JPH04327395A - Copper plated steel wire for gas shielded arc welding - Google Patents

Abstract

PURPOSE:To allow the use of the above wire without troubles, such as interruption even when used for long-term welding and to obtain a welding part of a high quality having no meandering of beads, etc. CONSTITUTION:This copper plated steel wire for gas shielded arc welding is the copper plated steel wire of <=1.6mm diameter to be loaded into a pale pack and is so formed that the content of Ca among the alkaline metals and alkaline earth metals interposed between the wire base and the plating layer on the surface is 1.0 to 100mg/m<2> and either or both of 0.3XCa content <=Na content <= 1.4 X Ca content -(1) 0.1 X Ca content <= Ba content <= 2.1 XCa content -(2) and the amt. of the lubricant to be applied on the wire surface is in a 0.04 to 0.70g/m<2> range.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel wire for gas metal arc welding using a shielding gas containing CO2 and Ar as main components. In detail, copper-plated steel wire (hereinafter referred to as wire) loaded in a pail pack, which is mainly used for automatic arc welding using robots, etc., can cause problems such as interruptions even when used for long welding. The present invention relates to a wire that can be used without any problems and can provide a welded part of good quality without bead meandering or the like.

0002

2. Description of the Related Art Recently, from the viewpoint of efficiency and quality, robot welding or automatic welding equipment that allows one person to operate ten or more torches at the same time has been adopted. Instead of the conventional spool-wound wire weighing less than 20 kg, the wire used in this case is often a wire packed in a so-called cylindrical pail pack that can hold 200 to 500 kg. The characteristics required of the wire loaded in such a pail pack are: (1) Since welding is performed continuously for tens of hours, wire feeding performance is maintained for a long time without interruptions due to tip clogging, etc. (2) Since people do not look at the arc during work, there is little runout at the wire tip, and the weld bead does not meander;
can be given.

However, the characteristics required of the wire loaded into these pail packs cannot be fully satisfied with the characteristics of conventional spool-wound wire, and the frequency of tip replacement is required to prevent welding interruption problems. Currently, measures are being taken to prevent bead meandering by increasing the number of beads, and by using wire straighteners to prevent bead meandering.

0004

[Problems to be Solved by the Invention] In order to solve the above-mentioned problems with wires loaded in pail packs, the present inventors first compared them with conventional spool-wound wires and explained the differences between them. investigated. As a result,
As stated in Publication No. 8-35068, the wire loaded in the pail pack has good straightness, and when the wire passes through the tip during welding, unlike the spool-wound wire, which has a radius of curvature in one direction. Therefore, the point of conduction from the inner wall of the chip to the wire is difficult to be fixed, but moves over a wide range of the inner wall of the chip, and as a result, small sparks are generated here and there on the inner wall of the chip, making the arc unstable. The inventors revealed that a hard Fe-Cu alloy is formed in that area that increases the frictional resistance when the wire passes through it, causing damage to the tip in a short period of time and eventually leading to a stop in feeding. In order to solve the problem, in a copper-plated steel wire with a diameter of 1.6 mm or less loaded in a pail pack, the amount of Ca interposed between the wire base and the wire surface plating layer is determined by the following formula including the Cu plating thickness.
Ca amount (mg/m2)≦28.1Cu plating thickness (
μm )+22.5 and the amount of oil adhesion is 0.30
Copper-plated steel wire for gas-shielded arc welding characterized by ~1.20g/10kg (Patent application No. 1-25
No. 8553 invention (hereinafter referred to as the "prior invention")) was invented, and good results were obtained regarding arc breakage, which is a problem with wires loaded in pail packs.

However, even if the amount of Ca is within the range proposed in the prior invention, there remain problems such as the welding arc becoming less sharp, the arc blowing worse, and even more spatter. There is.

[0006]

[Means for Solving the Problems] The present inventors have focused on this phenomenon, and have investigated the relationship between arc blowing due to the surface properties and adhering substances of wires loaded in pail packs, where the energizing point tends to shift frequently. We investigated gender. As a result, we investigated the amounts of Ca, Ba, and Na in the lubricant remaining between the copper plating and the steel substrate beneath the plating, as well as their mutual ratios, as well as the lubricant applied to the wire surface and the tensile strength of the wire. It has been found that the strength and tensile strength at break mutually greatly influence the arc blowing and other properties of the wire loaded in the pail pack.

That is, in a copper-plated steel wire with a diameter of 1.6 mm or less loaded in a pail pack, among the alkali metals and alkaline earth metals interposed between the wire base and the wire surface plating layer, the amount of Ca is 1. .0~100m
g/m2, and the weight ratio is expressed by the following formula (1), (2
) A wire for gas shielded arc welding that satisfies either or both of the following formulas and has a lubricant coating amount of 0.04 to 0.70 g/m2 on the wire surface is suitable for long-term welding. It was confirmed that good arc spraying could be maintained for a long time without any problems such as interruptions even when used.

Here, formula (1)...0.3×Ca amount≦Na amount≦1
．． 4×Ca amount (2) formula...0.1×
Ca amount ≦ Ba amount ≦ 2.1 × Ca amount In addition, by setting the tensile strength in the case of solid wire and the tensile breaking strength in the case of flux-cored wire within a certain range, the tip runout of the wire is small and the weld bead is It has been found that a welded part of good quality without meandering can be obtained.

[0009] Regarding the basic effects of the amount of Ca interposed between the wire base and the wire surface plating layer,
JP-A-1-24929 disclosing the invention by the present inventors
As already made clear in Publication No. 1, the present invention relates to a proposal regarding wires to be loaded into pail packs, which have been increasing in number recently.

0010

[Operation] The constituent elements of the present invention will be described below. First, in the copper-plated steel wire that is the object of the present invention, the amount of Ca interposed between the wire base and the wire surface plating layer is regulated by a specific formula in relation to the amount of Na or Ba for the following reasons. by.

[0011] That is, in a wire packed in a pail pack, the straightness is so good that the current-carrying point frequently moves between the inner wall of the chip and the wire, accompanied by short sparks. Sparks tend to continue, and short sparks turn into long sparks, damaging the chip in a short period of time. Also, when attempting to move to a new energizing point, if Ca oxide exists in that area, current flow is inhibited and phenomena such as the arc suddenly breaking occur, but in this case,
By setting the Na content or Ba content within the range of formula (1) or formula (2), not only the degree of occurrence of these phenomena is reduced, but also the arc spraying is improved. In addition,
When the amount of Na or Ba exceeds the range defined by formula (1) or formula (2), the adhesion of the plating to the wire base deteriorates, and a phenomenon of deterioration of wire feedability due to peeling of the plating occurs.

FIG. 1 and FIG. 2 are diagrams showing the relationship, and the results of the long-term welding feedability test show that the amount of Ca is 100 mg/m
2 or less and if formula (1) or (2) is satisfied, poor wire feeding performance will not occur for a long time even if the Ca content is on the high side, but if the Ca content is low to some extent. However, if either formula (1) or (2) is not satisfied, poor wire feedability may occur in a short period of time. However, if the amount of Ca exceeds 100 mg/m2, it is clear that the arc will break, that is, the wire feeding will be interrupted, regardless of equations (1) and (2). Furthermore, it has been found that when the amount of Ca is less than 1 mg/m2, the dissociation voltage becomes low and the welding arc lacks sharpness.

[0013] The welding test was conducted using JIS wire as wire.
A product corresponding to Z3312 YGW11 with a diameter of 1.6 mm was used, and the welding conditions were 400 A, 32 V, carbon dioxide shielding of 25 l/mm, and downward bead-on-brate welding. The test wire was loaded from a pail pack (inner diameter, 640 mm) with a general reverse twist, passed through a take-out device, a normal feeding device, and was then transferred using a conduit cable (length 6 m) and a pistol-type welding torch. Welded.

Furthermore, in order to conduct a long-term feedability test, the torch was fixed and the welding test plate was placed on a rotating jig and rotated to perform welding in which weld beads were continuously layered. Welding was carried out almost continuously for a maximum of 20 cycles, each cycle consisting of 5 minutes of continuous welding.Was welding possible until the end without any problems with feedability, or did welding be interrupted due to feed failure midway through?
Alternatively, the welding was not interrupted until the end, but it was determined whether the arc was unstable, that is, whether the welding arc had lost its sharpness, whether the arc spray had deteriorated, or whether there had been an increase in spatter.

In this case, the amount of lubricant applied to the wire is 0.0
It was carried out at a rate of 4 to 0.70 g/m2. Although Figure 1 shows experimental data for a wire diameter of 1.6 mm, results showing almost the same tendency were obtained for other wire diameters (1.4 mm and 1.2 mm), and also for flux-cored wire. Ta.

[0016] Ca, Na, or Ba can be used in the form of lime soap, sodium soap, or barium soap, which are lubricants used in wire drawing, or in the form of CaO, Na2O, or BaO by thermal decomposition in the case of annealing. remain. The method for quantifying the amount of Ca, Na, or Ba in the wire is to wash 100 g of wire with ethyl alcohol and
The wire was cut into a length of 0 cm and boiled in dilute hydrochloric acid (7%) for 10 minutes to dissolve and filter Ca, Na or Ba.
was quantified. In this case, the steel base is also dissolved to some extent, but since the amount of Ca, Na, or Ba contained in general steel is small, all the detected amounts of Ca, Na, and Ba are dissolved in the steel base and the wire surface plating layer. The amount of Ca, Na, or Ba present between

Various methods can be considered to control the amount of Ca, Na, or Ba present between the wire surface plating layer and the steel substrate, but the most effective method is considered to be a pretreatment method before plating. In particular, bipolar electrolytic degreasing is effective. However, in addition to this method, methods such as cathodic electrolytic pickling and ordinary anodic electrolytic degreasing are also effective. C
It is effective to adjust the ratio between the amount of a and the amount of Na and the amount of Ca and Ba as follows.

That is, by utilizing the difference in solubility of lime soap, sodium soap, and barium soap, it is possible to adjust the washing time after using these soaps as a lubricant, or to adjust the blending ratio when using these soaps as a lubricant. Combinations etc. are possible. The amount of lubricant applied on the wire surface is 0.
The restriction to 0.04 to 0.70 g/m2 is necessary in order to reduce the frictional resistance at the conduit and tip during welding and to improve feedability. In the case of pail pack wire, it is particularly undesirable to exceed 0.70 g/m2. The reason for this is that when loading the wire into the pail pack, it passes through straightening rollers to ensure straightness, but if the amount of lubricant applied exceeds 0.70 g/m2, slipping on the rollers tends to occur, so the wire is not loaded properly. This is because small waviness is likely to occur in the wire packed in a pail pack, and as a result, the two characteristics necessary for wire in a pail pack, namely, the wire tip does not shake and the wire has good long-term feeding performance, are impaired. It is.

The tensile strength of the wire affects both the long-term feedability of the pail-packed wire and the deflection of the tip of the wire during welding in conjunction with the amount of lubricant applied and the amount of Ca. In other words, if the tensile strength of each wire diameter is less than the lower limit,
Since the wire has low rigidity and easily follows the bent portion of the conduit cable during feeding, the wire tends to become curly, causing the wire tip to swing out. On the other hand, if the upper limit is exceeded, the feeding resistance will increase at the bent portion of the conduit cable during feeding, which will worsen the feeding performance. The tensile strength of the wire is also affected by the amount of lubricant applied during manufacturing when loading the wire into the pail pack; if it is too low, waviness tends to occur, and if it is too high, stable loading cannot be performed.

In the case of flux-cored wires, the inside of the wire is filled with flux, and the tensile strength obtained by dividing the tensile strength at break by the cross-sectional area cannot indicate the rigidity of the wire, so the tensile strength at break (kgf) of each wire diameter is It was stipulated as is. Note that these tensile strengths or tensile breaking strengths can be set by changing the components of the raw wire, raw pipe, or steel strip, whether or not annealing is performed in the manufacturing process, the annealing diameter, and the annealing conditions.

[0021]

EXAMPLES Below, the method of manufacturing the wire of the present invention will be explained in detail using examples. First, the solid wire has an original wire diameter of 5.5 mm, chemical components C: 0.07%, and Si: 0.78.
%, Mn: 1.50% (both by weight) hot-rolled steel wire was used as the raw wire, and after removing the scale by mechanical descaling, it was pickled, and then immersed in a suspension of lime soap, which is a lubricant. After coating and drying, use Na-based metal soap or Ba-based metal soap as a wire drawing lubricant to 2.0 to 2.4 mm.
After drawing the wire to the diameter, the wire of the present invention with a product diameter of 1.2 to 1.6 mm is subjected to the washing with washing water after drawing shown in Table 1, the presence or absence of annealing, the plating pretreatment step, and the plating step. A comparative wire was manufactured and subjected to the long-term welding feedability test described above. In the case of flux-cored wire, chemical component C: 0.
05%, Si: 0.01%, Mn: 0.40% 12m
After filling a pipe with a thickness of m thick with flux and drawing it to 2.4 to 4.0 mm using Ca-based metal soap, the presence or absence of washing with washing water after drawing as shown in Table 1, and pre-plating treatment. Wires of the present invention and comparison wires having product diameters of 1.2 to 1.6 mm were manufactured through a process and a plating process, and the long-term welding feedability test described above (the evaluation method was also the same) was conducted. The results are shown in Table 1 and Table 2 (continued from Table 1).

[0022]

[Table 1]

[0023]

[Table 2]

[0024] Here, the annealing conditions were 550 to 750°C for 3 hours, and nitrogen was used as the atmospheric gas. The plating pretreatment and plating conditions were as follows. (1) Bipolar electrolytic degreasing 50A/piece, 7-12V Solution NaOH 100g/l Liquid temperature 80℃ Linear speed 50-120m/min (2) Anodic electrolytic degreasing 110A/piece, 7-12V Solution NaOH 100g/l Liquid temperature 60 ~70℃ Linear speed 50~80m/min (
3) Cathodic electrolytic pickling 110A/piece, 7-12V Solution HCl 10-20% aqueous solution Liquid temperature 250°C
Line speed 50-80 m/min (4) Plating 70-130 A/piece, 7-12 V Solution KCN 5-20 g/l Liquid temperature 60°C Line speed 50-80 m/min The final wire drawing lubricant is a vegetable lubricant. It was used. As shown in Table 1, wires manufactured under various manufacturing conditions with wire characteristics that satisfy all the requirements of the present invention have obtained good results throughout the long-term welding test (Test No.
．． 1-14).

However, as shown in the comparison wire, the Na amount/Ca amount ratio or the Ba amount/Ca amount ratio is determined by the formula (1) or (
2) Items that do not satisfy the formula (No. 15, 17, 18, 2)
2, 26), the wire feeding was interrupted (x mark) or there was no interruption but the arc became unstable (△ mark). Also, no
．． In No. 21, wire feeding was interrupted due to inappropriate Ca amount. 19
, 23 had an inappropriate amount of lubricant applied and the arc was unstable.
In No. 20, the tensile strength of the wire was too high, causing arc instability. No. In No. 24, the wire tensile breaking strength was too low, causing arc instability.

[0026]

Effects of the Invention According to the present invention, when welding with pail-packed wire, which has recently been frequently used in robot welding, etc., there is no problem with feeding performance even during long-term continuous welding, and the tip of the wire does not run out. This provides an industrially useful effect in that a good welded portion without bead meandering can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the results of a long-term welding feedability test when the amount of Ca and the amount of Na interposed between the wire base and the wire surface plating layer were changed.

FIG. 2 is a diagram showing the results of a long-term welding feedability test when the amounts of Ca and Ba interposed between the wire base and the wire surface plating layer were varied.

Claims

[Claims] Claim 1: Diameter 1.6 loaded in a pail pack
In a copper-plated steel wire of 1.0 mm or less, the amount of Ca among the alkali metals and alkaline earth metals interposed between the wire base and the wire surface plating layer is 1.0 to 100 mg/m2.
And in terms of weight ratio, 0.3×Ca amount≦Na amount≦1.4×Ca amount −(1)
0.1×Ca amount≦Ba amount≦2.1×Ca amount
- A copper-plated steel wire for gas-shielded arc welding, which satisfies either or both of (2) and has a lubricant coating amount on the wire surface in a range of 0.04 to 0.70 g/m2. 2. The copper-plated steel wire for gas shielded arc welding according to claim 1, which is a solid wire having a wire tensile strength within the following range. For wire diameter 1.6mm 7
0~100kgf/mm2
1.4 〃 75～11
5 〃
1.2 〃 80～1
30 〃 3. The copper-plated steel wire for gas-shielded arc welding according to claim 1, which is a flux-cored wire having a tensile strength at break within the following range. For wire diameter 1.6mm 7
0~110kgf 1
．． 4 〃 65～90 〃
1.2
〃 55～80 〃