JP2542266B2 - Copper plated steel wire for gas shield arc welding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wire for gas metal arc welding, which uses a shielding gas containing CO ₂ and Ar as main components. Specifically, it is a copper-plated steel wire (hereinafter referred to as a wire) loaded in a pail pack that is mainly used for automatic arc welding performed by using a robot etc. Even if it is used for welding for a long time, it can be used without trouble such as interruption The present invention relates to a wire which can be formed and has a good quality welded portion without bead meandering.

(Prior Art) Recently, in view of efficiency and quality, robot welding or, for example, an automatic welding apparatus that can simultaneously operate a welding machine with 10 torches or more by one person is being adopted. As the wire used in this case, a wire wound in a so-called cylindrical pail pack capable of accommodating 200 to 400 kg is being widely used instead of the conventional spear wound wire having a weight of 20 kg or less. The characteristics required for the wire loaded in such a pail pack are as follows: (1) Since welding is continuously performed for tens of hours,
The wire feedability is stable for a long time, often due to interruptions due to chip clogging, etc. (2) Since the person does not work while seeing the arc, the tip runout of the wire is small and the welding bead does not meander.

However, the characteristics required for the wire loaded in these pail packs cannot be sufficiently satisfied only by the characteristics possessed by the conventional spool-wound wire. In addition, it is the original condition to deal with the meandering of beads by using a wire straightening machine.

(Problems to be Solved by the Invention) The present inventors have tried to solve the problems of the wire loaded in the pail pack as described above.
We investigated what is different from the conventional spooled wire. As a result, as described in JP-A-58-35068, 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 having a radius of curvature in one direction, it is difficult for the conduction point from the inner wall of the tip to reach a certain point, and the inner wall of the tip moves over a wide range. As a result, small sparks are generated here and there on the inner wall surface of the chip, and the arc becomes unstable and a hard Fe-Cu alloy that increases the friction resistance when the wire passes through is formed in that part, so the chip is damaged in a short time. It became clear that it would eventually stop feeding.

(Means for Solving the Problem) The present inventors have paid attention to this phenomenon and sent the property of the wire and the wire surface of the wire loaded in the pail pack in which the movement of the conduction point is likely to occur and the attached substance. The relationship with salability was investigated experimentally. As a result, the amount of Ca in the lubricant remaining between the copper plating and the iron substrate under plating, the amount of copper plating (thickness) and the amount of oil adhering to the wire surface, as well as the tensile strength of the wire or It has been found that the tensile rupture rate has a great influence on the feedability and other properties of the wire loaded in the pail pack, reciprocally. That is, in the copper-plated steel wire having a diameter of 1.6 mm or less loaded in the pail pack, the amount of Ca present between the wire base and the wire surface plating layer satisfies the formula (1) including the Cu plating thickness, and , The amount of oil adhered is 0.30 to 1.20g / 10kg
It has been found that the wire for gas shielded arc welding, which is characterized in that it can be used without trouble such as interruption even when it is used for welding for a long time (here (1)
Formula …… Ca amount (mg / m ² ) ≦ 28.1Cu plating thickness (μm) +22.
Five). It was also found that by setting the tensile strength for solid wires and the tensile breaking load for flux-cored wires to a certain range, it is possible to obtain good quality welds with less runout of the wire tip and the weld bead does not meander. It is a thing. The basic function and effect of the amount of Ca present between the wire base material and the wire surface plating layer has already been clarified in the specification of Japanese Patent Application No. 63-76193 by the present inventor. The present invention relates to a proposal regarding a wire which is loaded in a pail pack, which has been increasing recently.

(Operation) First, in the copper-plated steel wire, the amount of Ca existing between the wire base and the wire surface plating layer was regulated in relation to the Cu plating thickness for the following reason. That is, in the pail-pack wire, the straightness is too good, and the movement of the conduction point between the inner wall of the chip and the wire frequently occurs with a short spark, but if the Ca content is large, the spark is likely to continue due to the presence of Ca ions and is short. Spark turns into a long spark, damaging the tip in a short time. Also, when Ca oxide is present in the part when trying to move to the new energizing point, energization is obstructed, causing a phenomenon such as sudden disconnection of the welding arc.
In this case, when the copper plating thickness is large, the degree of occurrence of those phenomena becomes small. Fig. 1 is a diagram showing the relationship. As a result of the long-time welding feedability test, as the amount of Ca is larger, poor feedability occurs in a shorter time, but the thicker the copper plating is, the longer the time is. It has become. The experimental conditions are
As a wire, JIS Z3312 YGW11 applicable product, diameter 1.6 mm, welding conditions are 400 A, 32 V, carbon dioxide gas 25 / min, downward bead-on-plate welding.

The test wire was welded using a 6 m long conduit cable and pistol type torch from a pail pack (for 350 kg) loaded with a general reverse twist of 50 kg, through a take-out device, a normal feeding device. . Further, in order to carry out a long-term feedability test, the torch was fixed and the welding test plate was placed on a rotating jig and rotated so that the welding beads could be continuously formed. Welding was performed continuously for up to 20 cycles, with one cycle consisting of continuous welding for 5 minutes. Welding could be completed without any problems in feedability, or welding was interrupted due to poor feedability or until the end. Welding was not interrupted, but it was determined whether the arc became unstable. In this case, the amount of oil adhered to the wire was 0.5 to 1.0 g / 10 kg.

Although FIG. 1 shows the experimental data for the wire diameter of 1.6 mm, other wire diameters of 1.4 mm and 1.2 mm, and the flux-cored wire also showed similar results.

Ca remains in the form of lime soap, which is a lubricant used for wire drawing, or when it is annealed, it decomposes by heating and remains in the form of CaO.
To determine the amount of Ca in the wire, wash 100 g of the wire with ethyl alcohol and cut it to a length of 5-10 cm, boil this wire in dilute hydrochloric acid (7%) for 10 minutes, and dissolve and filter the Ca. Quantify Ca with an atomic absorption spectrophotometer. In this case, although the steel base material also dissolves to some extent, the amount of Ca contained in general steel is small, so all the detected Ca contents are taken as the amount of Ca existing between the steel base material and the wire surface plating layer.

There are various possible methods for controlling the amount of Ca existing between the wire surface plating layer and the steel substrate, but the most effective method is the pretreatment method before plating, and the bipolar electrolytic degreasing method is particularly effective. There is. However, in addition to this method, for example, methods such as cathodic electrolytic pickling, normal anodic electrolytic degreasing, and cleaning methods after using lime soap as a lubricant (cleaning method with pressure water, mechanical method such as brushing, etc.) It is effective to perform in addition to the plating pretreatment method.

The control of the copper plating thickness is easy and can be achieved by changing the plating size, plating current, time, and the like.

It is necessary to regulate the oil adhesion amount to 0.30 g / 10 kg or more in order to reduce the friction resistance at the conduit and tip during welding and improve the feedability, but in the case of pail pack wire, especially 1.20 g / It is not preferable to exceed 10 kg. This is because when the wire is loaded in the pail pack, it goes straight so that it passes through the straightening roller, but if the amount of oil attached exceeds this amount, a slip phenomenon is likely to occur in the roller, and thus a small waviness is likely to occur in the loaded wire. . This impairs the two characteristics required for the pail pack wire: the tip of the wire does not swing and the long-time feeding property is good.

The tensile strength of the wire affects the long-term feedability of the pail-packed wire and the amount of oil adhesion and Ca content on both sides of the wire runout during welding. That is, when the tensile strength of each wire diameter is less than the lower limit value, the rigidity of the wire is small and it is easy to follow the bent portion of the conduit at the time of feeding, and the wire is likely to be kinked, which causes a runout of the tip of the wire. On the other hand, if the upper limit is exceeded, the feeding resistance increases at the bent portion of the conduit during feeding, which deteriorates the feeding performance. The tensile strength of the wire influences the amount of oil adhesion even during the manufacturing of loading the wire into the pail pack. If it is too low, undulation tends to occur, and if it is too high, stable loading cannot be achieved.

In the case of a flux-cored wire, the inside of the wire is filled with flux and the rigidity of the wire cannot be indicated by the tensile strength obtained by dividing the tensile breaking load by the cross-sectional area.Therefore, the tensile breaking load (kgf) of each wire diameter is specified as it is. did. The tensile strength or the tensile breaking load can be set by changing the components of the wire or wire and the presence or absence of annealing in the manufacturing process, the annealing diameter and the annealing conditions.

(Example) Hereinafter, the method of manufacturing the wire of the present invention will be described in detail with reference to Examples.

First, the solid wire has an original wire diameter of 5.5 mm and a chemical composition of C: 0.0.
7%, Si: 0.78%, Mn: 1.50% hot-rolled steel wire is used as the original wire to remove scale by mechanical descaling, then pickled, dipped in suspension of lime soap as lubricant, applied and dried. After using Na-based metal soap as a wire drawing lubricant to draw up to 2.0 to 2.4 mm, the presence or absence of cleaning with pressure water shown in Table 1, the presence or absence of annealing, the plating pretreatment process and the plating process Product diameter
Inventive wires of 1.2 to 1.6 mm and comparative wires were manufactured and subjected to the above-mentioned long-time welding feedability test. In case of flux cored wire, chemical composition C: 0.05%, Si: 0.01%, Mn: 0.40
% 12mm original pipe filled with flux and drawn to 2.4 to 4mm using Ca-based metal soap, then washed with pressured water shown in Table 1, presence of annealing, plating pretreatment process Then, a wire of the present invention having a product diameter of 1.2 to 1.6 mm and a comparative wire were manufactured through the plating process, and the above-mentioned long-time welding feedability test (the same determination method was used). The results are shown in Table 1.

Here, the annealing conditions were 550 to 750 ° C. for 3 hours, and nitrogen was used as the atmosphere gas. The plating pretreatment and plating conditions were as follows.

1) Bipolar electrolytic degreasing 50A / piece, 7-12V solution NaOH 100g / liquid temperature 80 ℃, linear velocity 50-120m / min 2) Anode electrolytic degreasing 110A / piece, 7-12V solution NaOH 100g / solution temperature 60-70 ℃ , Linear velocity 50-80m / min 3) Cathodic electrolytic pickling 110A / line, 7-12V solution HCl 10-20g / liquid temperature 25 ℃, linear velocity 50-80m / min 4) Plating 70-130A / line, 7- 12V solution KCN 5 to 20 g /, liquid temperature 60 ° C. linear speed 50 to 80 m / min Incidentally, the final wire drawing lubricant was vegetable lubricating oil. First
As shown in the table, wires manufactured under various wire manufacturing conditions and having wire characteristics satisfying all the requirements of the present invention showed good results up to the end in the long-time welding test (○ test No. .1-12).

However, as shown in the comparative wire, the amount of Ca-copper plating thickness does not satisfy the formula (1) (No. 13 to 15 and No. 20 to
In the case of 21), wire feeding was interrupted (marked with X), or the arc was unstable (marked with △) without interruption.

Also, No. 16 to 17 and No. 22 are interrupted because the oil amount is inappropriate and N
o.19 was interrupted because the tensile breaking load of the wire was too low. No.1
In No. 8, the tensile strength was too high and the feedability was poor and the test was interrupted.

(Effects of the Invention) According to the present invention, in a pail-packed wire which is recently being frequently used for robot welding and the like, there is no trouble in feedability even in long-time continuous welding, and there is no bead meandering due to runout of the tip of the wire. Welding with good welds is now possible.

[Brief description of drawings]

FIG. 1 is a diagram showing the determination results of a long-time welding feedability test when the amount of Ca present between the wire base material and the wire surface plating layer and the copper plating thickness are changed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 54-131542 (JP, A) JP 2-80196 (JP, A) JP 53-26569 (JP, B2)

Claims (3)

(57) [Claims] 1. In a copper-plated steel wire having a diameter of 1.6 mm or less loaded in a pail pack, the amount of Ca present between the wire base and the wire surface plating layer includes the formula (1) including the Cu plating thickness. Satisfied and the amount of oil adhered is 0.30 to 1.20g / 10kg
Copper-plated steel wire for gas shielded arc welding, characterized in that Ca amount (mg / m ² ) ≦ 28.1Cu plating thickness (μm) +22.5 ……
Equation (1) 2. The copper-plated steel wire for gas shield arc welding according to claim 1, which is a solid wire having a tensile strength within the following range. Wire diameter, 1.6 mm 70 to 100 kgf / mm ² 1.4 mm 75 to 115 kgf / mm ² 1.2 mm 80 to 130 kgf / mm ² 3. The copper-plated steel wire for gas shield arc welding according to claim 1, which is a flux-cored wire having a tensile breaking load within the following range. Wire diameter, 1.6 mm 75 to 110 kgf 1.4 mm 65 to 90 kgf 1.2 mm 55 to 80 kgf