JPS5961592A - Steel wire for arc welding - Google Patents

Abstract

PURPOSE:To improve feedbability of a wire and to prevent the generation of spatter in large current welding of CO2 welding by forming an internal oxidized layer in a welding wire. CONSTITUTION:A titled wire contains 0.06-0.15% C (weight % and hereunder the same), 1.0-2.5% Mn, and 0.5-3.0% Si, respectively and consists of the balance Fe and unavoidable impurity elements. The wire has hexagonal-cracking or scratch like-cracking on the surface of copper plating and further the effective oxygen content specified by the following equation is 40-300ppm, which effective oxygen content is given by the internal oxidized layer: The effective oxygen content=(total oxygen content in the welding wire)-(the oxygen content of a wiere blank material).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steel wire for arc welding which has excellent workability with less bath welding.

Generally, CO2 gas shield welding, MIGil welding, etc. are copper plated. A 4 mm';l bath connecting wire is used. These bath welding wires are usually used for welding while being wound around a spool or bobbin, or loaded into a cylindrical container called an Ilpack. When these wires are used, the wires in the above state are attached to a feeder, which is a reliable device for welding, and passed through a feeding roller to a flexible conduit tube, welded m)-chip, for a length of 3 to 20 m. In many cases, it is used for welding after passing through core 1X chips.

In such welding, the wire is required to be fed at a constant speed, but the wire has to be fed at a constant speed. These resistance forces become large (as a result, the feeding speed of the welding wire becomes uneven, and eventually the feeding stops). As a result, the bending arc becomes unstable,
Unique bath contact defects such as irregular bead shapes, poor fusion, and undercuts occur.

Recently, as bath welding processes have become more complex, faster, and wider, welding methods that have low cross-friction resistance with flexible/pull conduit liners, smooth and stable feeding, and always feed at a constant speed have become necessary. There has been a strong demand for wire, that is, welding wire with good feedability.

Conventionally, in order to improve wire feeding performance, efforts have been made to increase the feeding power of a feeder or to improve the feeding performance of the wire itself. For example, in order to improve the feeding performance of the wire itself, methods are being used to apply liquid lubricant to the wire surface to increase the lubrication ability of the wire surface and reduce feeding resistance. No evidence of feedability was obtained.

The reason for this is that it is difficult to apply liquid lubricant evenly and stably to the surface of the copper-plated wire, and in order to obtain the desired performance, a large amount of lubricant must be applied. This is because it was not possible. Also, the VC is more expensive than necessary.
The lubricating oil applied to the surface of the wire is likely to cause changes in the material of the welded part or adversely affect welding workability.

In addition, apply strong pressure to the front side of the wire +fri,
There are methods to reduce the contact resistance by changing the surface roughness, but the effect is the same as the effect of improving feedability by applying lubricating oil, and is not yet satisfactory. On the other hand, carbon dioxide gas sealed welding (hereinafter referred to as CO□ welding) has the advantages of low efficiency and low cost, but on the other hand, it has low bath efficiency due to the phenomenon of frequent scattering of bath molten droplets called spatter during welding. This has been a major problem since it is tightly attached to the gas nozzle, which impedes gas shielding properties, resulting in bath contact defects, and furthermore, it takes effort to remove spatter.

This sputtering phenomenon is particularly noticeable under relatively thick conditions of 250 A or more (Σ region).
2) changes in the composition of the 7-metal gas, and 3) addition of alloying elements to the wire.

1) The output characteristics of the C02 bath welding machine, the fluorescent method, and the
The aim is to improve the control system for cables and wire feeders. However, since the generation of spatter is essentially caused by the arc phenomenon of contact with the CO□ bath, it has its own limits.

2) The shielding gas may be CO2 or an inert gas A.
This method is effective in stabilizing the arc and reducing spatter by using r gas as the main component, but it has the disadvantage of high cost.

3) is carried out by adding alloying elements to the wire; for example, Japanese Patent Publication No. 3256/1983 discloses the effect of adding Ti. Also, as is well known, JIS Z331
2, it has been standardized as YCW] and is widely used. However, with the prior art wires as described above,
Both solve the problem of spatter generation as mentioned above-3
- It is hard to say that it is sufficient.

As mentioned above, there are problems with conventional technology in both wire feeding performance in CO2 welding and MIG welding, and in particular in reducing the generation of ivy under bath contact conditions in the large current range of CO2 welding. , xyr *t 1g Mosquito treatment was required.

The present inventors have been conducting research to solve problems from the viewpoint of glazes for a long period of time, and by forming an internal oxidation layer on the welding wire, not only the wire feedability but also the wire feedability has been improved.
We have succeeded in developing a welding wire that does not generate ivy even during high current range welding in CO2 welding.

As is well known, by controlling the material composition and oxidation conditions, internal oxidation of metal materials can be performed within the metal substrate without external oxidation. After internally oxidizing the bath welding wire, there is an advantage that copper plating can be applied to the wire surface by simple pickling. Moreover, when wire is drawn after steel plating, tortoise-shell-like cracks occur on the glossy plating surface, which allows lubricating oil to accumulate in an appropriate amount and dramatically improves feedability. Furthermore, it was confirmed that when the amount of effective oxygen in the welding wire brought about by internal oxidation was 40 to 300 ppm, the generation of spatter was significantly suppressed.

The effective oxygen amount referred to here is calculated by subtracting the oxygen amount of the wire material from the oxygen amount (total oxygen amount) obtained by performing an oxygen analysis after copper-plating a welding wire that has undergone internal oxidation. refers to value.

Effective oxygen amount = (total oxygen amount in the welding wire) - (oxygen amount in the wire material) In other words, the present invention solves the problem of improving welding wire feedability and reducing the amount of spatter by changing the oxygen existing form in the wire and the oxygen This problem was solved by a new technical idea that is different from the conventional technology of intentionally adjusting and regulating the amount.

That is, the gist of the present invention is that, in terms of weight, C: 0.06 to 0.
15%, Mn: 1.0-2.5%, Si: 0.
5 to 3.0, or further contains Ti:0
．． 05-040%, Cr: 0.5-1.0%, Al
: Contains any one or more of 0.05 to 0.05%, however, q) The total of 2S or more of 11Cr and A1 is 20% or less, and the remainder consists of Fe and impurity elements inevitable in steelmaking, and the copper plating surface It has tortoiseshell-like or scratch-like cracks on the surface, and the effective oxygen amount defined by the following formula is 40 to 300. pp
The present invention provides a steel wire for arc welding which has excellent welding workability and is characterized in that the effective oxygen amount is provided by an internal oxidation layer.

Effective oxygen amount - (total oxygen amount of welding wire) - (oxygen amount of wire material) The present invention will be described in detail below.

Figure 1 shows the state of the internal oxidation layer of the wire of the present invention, 1, '2
This is a sketch diagram (inclination angle: 6°) obtained by obliquely polishing a mm-diameter wire and observing it with a metallurgical microscope at a magnification of 400 times. (a) is a conventional wire with no internal oxidation layer, (
b) is a wire of the present invention, in which an internal oxidation layer is observed from the wire surface toward the inside.

The reason for specifying the effective oxygen amount here is that if it exceeds 300 ppm, the oxide concentration in the internal oxide layer on the wire surface will become excessive, the copper plating performance will deteriorate, and the copper plating will peel off during the stretching process. be. Also, if 40 ppm is not added,
At the same time, the hexagonal cracks necessary for retaining lubricating oil on the plating surface are insufficient, and at the same time, it becomes ineffective against spatter.

FIG. 2 is a sketch diagram (magnification: xioo) obtained by observation with a metallurgical microscope, showing the aforementioned tortoise-shell-shaped cracks.

(a) shows the surface of a conventional wire with an effective oxygen content of 20 pp
(b) is the surface of the wire of the present invention, in which an effective oxygen amount of 150 pl)m was provided by the internal oxidation layer.

Next, alloying elements C, SiXMn and Cr5Al, T
The reason for specifying the content of i will be explained.

Originally, an internal oxidation layer is ideally formed in a welding wire that contains a specific amount of an alloying element that has a stronger affinity for oxygen than iron. These elements include Si, Mn, A1. There are Cr, Ti, etc., and each needs to be contained in an appropriate amount depending on the purpose.

When C is less than 0.06, the total amount of spatter 2 does not change, but large spatter is generated. Large particles of spatter adhere firmly to the nozzle and near the welding area, increasing the frequency of spatter removal problems. Therefore, in order to prevent this, the C content was set to 0.06 or more. 0.0
When the temperature was 6% C or higher, droplet transfer in the large current range became smooth, and spatter was slightly reduced. This is C02
It is believed that this is because the CO reaction in the droplets and molten pool becomes active during the welding arc.

However, when the C content of the wire exceeds 0.15%, the C content of the weld metal increases, the tensile strength increases, and the elongation decreases.
@Since impact toughness decreases, C was limited to 0.1.5% or less.

Si is an essential element for forming an internal oxidation layer on the surface of the steel wire. When Si is less than 0.5, the oxygen potential of the controlled atmosphere is PO2
m~IX1. Even if you adjust the heating to within the Oatm range,
The formation of an internal oxidation layer is extremely weak, and the amount of effective oxygen is 40
ppm, the wire feedability deteriorates, large spatters occur, and the Si in the CO2 weld metal
decreases, and a focus appears on the weld bead surface. When the Sl content is 0.5% or more, especially 0.7% or more, the formation of an internal oxidation layer becomes noticeable, the amount of effective oxygen increases, tortoiseshell-like cracks are formed on the wire surface, and the wire feedability also improves. In addition, the amount of ivy is also significantly reduced. However, when Si exceeds a coefficient of 3.0, the formation of an internal oxide layer is rather suppressed, and instead, the formation of an external oxide layer becomes significant, resulting in a marked decrease in plating adhesion.
Wire feeding resistance increases and welding workability deteriorates. Therefore, Si has a ratio of 0.5 to 3.0, preferably 0.7 to 3.0.
2.0 person in charge.

When 11vln exceeds 1.0%, the formation of an internal oxide layer is promoted when the Si content is 0.5% or more, especially 0.7% or more, but when it exceeds 2.5%, the Mn content of the weld metal increases. thicker, resulting in increased hardness. Therefore, the elongation is reduced and the impact toughness is also reduced. Moreover, when Si exceeds 3.0, 2.
Since Mn with a coefficient of more than 5 produces Mn S i 03 on the surface of the steel wire and promotes the formation of an external oxide layer, the range of Mn is 10 to 2.5, preferably 1.5 to 2.5ti6. .

Next, while satisfying each of the above-mentioned CXSiXMn ranges, Ti:
0.05-0.40%, Cr: 0.5-1. o%
, Al: 0.05 to 0.50%, with the exception of Ti
; Cr % When the total of two or more types of AI is 20%, it has the effect that the formation of an internal oxide layer becomes more remarkable. Below this range, there is almost no effect on the internal oxide layer, and above the upper limit of the above range, the formation of an external oxide layer is promoted rather than an internal oxide layer, and as a result, the adhesion of the plating is significantly reduced. It deteriorated and the feedability decreased significantly.

Next, the effects of the present invention will be explained in more detail with reference to Examples.

Example I A sample having a chemical composition of C, Si % IVIn, Cr, Als Ti as shown in Table 1 was melted and finished into a wire of 22 mm through forging and wire drawing steps. These wires are annealed in a Co-CO2 controlled hearth furnace (not shown in Table 2) to form an internal oxidation layer, and then pickled ().
After IC110%, 60℃), copper plating is applied and wire drawing is performed.
．． Welding workability was evaluated using a wire of 2 rraa. Third
The table shows the temperature at 800℃ in a co/CO2=2.571 atmosphere.
The thickness of the internal oxidation layer, the amount of effective oxygen, the feedability, and the amount of spatter generated are shown for the wire annealed for 120 minutes.

The amount of spatter generated was collected using a spatter collection box, and the feedability was determined by measuring the armature current value of the wire feeding motor, and the feedability was judged to be acceptable if the current value was below ZA.

Table 4 shows the measurement conditions.

FIG. 3 is an explanatory diagram showing the relationship between the amount of effective oxygen and the amount of sputtering in Table 3. In the figure, the broken line a indicates the copper fitting quality.

First, as shown in Figure 3, the amount of effective oxygen is 40 ppm.
Below and above 300 ppm, the amount of spatter is 4
rr/min or more (3rd front door 28,
&31, flatness 33.1636), below 40 ppm, no cracks on the wire surface are observed as shown in Table 3 A3, /I64, flattened 8, and the feeding performance deteriorates.

On the other hand, even if the effective oxygen amount is 40 to 300 ppm and there is hexagonal cracking, if the chemical composition of the wire is outside the range of the present invention, a decrease in workability is observed. (Table 3 J1
61.2.12.16.21) Example 2 Using sample 16.6, CO/C02 was adjusted to 25/1.4/1
Effective oxygen content, plating adhesion, surface cracking and feedability, amount of spatter, and wire annealed at 7oooC, -ooooC and 900oC for 8 minutes, 60 minutes and 120 minutes in a 6/1 atmosphere. I evaluated it.

(The welding conditions are the same as in Table 4.) Table 5 shows the results obtained. The Co/CO2 ratio is 25
It can be seen that excellent results in both feedability and spatter amount can be obtained by adjusting the temperature and time to be within a specific range and heating.

Table 2 The umbrella oxygen potential is defined as follows.

” 'II Fe25 i04 is the dissociation pressure of FetSiO number.

[Brief explanation of drawings]

Fig. 1 is a sketch diagram (magnification: 1x400) showing the cross-sectional state of the wire of the present invention, (a) is a conventional wire, (b) is a sketch diagram showing the surface state of the wire of the present invention, and Fig. 2 is a sketch diagram showing the surface state of the wire of the present invention ( Magnification x100), (a) is conventional wire, (b)
is the wire of the present invention, and FIG. 3 is a chart showing the relationship between the effective oxygen amount (ppm) and the amount of spatter (>'r) for the steel wire in Table 3. Bud/(a,) Rod(0-) Item (b 2) (b) Procedural amendment (voluntary) November 12, 1980 Kazuo Wakasugi, Commissioner of the Patent Office - Indication of the case 1 Patent Application No. 168430 of 1988 2 Name of the invention Steel wire for arc welding 3. Person making the amendment Relationship to the case Patent applicant Location
2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (66)
5) Nippon Steel Corporation Representative Takeshi 1) Toyota 4th generation Osamu Address 3-3-3 Nihonbashi, Chuo-ku, Tokyo Date of amendment order 5 Showa month/day (shipment date) 6th amendment Increasing number of inventions (Ll) Revise the claims as shown in the attached sheet. (2) Correct "frictional resistance" on page 3, line I, 9 of the specification to "frictional resistance." (3) Correct page 7, line 6 of the specification (4) Correct "Yes. Welding wire" in line 8 of the same line to "Raru. In other words, welding wire." (5) Correct 16 of the same line. Correct the line ``Kotokata confirmed.'' to ``Runode ruru.'' (6) Correct ``that is,'' in the 8th line of the same page, 8th line, to ``that is.'' (Power, same page 9, 5. Correct line ``polishing'' to ``polishing.'' (8) Correct line 10 of the same line, ``F is made.'' to ``It is done.'' (9) Page 1I, line 9 r of the same line, change PO2j to `` Po2J
I am corrected. (10) On page 122, line 9, ``2.5%'' is changed to ``
However, Mn is 25%.'' (Old) Line 19, "10.50%" is corrected to "0.5%." (12) On page 14, line 3, "Z A or less" is corrected to "2A or less." (13) Line 18 “(Table 3, AI, 2, 1.2
, 16, 21) J as "(Table 3/I61.I62./
l612. /l616. Atsushi 21)” is corrected. (14) Page 17, line 10 and line II “ΔG0T
Correct J as [ΔGOT J. (15) Line 11 [6750oj to [-67500J
I am corrected. (16) "Polishing" in Table 4 on page 19 is corrected to "polishing." Claim 1: C: 0.06 to 0.15% (same below weight%), Mn: 10 to 2.5%, Si: 0.5 to 3.0
%, the remainder consists of Fe and unavoidable impurity elements, the copper plating surface has hexagonal or scratch-like cracks, and the effective oxygen amount defined by the following formula is 40 to 30.
A steel wire for arc welding which has an effective oxygen content of 0 ppm and has excellent welding workability in that the effective oxygen amount is provided by an internal oxidation layer. Effective oxygen amount = (total oxygen amount in the welding wire) - (oxygen amount in the wire material) 2. C: 0.06 to 0.15% (weight% and below are the same)
, Mn: 10-2.5%, Si: 0.5-30%, and K Ti: 0.05-0.40%, C
Contains one or more of the following: r: 0.5-10%, A7: 0.05-05%, provided that the total of Ti + Cr t All over 2 m is 2.0% or less, and the remainder is Fe and unavoidable It consists of impurity elements, has tortoiseshell-like or scratch-like cracks on the copper plating surface, and has an effective oxygen amount of 40 to 300 ppm as defined by the following formula. A steel wire for arc welding that has excellent welding workability. Effective oxygen amount - (total oxygen amount in welding wire) = (oxygen amount in wire material)

Claims (1)

[Claims] lc:o, 06 to 0.15chi (the same applies below M amount chi), seed:
], 0 to 2.5%, Si: 0.5 to 3.0%, and the remainder consists of P'e and inevitable impurity elements,
The copper plating surface has hexagonal or scratch-like cracks, and the effective oxygen %4 defined by the following formula is 40 to 300 pp.
m, and the effective oxygen t'+''- is suppressed by an internal oxidation layer.A steel wire for arc welding with excellent workability. Amount) - (Amount of oxygen in wire material) 2C: 0.06 to 0.15% (weight: jt4: Same below S), Mn: 1.0 to 2.5, Si: 0.5 to 3
0 coefficient, and 'l'i: 0.05 to 0.
．． 40%, Cr: 0.5-1.0%, Al: 0
．． Contains any one or more of 05 to 05%, provided that Tl
s Cr % The total of two or more types of AI is 2.0 or less, the remainder consists of Fe and unavoidable impurity elements, the copper plating surface has hexagonal or scratch-like cracks, and is further defined by the following formula: effective oxygen amount is 40 to 3001)I)m
A steel wire for arc bath welding which has excellent bath welding workability and is characterized in that the effective oxygen amount is provided by an internal oxidation layer. Total effective acid = (total oxygen content of welding wire) - (oxygen content of wire material)