JPS5823593A - Sintered flux for submerged arc welding - Google Patents

Abstract

PURPOSE:To obtain a titled flux where the flux consumption rate is low and the peeling property of the slag and the stability of the arc are high, by containing a specific composition of SiO2, TiO2, Al2O3, ZrO2, CaF2 and MgO, and blending Fe and etc. as required. CONSTITUTION:A flux for submerged arc welding which contains 15-37wt% SiO2, 25-44wt% TiO2, 5-28wt% Al2O3, <=21wt% ZrO2, <=10wt% CaF2, and <=12wt% MgO and has <=0.5 ratio of ZrO2/TiO2 is obtained by the sintering method, and consists of <=65% rough particles of >=20 meshes and <=35% fine particles of <=48 meshes in respect to particles. Further, <=10% BaO is blended in the flux to suppress the generation of pockmarks. Physical properties of a weld metal are improved and the flux consumption rate is reduced by blending <=40% iron powder and/or <=8% metallic powder other than iron powder.

Description

Detailed Description of the Invention The present invention relates to a sintered flux for submerged arc welding that has a low flux consumption rate (flux consumption amount/v fire melting amount), and furthermore, the low flux consumption rate improves slag removability. The present invention also relates to a sintered flux for clear arc welding that also has improved arc stability.

Since the submerged arc connection method allows the use of higher currents than manual welding, gas shield welding, etc., it has been praised as a highly efficient connection method. In this method, arc welding is performed within flux that has been sprinkled in advance (inside the melt parton), and the flux melted by welding heat is applied to the V of the welding blade.
It is involved in metallurgical reactions, metallurgical reactions, etc., and plays a major role in the integrity of the welded joint.It is also considered to be an extremely excellent method from the production environment point of view, as it does not generate neem or arc light. These effects are often influenced by the components of the flux, and various studies have been conducted on the composition of flux components, and the number of applications for welding is increasing. However, as the number of applications increases, new problems have come to be recognized, and we are now at a turning point. The first is the amount of slag produced (amount of flux consumed), and the second is the removability of the slag.According to research by the present inventors, there is a significant difference between the amount of slag generated and the removability of the slag. I have come to realize that there is a relationship.

The flux consumption rate of conventionally used fluxes is approximately 1.2, and it is said that it exceeds 1.6 in most cases. In other words, at least the same amount of flux as the amount of Mayer used is consumed and turned into slag, which is an important factor for the economic efficiency of submerged arc welding.

On the other hand, high heat input pot electrode welding of thick steel plates is being promoted in order to make the high efficiency achieved by submerged arc welding even more remarkable.
One example of this is the low peelability of slag in the layer I bus weld. As a means to improve the slag releasability,
■Method of widening the groove angle, ■Method of restricting welding conditions and performing welding at low current and low speed, ■As shown in Fig. 1, CO8 weld 1 at the bottom of the groove, and a submerged arc weld above it. The method of laminating the layers is known. However, widening the groove angle increases the amount of welding material used, which causes another problem in terms of welding economy.Also, despite the large heat input and multi-electrode, the welding heat affected zone There is a drawback that the improvement in work efficiency due to several times the slag removability is offset by embrittlement. It is also conceivable to use it in conjunction with other welding methods, but since this would complicate the work, it would be better to narrow the groove angle to further improve the O efficiency while improving the slag releasability by other means. It's getting stronger. However, for single-layer, one-pass welds, the allowable range of welding conditions is generally narrow, and Sugami sets the conditions of low current and low speed, but by narrowing the groove angle, the allowable range of f# contact conditions is further increased. Because of the narrowing, it became necessary not only to improve the slag removability several times as much as in such a one-layer, one-bus weld, but also to further improve the arc stability. When we investigated the causes of deterioration in slag removability and arc instability, we found that the cause was largely due to the amount of slag generated during welding, and we found that
The present invention was completed based on the knowledge that if a reduction in flux consumption rate was achieved, the amount of slag produced would be reduced, slag peelability would be improved, and arc stability would also be improved.

That is, the present invention aims to reduce the flux consumption rate by specifying the flux composition and its manufacturing method, and at the same time improve the slag removability and arc stability. The 7 futsus that arrived is Sin.

: 16-8 chouman (meaning of weight, the same applies hereafter), T breath 0.
:26-449II%jl, O5:5-28-1zro
, ≦gts%cair, ≦1 (1, MgO≦1!IIt
It is a sintered type 7-box which contains ZrO, /TIO, ≦0.50, and can be blended with re powder or metal powder for alloying if necessary. Naomoto Fox is 1011. The following 3aσ may be included.As long as the above component composition is satisfied, the flux consumption rate can be reduced, but as we have learned that the flux consumption rate and welding workability differ depending on the particle size structure, we will not discuss these in this specification. I will also add an explanation.

First, the reason for limiting the component composition in the flux of the present invention will be explained.

810 is essentially a slag forming agent, but as its content increases, the flux consumption rate tends to decrease.

However, as the content increases, the bead width becomes narrower9, pockmarks and herringbones occur in the center of the bead, deteriorating the bead appearance and deteriorating the slag releasability1, so the upper limit is 87 g. On the other hand, if it is less than 15 liters, the consumption rate of flux is not reduced, and the p-bead meandering occurs due to the blow-up phenomenon during welding, resulting in deterioration of welding workability. Therefore, the appropriate range for 5to2c was determined to be 16 to 8 teeth.

When the content of 108 is increased, the bead appearance and shape become better, but the flux consumption rate increases, contrary to the case of sine. Also, if the content is too high, wrinkled beads may be formed and undercuts may occur, which is undesirable.
Therefore, the upper limit of TlO2 was set to 44 s. On the contrary, TlO2
If it is less than 25%, the slag is likely to seize, which not only impairs the peelability but also makes the bead shape convex, so the range of TlO2 is limited! ! It was set as 6 to 44 vomits.

A#20. Although it does not have a large effect on the flux consumption rate, it is an effective component for adjusting welding workability. However, if it exceeds 28 yen, it becomes a convex bead.

Also, if it is less than S-, the stability of the arc deteriorates, so Al2O
The m radius of 3 was determined to be 5 to 28-.

Flux medium KZτ0. If the flux is contained, the flux consumption rate will be reduced. However, if it exceeds 21-, when the molten slag solidifies, it will split into two layers, and the surface layer will solidify more quickly, and the gas generated during welding will solidify before it can fully escape.

The generated gas remains between the weld metal and the lower layer of the slag, resulting in large unevenness on the bead 9 and gas traces. Also, zjO□ is a tie for workability! ! However, as the content increases, the bead shape becomes narrower and convex, especially for ZrO and /TIO.
When the ratio of , is high, this tendency becomes strong and impairs the bead appearance and welding workability. However, if the ratio is below O, SS, good weldability can be obtained.

cap2 is blended in the present invention to ensure the impact performance of the weld metal. However, if the content is too large, the consumption rate of flux will increase, and the gas generated during welding will be accompanied by an odor, so the upper limit is set at 10 liters.

MgO is essential for preventing slag seizure,
Also, it is included in the molten slag to reduce the tj property, but if it is in excess, the consumption rate will increase and the bead surface will be exposed. A value of 1211 or less is preferable since marks are generated.

The essential components of the present invention have been explained above, and iron powder and metal powder can be mentioned as materials that can increase the yield and increase the physical properties of weld metal by several times.

Powdered iron powder also has the effect of increasing the adhesion of the weld metal. It also works to reduce the flux consumption rate, similar to when iron-based fillers are placed inside the groove. However, if too much is added, If the flux consumption rate is reduced too much, the weldability will be impaired, so the upper limit should be 40. Alloy powders other than iron powders are
Although it varies depending on the base material and the composition of the welding wire, the upper limit is generally 8s, and only one of the iron powder and the metal powder may be mixed, but if necessary, both may be mixed. When welding using iron powder-based flux or placing iron-based filler in the groove, the flux consumption rate tends to be lower than when using non-iron powder brown flux or when there is no filler. - In addition to the above ingredients, various ingredients can be blended in I19 that do not have an adverse effect on submerged arc welding, and the types and amounts can be determined freely according to each purpose. This will be explained with BaO as a representative component. BmO has the effect of suppressing the formation of marks during fillet submerged arc welding using the flux of the present invention, and if the content is less than 10%, it will increase the flux consumption rate. If it exceeds 7 liters, it will not only increase the consumption rate (it will deteriorate the bead conformability, so it is desirable to keep it below 10 liters).

In order for the flux consumption rate to be reduced by the above-mentioned flux composition, the flux must be a sintered type flux produced by a sintering method, i.e., as the flux consumption rate is reduced, the heat capacity of the slag is reduced. Therefore, the solidification speed of the slag will naturally be faster, but if the gas generated during welding does not escape quickly to the outside of the parton, solidification will be completed at t't when the gas is contained, and the bead shape will become uneven. 9. Inconveniences such as pockmarks occur. In general, when the bulk specific gravity of flux increases, in addition to the above-mentioned phenomenon, there is a problem that the bead tends to become mid-height. To prevent these phenomena, it is necessary to widen the voids between flux particles to improve gas release, but if the particles are coarsened with molten flux, the bulk specific gravity becomes high and the bead appearance and The shape deteriorates. On the other hand, it is not impossible to make the molten type 7 flux a foam type to lower the bulk specific gravity, but this tends to increase the amount of diffusible hydrogen in the weld metal, and in any case, a problem remains.In contrast, the sintered type flux Therefore, even if the flux particles are formed relatively coarse, the bead appearance is good, and the generated gas is easily removed, so there are no inconveniences despite the rapid solidification of the slag that accompanies the reduction in flux consumption rate. Furthermore, as mentioned above, fluxes with a fast slag solidification rate generally have a high melting point.

Because molten flux has a relatively low melting point due to manufacturing reasons, even if the above-mentioned flux composition is employed, the effect of reducing the flux consumption rate cannot be obtained, and as described above, the appearance of the bead also deteriorates. On the other hand, the sintered type satisfies the high melting point and can fully exhibit the effect of reducing the flux consumption rate without damaging the bead appearance. By performing latent arc welding using a sintered flux that satisfies these conditions, slag removability is always good and welding work efficiency is improved regardless of the magnitude of heat input or the welding speed. In addition, it is possible to perform economical submerged arc welding with a low flux consumption rate. Further, as a result of welding, a welded joint with excellent bead appearance and shape and mechanical properties can be obtained. Note that backing flux is known as something similar to the above structure, but since backing flux simply supports the bead, the amount of melting is originally small, whereas the amount of melting is large like flux sprinkled on the front side. In these cases, the problem of the present invention becomes important. Furthermore, since the flux sprayed on the front side exerts an important influence on the metallurgical reaction of the molten metal or the arc phenomenon, the problem of the backing flux is different from that of the flux sprayed on the front side. contains phenolic resin, which increases the caking between the 7 fluxes and improves the supporting function of the bath molten metal. However, the function of the flux in the submerged arc welding of the present invention is completely It's different.

The above-mentioned seven methods according to the present invention are effective only when used in submerged arc welding, and can also be applied to other welding methods, such as sensual welding using a strip electrode (V-cut slag welding). In this case, it is necessary to form a large amount of slag in order to obtain V-annealing heat, which not only increases the flux consumption rate but also makes the slag peelability extremely poor.

By the way, it has been found that the flux consumption rate of the above-mentioned flux varies depending on its particle size structure, so an explanation will be added. That is, in the flux of the present invention, when the number of coarse flux particles is increased, the flux consumption rate decreases, whereas when the number of fine particles is increased, the flux consumption rate tends to increase. Furthermore, if a large amount of coarse particles is contained, the width of the bead tends to be narrow, and pock marks are likely to occur in the unevenness. On the other hand, when a large amount of fine particles is contained, welding workability is improved. Therefore, the optimum particle size composition of the flux of the present invention was determined from the viewpoints of flux consumption rate, bead appearance, shape, and workability.
It is advantageous in terms of flux consumption rate to contain more coarse particles with a diameter of 0 METSU V2 or more, but if the content exceeds 6M, the appearance and shape of the bead will deteriorate, and if particles with a diameter of 48 METSU VU or less If it exceeds -, the consumption rate of 7 tx will increase, which is undesirable.
It was concluded that it is preferable to set the fine particles of S1& or less and 48 METSU VU or less to 861& or less.

Although the sintered flux with the above structure satisfactorily achieves the intended purpose in that it provides a slag with a low flux consumption rate and good releasability, the use of this flux has the potential to reduce the O effect. An explanation from the practical aspect of arc welding is as follows.

The state of single-layer, single-pass welding within the groove is as shown in FIG. 2 and the sectional view taken along line 11-1 in FIG. 7 (FIG. 8). S
Number 8 in the middle shows scattered flux, 4 shows solidified slag, 6 shows weld metal, 6 shows molten slag, and 7 shows rays of pufferfish.In the state of molten slag, it shows both sides of the groove.

Since the wall prevents lateral flow, the melting date A/
, and in some cases may precede the arc and disturb the stability of the arc. Therefore, the arc is on the groove side I! is melted and slag flows into this part.
The so-called groove licking phenomenon occurs and tends to impair the peelability of the slag.Also, the excess slag increases the thickness of the slag, which increases the contact area with the groove sidewalls. Since the groove tends to become narrower depending on the welding heat yield, the slag entrapment phenomenon occurs due to these influences,9 and the slag peeling becomes more susceptible to deterioration.

From this point of view, it is desirable to keep the amount of slag generated in one pass (1 m) of welding within the groove to the necessary minimum, but if the above-mentioned flux is used, the flux consumption rate will be approximately 0.4 to 0. Since it becomes about .9, the amount of slag produced also decreases, and a favorable one-latency condition for slag removability can be obtained.

Since it is known that the amount of slag produced varies depending on welding conditions, etc., the following method was used to measure the standard flux consumption rate. That is, welding conditions were 600A-84V-4011/min using a 2m wide solid sire, and the sire protrusion length 'g:! Measurements were made by contacting the V-ring bead tS on a mild steel flat plate at a height of 6 m, and the (slag production amount/W fire consumption amount) at this time was determined. The power supply characteristics were DC constant voltage and reverse polarity. In other words, in one-layer, one-pass welding within a groove, if the flux consumption rate exceeds o, et, the amount of slag produced increases, and the arc is disturbed by phenomena such as molten slag leading the arc or flowing into the welding area. and set the bevel angle to 8
Even if the arc is relatively wide (0 to 70"), it creates a situation where the arc melts the sidewalls of the groove, worsening the slag removal property in the single-layer, single-pass weld of groove angle multilayer welding. Furthermore, the above-mentioned phenomenon caused by arc disturbance is suppressed. One possible means is to keep the arc voltage low, but this cannot be used because the bead becomes convex and the peelability deteriorates to pI!.In this regard, conventional flux consumption rates are generally 1 to 1.6, but Due to the large amount of slag produced, the slag peelability was poor.

On the other hand, when the weight loss rate is less than 0.4 t-, the amount of slag is small, and apertures during bottom marks are likely to occur on the bead surface, and irregularities appear on the bead. In this regard, when the flux of the present invention is used, the amount of slag O produced can be maintained to a certain extent, so the above-mentioned drawbacks do not occur.

゛The slag removability of a single-layer, one-pass weld in groove angle multi-layer welding is such that as the groove angle becomes narrower, the above-mentioned flux consumption rate decreases to 0.
Even if it is between 4 and 0.9, it will deteriorate. In particular, when the groove inner thickness becomes less than 20", the deterioration of slag removability is remarkable, so it is necessary to adjust the groove angle and groove width accordingly. The results of examining the optimal amount of slag.

It has been found that if the flux has a flux consumption rate of t0.4 to 00, it is possible to maintain good slag releasability even at a groove angle of 20 or less. Also LIIN
In the case of an asymmetrical bead like the one mentioned above, one of the bevel angles becomes narrower, but in this case, as shown in Figure 4, the bevel at the part where it touches the toe of the single-layer, single-pass weld bead. Side I! Bevel where the angle formed by (#11#!) is within !O@, or #
At the l-joint part, it is essentially no different from a symmetrical groove of 20＠ or less.
In order to improve the slag removability of the welded part, the amount of slag generated using a flux with a low flux consumption rate should be It is effective to reduce the flux consumption rate, but if the groove angle is relatively wide, use one with a flux consumption rate of 0.4-0.9, 20 or less,
Alternatively, if the sum of the angles of the groove side walls in contact with each other at the re-toe of a one-pass weld bead is less than 20, using a flux with a flux consumption rate of 0.4 to 0.7 will improve the slag releasability. It is multiplied by the width.

However, if the groove angle shown in FIG. 4 is below O, the slag releasability will not be improved, so a groove angle above Of is required.

Since the present invention is constructed as described above, the S welding cost F is reduced by reducing the flux consumption rate, and the slag releasability and arc stability are also improved.

Next, examples of the present invention will be shown.

Bracing arc welding was performed using sintered fuses having the compositions shown in Table 1, and the fufutsuknu consumption rate, slag removability, and bead appearance were observed and recorded in the same table.

In the same manner, the O mark means good, the x mark means bad, and the others in the blacks component mean Na 20, 20*L import, y・o #B: ao 3 e M 110, etc. .

The alloy components, deoxidizing components, and iron powder are expressed as a blending ratio to 100% of the blacks component.

The flux ht-s satisfied all the requirements of the present invention and achieved excellent results in all categories including flux consumption rate, slag removability, and bead appearance.

Flux Na@ has a lot of SIO□, so the bead appearance deteriorates, and the lack of TiO□ causes the slag to heat up and heat up.
Slag removability was poor. Flux rod 7 is zro
The appearance of the bead is poor because the ratio of zro, /Tl0fA is high. Flux rod 8 is TIO! !
There are few z ro.

and MgO, the bead appearance was quite bad. Flux Nagi 9 had he2o, Ik<<, which resulted in poor bead appearance, and poor slag removability due to low TiO□. Flux-10 had a large amount of sio, which deteriorated the bead appearance, and the lack of TlO2 resulted in poor slag releasability. Flux 11&&11 has a small amount of Sin, but a large amount of T10°, and the flux consumption rate increases. Flux rod! has a high flux consumption rate because S i02 is small, and A#, 0. The appearance of the bead is poor due to the large amount of Flux Na1B has a lot of z'0. in TiO□ Fuchs 414, so the bead appearance is particularly bad. Fluxes Na15 and 16 do not contain or contain a small amount of T10Q, and are zro.

The flux consumption rate is high because it does not contain

[Brief explanation of drawings]

The first factor is a cross-sectional view showing a conventional weld, FIG. 2.8 is a cross-sectional view of a submerged arc weld, and FIG. S fist - Flux 4-11 Hard slag 6 -- Weld metal

Claims (1)

[Claims] (υB10.:do~871 (l amount: same below). T 0 thought: 1!5~44-1 An, o, :s #18 小, zro, :gi-, Ct F z * i 0-
Below, MgO: 12ml or less t-containing L, 210II/
A sintered flux for submerged arc welding, characterized in that the ratio of τ10 to failure is 0.6 or less. 1) In claim 1, it is stated that 1 in the flux.
A sintered flux for submerged arc welding that contains less than 0% BaO. (3) In claim 1 or 2, the sintered type for submerged arc welding is characterized in that the flux particles are coarse particles of 20 mesh or more: 66s or less, fine particles of 48 mesh or less: 86- or less. Flux a (4) 810 laziness: 15-8
7-(weight-: same below), 'rto, 15-44-1
A#QO, :5~28, zro, :SS* below, C"
F11: Contains 1O- or less, MgO: 4ji- or less, and the ratio of zro, 7'TIO, is 00- or less, iron powder: 40- or less, and/or metal powder excluding iron powder:
A sintered flux for submerged arc S* characterized by containing 8s or less. (6) In claim 4, K in flux
IO-12) Sintered flux for submerged arc welding containing BaO. (6) In Claim 4 and Paragraph 6, the flux particles are coarse particles of 110 mesh or more: SS* or less, fine particles of 48 mesh V: L or less: latent arc welding performed at 86 g or less. Yaki #I! ! Fuchs.