TWI231240B - Plating-free solid wire for welding - Google Patents

Abstract

A plating-free solid wire for welding of the present invention contains C: 0.04 to 0.12 mass%, Si: 0.5 to 1.1 mass%, Mn: 1.0 to 1.7 mass%, Ti: not more than 0.03 mass%, and remainder Fe. In addition, the expression: Si+Mn+(10xTi) <= 2.5 is satisfied, where Si, Mn, and Ti denote the contents of respective elements in the wire. The tensile strength of the wire is 900 to 1300 (N/mm<2>). A potassium compound is present in an amount of 2 to 10 ppm in terms of potassium; MoS2, 0.01 to 0.5 g per 10 kg of the wire; and an oil containing polyisobutene, 0.3 to 1.5 g per 10 kg of the wire, on the surface and/or immediately under the surface of the non-plated wire. With such a constitution, it is possible to improve both the wire feedability and the arc start characteristics.

Description

1231240 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to an unplated solid welding wire made of unplated steel wire, and particularly relates to a medium plate (a plate having a thickness of 2 mm to 4 mm) ) Or semi-automatic welding or automatic welding of thin plates (thickness less than 2 mm), unplated solid welding wire with excellent wire feedability and arc initiation. [Prior art] Currently, especially in the thin-plate welding process of the automotive industry, the efficiency has been promoted, and the welding speed has been increased. On the other hand, in order not to reduce the quality of the welding, it is desired to provide a method capable of shortening the time required for the arc to stabilize as soon as possible after the arc is ignited. And, the need exists even when the arc is repeatedly turned on / off frequently. However, in the case of a copper-plated welding wire, copper-plating chips are deposited on the inside of a pipe, a welding tip, or the like, and the feedability is easily impaired, so it is difficult to maintain excellent arc-ignition properties for a long time. However, there is no method to improve the arc initiation property without copper plating. That is, since copper is not plated, there is a disadvantage in that oxidation of the surface of the welding wire is promoted near the top of the arc, and an oxide film is easily attached to the tip of the welding wire after the welding is completed. In addition, if an arc occurs in this state, the oxide film functions as an insulator and deteriorates arc-ignitability. Therefore, it is desirable to reduce the oxide film as much as possible in order to improve the arc-initiating property of a non-copper wire. Since -6-(2) 1231240 is the majority of the oxide film, it is composed of oxides of Fe, Si, Mn, and Ti, which are the main components of solid welding wire. Therefore, in order to maintain good arc ignition, it is necessary to control the The amount of components (Si, Mn, Ti) added. In order to maintain excellent arc initiation even if there is no exchange or sweeping of the catheter and inner tube for a long time, it is not only necessary to reduce the amount of clogging of the metal chips, improve the feeding performance of the welding wire, and the stability of the arc, but also To optimize the chemical composition, even if there is some insulation on the tip of the welding wire, the ability to break through the insulation and stably energize it, that is, to increase the strength of the welding wire is required. Among the conventional technologies for improving arc ignition performance (including the stability of the arc and the feeding performance of the welding wire), the technologies involving uncoated copper wires include JP 1 999-342494 and 1 999-4798 1 etc., and Conventional technologies that do not specifically limit copper plating but limit the chemical composition of the welding wire include JP-A 200 1 -1 29683, JP 1 994-23 5 84, and JP 1 993-23 8 84. However, none of these conventional techniques satisfies the requirements described in combination with the tensile strength of the welding wire. No technology has been developed that focuses on controlling the oxide film attached to the tip of the wire. Therefore, using the above-mentioned conventional technology, there is a limitation in sufficiently improving the arc-ignition property. SUMMARY OF THE INVENTION The present invention has been made in view of the problems described above, and an object thereof is to provide an uncoated solid welding wire capable of simultaneously improving wire feedability and arc ignition performance. The unplated solid welding wire of the present invention contains C: 0.0 4 to 0 · 12 quality (3) (3) 1231240% by weight, Si: 0.5 to 1.1% by mass, Mn: 1.0 to 1.7% by mass, Ti: 0.03% by mass or less, and the rest is Fe. Here, control the content of Si, Mη, Ti so that they satisfy the mathematical formula (1)

Si + Mn + (10x Ti) ^ 2.5 (1) (In the above formula, Si, Mn, and Ti are the contents of each element in the welding wire) and the tensile strength of the welding wire is 900 ~ 1 300 (N / mm2). At least one oil selected from the group consisting of potassium compounds, MOS2, mineral oils, animal and vegetable oils, and synthetic oils is present on and / or directly below the surface of the unplated welding wire. At this time, the potassium compound is present in terms of potassium It is 2 to 10 ppm, the amount of MOS 2 present is 0,1 to 0.5 g per 10 kg of welding wire, and the amount of the oil is 0.3 to 1.5 g per 10 kg of welding wire. According to the above configuration, an unplated solid wire for welding that is not plated can obtain an extremely excellent arc striking effect. Here, the following meanings are on the surface of the welding wire and / or directly below the surface. In consideration of the existence of fine depressions on the surface of the welding wire, the surface of the welding wire refers to a state in which an object substance is attached to the surface of the welding wire, and directly below the surface means a state in which the object substance exists inside the depression. In the unplated solid welding wire, it is desirable that the particle diameter of the MoS2 is 0.1 to 10 / z m. And more desirably, the K compound is K borate. [Embodiment] -8- (4) 1231240 The present invention will be described in more detail below. The effects of the present invention applied to a solid wire for MAG welding will be described in detail below. As described in the conventional art, in the case of a solid copper-plated welding wire, the deposition of plating debris inside the catheter or the tip becomes a problem ', which increases the possibility of impairing the feedability and arc initiation. Therefore, an attempt was made to improve feedability and arc initiation by using a solid welding wire composed of a non-copper-plated steel wire as a base material. However, as another problem, it was confirmed that a significantly larger amount of oxide film was formed near the tip of the wire after completion of welding than in the case of a solid copper wire. Fig. 1 (a) shows the case of a copper-plated welding wire. The oxide film attached to the tip of the welding wire is thin, and the current is easy to conduct during arc initiation. In contrast, Fig. 1 (b) shows a case of a non-copper-plated welding wire. The thickness of the oxide film attached to the tip of the welding wire makes it difficult to energize the arc. This is because in the case of an unplated wire, oxidation of the wire surface is promoted directly above the arc during the welding process. The inventors have found that when the upper limit of Si, Mn, and Ti as the residue forming agent is set for the oxide film, the content of these residues is controlled, and the addition amount of these residue forming agents can be reduced to an appropriate amount. The amount of the oxide film. In addition, even if the oxide film attached to the tip of the welding wire can be made thin and kept small, as long as the oxide film is an insulator, it is easy to hinder current flow. In order to obtain a smoother arc-initiating property, it is necessary to break through the insulator as early as possible to flow current. One way to achieve this is to increase the tensile strength of the wire. When the tensile strength of the wire is set to be high, the squeezing force of the tip of the wire against the object to be welded becomes stronger. As a result, the insulator is quickly destroyed, and an arc can be generated more quickly. -9- (5) 1231240 Figures 2 (a) and 2 (b) show the current energization conditions during arc initiation when the tensile strength of the welding wire is low and when the tensile strength is high, respectively. When the tensile strength of the welding wire is high, the squeezing force of the welding wire is high, and the insulator on the tip of the welding wire can be quickly destroyed. In addition, when an appropriate amount of K, which is an alkali metal, exists on the surface of the welding wire or directly below the surface of the welding wire, it is easy to emit electrons, so that the arc creep is promoted to rise above the droplet. Figures 3 (a) and 3 (b) are shown in A graph showing the difference in arc creep when arc is initiated when K is not present on the wire surface and when K is present on the wire surface. As shown in the figure, when K is present on the surface of the wire, the creep of the arc is promoted. As a result, it is possible to achieve a stable arc-igniting property. The potassium source used as the Jp arc stabilizer is preferably potassium borate. It is easy to obtain fine particles of potassium borate. By using potassium borate in combination with an oil as a viscosity modifier, it is difficult for potassium borate to come off the surface of the wire. The oil is at least one oil selected from the group consisting of mineral oil, animal oil, vegetable oil, and synthetic oil. In addition to potassium borate, potassium stearate, potassium palmitate, potassium oleate, potassium behenate, and the like as organic salts of potassium, and potassium glass powder, potassium feldspar powder, and fluorosilicic acid as inorganic potassium compounds can be used. Potassium and so on. However, organic potassium compounds having a carbon chain length such as potassium stearate used in wire drawing lubricants and the like can easily fall off the surface of the wire even if they coexist with oil. M0S2 and oil have the effect of stabilizing the feedability of the wire by being present in an appropriate amount on the surface of the wire or directly below the surface of the wire. Because the welding wire can be stably delivered even at the moment of arc starting, if this component is present on the surface of the wire (6) 1231240 or directly below the surface of the wire, the arc starting error can be greatly controlled. In addition, as the oil, it is most desirable to effectively retain M0S2 on the surface of the welding wire. An analysis method of each component will be described below. [K analysis method] About 20 g of a cut sample of a welding wire to which K is attached is prepared with a length of about 20 mm to 30 mm. A mixed liquid of hydrochloric acid and hydrogen peroxide was poured into a quartz beaker, and the cut sample was added to the quartz beaker for immersion for several seconds, and then the cut sample was taken out, and the remaining liquid was filtered. The atomic absorption method was used to measure the K concentration in the filtered liquid, and the amount of K attached to each 10 kg of welding wire was quantified. The washing liquid was filtered, and then the filter paper was dried. The filter paper was treated with white smoke to dissolve MOS2, and Mo (a) was quantified by atomic absorption method. Then, the welding wire washed with ethanol was immersed in hydrochloric acid (HCl: H2O: = 1: 1) to dissolve, dissolved in MOS2, filtered with filter paper, and then dissolved in MOS2 by white smoke treatment, and quantified Mo by atomic absorption (b). The total amount of Mo (a) + Mo (b) was converted by M0S2 and the mass of the wire was divided to measure the coating amount of M0S2 per 10 kg of wire. (Quantitative analysis method of oil amount) -11-(7) 1231240 A carbon tetrachloride solution containing at least one kind of oil selected from the group consisting of mineral oil, animal oil, vegetable oil, and synthetic oil at a certain concentration is prepared and used as Use of standard solution. Prepare a cut sample of about 20 g of welding wire with a length of about 20 mm to 30 mm. The cut sample was then immersed in carbon tetrachloride and washed, and the washing liquid was measured by the ultraviolet absorption method, and compared with the standard liquid, and the oil adhesion amount per 10 kg of the welding wire was measured. Next, each component added to the wire composition of the present invention and the reason for limiting the composition will be explained. Φ [C: 0.04 to 0.12% by mass] If the amount of C added is less than 0.04% by mass, the tensile strength of the welding wire is reduced, so the arc strikeability is deteriorated. On the other hand, if it exceeds 0.12% by mass, the tensile strength of the welding wire becomes too high, thereby hindering the feedability of the welding wire. [Si: 〇_5 to 1.1% by mass] If the amount of Si added is less than 0.5% by mass, the tensile strength of the welding wire is lowered, so the arc initiation property is deteriorated. On the other hand, if the amount of Si added exceeds 1.1% by mass, oxides are likely to be formed at the tip of the wire, and arc initiation is also deteriorated. [Mn: 1.0 to 1.7 mass%] If the amount of Mn added is less than 1.0 mass%, the tensile strength of the welding wire is reduced, so the arc initiation property is deteriorated. On the other hand, if the amount of Mn added -12- (8) 1231240 exceeds 1 · 7% by mass, it is easy to form an oxide at the tip of the wire, and the arc initiation property is also deteriorated. [Ti: 0.03 mass% or less]

Ti is an element effective for improving arc stability. But it is also one of the ingredients that are most likely to cause residue. Therefore, it is necessary to control the content thereof to not more than 0.03% by mass. If the content of Ti exceeds 0.03% by mass, oxides are liable to be formed at the tip of the welding wire, and the arc initiation property is deteriorated. Lu [Mathematical formula Si + Mn + (10xTi) 値: 2.5 or less] When Si, Mn, and Ti are used as the content of each element, if Si + Mn + (10x Ti) 値 exceeds 2.5, it is easy An oxide is formed at the tip portion, which deteriorates arc-ignitability. By setting Si + Mn + (10xTi) to 2.5 or less, slag can be reliably reduced. In addition to C, Si, and Mn, other elements may be appropriately added as needed, as long as the effect of the present invention is not impaired. As such an element, Cr, Mo, V, Nb, etc. can be mentioned. [Tensile strength of welding wire: 900 to 1 300 N / mm2] If the tensile strength of the welding wire is less than 900 N / mm2, the strength of the welding wire is insufficient, and arc initiation is deteriorated. On the other hand, if it exceeds 1300 N / mm2, the tensile strength of the welding wire becomes too high, so that the feedability of the welding wire is hindered. As a method of arbitrarily controlling the tensile strength of a welding wire, a manufacturing method of a welding wire for welding -13- 1231240 〇) is exemplified. As a manufacturing equipment for welding wire, it is extremely important to control the manufacturing cost. Therefore, the welding wire of the present invention is premised on the premise that it is manufactured using equipment that eliminates the annealing step from the manufacturing process. A specific manufacturing method will be described below. First, the "raw wire" of the welding wire is produced by hot rolling. This raw thread is treated with pickling with hydrochloric acid or the like, and then drawn by cold working. The pickling process is a step of chemically removing scale from the raw wire produced during hot rolling. This oxide scale can also be removed by mechanical means such as bending or screwing. For MOS2 and Kφ, etc., it can be applied during the drawing process, or processed to the final product diameter, and then mixed with polyisobutylene-containing oil and applied. In order to control the tensile strength of the welding wire within the scope of the claims for the diameter of the final product, the rolling temperature and reduction ratio of the hot rolling during the original wire processing can be adjusted, or the reduction of the cross section during the cold drawing process can be adjusted. rate. In the wire drawing step of bringing the diameter to the final product diameter, a wire die, a micro mill, or a roller wire drawing die is used to process the welding wire. By optimizing the hot rolling conditions, that is, by controlling the rolling temperature and optimizing the reduction in area, the annealing step can be omitted from the manufacturing process. In this case, if the tensile strength of the welding wire exceeds 1 300 (N / mm2), it is also a method to use a micromill or a roller drawing die to draw the wire and control the work hardening to the specified strength as much as possible. As another method for controlling the tensile strength of the welding wire, a method of adjusting the amount of C (carbon) added to an appropriate amount is effective. The addition of Si, Mn, Ti, etc. can also increase the tensile strength of the wire. However, as described above, this will cause the oxide film on the tip of the wire. When C is added -14-(10) (10) 1231240, C reacts with oxygen to form CO or C02 and returns to the protective gas. In this way, if C is used, the level of wire tensile strength can be controlled without increasing the cause of the occurrence of an oxide film. However, when the tensile strength of the welding wire is controlled by C, which is the chemical composition of the welding wire, it is of course a prerequisite that the mechanical properties of the welding metal are sufficiently satisfied. [Wire adhesion amount of potassium compound: 2 to 10 ppm in terms of potassium] If the amount of potassium compound adhesion on the wire surface or directly below the wire surface is less than 2 ppm in terms of potassium, it is difficult to achieve creep of the arc to the upper part of the droplet , Can not get good arc ignition. On the other hand, if the amount of the potassium compound attached is higher than 10 ppm in terms of potassium, it may cause a clogging inside the catheter, and the feedability may deteriorate. [The attachment amount of M S 2 with a particle size of 0.1 to 1 0 // m: 0.01 to 0.5 g per 10 k g of welding wire] The particle size of M0S 2 is preferably from 0.1 to 10 # m. If the particle diameter of M0S2 is less than 0 · 1 // m, slippage cannot be achieved, and good feedability cannot be obtained. On the other hand, if the particle diameter of MoS2 exceeds 10 // m, slip properties are obtained, but MoS2 is likely to be peeled off from the surface, causing clogging and poor feedability. If the adhesion amount of MoS2 is less than 0.01 g per 10 kg of welding wire, slippage is insufficient, and feeding is unstable. In addition, if the adhesion amount of MoS2 exceeds 0.5 g, it becomes a cause of clogging and the feedability is deteriorated. [Selection of at least one oil of -15- (11) 1231240 from the group consisting of mineral oil, animal oil, vegetable oil, and synthetic oil: 0.3 to 10 kg of welding wire. If selected from mineral oil, animal oil, vegetable oil, and synthetic The amount of adhesion of at least one oil per 10 kg of the wire is less slippery and insufficiently fed into the unstable. If the oil exceeds 1 stopper, the feedability becomes poor. As an example of a synthetic oil, isobutan. Examples of animal oils and vegetable oils include fats, rapeseed oil, palm oil, and the like. Examples of the mineral oil include sub-oil. Examples Hereinafter, examples will be described in comparison with comparative examples which depart from the scope of the present invention. Table 1 below shows the welding conditions, and Table 2 below shows the price. In addition, all of the following are comparative examples based on a solid wire composed of a copper-plated steel wire having a wire diameter of copper. In the following examples and comparative examples, oil containing polyisobutylene as a main component was used. 1 · 5g] oil composed of 0.3, then .5g, can be exemplified as a plug, can be used for tallow machinery oil, ingots to evaluate the arc's arcability of the appraisal of the example · 2 mm All the oil is (12) 1231240 Table 1 Shielding gas _ 100% C〇2 Welding current 200 (A) Welding wire protruding length, 20 (mm) Torch angle _, _ ,,-Vertical test board one. SM490 Welding posture_ _ Bead on plate (horizontal welding) Wire diameter .. diameter 1.2mm Table 2 Arc strikeability _-Evaluation point is stable ...._ 2 points slightly stable-1 point unstable _ 0 points

In the welding test, an operation in which an arc generation time was 3 seconds and an arc stop time was 30 seconds was used as one set, and the set was repeated. In this 100 group, according to the total number of evaluation points ^ t _ M 4, according to the criteria of Table 3 below, it is graded 0 -17- (13) 1231240 Table 3

Total number of evaluation points 171 to 200 points ◎ 121 to 170 points 〇 61 to 120 points △ 0 to 60 points X

The results are shown in Tables 4 and 5 below. Comparative Examples 1, 3, 5, 11, 13, 15, 17 are examples in which one or two of them are lower than the conditions specified in the present invention, and they have poor arc ignition properties. In particular, since the wire slip properties of the comparative examples 15 and 17 were significantly inferior, arc initiation properties were also extremely poor. In addition, Comparative Examples 2, 4, 6, 7, 8, 9, 10, 12, 14, 16, 18 are examples in which one or two of them are higher than the conditions specified in the present invention, and their arc ignition properties are also poor. . In particular, in Comparative Examples 2 and 12, the tensile strength of the welding wire was too high, and the feedability was impeded, so the arc initiation property was extremely poor. Comparative Example 14,

After a long time of welding, 1, 18, it is easy to produce blockages. In this case, the arc-igniting performance also becomes extremely poor. On the other hand, Examples 19 to 29 satisfying the requirements of the present invention are excellent in arc initiation properties. In Examples 20A and 24A, potassium stearate was used as a K source. Other examples use potassium borate. In addition, Examples 20A and 24A using potassium stearate were slightly inferior in arc initiation in continuous welding. Examples 20B and 24B are examples in which the particle size of MoS2 deviates from the lower limit of the particle size of the ideal MoS2 of the present invention by 0.07 (# m) and the upper limit of the particle size of the ideal MoSa of the present invention is 1 8 ( # m) For example, compared with Examples 20 and 24, the results showed that the feeding stability was slightly worse, and the arc initiation performance was somewhat worse. -18- (14) 1231240 De mm stabbing mm mm #i side mm Μ delete mm μ

SP account x &lt; l &lt;

X ο &lt; &lt; &lt; l &lt;

X &lt;

X &lt;] ιοο · ΐs 6Ό inch ο ιοαι'Ι —loli 000 5 Vo 9 · 0 ΓΙ ΙΊ 5 8101 ΙΟΟΙΌ 5 Ϊ · Ι 1001101 3Ι0§ h S (m r /) Leak

9.1 8.1 Η Inch · I W ΜΗ 90 w HM MH M N w TT NM TT 30§-s〇2 95 900 —5 — 00000 ΤΓΟ— 9Γ0 0000 mm NM 6S i SO SO ΗΌ UO Inches sςιοι (md d) Inches

IF inch (SIII / M)

0101 OS- 096 OUI 05oolcslli OS 05 §1 06 π 05— ΟΠΐ 0 卜 8 OIICSIII οςιοοι OS OH

(u XOI) + US + S

ίίζζττ 66.ΐπί · ι Kloil inch inch lesil e inch τQz.z NM LUl 6Z / ICV11 ZVl inch inch loil ST 1CSII inch · ICNI α · i LVl ocnlT (次 _ ») 负 chain # ^ 进 失 us is u SO i ΙΟΌ 100 1010 100 1W ΙΟΌ go ΙΟΌ NM IQlol SO 1010 100 ΙΟΌ 9ΓΙ い ΐ · LI · N ς · 151 N or NNNNNNNN CNI 寸 8810 uo 99 Ό Is 08Ό Bu 8101 SI S6.0Isllol nh is 06ΌorT Icvll inch Ό ss inch 001.0

60Ό 900 slol— 900 90Ό 90ΌΙ 600 SO SO SO— inch 0101— 6lgl— 90Ό 80Ό 60101 90 Ό— ΗΌ SO

ON inch

81 LI N Si H N cslI TT

0 qJ-A -19- (15) 1231240 Reference potassium stearate potassium stearate SK 11 Arc strike evaluation results 0 ◎ 〇〇 ◎ ◎ ◎ ◎ 〇 〇 〇〇 ◎ 〇 ◎ ◎ Oil containing polyisobutylene (g / l〇kg) 00 0 oo 0 oo 0 oo 〇 r—H 11 a4 00 d ON 〇os c5 ON 〇 os 0 Ον 〇 ON 〇inch 〇On 〇MoS2 particle size (// m) 00 0 CNl r— &lt; Inch rH 〇〇〇VsO 0 〇CO rH ΙΟ 0 06 τ—Η 〇 t—H 10 CN CM ί ..... 4 OO t—H M0S2 (g / l〇kg) ο 0 〇〇Oi 0 CNl CNl 〇ON s inch o VO 0 VD ^ -Η Ο MD r — *-4 Ο S ο 〇VO CSI 〇CN CN CD 00 〇K (p pm) UO v〇VO CO 0 〇〇〇 MD r- wire drawing Tensile strength (N / mm2) 〇 g CN 〇00 04 rH g CNl f—H τ—H dec T ~ ί § t—H r * H Ο ΝΝτ—Η τ—Η 〇 σ \ τ—Η r— H § gr—4 § ^ ~ (§ r—H § r_ i S1 + M11 + (10x Ti) csi CNI r- οά r ^ oi r- r—H c4 CN CO CN oi 0 * oi bu CN ο * rH οί ι &gt; · y 4 oi r- CN r- bu! &gt; · r- oi wire chemical composition (mass%) * r—H 〇τ—Ή O t—H 〇rH 〇r-H 〇fH 0 r— H 〇rH 〇r—Η 〇 t-Η ο rH 〇 rH 〇rM A 〇r-H 〇t-H 〇at-H cs CO t-H &lt; N CO r__ 《oa CO rH inch rH § t · H rH rH rH r * H CN r—H CN rH ^ ~ 4 rH c— OJ r 1 i 〇r- 〇 ... 0 〇rH CO un 〇§ 〇〇〇 οο ο § 0 〇〇§ 〇§ 〇§ 〇U Inch o 0 t— &lt; 〇rH r—H 〇rH tH 〇〇δ 〇g 〇g 〇g 0 S ci 〇〇〇〇〇〇〇2 ON &lt; c PQ CNi 04 CO CNl &lt; Ά CM VO CM 00 CNl ON CN

-20-

Claims (1)

1231240 (1) r Amend Patent application scope No. 921 08 145 Patent application Amended on January 7, 1994 1 · An unplated solid welding wire containing C: 0.04 to 0.1 2% by mass' Si: 0.5 to 1.1% by mass, Mn: 1.0 to 1.7% by mass, Ti: 0.03 mass% or less, the rest is controlled by Fe content of Si, Mn, and Ti so that they satisfy the mathematical formula (1) Si + Mn + (10x Ti) ^ 2.5 (1) S i, Mn, T i in the above formula Respectively the content of each element in the welding wire; And the tensile strength of the welding wire is 900 ~ 1 300 (N / mm2). On the surface of the unplated welding wire and / or directly below the surface, there are potassium compounds, MOS 2 and mineral oil, animal oil, vegetable oil and synthetic 〇1〜〇. 5 At least one oil selected from the group consisting of oil. At this time, the potassium compound is present in an amount of 2 to 10 ppm in terms of potassium. Μ 〇S 2 is present in an amount of 0.1 to 0.5 kg per 10 kg wire. g, the oil is present in an amount of 0.3 to 1.5 g per 10 kg of welding wire. 2. The unplated solid welding wire according to item 1 of the scope of the patent application, wherein the particle size of the MOS 2 is 0.1 to 1 〇 // m. 3. The unplated solid welding wire according to item 1 of the scope of the patent application, wherein the K compound is potassium borate.