JP2018144103A - Arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arc welding method which enables a reduction in sputter generation and has a favorable slag coagulation property in spite of increasing a welding speed.SOLUTION: An arc welding method for welding a steel plate while controlling the supply of a welding wire in advancement and retreat directions comprises the use of a welding wire containing C, and containing, by mass %, Si:0.2% or more and 1.3% or less, Mn:0.2% or less and 1.5% or less, and S:0.01% or more and 0.05% or less with the remaining consisting of Fe and inevitable impurities, and an Ar-containing gas to perform welding with a frequency of 35 Hz or more and 160 Hz or less of the welding wire in advancement and retreat directions.SELECTED DRAWING: None

Description

  The present invention relates to an arc welding method, and more particularly to an arc welding method in which welding is performed while feeding control of a welding wire in a forward / backward direction.

  As an arc welding method capable of reducing the occurrence of spatter during welding of a thin steel plate, an arc welding method is known in which welding is performed while feeding in the forward and backward directions of the wire is controlled.

  For example, in Patent Document 1, as an arc welding method for suppressing the generation of pores such as blow holes and the generation of spatter, a short-circuit and an arc are repeatedly arced using a welding wire for a surface-treated member. A welding method for performing welding is disclosed. This welding method includes a step of transferring a droplet formed from a wire to the member side, and pressing the molten pool in a direction opposite to the welding progress direction to weld the member so that gas generated from the member escapes from the generation point. And steps. Then, by retracting the wire, the distance between the wire and the molten pool is set within a predetermined range, a predetermined welding current for generating an arc force for pushing the molten pool is supplied, and the welding current is supplied for a predetermined period. In the meantime, it is constant or gradually increases or decreases.

Japanese Patent No. 6044369

  By the way, a steel sheet used for automobiles, building materials, electrical equipment, and the like may be subjected to an electrodeposition coating process after arc welding. In such a case, if the slag does not sufficiently aggregate in the welded part during arc welding, the slag remains in the welded part. And when slag remains in a welding part, there exists a problem that adhesiveness of the coating film formed by subsequent electrodeposition coating cannot fully be ensured. Therefore, in such a use, it is calculated | required that the slag aggregation property at the time of welding is favorable.

  However, in the arc welding method described in Patent Document 1, the cohesiveness of the slag has not been sufficiently studied, and there is room for improvement. That is, if the slag does not sufficiently aggregate at the time of welding, the slag may remain in the welded portion, resulting in the above-described problem. In particular, in thin plate welding, it is also required that the welding speed is high, and it is also required that the slag cohesiveness is good while increasing the welding speed.

  The present invention has been made paying attention to the above-mentioned circumstances, and the object thereof is to provide an arc welding method capable of reducing the occurrence of spatter and improving the slag cohesiveness while increasing the welding speed. There is to do.

The present invention is an arc welding method for welding a steel plate while feeding control the welding wire in the forward and backward direction,
Containing C,
% By mass
Si: 0.2% to 1.3%,
Mn: 0.2% or more and 1.5% or less, and S: 0.01% or more and 0.05% or less,
A welding wire with the balance being Fe and inevitable impurities;
Using a gas containing Ar,
The present invention relates to an arc welding method in which welding is performed with a frequency in the advancing and retreating direction of the welding wire being 35 Hz to 160 Hz.

In a preferred embodiment of the arc welding method of the present invention, the welding wire may contain, by mass%, Al: 0.1% or more and 0.5% or less.
Moreover, in the preferable one aspect | mode of the arc welding method of this invention, a welding wire may contain Mo: 0.1% or more and 2.0% or less further by the mass%.
Moreover, in the preferable one aspect | mode of the arc welding method of this invention, a welding wire may contain Ti: 0.3% or less by the mass%.
Moreover, in the preferable one aspect | mode of the arc welding method of this invention, a welding wire may contain Cu: 0.4% or less by the mass%.

  In a preferred aspect of the arc welding method of the present invention, the S and Al contents in the welding wire may satisfy 0.3 ≦ S × 10 + Al ≦ 0.7.

  Moreover, in a preferred embodiment of the arc welding method of the present invention, the plate thickness of the steel plate may be 0.6 mm or more and 5 mm or less.

  Further, in a preferred aspect of the arc welding method of the present invention, welding may be performed with a frequency in the advancing / retreating direction of the welding wire of 45 Hz to 130 Hz, more preferably 70 Hz to 110 Hz.

  In a preferred embodiment of the arc welding method of the present invention, welding may be performed with an average value of welding current of 80 A or more and 350 A or less and a welding speed of 60 cm / min or more.

  According to the arc welding method of the present invention, the generation of spatter can be reduced, and the slag cohesiveness can be improved while increasing the welding speed.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

  An arc welding method according to an embodiment of the present invention (hereinafter also referred to as a welding method according to an embodiment of the present invention) is an arc welding method of welding a steel sheet while feeding control the welding wire in the forward and backward direction, While containing C, in terms of mass%, Si: 0.2% to 1.3%, Mn: 0.2% to 1.5%, and S: 0.01% to 0.05% It is an arc welding method in which welding is performed with a frequency in the advancing / retreating direction of the welding wire of 35 Hz or more and 160 Hz or less using a welding wire that contains Fe and the inevitable impurities remaining, and a gas containing Ar.

  In the welding method according to the embodiment of the present invention, arc welding is performed while controlling feeding in the forward and backward directions of the wire. More specifically, while controlling the feeding of the wire in the forward and backward direction, the wire is advanced (forward feeding) while generating an arc, and the molten metal at the tip of the molten wire is brought into contact with the molten pool to extinguish the arc. Thereafter, the wire is moved backward (reversely fed) to transfer the molten metal. By performing welding in this way, it is possible to reduce the occurrence of spatter during welding. In the welding method according to the embodiment of the present invention, the frequency in the forward / backward direction of the wire is defined as one period of forward advance (forward feed) and backward (reverse feed) of the wire. The welding method according to the embodiment of the present invention includes, for example, Cold Metal Transfer welding.

[Welding wire]
Subsequently, in the following, the reason for limiting the content of each element of the welding wire (hereinafter also referred to as a wire according to an embodiment of the present invention or simply a wire) used in the welding method according to the embodiment of the present invention. Will be described. In addition, content of these each element is content with respect to the wire total mass. Moreover, in this specification, the percentage (mass%) based on mass is synonymous with the percentage (weight%) based on weight.

(Contains C)
C is an element that improves the strength. In the wire according to the embodiment of the present invention, it is only necessary that C is contained, that is, the content of C should be more than 0%. However, in order to achieve the above effect better, 0.02 mass. % Or more is preferable, and 0.04% by mass or more is more preferable.
The upper limit of the C content is not particularly limited, but from the viewpoint of suppressing spatter reduction and high-temperature cracking, the C content is preferably 0.15% by mass or less, more preferably 0.10% by mass or less. preferable.

(Si: 0.2 mass% or more and 1.3 mass% or less)
Si is an effective deoxidizer and is an indispensable element in deoxidation of weld metal. When the Si content is less than 0.2% by mass, the deoxidation effect is impaired, the surface tension is lowered, and pore defects such as pits and blowholes are likely to occur. Moreover, slag cohesiveness falls. Accordingly, the Si content is 0.2% by mass or more, preferably 0.3% by mass or more, and more preferably 0.5% by mass or more.
On the other hand, Si has a feature that the electrical resistance of the wire decreases as the content decreases, and the wire is less likely to melt as the electrical resistance of the wire decreases (the electrical resistance heat decreases). As a result, the arc force is increased, so that pore defects such as pits and blowholes can be suppressed. On the other hand, if the Si content exceeds 1.3% by mass, the amount of slag generated on the bead surface increases, and the slag cohesiveness also decreases. Therefore, the Si content is 1.3% by mass or less, preferably 1.2% by mass or less, more preferably 1.0% by mass or less.

(Mn: 0.2 mass% or more and 1.5 mass% or less)
Mn is an effective deoxidizer similar to Si, and is an element that easily binds to S. When the Mn content is less than 0.2% by mass, the deoxidation and desulfurization effects are impaired, the surface tension is lowered, and pore defects such as pits and blowholes are likely to occur. Moreover, slag cohesiveness falls. Therefore, the Mn content is 0.2% by mass or more, preferably 0.3% by mass or more, and more preferably 0.5% by mass or more.
On the other hand, if the Mn content exceeds 1.5% by mass, a thin oxide film that hardly peels off is generated on the bead surface. Moreover, slag cohesiveness falls. Therefore, the Mn content is 1.5% by mass or less, preferably 1.3% by mass or less, more preferably 1.1% by mass or less.

(S: 0.01 mass% or more and 0.05 mass% or less)
S is an element that contributes to the aggregation of slag, but if it is less than 0.01% by mass, the effect cannot be obtained, so the S content is 0.01% by mass or more, preferably 0.02% by mass. That's it.
On the other hand, when the S content exceeds 0.05 mass%, the flow on the surface of the molten pool is greatly changed, and as a result of the slag coming close to the vicinity of the arc and greatly vibrating, the agglomeration effect is lowered. Therefore, the S content is 0.05% by mass or less, preferably 0.04% by mass or less.

  The remainder of the wire according to the embodiment of the present invention is composed of Fe and unavoidable impurities, and examples of the unavoidable impurities include P, Cr, Ni, N, O, and the like, as long as the effects of the present invention are not hindered. It is allowed to contain.

  Moreover, in addition to the above-described chemical component, at least one of the following components may be added to the wire according to the embodiment of the present invention.

(Al: 0.1 mass% or more and 0.5 mass% or less)
Al is an element that contributes to slag aggregation. In the wire according to the embodiment of the present invention, the addition of Al is not essential, but when the Al content is less than 0.1% by mass, it is difficult to obtain the slag aggregation effect. The content is preferably 0.1% by mass or more, and more preferably 0.2% by mass or more.
On the other hand, if the Al content exceeds 0.5% by mass, droplet detachment becomes unstable, vibration of the molten pool is disturbed, and as a result of frequent spattering, the slag aggregation effect may be reduced. Therefore, when adding Al, it is preferable to make the content into 0.5 mass% or less, and it is more preferable to set it as 0.4 mass% or less.

(Mo: 0.1% by mass or more and 2.0% by mass or less)
Mo is an element that contributes to improvement in strength. In the wire according to the embodiment of the present invention, addition of Mo is not indispensable, but in order to exhibit such an effect satisfactorily, when adding Mo, the content may be 0.1% by mass or more. Preferably, it is more preferably 0.3% by mass or more.
On the other hand, when Mo exceeds 2.0 mass%, the effect is saturated because Fe and an intermetallic compound are formed at a high temperature. Therefore, when adding Mo, it is preferable to make the content into 2.0 mass% or less, and it is more preferable to set it as 1.5 mass% or less.

(Ti: 0.3% by mass or less)
Ti is a strong deoxidizing element and can reduce the amount of oxygen in the molten metal and reduce the surface tension. Therefore, it is effective when the amount of oxygen in the wire is high. However, if added over 0.3 mass%, a large amount of slag is generated. Therefore, when adding Ti, the content is preferably 0.3% by mass or less, and more preferably 0.2% by mass or less.

(Cu: 0.4 mass% or less)
Cu is an element that is effective in improving the electrical conductivity and rust resistance. When Cu is contained, the lower limit value of the content is not particularly limited, but is preferably 0.1% by mass or more in order to obtain this effect more favorably. Moreover, it is preferable that content of Cu is 0.4 mass% or less from a viewpoint of suppressing generation | occurrence | production of a hot crack. The wire of this embodiment may be subjected to Cu plating if desired. Here, Cu is a value obtained by adding up the amount contained in the base material of the wire and the amount of Cu plating.

(0.3 ≦ S × 10 + Al ≦ 0.7)
In the wire according to the embodiment of the present invention, it is preferable that the contents of S and Al satisfy the following relational expression. In this case, the slag cohesiveness can be further improved by adjusting the S and Al contents so as to satisfy the relational expression.
0.3 ≦ S × 10 + Al ≦ 0.7

(Wire diameter)
In the embodiment of the present invention, the diameter of the wire is not particularly limited, and may be appropriately selected from a normally applied range. The diameter of the wire is, for example, 0.8 mm to 1.4 mm.

  As a method for manufacturing the wire, for example, a steel wire having a predetermined composition may be drawn to a predetermined diameter. The wire drawing process may be either a method using a hole die or a method using a roller die. Moreover, when performing Cu plating, you may wire-draw after Cu plating.

[Shielding gas]
The shield gas used in the welding method according to the embodiment of the present invention only needs to contain Ar, and may consist only of Ar. Alternatively, in addition to Ar, CO ₂ , O _2, or the like may be contained. For example, about 5 to 30% by volume of CO ₂ to O ₂ and the balance of Ar may be used. The shield gas can also contain N ₂ , H _2, etc. as inevitable impurities.
Here, since the amount of slag decreases as the content ratio of Ar in the shield gas is higher, it is desirable that the content ratio of Ar in the shield gas is higher. From this viewpoint, the content ratio of Ar is preferably 70% by volume or more, and more preferably 80% by volume or more. On the other hand, as described above, the shielding gas may be composed only of Ar (that is, the Ar content may be 100% by volume). For example, the Ar content may be 70% by volume or less. .

[Frequency of wire in the forward and backward direction: 35Hz or more and 160Hz or less]
In the welding method according to the embodiment of the present invention, in controlling the feeding of the wire in the forward / backward direction, the frequency in the forward / backward direction of the wire is controlled to be 35 Hz or more and 160 Hz or less.
As a result of intensive studies, the present inventors have found that the natural frequency of the molten metal is about several tens of Hz, and by controlling the frequency in the advancing and retreating direction of the wire to an appropriate range so as to match the natural frequency of the molten pool It has been found that the vibration of the molten pool surface becomes optimal, the hot water flow on the molten pool surface changes so as to involve slag, and the slag cohesiveness can be improved. If the frequency in the wire advance / retreat direction is less than 35 Hz, short circuit occurs frequently in the peak current period, regular droplet transfer cannot be performed, the molten pool vibration is disturbed, and good slag cohesiveness cannot be obtained. The frequency in the advancing / retreating direction of the wire is 35 Hz or more, preferably 45 Hz or more, more preferably 70 Hz or more. On the other hand, if the frequency in the wire advance / retreat direction exceeds 160 Hz, the effect of depressing the molten pool by the arc in the peak period is reduced, and sufficient molten pool amplitude cannot be obtained, and good slag cohesiveness is obtained. Therefore, the frequency in the advancing / retreating direction of the wire is 160 Hz or less, preferably 150 Hz or less, more preferably 130 Hz or less, and further preferably 110 Hz or less.

[Base material]
The base material to be welded in the welding method according to the embodiment of the present invention may be a steel plate, and the composition, thickness, etc. of the steel plate are not particularly limited. For example, the thickness is 0.6 mm or more and 5.0 mm or less. It can also be applied to thin steel sheets. In addition, the steel type may be, for example, mild steel or high-tensile steel up to 590 MPa class. The surface of the base material may be subjected to various plating treatments such as galvanization and aluminum plating.

[Welding conditions]
In addition, welding conditions such as a welding current, a welding voltage, a welding speed, and a welding posture in the welding method according to the embodiment of the present invention are not particularly limited, and may be appropriately adjusted within a range applicable in the arc welding method.
Here, the average value of the welding current is, for example, 80 A or more and 350 A or less, and preferably 100 A or more and 300 A or less. Moreover, as a welding speed, it is 60 cm / min or more, for example. According to the welding method according to the embodiment of the present invention, welding can be performed with good slag cohesion even under these welding conditions.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples, and may be implemented with modifications within a range that can be adapted to the gist of the present invention. All of which are within the scope of the present invention.

Using a wire with a diameter of 1.2 mm having the composition shown in Tables 1 and 2, welding was performed under the conditions shown below while controlling the frequency of the wire in the forward / backward direction to the frequency shown in Tables 1 and 2. Carried out.
(1) Steel plate A steel plate having a length of 200 mm, a width of 60 mm, and a thickness of 3.2 mm was used. The steel type of the steel plate is SPHC590.
(2) Welding posture Horizontal overlap fillet welding was performed.
(3) Shielding Gas In Examples 1 to 28 in Table 1 and Examples 30 to 59 in Table 2, Ar + 20 volume% CO ₂ was used as the shielding gas.
Further, in the example 29 and example 60 in Table 2 of Table 1, it was used 100 vol% CO ₂ as a shielding gas.
(4) Welding current and welding voltage Welding was carried out at a welding current of 240 A and a welding voltage of 18 V.
(5) Welding speed and welding length The welding speed was 100 cm / min. Further, welding was performed up to a welding length of 150 mm.

  In Tables 1 and 2, “wire component (% by mass)” represents the amount of each component (% by mass) per the total mass of the wire. “-” Means that the content is less than the detection limit. Further, the Cu content shown in Table 2 includes a Cu plating content. The balance is Fe and inevitable impurities.

(Evaluation of slag cohesiveness)
With a weld length of 150 mm, the slag on the bead surface was visually observed, and the slag on the surface was collected and evaluated according to the following criteria. In addition, (double-circle) and (circle) are set as pass, and x is set as disqualified.
A: 90% by weight or more of slag out of the total amount of slag is present (aggregated) in the vicinity of the crater portion.
○: 50% by weight or more and less than 90% by weight of slag is present (aggregated) in the vicinity of the crater part.
X: Only slag of less than 50% by weight of the total amount of slag is present (aggregated) in the vicinity of the crater portion.

  Of Examples 1 to 60, Examples 1 to 20 and Examples 30 to 51 are examples, and Examples 21 to 29 and Examples 52 to 60 are comparative examples. As shown in Table 1 and Table 2, in Examples 1 to 20 and Examples 30 to 51 that satisfy the requirements of the present invention, good slag cohesiveness was obtained.

In Examples 21 and 52, the S content in the wire was too low, and in Examples 22 and 53, the S content in the wire was too high, so the slag cohesiveness deteriorated.
In Example 23 and Example 54, the frequency in the wire advance / retreat direction was too large, and in Example 24 and Example 55, the frequency in the wire advance / retreat direction was too small, so the slag cohesiveness deteriorated.
In Examples 25 and 56, the Si content in the wire was too low, and in Examples 26 and 57, the Si content in the wire was too high, so the slag cohesiveness deteriorated.
In Examples 27 and 58, the Mn content in the wire was too low, and in Examples 28 and 59, the Mn content in the wire was too high, so the slag cohesiveness deteriorated.
In Example 29 and Example 60, 100% CO ₂ gas containing no Ar was used as the shielding gas, so the slag cohesiveness deteriorated.

Claims (10)

An arc welding method for welding a steel plate while controlling the feeding of the welding wire in the forward and backward direction,
Containing C,
% By mass
Si: 0.2% to 1.3%,
Mn: 0.2% or more and 1.5% or less, and S: 0.01% or more and 0.05% or less,
A welding wire with the balance being Fe and inevitable impurities;
Using a gas containing Ar,
An arc welding method in which welding is performed with a frequency in the advancing / retreating direction of the welding wire set to 35 Hz or more and 160 Hz or less. The arc welding method according to claim 1, wherein the welding wire further contains Al: 0.1% or more and 0.5% or less in terms of mass%. The arc welding method according to claim 1 or 2, wherein the welding wire contains, by mass%, Mo: 0.1% or more and 2.0% or less. The arc welding method according to any one of claims 1 to 3, wherein the welding wire further contains Ti: 0.3% or less in terms of mass%. The arc welding method according to any one of claims 1 to 4, wherein the welding wire further contains Cu: 0.4% or less in terms of mass%. S and Al content in the welding wire,
0.3 ≦ S × 10 + Al ≦ 0.7
The arc welding method according to any one of claims 2 to 5, wherein:   The arc welding method according to any one of claims 1 to 6, wherein a thickness of the steel sheet is 0.6 mm or more and 5 mm or less.   The arc welding method according to any one of claims 1 to 7, wherein welding is performed with a frequency in the advancing / retreating direction of the welding wire being 45 Hz or more and 130 Hz or less.   The arc welding method according to claim 8, wherein welding is performed with a frequency in the advancing and retreating direction of the welding wire set to 70 Hz to 110 Hz. The arc welding method according to any one of claims 1 to 9, wherein welding is performed at an average value of a welding current of 80 A to 350 A and a welding speed of 60 cm / min or more.