability, good feeding resistance and straightness during welding, and a good weld bead can be obtained. ing. The amount of lubricant applied to these twisted wires was in the range of 6 to 9 ppm, and no blowhole defects were observed in the weld beads. Example 2 Using wires with the same chemical composition as those used in Example 1, we created four types of twisted wires with different cross-sectional shapes (each with a lubricating oil adhesion amount of 6 to 9 ppm), and evaluated the performance of each wire. Examined. The results are summarized in Table 2, and since all wires met the specified requirements of the present invention, good results were obtained in all performances.

[Table] Example 3 In this example, stainless steel or nickel-based alloy other than those mentioned above was used as the wire, and the performance as a twisted wire was investigated in the same manner as above. However, the cross-sectional shape of the twisted wires was as shown in FIG. 2A, and the degreasing conditions were set so that the amount of lubricant deposited was 20 ppm or less. Table 3 shows the chemical components of the wire and the performance test results.

【table】

【table】

〔Effect of the invention〕

The present invention is constructed as described above, but the key point is to limit the amount of lubricant applied to the twisted wire made of wires made of stainless steel or nickel-based alloy, and to improve the tensile strength and strength of the wire. By strictly specifying the twisting pitch, it is possible to minimize feeding resistance, ensure stable feeding performance and excellent straightness, and obtain extremely sound weld metal with no porosity defects. , we were able to further improve the performance of the twisted wire.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams illustrating the cross-sectional shape of the twisted wire, FIG. 3 is a partial side view of the twisted wire,
Figure 4 is a graph showing the relationship between the amount of lubricating oil deposited and the number of blowholes, Figure 5 is a graph showing the relationship between twisting pitch and feeding resistance, and Figure 6 is an explanatory diagram showing the method for measuring feeding resistance. , FIG. 7 is a graph showing the relationship between tensile strength and feeding resistance, and FIG. 8 is an explanatory diagram showing a wire straightness test method. 1a, 1b,...: Element wire, 2... Wire reel, 3... Pressure feeding roller, 4... Conduit cable.

Claims (1)

[Claims] 1. A welding twisted wire made by twisting a plurality of wires made of stainless steel or nickel-based alloy, the wire having a tensile strength of 90 to 190 Kg·f/
mm, and the diameter (d) of the wires to be twisted and the twisting pitch (pt) satisfy the relationship of the following formula, 15d≦pt≦45d, and the amount of lubricant attached is suppressed to 20ppm or less. Characteristic twisted wire for welding.