JPH07303995A - Wire for gas shield arc welding - Google Patents

Abstract

PURPOSE:To reduce generation of sputter and to significantly reduce unstable condition of arc like short time short circuit between wire and molten pool, arc breakage, etc., so as to sufficiently reduce generation of welding defect and fatigue of worker. CONSTITUTION:An impurity in wire surface is controlled to <=5mug per 1cm<2> apparent wire surface area and a Ca quantity in total wire is controlled to <=10ppm, a surface Ca quantity to 3ppm. Also, a mass not passing a filter paper having 10mum hole size is controlled to <=40wt% mass of total wire surface impurity, a copper content 4 (in term of copper in case of copper compound) in total wire surface impurity to 30wt.%. Further, in the wire containing wire surface impurity, Na and/or K is contained by 0.1 to 10ppm respectively, in a wire solid surface part, a solid surface Na and/or solid surface K is contained by <=0.1ppm in total. A total oxygen quantity of wire is controlled to 30 to 200ppm as well as a surface oxygen quantity to 20 to 180ppm.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to improvements in gas shielded arc welding wires.

[0002]

2. Description of the Related Art Gas shielded arc welding used in the manufacturing process of industrial machinery, automobiles, steel frames, etc. has been required to improve performance year after year, and improvements have been made to achieve high speed, high quality and high efficiency. Has been done. As a means of improving such a gas shielded arc welding method, examination of shield gas components and inverter control of a welding power source have been conducted.

However, in order to efficiently obtain a high quality welded portion at low cost, it is most important to prevent defects due to instability of the welding arc and maintain a stable welding arc for a long time. The instability of the welding arc here means not only fluctuations in the arc length that can be seen with the naked eye, but also short-term arc breakage that cannot be recognized with the naked eye and short-term short circuit between the wire and the molten pool (hereinafter, short circuit). That) is included. When the welding wire becomes unstable, the shape of the molten pool fluctuates irregularly, and defects such as undercuts and overlaps in the bead shape are likely to occur.
Further, in the multi-layer welding, a slag inclusion defect is likely to occur. In addition, the unstable arc promotes the generation of spatter to deteriorate the welding quality, causes fatigue of the operator, and lowers the welding efficiency.

Various efforts have been made in the past to stabilize the arc. For example, in Japanese Examined Patent Publication No. 3-77035, after the residual lubricant is removed, the carboxylate potassium salt is fixed on the wire surface, and the amount of the fixed amount and the amount of free iron powder or free copper powder generated in the fixing process are regulated. Due to
Techniques for stabilizing the arc discharge phenomenon have been proposed.
Further, in Japanese Patent Laid-Open No. 61-3696, the amount of copper powder remaining on the surface of a wire having a copper plating is regulated to prevent abrasion of a conductive copper chip and blockage of a flexible conduit tube for wire feeding. Technology is proposed.

[0005]

However, in the above-mentioned conventional technique, it is not possible to sufficiently reduce the occurrence of short-time arc breaks and short circuits which cannot be recognized by the naked eye. It was not enough to prevent the fatigue of the person.

The present invention has been made in view of the above problems, and it is possible to reduce the occurrence of spatter and to significantly reduce arc instability such as short-circuiting between the wire and the molten pool and arc breakage. It is an object of the present invention to provide a gas shielded arc welding wire capable of sufficiently reducing the occurrence of welding defects and the fatigue of workers.

[0007]

The wire for gas shielded arc welding according to the present invention regulates the impurities on the wire surface to 5 μg or less per 1 cm ^{2 of the} apparent surface area of the wire, and the amount of Ca in the entire wire is 10 ppm or less and the surface. It is characterized in that the amount of Ca is regulated to 3 ppm or less.

However, in the present invention, the mass of impurities on the wire surface is measured by the following method. Mass of wire surface impurities Ultrasonic cleaning of wire in organic solvent such as petroleum ether,
After removing the wire body from the organic solvent, the organic solvent is filtered using a filter paper (membrane filter) having a pore size of 0.2 μm, and the residue on the filter paper is used as wire surface impurities. The mass of wire surface impurities is the weight of the residue on the filter paper. According to this method, except for the delivery lubricant and the rust preventive oil and fat which are soluble in an organic solvent, dust other than that, residual wire drawing lubricant, and wire drawing lubricant degenerated,
It is possible to effectively measure copper powder, iron powder, and an alkali or alkaline earth compound attached as an arc stabilizer.

The mass of the wire surface impurities is per cm ^{2 of the} apparent surface area of the wire. Therefore, the wire surface impurity amount is obtained by dividing the total amount of extracted impurities by the apparent surface area of the wire. The apparent surface area of this wire is
It is expressed by the following mathematical formula 1.

[0010]

## EQU1 ## (Apparent wire surface area) = (Average value of wire diameter) × (Circular constant) × (Length of wire) The amount of surface Ca is measured by the following method. Surface Ca content The wire is dipped in an appropriate acid such as hydrochloric acid to completely dissolve the plating layer on the wire surface, and further to slightly dissolve the underlying wire core portion. Then, the total weight of the wire before being dipped in the acid is a gram, the weight of the wire dissolved is b gram, and the weight of Ca existing in the dissolved wire is determined by acid analysis to obtain c ₁ and g, when the Ca concentration of the remaining wire core without being dissolved was d ₁ (%), since the amount of Ca was present in the wire core, which is slightly dissolved is calculated by b × d _1/100 , The amount of surface Ca is calculated by the following mathematical formula 2.

[0011]

[Number 2] surface Ca amount _{(ppm) = {(c 1} -b × d 1/10
0) / a} × 1000000 In claim 2, the pore diameter is 0.2 μm as described above.
Of the wire surface impurities extracted by filtering using a No. filter paper, the mass of the wire surface impurities that do not pass through the filter paper (membrane filter) with a pore size of 10 μm is set to 40% or less of the total wire surface impurity mass, and the total wire surface The amount of copper component of impurities (copper compound is converted to copper) is 30% or more.

In the present invention, the wire surface impurities,
0.1 to 1 of Na and / or K is contained in all the wires including wire surface deposits such as lubricant for feeding and oil and fat for rust prevention.
Contains 0 ppm.

Further, in the present invention, when the wire solid surface portion is formed by combining the plating layer, the interface between the plating layer and the wire core portion, and the wire core portion surface of about several tens of μm, It is characterized in that the total amount of solid surface Na and / or solid surface K is 0.1 ppm or more.

In this case, the solid surface Na is measured by the following method. The solid surface Na wire is degreased with an organic solvent and immersed in an appropriate acid such as hydrochloric acid to completely dissolve the plating layer on the wire surface and further dissolve the wire core portion thereunder in a small amount. Then, the total weight of the wire before being immersed in the acid is a gram, the weight of the wire dissolved is b gram, and the weight of Na existing in the dissolved wire is determined by acid analysis to obtain c ₂ Gram, the Na concentration of the wire core remaining without being dissolved is d
₂ when a (%), the amount of Na was present in the wire core, which is slightly dissolved is calculated by b × d _2/100, solid surface Na is calculated from the following equation 3.

[0015]

Equation 3] the solid surface Na (ppm) = {(c 2 -b × d 2/1
00) / a} × 1000000 Similarly, the solid surface K is measured by the following method. The solid surface K wire is degreased with an organic solvent and immersed in an appropriate acid such as hydrochloric acid to completely dissolve the plating layer on the wire surface, and further to slightly dissolve the wire core portion thereunder. Then, the total weight of the wire before being dipped in the acid is a gram, the weight of the wire dissolved is b gram, and the K weight existing in the melted wire is determined by acid analysis to obtain c ₃ Gram, and the K concentration of the wire core remaining without being melted is d
₃ when a (%), the amount of K that existed wire core which is slightly soluble is determined by b × d _3/100, solid surface K is determined from the following equation 3.

[0016]

Equation 3] the solid surface K (ppm) = {(c 3 -b × d 3/10
0) / a} × 1000000 In the invention according to claim 5, the total oxygen content of the wire is 30 to 200 ppm, and the surface oxygen content is 20 to 180 p.
pm.

However, the total amount of oxygen in the wire is measured by the following method. Total oxygen content of the wire Degrease the surface of the wire with an organic solvent, and measure the oxygen content after drying it as the total oxygen content (ppm).

The surface oxygen content is measured by the following method. Surface oxygen content The surface oxygen content (ppm) is obtained by subtracting the oxygen content of the wire core after grinding and removing the thickness of 50 μm or more on the wire surface from the total oxygen content of the wire.

[0019]

[Function] From the result of observing the welding arc phenomenon using a high-speed video camera and a data recorder and the analysis result of the wire and the wire surface, the substance adhering to the wire surface is the electrical contact between the current-carrying tip and the wire. The physical contact,
It was found to destabilize the arc. The wire surface deposits include dust, residual wire drawing lubricant, deteriorated wire drawing lubricant, copper powder, iron powder, and alkali or alkaline earth compounds deposited as an arc stabilizer. is there.

In other words, considering the electrical contact between the current-carrying tip and the wire, all substances attached to the wire surface have a bad influence. However, the effect depends on the substance, and substances with large dimensions have a greater adverse effect than the difference in composition, and metal wire surface impurities tend to have less adverse effects than non-metal wire surface impurities. Admitted.

Although various methods of analyzing the substance adhering to the wire surface are conceivable, as a result of many experimental studies by the inventors of the present application, the method of ultrasonically cleaning the wire in an organic solvent such as petroleum ether is the most preferable. It was effective. Since this method can easily analyze a wire of several kg or more, it is possible to accurately capture a trace amount of wire surface impurities.

The degree of ultrasonic cleaning at this time must be so strong that the sound wire surface is damaged and copper powder and iron powder are produced, and the wire surface is not damaged. Regarding the cleaning time, the ultrasonic cleaning time of the wire is gradually increased, and the cleaning is completed when the amount of impurities on the wire surface becomes stable.

Further, in the present invention, from the viewpoint of electrical contact between the current-carrying tip and the wire, the amount of wire surface impurities (μg) is defined by the amount per 1 cm ^{2 of} apparent surface area of the wire.

Further, it has been found that, in order to reduce the amount of spatter generation, in addition to reducing the impurities on the wire surface to stabilize the arc, it is necessary to reduce the amount of Ca in the wire. In particular, it is effective not only to reduce the Ca content of the entire wire, but also to reduce the plating and the interface between the plating and the wire core and the Ca on the surface of the wire core.

Although various methods of analyzing Ca on the surface of the wire are conceivable, as a result of experimental supply by the inventors of the present application, the above-described method for measuring the amount of surface Ca was most effective. According to this method, since only the surface portion can be easily analyzed, a trace amount of Ca can be accurately captured. Regarding the degree of acid dissolution at this time, the dissolution time is gradually increased from the time when the plating is almost dissolved, and the time when the Ca amount is stable until the wire core surface is slightly dissolved is the end point.

In order to further stabilize the arc, it is necessary to make the droplet transfer at the tip of the wire more stable. Therefore, it was found that it is effective to reduce impurities on the surface of the wire and reduce the amount of Ca in the wire, and also to include one or two of Na and K. In particular, not only are these Na and K contained in the entire wire, but also at the portion considered to be the wire solid surface portion, that is, the plating layer, the interface between the plating layer and the wire core portion, and the wire core portion surface, Na It has been found to be more effective to include and / or K. this is,
Na and K on the wire surface are Na of the wire surface deposit
And K and Na and K of the wire core portion are presumed to be emitted to the arc space at a location effective for arc stabilization. It is considered that Na and K in the deposit on the wire surface are released early from the part exiting the current-carrying tip, and Na and K in the wire core are not released effectively until they become suspended droplets. .

Various methods of analyzing Na and K on the wire surface portion are conceivable. As a result of various tests, the above-described method for measuring solid surface Na and solid surface K, which is similar to Ca, was effective. . With this method, since only the surface portion can be easily analyzed, trace amounts of Na and K can be captured with high accuracy. Regarding the degree of acid dissolution at this time, the time when the plating amount is almost dissolved is increased to the time when the dissolution time is increased until the wire core surface is slightly dissolved. And

Further, if the amount of oxygen on the surface of the wire is controlled within an appropriate range, the droplet transfer will be smooth.

Next, the reasons for limiting the numerical values in the present invention will be described. Wire surface impurity amount: 5 μg / cm ^{2 If the} wire surface impurity amount exceeds 5 μg / cm ² , the arc becomes unstable, arc breakage and short circuit significantly increase, and welding defects such as undercut and overlap easily occur. , Workers are more likely to feel fatigue. When the amount of impurities on the wire surface is further reduced to 2 μg or less, a more excellent effect can be obtained.

Large-grain impurities: 40% by weight or less
Amount of copper component: 30 wt% or more, and the mass of large surface wire impurities that do not pass through a filter paper (membrane filter) having a pore size of 10 μm is set to 40 wt% or less of the total extracted surface impurity mass, and copper in all extracted impurities The workability is improved by increasing the amount of the component (copper compound is converted to copper) to 30% by weight or more to reduce the impurities of large particles to a predetermined amount or less and increasing the amount of the copper component in the impurity.

Ca content in all wires: 10 ppm or less, surface
Ca amount: 3 ppm or less When the Ca amount in the wire exceeds 10 ppm, the spatter generation amount increases rapidly. Therefore, the amount of Ca in the wire is 10ppm
It is preferable that the amount be less than the above, but if the amount is further reduced to 3 ppm or less, the spatter generation amount is sharply reduced, and a better result is obtained.

When the amount of surface Ca exceeds 3 ppm, the amount of spatter generated sharply increases. Therefore, the surface Ca amount is 3 pp
It is preferable that the amount is less than m, but if the amount of surface Ca is further reduced to 1 ppm or less, the spatter generation amount is sharply reduced, so that better results can be obtained.

Na and / or K in all wires: 0.
1 to 10 ppm If all wires including wire surface impurities, feed lubricants, rust preventive oils, and other wire surface deposits contain 0.1 ppm or more of one or two of Na and K, the arc is stable. The operator's feeling of fatigue is reduced, but less than 0.1 ppm is insufficient. Further, when Na and / or K are contained in the range of 0.2 ppm to 5 ppm, respectively, the stability of the arc is greatly improved and a better result is obtained. Further, if either Na or K exceeds 10 ppm, the arc concentration is greatly deteriorated, which is not desirable. At least one of Na and K may be added, but when it is added, it is necessary to set it to 0.1 to 10 ppm.

Solid surface Na and solid surface K: 0.1 each
~ 10ppm If the wire fixing surface contains 1 or 2 kinds of Na or K,
The arc stability is remarkably improved and the fatigue feeling of workability is further reduced, but less than 0.1 ppm is insufficient. 0.5ppm
By containing the above, the stability of the arc is greatly improved,
Better results are obtained. Further, if either Na or K exceeds 10 ppm, the arc concentration is greatly deteriorated, which is not desirable.

Total oxygen content of wire: 30 to 200 ppm,
Surface oxygen content: 20 to 180ppm, and total wire oxygen content is 30 to 200ppm,
Moreover, when the surface oxygen amount is 20 to 180 ppm, the transfer of droplets becomes smooth, and the operator's feeling of fatigue is reduced.
In this range, fine cracks are often found on the wire surface in a direction inclined by about 45 ° from the wire circumferential direction with a length of several tens of μm, and the wire surface layer has a few μm.
Grain boundary oxidation with a depth of 1 to several tens of μm and fine oxides of submicron size are often observed. However, if the total oxygen content of the wire is less than 30 ppm, the effect is insufficient, and if it exceeds 200 ppm, the adhesion of the plating becomes poor. Further, if the surface oxygen amount is less than 20 ppm, the effect is insufficient, and if it exceeds 180 ppm, the adhesion of the plating is deteriorated. In the case where the amount of surface oxygen is in the range of 30 ppm to 100 ppm, the stability of the arc is greatly improved and the feeling of fatigue is less, so that better results can be obtained.

The solid wire for welding may have any composition within the range specified in JIS Z3312, and the effects of the present invention can be sufficiently exhibited. For example, C; 0.001 to 0.15% by weight, Si; 0.30 to 1.10% by weight, Mn; 0.85
~ 2.60 wt%, P; 0.001-0.030 wt%
Hereinafter, S; 0.001 to 0.030% by weight or less, Cu;
A composition containing 0.01 to 0.50% by weight or less and the balance of iron and inevitable impurities is desirable.

C: 0.001 to 0.15 wt% C is an essential component for obtaining deoxidation and strength of the weld metal, but if it is less than 0.001 wt%, both deoxidation and strength are insufficient. If the content exceeds 0.15% by weight, high temperature cracking easily occurs in the weld metal, so 0.001 to
0.15% by weight is desirable.

Si: 0.30 to 1.10 wt% Si is an essential component for deoxidizing the weld metal,
If it is less than 0.30% by weight, deoxidation is insufficient.
If it exceeds 10% by weight, the toughness of the weld metal tends to decrease, so 0.30 to 1.10% by weight is desirable.

Mn: 0.85 to 2.60 wt% Mn is an essential component for obtaining deoxidation and strength of the weld metal, but if it is less than 0.85 wt%, both deoxidation and strength are insufficient. If the amount exceeds 2.60% by weight, cold cracking easily occurs in the weld metal, so 0.85-2.6.
0 wt% is desirable.

P: 0.001 to 0.030 wt% or less P is an essential component for obtaining a smooth detachment of droplets from the wire tip, but if it is less than 0.001 wt%, its effect is not satisfactory. Sufficient, and if it exceeds 0.030% by weight, high temperature cracking easily occurs in the weld metal,
0.001 to 0.030% by weight is desirable.

S: 0.001 to 0.030 wt% or less S is an essential component for obtaining a smooth detachment of droplets from the wire tip, but if it is less than 0.001 wt%, its effect is unsatisfactory. Sufficient, and if it exceeds 0.030% by weight, high temperature cracking easily occurs in the weld metal,
0.001 to 0.030% by weight is desirable.

Cu: 0.01 to 0.50% by Weight or Less Cu is an essential component for obtaining the electrical conductivity of the wire and the strength of the weld metal, but if less than 0.01% by weight, both electrical conductivity and strength are obtained. Insufficient, and if it exceeds 0.50% by weight, high-temperature cracking easily occurs in the weld metal, so
01 to 0.50% by weight is desirable. Cu may be in the form of plating on the wire surface, in the form of a solid solution, or in the form of wire grain boundary precipitates, but in order to improve the electrical conductivity of the wire, It is preferably 0.10 to 0.40% by weight in the form of plating.

Remainder: iron and unavoidable impurities As unavoidable impurities, for example, Be, B, N, Mg,
Ca, V, Co, Zn, As, Se, Sr, Y, Nb,
Cd, In, Sn, Sb, Te, Ba, W, Hg, T
1, Pb, Bi, etc., and these impurities are 0.0
You may contain 5 weight% or less, and 0.50 weight% or less in total. Although it is desirable that the wire surface impurities be as small as possible, removing the wire surface impurities unnecessarily leads to a rapid increase in manufacturing costs. If the content of any one of the above elements exceeds 0.05% by weight, arc instability increases and adverse effects such as increase in crack susceptibility are adversely affected. Further, even if the total amount of these elements exceeds 0.50% by weight, the same adverse effect is exerted.
It is preferably 50% by weight or less.

In addition to the above components, one or more of the following components may be contained in appropriate amounts, if desired. Ni: 0.01-1.80 wt% Ni is an effective component for obtaining the low temperature toughness and strength of the weld metal, but if it is less than 0.01 wt%, both the low temperature toughness and the strength are insufficient. Further, when the content exceeds 1.80% by weight, high temperature cracking easily occurs in the weld metal.
01 to 1.80% by weight is desirable.

Cr: 0.01 to 0.70 wt% Cr is an effective component for obtaining the strength of the weld metal,
If it is less than 0.01% by weight, it is insufficient, and 0.70
When the content exceeds 0.01% by weight, the weld metal tends to have insufficient elongation and cold cracking tends to occur.
˜0.70% by weight is desirable.

Mo: 0.01 to 0.65% by Weight Mo is an effective component for obtaining the low temperature toughness and strength of the weld metal, but if it is less than 0.01% by weight, both the low temperature toughness and the strength are insufficient. Yes, and if it exceeds 0.65% by weight,
High temperature cracking is likely to occur in the weld metal, and the elongation of the weld metal is likely to be insufficient, so 0.01 to 0.65 wt% is desirable.

Al: 0.01 to 0.50 wt% Al is an effective component for deoxidizing the weld metal and shaping the weld bead, but if it is less than 0.01 wt%, deoxidation and bead shaping properties are achieved. Is insufficient, and if it exceeds 0.50% by weight, hot cracking easily occurs in the weld metal, so 0.01 to 0.50% by weight is desirable.

Ti + Zr: 0.01 to 0.30 wt% Both Ti and Zr are effective components for deoxidizing the weld metal and reducing spatter. Therefore, Ti and Zr are added alone or in combination, but if the total amount is less than 0.01% by weight, deoxidation and reduction of spatter are both insufficient, and 0.30% by weight is added. If it exceeds the above range, hot cracking is likely to occur in the weld metal, so the total amount is 0.01 to 0.
30% by weight is desirable. Further, Ti is more effective in reducing spatter than Zr, and the content of Ti should be Z
It is more desirable to increase the content of r.

[0049]

EXAMPLES Next, examples of the present invention will be described. After rolling or wire drawing treatment, heat treatment is carried out if necessary, and then a cleaning step, a copper plating step, a cleaning step, a finish wire drawing step, a cleaning step, an oil application step for feeding or rust prevention, a spool rewinding or Each step of the large-capacity pack manufacturing process was sequentially performed.
The conditions of each step were changed appropriately. The diameter of the obtained welding wire is 1.2 mm. Regarding these welding wires, the amount of wire surface impurities, the proportion of large wire surface impurities of 10 μm or more, the proportion of copper in the wire surface impurities,
When the relationship between the amount of Ca and the amount of surface Ca and the arc stability, the sensory workability, and the feeling of fatigue of the operator was examined, the results shown in Tables 1 and 2 below were obtained.

Further, when the relationship between the amount of Na, the amount of K, the amount of Na on the solid surface, and the amount of K on the solid surface and the sensory workability and the feeling of fatigue of the operator was examined, the results shown in Table 3 below were obtained. It was

Further, when the relationship between the total oxygen amount and the surface oxygen amount and the sensory worker characteristics and the worker's feeling of fatigue was investigated,
The results shown in Table 4 below were obtained.

The wire surface impurity amount, surface Ca amount, solid surface Na amount, solid surface K amount, total oxygen amount, and surface oxygen amount in each table are the amounts measured by the above-mentioned respective methods.

Regarding the arc stability, DCEP
(DC, wire plus), welding current: 220 A, arc voltage: 30 V, welding time: 60 cm / min, shielding gas:
Measure the change in arc voltage under CO ₂ welding conditions
The above was judged to be an arc break, and the number of occurrences per second was examined.

Regarding sensory workability and worker's fatigue, DCEP, welding current: 250A to 340A, arc voltage: 32V to 34V, welding time: 20 to 40cm /
Min, shield gas: CO ₂ was examined under welding conditions.

The chemical composition of the solid wire used is C: 0.04% by weight, Si: 0.75% by weight, M
n; 1.70% by weight, P; 0.015% by weight or less, S;
0.010% by weight, Cu; 0.25% by weight, Ni;
02% by weight, Cr; 0.04% by weight, Mo; 0.005
Weight% or less, Al; 0.008% by weight, Ti; 0.18
Including weight, the balance is 96.5% by weight or more of Fe and unavoidable impurities.

[0056]

[Table 1]

However, Examples 1 to 13 correspond to claim 1, and Examples 14 to 18 correspond to claim 2. Further, Comparative Examples 19 to 23 are claimed in Claim 1.
It is something out of the question.

[0058]

[Table 2]

However, in Table 2, the sensory workability is that 1 is inferior, 2 and 3 are good, and 4 and 5 are excellent, and the larger the number, the better.

The operator's feeling of fatigue is 1 when the feeling of fatigue is large, 2 and 3 are good, and 4 and 5 are small. Also in this case, the larger the number, the less the feeling of fatigue and the better.

[0061]

[Table 3]

However, Examples 24 to 31 correspond to claim 3, and Examples 32 to 40 correspond to claim 4. Further, Comparative Examples 41 to 44 deviate from Claim 3 or 4, and Claim 1 is satisfied.

Wire surface impurities: 3 to 4 μg / cm ² Wire surface impurities of 10 μm or more: 5 to 35% by weight Copper in wire surface impurities: 50 to 95% by weight Ca content of wires: 3 ppm or less Wire surface Ca Amount: 1 ppm or less Sensory workability: 1 (poor) -2-3 (good) -4-5
(Excellent) Worker fatigue: 1 (Large) -2-3 (Good) -4-5
(small).

[0064]

[Table 4]

Examples 45 to 54 correspond to claim 5 of the present invention, and comparative examples 55 to 61 deviate from claim 5, but claim 1 is satisfied.

However, wire surface impurities: 3 to 4 μg / cm ² Wire surface impurities of 10 μm or more: 5 to 35% by weight Copper in wire surface impurities: 50 to 95% by weight Ca content of wires: 3 ppm or less Wire surface Ca Quantity: 1 ppm or less Wire Na quantity: 0.8 to 2.5 ppm Wire K quantity: 0.7 to 2.9 ppm Wire solid surface Na quantity: 0.5 to 2.4 ppm Wire solid surface K quantity: 0 0.5-2.8 ppm Sensory workability: 1 (poor) -2-3 (good) -4-5
(Excellent) Worker fatigue: 1 (Large) -2-3 (Good) -4-5
(small).

As can be seen from these tables, the welding wires of the examples of the present invention have an excellent effect as compared with the welding wires of the comparative example.

That is, in Tables 1 and 2, as shown in Examples 1 to 13 of the present invention, the amount of impurities on the wire surface was 5 μg or less per 1 cm ^{2 of the} apparent surface area of the wire, and the amount of Ca in the wire was 10 ppm or less. Further, it can be seen that by setting the surface Ca amount to 3 ppm or less, the arc becomes stable, the workability is improved, and the operator's feeling of fatigue is reduced. It is better that the amount of impurities on the wire surface, the amount of Ca, and the amount of Ca on the surface are smaller, and the arc can be further stabilized if the amount is 2 μg or less, 3 ppm or less, and 1 ppm or less, respectively.

Further, in Tables 1 and 2, Examples 14 to 1
As shown in FIG. 8, it is found that even better results are obtained by setting the ratio of wire surface impurities of 10 μm or more to 40 wt% or less and the ratio of copper in the wire surface impurities to 30 wt% or more. .

Further, in Table 3, Example 24 of the present invention
As shown in ~ 31, each of Na and K is 10 ppm or less,
Further, it can be seen that by containing Na and / or K in an amount of 0.1 ppm or more, the arc can be stabilized and the operator's feeling of fatigue can be reduced. Na and K are preferably in the range of 0.2 ppm to 5 ppm, in which case the arc can be further stabilized.

Further, in Table 3, as shown in Examples 32 to 40, the solid surfaces Na and /
Or, by including the solid surface K in an amount of 0.1 ppm or more,
Further, it can be seen that the arc can be stabilized and the operator's feeling of fatigue can be reduced. Solid surface Na and solid surface K are 0.2 pp
A range of m to 5 ppm is preferable, and in this case, workability can be further improved and fatigue can be reduced.

Further, in Table 4, as shown in Examples 45 to 54, when the total oxygen amount is 30 ppm to 200 ppm or less and the surface oxygen amount is 20 ppm to 180 ppm,
It can be seen that the operator's fatigue can be reduced. Further, it can be seen that by setting the surface oxygen amount from 30 ppm to 100 ppm, the arc is further stabilized and the feeling of fatigue of the operator can be greatly reduced. At this time, uniform hexagonal surface cracks were observed on the wire surface.

Among these steps, the contributions of the steps after the heat treatment were relatively large, and sufficient results could not be obtained unless proper control was performed in each step.

If the wire surface is not damaged in each cleaning step as much as possible, when the wire is used, the wire surface is likely to be peeled off due to contact with the flexible conduit tube, which hinders the feeding. become.

Similar results are obtained not only for the wire having a diameter of 1.2 mm shown in Table 1 but also for wires having other diameters and components. Similar results have also been obtained with a copper-plated flux-cored wire.

[0076]

As described above, according to the present invention,
A wire whose wire surface impurity amount and Ca amount are regulated within a predetermined range has significantly improved the stability of the welding arc, is less likely to cause welding defects due to arc instability even at high-speed welding, and also causes fatigue of workers. And the quality and work efficiency are improved. As described above, the present invention makes a great contribution to the technical field of performing gas shielded arc welding.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C22C 38/50

Claims (7)

[Claims] 1. Impurities on the wire surface are regulated to 5 μg or less per 1 cm ^{2 of the} apparent surface area of the wire, and C in all the wires is controlled.
A wire for gas shield arc welding, wherein the amount of a is regulated to 10 ppm or less and the amount of surface Ca is regulated to 3 ppm or less. 2. Of the impurities on the surface of the wire, the pore diameter is 10
The mass of substances that do not pass through a μm filter paper (membrane filter) is restricted to 40% by weight or less of the mass of all wire surface impurities, and the amount of copper components in all wire surface impurities (in the case of copper compounds, converted to copper) The gas shielded arc welding wire according to claim 1, wherein the content is 30% by weight or more. 3. The wire for gas shielded arc welding according to claim 2, wherein Na and / or K are contained in an amount of 0.1 to 10 ppm in all the wires including impurities on the surface of the wire. 4. The wire for gas shield arc welding according to claim 3, wherein the solid surface portion of the wire contains solid surface Na and / or solid surface K in a total amount of 0.1 ppm or more. 5. The total oxygen content of the wire is 30 to 200 pp.
The gas shielded arc welding wire according to claim 4, wherein the wire has a surface oxygen content of 20 to 180 ppm in addition to m. 6. The wire composition is C: 0.001 to 0.
15% by weight, Si: 0.30 to 1.10% by weight, M
n: 0.85 to 2.60% by weight, P: 0.001 to 0.030% by weight, S: 0.001 to 0.030% by weight, Cu: 0.01 to 0.50% by weight The balance is iron and unavoidable impurities, The wire for gas shielded arc welding according to claim 5, wherein 7. The wire composition is C: 0.001 to 0.
15% by weight, Si: 0.30 to 1.10% by weight, M
n: 0.85 to 2.60% by weight, P: 0.001 to 0.030% by weight, S: 0.001 to 0.030% by weight, Cu: 0.01 to 0.50% by weight , Ni: 0.01 to 1.80% by weight, Cr: 0.0
1 to 0.70 wt%, Mo; 0.01 to 0.65 wt%, Al: 0.01 to 0.50 wt% and [Ti +
Zr]: at least one component selected from the group consisting of 0.01 to 0.30% by weight, the balance being iron and unavoidable impurities. Arc welding wire.