JPS59127995A - Composite wire for gas shielded arc welding - Google Patents

Abstract

PURPOSE:To provide a composite wire for gas shielded arc welding which provides good slag removability and impact toughness of a weld metal, produces less welding fume and is usable for all position welding by packing a specifically composed flux in a steel pipe as a sheath metal. CONSTITUTION:A composite wire for gas shielded arc welding is usable for all position welding including vertical down welding and generates less fume in the stage of welding. A flux prepd. by adding 2-10% TiO2, 0.05-2.0% SiO2, 0.2- 2% ZrO2, adding Al and Al2O3 so as to be contained at 0.2%<=Al2O3+2Al<= 3.5% and further adding 1-6.5% a deoxidizing such as Si, Mn, Mg or the like except Al, and further adding B and B2O so as to be contained at 0.001<=B+0.1 B2O3<=0.03% with respect to the total weight of the wire is wet mixed with water glass as a binder and the mixture is packed in the wire, whereby the composite wire for gas shielded arc welding is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite wire for gas-shielded arc welding. This invention relates to a composite wire for automatic and semi-automatic welding, which produces a slightly lower fumes during welding.

Currently, a wide variety of composite wires are manufactured, but wires with rutile as the main component of the flux have an extremely stable arc even in a CO2 atmosphere, generate less spatter, and have a good bead shape. Special Public Service 1977
As seen in Example 1 of Publication No. 2463, it has been used for a long time because of its superior welding workability.

However, the disadvantages of this type of wire are that when the groove solution is applied, the slag is hard and the releasability is significantly deteriorated, and the impact toughness of the weld metal is low. In recent years, there has also been a strong demand for reducing the amount of welding fume and improving weldability in all positions, including vertical and downward welding. Regarding the toughness of weld metal, as seen in Japanese Patent Application Laid-Open No. 116351/1983, there are efforts to improve the toughness by increasing the yield of appropriate amounts of T1 and B in weld metal, but this is not always sufficient. Without.

For this reason, it is still only used for welding important structures. Regarding vertical downward welding, the present inventors have already revealed the direction of the vertical welding method in Japanese Patent Application Laid-open No. 5, No. 2795, Publication No. 4. It cannot be said that a composite wire that is satisfactory in all aspects including weldability in all positions, slag stripping property, high mechanical impact toughness, and low weld fume has yet been developed.

Therefore, the present invention Nagisa et al. As a result of various studies aimed at creating a low-bath welded fume wire with good impact toughness and excellent impact toughness, we found that all-position weldability 1, including vertical downward welding, is mainly composed of TlO2 and 5i0.
2. This is possible by appropriately adding ZrO2, jV, 203, etc., and the removability of these slags is B
By adding one to i7.

It was found that the results were significantly better even in narrow grooves.

The impact toughness of the weld metal can be stably improved by limiting the amount of 9 elements in the outer skin metal and adding B, and the welding toughness can be significantly reduced by wet-mixing the flux with water glass. The present invention was developed based on this knowledge.

That is, 1. The feature of the composite wire of the present invention is that 2 to 10 inches of TiO2 and 5 inches of 0.05 to 2.0 inches of TiO2 are added to the total wire weight
．． 0.2-2.0% ZrO2, AJ, and Ap, 20
Contains one or both of 3 in the range shown by the following formula, and further contains J
In addition to containing deoxidizing agents other than V] and O to 6.5, B1 is contained in the range of 0.001 to 0.5% in one or both of the filling flux and the outer metal. .

Furthermore, for the purpose of improving impact toughness, the amount of nitrogen in the outer metal was increased by 50%.
ppm or less, or -0 for the filling flux.
,001%≦B11B203≦0.03%, or by adding one or both of B or B2O3 to the deoxidizing agent, and further welding. It is characterized in that one filling flux is wet-mixed with water glass to reduce fumes.

0.2 poly≦AA203+ 2 X AA≦3.5% Note that “chi” as used herein means weight.

5- Below, the reason why the composite wire according to the present invention has the above-mentioned structure will be explained in detail.

The reason why TlO2 is added in an amount of 2 to 10% by weight of the wire in the present invention is mainly to expect an effect of stabilizing the arc and an effect of improving the bead shape by the generated slag. If the amount added is less than 2 g, the above effects cannot be expected, and arc C becomes unstable during positional welding, making it impossible to obtain a beautiful weld bead. On the other hand, if more than -10 g is added, the arc becomes stable, but the viscosity of the slag decreases too much, making it difficult to keep the molten metal within the groove in vertical and upward position welding. Therefore, in the present invention, TlO2 is added to the flux in an amount of 2 to 10 parts relative to the total weight of the wire, taking into consideration the arc stabilizing effect and the bead forming effect.

Incidentally, this TlO2 is partially reduced in coexistence with AL and Mg, which will be described later, and a trace amount of TiO becomes a generation nucleus of yield acicular ferrite in the weld metal, which also exerts the effect of making the structure finer.

5i02 Adjust the viscosity of the slag and add it with the aim of forming a bead during vertical downward welding. If the welding speed is less than 0.05, the effect will not be exhibited, and if two grooves are worn, the slag will become too viscous even in vertical downward welding using high current, and if the welding speed is high, it may encapsulate the bead. I'm exhausted. In fact, the amount of Sl in the weld metal becomes too large, reducing the impact toughness of the weld metal and deteriorating its cracking resistance. Therefore, in the present invention, SiO□ is set in a range of 0.05 to 2.0.

Adding Zr oxide in the range of 0.2 to 2.0% not only smoothes the solidification of the slag, but also improves the compatibility of the molten metal with the base material by adjusting the viscosity of the slag. To prevent the melt from falling.

This is to efficiently perform vertical downward welding using high current.

To achieve this purpose, a small amount of Zr oxide is required, at least 0.2%.

However, if it is added in an amount exceeding -2.0%, the slag solidifies too quickly and slag entrainment defects are likely to occur, so it must be avoided. Therefore, it is necessary to add the +Zr oxide in a range of 0.2 to 2.0%. The addition means may be zirconium oxide, zircon sand, or the like.

In addition to ZrO2, Ag203 is required in the slag in order to increase the solidification point and viscosity of the slag in the wire of the present invention used for vertical downward welding at a relatively high current. In the wire of the present invention used for main CO2 gas-shielded arc welding, the yield of AP to the weld metal is around 3, and almost all of the AP added to the flux becomes an oxidizing agent and turns into slag. . Therefore, in the wire of the present invention, Al'203-i or Ai' may be added alone, or AQ203 and Al' may be added in combination, but Ai', 203 and AC The sum of one or both of them is 0.2 coefficient ≦M2O3
It is necessary to add within the range of + 2 X AQ≦3.5.

Ap7203 and 2XAl! The sum of one or both of is 0.
If the ratio is less than 2, the amount of A9203 is insufficient during welding L - the above effect will not appear. On the other hand, if it is added in excess of 3 or 5, Af! , 203 becomes too large, and the freezing point of one slag becomes too high, causing slag entrainment.

8- AI'203 and A1. There is no change in its effect after it becomes slag during welding, but 80 has the effect of accelerating the oxidation and solidification of molten metal, so adding a small amount can have the effect of preventing the metal from melting. So.

For wires used in oxidizing gas, AP, 203 to A
It is more economical and better to mainly add a. However, A
, + AP for r-002 mixed gas shield welding, etc.
, when added mainly, the yield of An increases in the weld metal and the toughness of the weld metal decreases. In such a case, + AP, 20
3 It is easier to get better results when added to the main ingredient. Note-
AA can be added in the form of an alloy with other metals, such as Fe-AC or AC-M1 alloy, in addition to metal AC.

The deoxidizing elements other than Al in the wire of the present invention include +
Si, Mn, Ti, Mf, etc. are added mainly from flux, but the amount added is based on the total amount of wire.

The total ratio is 1.0 to 6.5. If the amount of these deoxidizing elements added is less than 1.0%, deoxidation will be insufficient.

Weld metal is porous and its performance deteriorates. On the other hand -6
, If added in excess of 5%, the deoxidizing element will cause the weld metal to become stiff, causing the weld metal to harden.

=9- This results in a decrease in characteristic toughness and cracking resistance. This is no good.

In the wire of the present invention, the deoxidizing element in the flux is:

The wire weight ratio is limited to a range of 1.0 to 6.5 inches.

These deoxidizing elements can be added singly or as an iron alloy or an alloy of these elements. Among these deoxidizing elements, Sl and Mn are mainly used for the purpose of adjusting the strength of the weld metal, but Mg has a higher free energy of oxide formation than T1 of TlO2, which is the main component of the wire of the present invention. Due to its small size, T 1 in an arc atmosphere
．． A part of 02 is reduced and retained in the weld metal as T]O as described above, resulting in the effect of refining the microstructure. Especially My.

When added in an amount of 0.3 to 2.0% by weight of the wire, the amount of oxygen in the weld metal is significantly reduced and the impact toughness is greatly improved.

When T1 is added in the form of Fe-Ti or an alloy with other metals, it can be expected to work to directly refine the weld metal as TiO as described in 17 above, and also prevent the oxidative consumption of B, which will be described later, and effectively enhance the function of B. Make it. but.

If added in excess of 0.5%, a large amount of T1 will be added to the weld metal.
By staying at 0-, the impact toughness deteriorates on the contrary.

Therefore, it is desirable that T] be 0.5% or less based on the total weight of the wire.

Furthermore, B1 is added to the wire of the present invention in order to improve the slag releasability. That is, the wire weight ratio is 25% TiO, 21% 5i0, and 21% Zr.

1d2030.7% slag former composition and Fe-8
i (45%Si) 1.5%, Me-Mn
2.0% deacidifying element system and 0.2% Fe-B (5% B)
Composite wire 1 for CO2 welding is manufactured by filling and forming a mild steel sheath with a flux consisting of a basic flux and a flux in which B1 is added in one step in the range of 0-1.0% by weight of the wire. Using .2φ, the relationship between the amount of Bl in the wire and the slag removability was clarified.

The test is a 60 degree ■groove with a 2'i'0A-31V-30 saw/
A 5 K9 weight was dropped from a height of 1.5 m onto the back surface of the test specimen welded under the conditions of -co220 t/min, and the slag removability was evaluated as the peeling rate of the slag peeled off by this impact.

Figure 1 shows the test results, with Bli in the wire being 0.00.
If the ratio is less than 1, the slag stripping rate will not be improved.
Addition of 0,001% or more results in a peeling rate of 56, which exceeds the majority. Therefore, the amount of Bi added to the wire of the present invention should be 0.001% or more.

Addition of 0.006% or more will result in a peeling rate of 100%, but adding more than 0.5% will not produce any particular effect; on the contrary, the bead shape will become slightly distorted. Since the welding fume increases, the upper limit of Bi is Ol, 5
%.

In addition, as a Bi source, metal bismuth, bismuth oxide,
It has been found that single or any bismuth compounds such as bismuth fluoride-bismuth sulfide, bismuth hydroxide, and bismuth chloride are effective for stripping slag. Further, B1 can be added from the filling flux, or as an alloy component of the shell metal, or both.

In either case, it is necessary to add 0.001% or more of Bi to the wire in total to improve the slag releasability.

The gist of the wire of the present invention is a composite wire for gas shield welding that contains a flux that has the above-mentioned components and ranges, but in order to further improve the impact toughness, a low-carbon flux with a nitrogen content of 50 ppm or less or a It is used to fill a steel shell such as low-alloy chime. The reason why the nitrogen content in the outer skin metal was set to 50 ppm or less was based on the experimental results shown in FIG.

That is, the nitrogen content is 22 ppm, 31 ppm,
45ppm, 54ppm, 63ppm, 75ppm,
TiO245.0%, 5i based on the total weight of the wire, using mild steel skin materials with 83 ppm and 98 ppm.
020.3%, Zr020.6%, AP, 2030
．． 5%, Fe-8i (45% Si) 1.2%
, Me-Mn 2.0%, AU-My (40%
AP, -60%Mg) 0.4%, iron powder 2%, Fe-
A composite wire of 1.6φ containing a flux consisting of 0.2% B (5%B) and 05% BIO was prototyped, and the relationship between the nitrogen content in the sheath metal and the impact toughness of the weld metal was investigated.

32. of 32'E on the test board. , Assemble thick steel plates with a 50°V groove, welding current 450A, arc voltage 38.■.

13- Welding speed 20 rm 1 minute, shielding gas CO2201/
The relationship between the impact toughness at -40°C and the amount of 9 elements in the weld metal was clarified.

As is clear from the actual test results in FIG. 2, as the nitrogen M in the l1ti outer skin increases, the amount of nitrogen in the weld metal also increases proportionally. The experiment was conducted using automatic welding in a laboratory with no wind, so there was no air entrainment due to welding.

As is clear from the experimental results, the impact toughness of the rutile composite wire deteriorates rapidly when the amount of nitrogen in the outer sheath metal is 55 ppm or more (the amount of nitrogen in the weld metal is 50 ppm or more). This is because Ti-B coated arc welding metal
80~], which is a major drawback compared to the fact that even with an amount of nitrogen of OOppm, there is no significant deterioration.

Therefore, in order to ensure the impact toughness of a rutile-based composite wire with a high welding rate, it is necessary to adjust one alloy component and at the same time reduce the amount of nitrogen in the weld metal to 50 ppm or less. Usually the ratio of the outer metal to the total weight of the wire is 0.8
Since it is around 5, it means that the nitrogen content in the outer metal may be around 60 ppm.

14- In reality, the filling flux raw material also contains some nitrogen, and considering that some nitrogen is picked up from the honey atmosphere during welding, the wire of the present invention uses a metal sheath containing 50 ppm or less.

The wire of the present invention is B, B alone, or Fe.

Ti, AI', Zr, Mn, Cr, Mo
, Ni, etc., or in the form of an oxide, or in the form of both a metal and an oxide.

Flux is added within the range that satisfies the relationship.

When one or both of B and B2O3 is added in the above range, B segregates at the austenite grain boundaries and the free energy of one grain boundary decreases, which suppresses the formation of pro-eutectoid ferrite and refines the structure of the weld metal. Impact toughness is improved.

However, the amount of addition of one or both of B and B2O3.

If the lower limit of the range specified in the present invention is not reached, no effect of B on microstructuring the structure can be expected. On the other hand, if B is added in excess of the upper limit, a large amount of B will be lost in the weld metal, resulting in hardening and a decrease in impact toughness. Therefore, the range is set to satisfy the relationship of 0.03% of B or B2O3 in one wire of the present invention.

In order to further reduce the amount of welding fume, the flux is wet mixed in a water glass prior to being filled into the metal shell. The reason why the amount of fume generated is reduced by wet mixing the flux is obvious.The reason is that the flux reacts with the alkaline components in the water glass and forms an inert substance on the surface, which causes This is thought to be because the amount of vaporization decreases.

Furthermore, during wet mixing, fine powder adheres to the surroundings of large particles, which reduces the amount of fine powder that is easily vaporized.

In this respect as well, the amount of welding fume tends to decrease. There is no difference in the amount of fume generated whether the flux is dried or undried. Potassium silicate, sodium silicate, lithium silicate, and the like can be used as water glass, but potassium silicate is particularly effective in reducing hume. In the case of the flux composition of the present invention, it is sufficient to add water glass in an amount of about 1.5 to 7 to 9 to 100 of the flux.

As for the form of the metal sheath, an open seam wire with a seam at the Tagawa part may be used, but a closed seam wire without an opening on the outer periphery is less likely to cause cold cracking of the weld metal because the filling flux does not absorb moisture. It will be advantageous. In particular, in the case of wires that are filled with flux wet-mixed with water glass in order to reduce the amount of welding fume generated, the flux tends to absorb moisture after drying, so there is an open seam in the metal shell. The filling flux may absorb moisture during storage, causing pores and hydrogen cracking in the weld metal. Therefore, for the purpose of reducing welding fumes,
For wires whose flux is wet-mixed and filled with water glass, closed-seam wires without openings are better.

According to research conducted by the present inventors, a composite wire manufacturing method in which a flux containing a large amount of water is filled into a pipe having no openings except at one end, and the composite wire is manufactured by reducing the diameter to a predetermined diameter can also be used. , during the manufacturing process 17- Sufficient high temperature 1 e.g.], 100' CFi! Hot rolled at 300 degrees.

It has been confirmed that by stretching or annealing the wire at about 650° C., the moisture inside the wire is completely removed and a weld metal with a small amount of hydrogen can be obtained.

Furthermore, the closed seam wire without openings has Cu, Ni, Ai', Cr on the wire surface.
By applying a metal coating such as, it is possible to improve the four-roast properties of the wire, and the power supply is stable during welding, and since the wire has no directionality, there is no meandering of the wire, etc.
Since it has excellent feedability, it has the advantage of allowing more stable welding to be performed.

The main composition of the wire of the present invention is as described above, but Li, Na, and Li are added for the purpose of stabilizing the arc.

Various compounds such as Rb, Os, C6, Sr, Ba, etc. can be added. Furthermore, Ni, Or, Mo,
Nb, V, etc. can also be added to improve the strength and properties of the weld metal.

Next, the present invention will be explained and explained in more detail using Examples.

18- Example Table 1 shows the configuration of the prototype wire, and Table 2 shows the test results. In the same table, Nαl-4 is Nα5~1 in the comparative example.
3 is an example of the wire according to the present invention.

All wires use soft inner and outer skins, and in the case of open seam wires, they are filled with flux, shaped and drawn, and are made to 1.6
Finished to maφ and fired at 350℃.

Graphite and molybdenum disulfide were applied to the wire surface to improve feedability during welding.

In the case of closed seam wire, 11m prepared in advance
An electric resistance welded steel pipe of xφ was filled with flux and the pipe while being vibrated, and in the middle of wire drawing, annealing was performed at 650° C. for 4 hours, and the surface of the wire was plated with O to finish it with a bar diameter of 1.6.

First, perform vertical advancement welding and vertical downward welding on the corner joint, observe the arc stability, slag, and metal conditions, and then check only the wire that is easy to use according to the JIS standard for low-temperature steel plates.
SLA 33B Assemble 25 t to 50° V groove 2
Three layers and three passes of vertical advancement welding were performed at 20A = 19- to investigate the welding cost components and impact toughness. Note that N[17
Only the wires were welded with a mixed gas of 90% Ar-10% CO□, and the others were welded with a CO2 shield.

The slag peelability was measured using SM-50B 25 thick steel plate.
After temporary attachment to the 0°V groove and welding under the conditions of z5oA-3ov-3°Cm7 minutes, the circumference was inspected in the same manner as in FIG.

Measurement of welding fume is + JIS Z 3930 [
Measurement method for total fume % of coated arc welding rods. That is, in a chamber with an internal volume of 0.34 m3, an arc was generated for 130 seconds on a mild steel plate with a polished surface under the conditions of 300 A - 28 V - 30 tin for 1 minute, wire protrusion length 25 degrees, and shielding gas 20 tons/minute. After sucking the fume for a minute, the total amount of fume attached to the V paper was measured.

Furthermore, the amount of diffusible hydrogen in the weld metal is determined by JIS Z 313.
33OA-29V-35 fight/ by glycerin placement method
The welding conditions were -25 g Ext, gas flow N 20 /, and 7 minutes at various times.

As is clear from the test results in Table 2, weld metal analysis and impact tests were not conducted because the arc was not stable and vertical advancement welding was not possible with the Nfll wire whose TiO2 content was less than the lower limit of the present invention. There wasn't. Furthermore, since it does not contain Bi, the results of the slag releasability test conducted in a downward position were also extremely poor. Furthermore, the amount of welding fume is large.

Nn2 wire has too much TlO2, 5i02,
Since it does not contain ZrO2, the arc is stable, but the slag and metal tend to flow, making it difficult to weld in position. Therefore, joint performance tests using vertical advancement welding were not performed on this wire either. Furthermore, since the Bj content is only 0.0005%, the slag removability is poor.

The arc of the N[L 3 wire is stable, but the At! Since the amount of 203 was too large, the slag solidified too quickly, making it difficult to achieve stable slag coverage. Still +
Since there is too much Bi, weld fumes are extremely large.

Furthermore, the impact toughness of the weld metal is low because the amount of 9 element in the outer skin metal is large and the amount of B added is small.

Due to the lack of AQ203 in NIL 4 wire, slag tends to take the lead during vertical downward welding. Blowholes occur in the weld metal due to lack of deoxidizing agent.1-.

For this reason, no impact tests were conducted on the weld metal. Furthermore, since it does not contain B1, slag peeling is also extremely poor.

On the other hand, the M5 to M13 wires according to the present invention all exhibited good position weldability and slag releasability under stable arc conditions. Furthermore, the impact toughness of the weld metal can be improved by appropriately adding B, by limiting the amount of nitrogen in the outer metal to 50 ppm or less, by adding Mf in the range of 0.3 to 2.0 mm, or by controlling these components. It was confirmed that by controlling at the same time, further improvement could be achieved.

Floors 5 and 6 were still filled with flux that was wet mixed with water glass. ”、9、10、11゜12.13
The amount of weld fume is significantly reduced in the wires compared to the wires without wet mixing.

Further, in the case of a wire having no openings in the outer sheath, even when filled with wet-mixed flux, the amount of diffusible hydrogen in the weld metal is extremely small.

As clarified by the above embodiments, the composite wire for gas shield welding according to the present invention is a rutile-based composite wire having excellent arc stability, and is capable of being used in a vertical direction, which has traditionally been considered a drawback of this type of wire. This improves weldability in all positions, including downward movement, and also significantly improves the impact toughness and slag removability of the weld metal. Furthermore, since the amount of welding fume has been significantly reduced, the effect of improving the environment at the welding site is also extremely large.

In this way, the wire of the present invention solves all the problems of the conventional rutile-based wire, so it will be possible to use mild steel, 50%
It is applied to fillet and butt welding of a wide range of steel types, mainly Kilo-HT steel, and is expected to greatly contribute to improving the working environment, welding efficiency, and reliability of joints.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the amount of B1 and slag removability, and FIG. 2 is a graph showing the relationship between the amount of nitrogen in the outer metal and toughness. 25- Procedural amendments to the case of Mr. Kazuo Wakasugi, Commissioner of the Higasaki License Agency in February 1980, Showa Oro II License No. 3181 of 1980, 2
, Title of the invention Composite wire for gas shielded arc welding 3, Relationship with Ministry of Affairs and Place Patent applicant Place No. 3, Ote III'J-2-6-6, Chiyoda-ku, Tokyo Name (665) Japan 1) Tatami 4, Representative Address: 3-3-3, 3-3, Nissho, Chuo-ku )531-

Claims (1)

[Claims] l Ti022 to 10% based on the total weight of the wire. 81020.05-2.0%, Zr020.2-2.
0%, contains one or both of AN and Ae203 in the range shown by the following formula, and further contains a deoxidizing agent other than Aε in a range of 1.0 to 1.0%.
6.5%, and 0.001 to 0.5 of B1 in one or both of the filling flux and the outer shell metal.
A composite wire for gas-shielded arc welding, characterized in that the content is within a range of %. 0.2%≦Aε20. +2XA, ≦3.5 ratio 2 +, TiO22~10% based on the total weight of the wire. 81020.05-2.0%, Zr○20.2-2.
0%, Ap, and Ap20. Contains one or both of these in the range shown by the following formula, and further contains a deoxidizing agent other than A2 in a range of 1.0 to
6.5%. o, o O1%≦B + ,% B20. ≦0.03
Contains B or B2O3 that satisfies the relationship of +
One or both of Bi-filled flux and outer metal 1
- A composite wire for gas-shielded arc welding, characterized in that it contains 0.001 to 0.5 g, including 1 to 1. 0.2 ratio ≦A9□o3+ 2 X Ap, ≦3.5 ratio 3
The composite wire for gas shielded arc welding according to claim 1 or 2, wherein the backbone content of the outer skin metal is 50 pprr+ or less. 4. The composite wire for gas shielded arc welding according to claim 1, 2, or 3, wherein the deoxidizing agent other than color A contains Mg 0.3 to 2.0. 5. The composite wire for gas shielded arc welding according to claim 1, 2, 3, or 4, wherein the entire filling flux is wet-mixed with water glass.