JPS63192593A - Bonded flux for submerged arc welding - Google Patents

Abstract

PURPOSE:To improve a slag peeling and bead external appearance by contg. at specific weight % 10-50% Fe powder, 5-20% SiO2, 5-15% MgO, 10-40, Al2O3 and 5-19%. TiO2 in the whole flux. CONSTITUTION:The composition of the bonded flux components for submerged arc welding is composed by contg. at weight 10-50% Fe powder, 5-20% SiO2, 5-15% MgO, 10-40. Al2O3 and 5-19% TiO2 against the whole flux. Fe powder component is transferred in a welding metal during welding to increase the deposition amt., so the slag forming amt. is reduced. SiO2 components make a slag vitreous to better its peeling, and Al2O3 reduces the slag forming amt. and is effective in bead shaping as well. The components of MgO and TiO2 stabilize the bead shape respectively as well, promoting the vitreousness of the slag. Consequently the flux improves a slag peeling and bead external appear ance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to submerged arc welding flanks used for butt welding of mild steel or high tensile strength steel of 50 kg or more, and corner joint welding of ZX columns.

More specifically, the present invention relates to a trap flux that has a high welding rate and excellent slag removability in high heat input multilayer welding of thick plates.

[Conventional technology]

In recent years, as steel structures have become larger and buildings have become taller, there has been a marked tendency for the plate thickness of the material to be welded to be thicker.
Welding of the thick plates of the Q+ gate is being done in various places. Since such thick plates are welded using a normal welding method, the number of welding passes is unnecessarily large, resulting in inefficiency. The main ways to improve the efficiency of welding such thick plates are ■
One method is to reduce the amount of welding by making the cross-sectional area of the groove as narrow as possible, and the other is to use adult heat to increase the welding speed.

However, in a narrow groove, it is necessary to lower the welding current correspondingly, and the groove cross-sectional area decreases.
However, the number of passes itself cannot be reduced as much as expected.

In method (2), if multi-electrode welding with a large current is performed, the welding speed will increase accordingly and efficiency can be increased.

By the way, the commonly used welding method is covered arc welding.

There are gas shielded arc welding methods and submerged arc welding methods, but the submerged arc welding method in particular can easily increase the current value compared to other welding methods.

This is because the arc occurs in the flux and is invisible, making welding work easier.

Widely used for high-current, high-efficiency welding. Furthermore, since iron powder can be added to the flux during submerged arc welding, a higher deposition rate can be expected. However, the biggest problem with submerged arc welding is that the slag produced by melting the flux gets stuck inside the groove, and it takes a lot of effort to remove this slag. This tendency especially increases as the temperature increases. In this case, if the groove is filled with one pass of welding, the slag is generated on the outside of the groove and can be easily removed without getting stuck inside the groove.

By the way, when the thickness of the plate becomes thick, it is difficult to completely fill the groove with only one pass even if the current value is increased to the maximum, and it is especially difficult to weld only from one piece, such as a corner joint of a box column. In this case, if the plate thickness exceeds 50 m, it is not possible to complete the joint with I-no-ξ even if multi-electrode, high-current welding is performed.

Conventional measures for improving slag removability, JP-A-56-89396
No., Japanese Patent Publication No. 57-202996, % Publication No. 58-134
No. 93, JP-A-55-92292, JP-A-55-12
This method has been proposed in the respective publications of No. 0488 and %Kokai No. 58-23593.

[Problem that the invention seeks to solve]

By the way, Japanese Patent Application Laid-Open No. 56-89396 contains a large amount of MfO.
This relates to a highly basic sintered flux that produces a slag that contains milled Ba0 (z) and contains periclase crystals and barium mica crystals, but this flux contains a large amount of MfOf and is a crystalline hard slag. When high heat input welding is performed to generate this, undercarriage is generated on the groove wall, and it is extremely difficult to remove as it penetrates deeply into the groove.

Similarly, the flux disclosed in Japanese Patent Publication No. 57-202996 contains a large amount of metal carbonates such as Myo, B.aO, and produces hard slag.

Originally designed as a flux for narrow gap welding,
There is no improvement in slag peeling in high heat input welding.

The flux of the method according to JP-A-58-13493 and the flux ri of JP-A-58-23593
% 8 t O'2 * T t 02 has MtO vh This is a flux whose main component is mt2o3, and its purpose is to improve slag removability and reduce flux consumption. However, the composition of these fluxes is not necessarily appropriate (b) The content of TlO2 is excessive, and when high heat input welding is performed, the fluidity of the slag becomes excessive, making it difficult to form a bead shape, making it impractical.

Also, Japanese Patent Application Laid-open No. 55-92292 discloses AI! 203° TiO2 This relates to a flux whose main component is S i 02, and since the flux T i 02 is excessive, it is unfavorable in terms of the pead shape.

The present invention solves the problem that 1% slag gets stuck in the groove and is difficult to remove in multi-layer submerged arc welding with high heat input of thick plates, and slag peels off extremely easily even in high heat input welding. The present invention provides a Zend flux for submerged arc welding that can obtain an excellent nine-bead appearance.

[Means for solving problems]

The present invention rt, iron powder io ~ 1% by weight based on the total flux
50%, SiO2 ~20%, M#05~15%, A1
This is Zendflux for submandial arc welding, which is characterized by containing 10% to 40% TlO and 25% to 19% TlO.

[Function] First, the reason for limiting the iron powder to 10 to 50 in the flux of the present invention will be explained. It has the two effects of improving welding efficiency and improving slag removability on the iron powder addition I].

First, the iron powder added with VC in the flux migrates into the weld metal during welding, increasing the amount of bath deposition and increasing the welding speed, improving welding efficiency. . By adding iron powder, it is possible to improve the welding speed If by 10 to 40%. On the other hand, the amount of melted flux is suppressed to the extent that the iron powder is melted, and the amount of slag produced is reduced, but this makes it much easier to remove the slag. That is, if the amount of slag produced is large.

Slag tends to get caught in the groove, resulting in undercuts at the edges of the slag, and a large amount of slag gets stuck there, making it difficult to peel off, but adding an appropriate amount of iron powder is extremely effective in preventing this. be. In addition, the amount of edge welding to the iron powder increases, and compared to the case of 7lux that does not contain iron powder, the bead surface is above the groove, so there is less tendency for edges and slag to get stuck inside the groove. This also has the effect of making it easier for the slag to peel off. This effect of iron powder can be obtained when the amount of iron powder exceeds 10% of the total weight of the flux, but if the amount of iron powder exceeds 50% of the total weight of the flux, the amount of slag forming agent will be insufficient.
The amount of iron powder added must be 50% or less because the bead shaping action is insufficient and protrusions tend to form on the bead surface, which adversely affects welding workability.

Therefore, the appropriate range of iron powder is determined to be 19 to 50%, and it is necessary to contain 5 to 20% of 8102 tri. It increases the viscosity of 8t02ri slag, is an extremely effective component for bead shaping, and has the property of vitrifying the slag, thus producing a slag that is easily friable and has good peelability. This effect of Una 8102 can be obtained by adding 5% or more to the total flux.

On the other hand, if it is added in excess of 20%, the melting point of the slag will decrease and the bead shape will become unstable during high heat input welding, which will worsen slag peeling and also cause slag seizure, so the addition amount of 5t02 r120 % or less. or.

The amount of 5i02 has a large effect on the amount of oxygen in the weld metal.

Adding too much will increase the amount of oxygen in the weld metal.

Excessive addition of 8102 is undesirable from this point of view as well, since the toughness of the weld metal used therein deteriorates.

The raw materials added to 5i02 are SiO-based materials such as borax, wollastonite, and olivine sand) S or SiO2
An oxide ore containing . In addition, water glass SiO2 used when granulating raw materials for flux
It can be considered as the amount of O2 component added.

5-15% of the total KMtOμ flux is required. In other words, MPOri has a high melting point (2700 tl) and has the effect of imparting high fire resistance to the flux and stabilizing the bead shape in high heat input welding, so it is necessary to add 5% or more. On the other hand, when a large amount of M#Ori is added, crystals such as periclase are formed, the slag becomes hard, and once it gets stuck in the groove VC, it becomes extremely difficult to peel it off.

However, if a large amount of 710 is added, the consumption of 710 will increase and the amount of slag produced will also increase, so in order to improve the slag removability, it is necessary to add MfO to 15% or less. Others [Mho has the effect of reducing oxygen in the weld metal and improving toughness.

The material to be added to MfOi is magnesia clinker.
(Mho), olivine sand (MfO, S i O2
) MIIO such as spinel (MfO9A1203) is a product, or oxides containing MfO, magnesite (M#003), dolomite (Mt Oa O20
6) Use a carbonate containing MtO.

Furthermore, in the flux of the present invention, AI of 10 to 40
! It is necessary to add 203. AI! 203 is a refractory component and has a relatively high melting point of t/'1205oC. Therefore, it is extremely effective for bead shaping in high heat input welding, and is also essential in the flux of the present invention in which the amount of MtO, which has a high melting point, is suppressed. Further, since the flux added in a large amount of k1203f is difficult to dissolve, the amount of slag produced is reduced, and it also has the effect of improving slag peeling.

Furthermore, a large amount of AI is added to the important point of Al2O3! The addition of 206 has the effect of narrowing the bead width, which is also effective in improving slag peeling. In other words, if the bead width is wide, the sidewalls of the groove will be melted and under-cara tra will be formed within the groove, but if this slag gets stuck, it will be impossible to remove it at all, but it is necessary to add it to SA/'203. The bead width becomes narrower, and it is necessary to add 10% or more to the amplifier, but if it is added in excess of 4Q, it is not preferable because it will deteriorate the conformability of the edge of the peed and cause slag inclusions. . ”-Also, A/203'(i
Adding 1 m excess will result in a convex bead shaped like a horse's back. From this point of view as well, it is necessary to keep Al2O3 at a ratio of 40 or less.

Al2O5 is alumina (AI!203) or spinel (A/, 20.MPO), chamotte (AI!20)
AI such as 3.5io2)! An oxide containing or containing 203 as a main component shall be used.

Next 1c T + 02 de・a・）rugah T t 0
2) The pinid appearance and bead shape are good, giving fluidity to the slag, which is effective for forming smooth beads, and s
Like 8102, it has the effect of making the slag vitrified, making it more crumbly and improving the slag removability. In addition, when the flux vcT t O2 containing a large amount of A/'203 of the present invention is starved,
In addition to the formation of aluminum titanate (AI!203.TiO□), it also has the effect of improving slag removability due to the solidification shrinkage phenomenon during the cooling process of the slag.

In order to obtain the effect of T + 02 as described above, Ic ri
* It is necessary to add 5% or more of T r O2 to the entire flux; on the other hand, if the amount added exceeds 19%, not only will the amount of slag generated increase, but the coagulation waves on the bead surface will become rough, leading to the occurrence of undercuts. Therefore,
It is necessary that TlO2u be 19% or less.

fz o, TlO2u rutile (T t 02 ) or titanium slag (T IO2, T t s O!5)
Add the same amount. Further, the amount of addition n is determined by converting it into the equivalent amount of lower oxidation #jpoTiO□ such as Ti3o5.

The specific components in the flux of the present invention have been described above, but in addition to the above-mentioned components, ordinary flux components may be added to the flux of the present invention as appropriate.

First, metal fluorides will be explained. If the metal fluoride is added in an amount of 15% or less of the total flux n-r, the amount of slag produced will not increase and the amount of slag produced will not be adversely affected. However, if it exceeds 15%, the fluidity of the slag becomes excessive due to the low melting point of the metal fluoride, and the arc becomes unstable, causing undercuts and the like, resulting in poor bead shape. It is necessary to do the following. What is metal fluoride? Oa F21 N a I'
−klPs s +VifF2, B a F 2−
Na 3A/! It shall be used as a raw material for welding materials such as F6.

Next is OaO, as long as it is 0aO8"110% or less. Oa (M; is replaced by lime carbonate (Oa003) -
Added from wollastonite (Oa O, S A02) etc.
Like MfO, it is a basic component that is effective in improving the toughness of weld metal, but in terms of slag removability, the flux contained in TiO2 reacts with OaO and T s 02 to form calcium titanate (OaO-T' +02) 'c
This occurs at the interface between the peed surface and the slag,
Seizing occurs and slab removability deteriorates. For this reason, Oa
If it is less than Oril O, will it prevent the production of calcium titanate? If it exceeds OaO, the bead shape and convex beads and coagulation waves will become rough, so OaO was set to 10% or less.

Other oxides of MtiO, B2O5, Ba00
3,8rOO5 carbonate, Si, A4Ti, M
Alloying agents such as deoxidizing agent 9M01Ni etc. can be added as appropriate. Furthermore, the flux of the present invention is a flux of the present invention, and also contains components of a fixing agent such as water glass, alumina sol, and silica gel, which are used when granulating raw material powder. When the component added from the fixing agent corresponds to a specific component of the flux of the present invention, the amount thereof shall also be defined as the amount of addition specified by the present invention.

The present invention has been described in detail above, but in order to clarify the effects of the present invention, examples will be described below.

[Five actual cases]

Five types of Zendfluxes, PL to F-1, as shown in Table 1 were prepared. That is, the raw material powder shown in the flux raw material composition column was granulated as water glass (sodium silicate)'f: a fixing agent, and then fired under the firing conditions of 3801Z'X120 minutes to obtain a flux with a particle size of 12XLOO mesh. Among the finished fluxes, F1 to F7 are examples of the present invention and are %
F8 to F15 are main steel plates, the test wires (Mn-based steel wire) are shown in Table 3, and the welding conditions are shown in Table 4.
It is shown in the table and FIG. In Fig. 1, 1 is the material to be welded,
261) This is the backing metal attached to the joint.

The overlap results are shown in Table 5. Regarding the slag removability, the peeling in the first pass and the hardness were investigated. As a result, results were obtained that were satisfactory in terms of the effects of the present invention, tK l -g 7 'U of the present invention, but 8-L of the comparative example.
All samples of i5 had poor slag removability, and no satisfactory results were obtained.

Table 2 Table 3 Table 4 Wire diameter is 4.8φ for the L pole and 6.4φ for the T pole [Effects of the invention] As described above, if the flux of the present invention is used, a large amount of wire diameter can be used in multi-layer welding of thick plates. Even in thermal submerged arc welding, slag can be easily removed, and it is possible to achieve excellent welding efficiency and a welded appearance.

[Brief explanation of the drawing]

FIG. 1 is a front view for explaining the groove shape adopted in the embodiment of the present invention. l... Material to be welded, 2... Backing metal. Agent: Patent attorney Masamitsu Akizawa and one other person (illustration)

Claims (1)

[Claims] A bond flux for submerged arc welding characterized by containing 10 to 50% Fe powder, 25 to 20% SiO, 5 to 15% MgO, 10 to 40% Al_2O, and 25 to 19% TiO by weight based on the total flux. .