JP2002346790A - Mixed flux for submerged arc welding and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the regenerating utilization of welding slag generated after submerged arc welding, and further to improve the peelability of the slag and the shape of beads. SOLUTION: The welding slag of bond flux used for submerged arc welding and the welding slag of melting type flux are mechanically mixed in a ratio in which the content of the welding slag in the bond flux is controlled to 10 to 90 mass% of the total content. The flux has a grain size <=2.36 mm and bulk density as much as 1.30 to 1.90 g/cc, and has a chemical composition containing, by mass, 15 to 55% SiO2 , 2 to 25% Al2 O3 , 2 to 40% MnO, 0.4 to 30% MgO, <=30% CaO and <=20% CaF2 , and also satisfying (the mass% of MgO)/(the mass% of SiO2 )<=1. The difference between the bulk density of the welding slag in the bond flux and the bulk density of the welding slag in the melting type flux is <=0.50 g/cc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed flux for submerged arc welding and a method for producing the same, which aims at recycling welding slag generated after submerged arc welding, and more particularly to butt welding from thin steel plate to thick steel plate. The present invention relates to a mixed flux for submerged arc welding suitable for downward fillet welding and a method for producing the same.

[0002]

2. Description of the Related Art Due to the rapid increase in the amount of industrial waste in recent years and the social situation that it is not easy to construct a new industrial waste disposal site, there is a concern that there is a shortage of industrial waste disposal sites. Therefore, controlling industrial waste emissions has become a major issue today. Conventionally, flux welding slag used for submerged arc welding (hereinafter, welding slag) has been disposed of as industrial waste.However, considering the social situation and effective use of resources as described above, recycling of welding slag Is being considered. For example, JP-A-51-21537 and JP-A-11-188496 disclose that a raw material whose components are adjusted in advance is added to a welding slag to form a sintering flux (Conventional Example 1). ).

[0003] Japanese Patent Application Laid-Open No. 57-181796 discloses a method in which the mixing ratio of welding slag and unused flux is specified and the welding slag is recycled (conventional example 2).

Japanese Patent Application Laid-Open No. 63-188493 discloses a method in which a molten material whose components have been adjusted in advance is added to welding slag to provide a flux having a quality equivalent to that of a new product (conventional example 3). ).

On the other hand, mixed fluxes for submerged arc welding are disclosed in JP-A-63-203296, JP-A-63-15074 and JP-A-1-181199.
In Japanese Patent Publication No. 3 (2003), the influence of the chemical components of the flux, the mixing ratio, or the particle size composition is studied (conventional example 4).

Japanese Patent Application Laid-Open No. 7-227694 discloses a mixed flux for submerged arc welding in which a welding slag and a foamed flux are mechanically mixed. By specifying the mixing ratio of the welding slag and the foamed flux, the particle diameter, and the bulk density, welding workability with a thin steel plate is improved (conventional example 5).

[0007]

However, the flux of the prior art 1 is a fired flux and does not relate to the reuse of the mixed flux for submerged arc welding as in the present invention.

In the conventional example 2, a flux having the same component range as that of the initial flux is added, and a flux of a completely new component system is not obtained.

Further, Conventional Example 3 relates to reusing and dissolving and regenerating welding slag as a raw material by adding welding slag as a raw material to a preliminarily mixed molten raw material, and relates to the reuse of a mixed flux for submerged arc welding as in the present invention. is not.

[0010] Furthermore, Conventional Example 4 relates to a mixed flux for submerged arc welding, but does not relate to recycling of the welding slag.

[0011] Furthermore, Conventional Example 5 is a flux manufactured by mechanically mixing a welding slag generated after submerged arc welding with a foamed flux, but only a thin steel plate is studied. In addition, since the particle size ranges of the welding slag and the foaming flux to be mixed are completely different, and the difference between the respective bulk densities is 0.558 g / cc or more, the welding slag and the foaming flux are supplied in the flux during welding. Segregation may occur.

The present invention has been made in view of the above problems, and aims to recycle welding slag generated after submerged arc welding to make effective use of resources. An object of the present invention is to provide a mixed type flux for submerged arc welding which is applicable to downward fillet welding, prevents flux component bias, and has excellent slag removability and bead shape.

[0013]

The mixed type flux for submerged arc welding according to the present invention is characterized in that the welding slag of the bond flux and the welding slag of the molten flux used for the submerged arc welding are combined with the welding slag of the bond flux. A mixed flux for submerged arc welding in which the content is 10 to 90% by mass of the total amount, which has a particle diameter of 2.36 mm or less and a bulk density of 1.30 to 1.90 g / cc. And SiO ₂ : 1
5 to 55% by mass, Al ₂ O ₃ : 2 to 25% by mass, M
nO: 2 to 40% by mass, MgO: 4 to 30% by mass,
CaO: 30 wt% or less, and _CaF 2: containing 20 wt% or less, and (MgO mass%) / (SiO ₂ mass%)
It has a chemical composition satisfying ≦ 1.

In the mixed flux for submerged arc welding, the difference between the bulk density of the welding slag of the bond flux used for the submerged arc welding and the bulk density of the welding slag of the molten flux is 0.50 g / c.
It is preferably not more than c.

[0015] Another mixed flux for submerged arc welding according to the present invention comprises a welding flux of the bond flux used for submerged arc welding and a molten flux solidified and pulverized by a dry cooling method. Is a mixed flux for submerged arc welding, which is mechanically mixed at a ratio of 10 to 90% by mass of the total amount, with a particle diameter of 2.36 mm or less and a bulk density of 1.30 to 1.90 g /. cc and S
iO ₂ : 15 to 55% by mass, Al ₂ O ₃ : 2 to 25
% By mass, MnO: 2 to 40% by mass, MgO: 4 to 3
0% by mass, CaO: 30% by mass or less, and CaF ₂ : 20
% By mass and (MgO mass%) / (SiO 2
₂ % by mass) ≦ 1.

In the mixed flux for submerged arc welding, the difference between the bulk density of the welding slag of the bond flux used for the submerged arc welding and the bulk density of the molten flux is 0.50 g / cc or less. Is preferred.

[0017] Still another mixed flux for submerged arc welding according to the present invention comprises a weld flux of bond flux used for submerged arc welding, a welded slag of molten flux, and a molten flux solidified and pulverized by a dry cooling method. Is a mixed flux for submerged arc welding in which the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount, the particle size is 2.36 mm or less, and the bulk density is But,
1.30 to 1.90 g / cc, and SiO ₂ : 15
To 55% by mass, Al ₂ O ₂ : 2 to 25% by mass, Mn
O: 2 to 40% by mass, MgO: 4 to 30% by mass, C
aO: 30% by mass or less, CaF ₂ : 20% by mass or less, T
iO ₂ : It is characterized by containing 20% by mass or less and having a chemical composition satisfying (MgO mass%) / (SiO ₂ mass%) ≦ 1.

In the mixed flux for submerged arc welding, the difference in bulk density between the welding slag of the bond flux used for the submerged arc welding and the welding slag of the molten flux and the molten flux solidified and pulverized by the dry cooling method is used. , 0.50 g / cc or less.

Further, in the submerged arc welding mixing type flux according to claims 1 to 6 of the present invention, MgO / SiO ₂ compositional ratio per weight of the weld slag bonded flux used for submerged arc welding of 0.7 or more And Mg of molten flux solidified and pulverized by welding slag of molten flux or dry cooling method
The O / SiO ₂ composition ratio is preferably 0.5 or less.

On the other hand, the method for producing a mixed flux for submerged arc welding according to claim 1, 2 or 7 of the present application is as follows.
Submerged arc welding in which the welding slag of the bond flux and the welding slag of the molten flux used in the submerged arc welding are mechanically mixed at a ratio such that the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. It is a mixed type flux for collecting welding slag of bond flux, performing coarse grinding, drying, grinding, particle size adjustment and bulk density adjustment, while collecting welding slag of molten flux, coarse grinding, drying, It is characterized in that pulverization, particle size adjustment and bulk density adjustment are performed, and these are mechanically mixed.

Further, a method for producing a mixed flux for submerged arc welding according to claim 3, 4 or 7 of the present application is as follows.
The welding slag of the bond flux used in the submerged arc welding and the molten flux crushed and pulverized by the trunk-type cooling method are machined at a rate such that the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. Is a mixed flux for submerged arc welding, which is partially mixed, recovers the welding slag of the bond flux, performs coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment, while solidifying by a dry cooling method The cullet of the mold flux is roughly pulverized, pulverized, adjusted in particle size and adjusted in bulk density, and mechanically mixed.

Further, the method for producing a mixed flux for submerged arc welding according to claim 5, 6 or 7 of the present invention is characterized in that:
The welding slag of the bond flux used for the submerged arc welding, the welding slag of the molten flux, and the molten flux solidified and pulverized by the dry cooling method are combined with the welding slag of the bond flux in an amount of 10 to 90% by mass of the total amount. It is a mixed type flux for submerged arc welding that is mechanically mixed at the following ratio, collects welding slag of bond flux, performs coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment, welding of molten flux Collect the slag, perform coarse grinding, drying, grinding, particle size adjustment and bulk density adjustment, and further perform coarse grinding, grinding, particle size adjustment and bulk density adjustment of the cullet of the molten flux solidified by the dry cooling method. And mechanically mixing them.

In the method for producing a mixed flux for submerged arc welding according to claim 1, 2 or 7, the welding flux of the bond flux used for the submerged arc welding and the welding slag of the molten flux are combined with the bond flux. A mixed flux for submerged arc welding in which the content of the welding slag is mechanically mixed at a ratio of 10 to 90% by mass of the total amount, the welding slag of the bond flux and the welding slag of the molten flux are collected,
These are simultaneously introduced, and are characterized by coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment.

According to a third aspect of the present invention, there is provided a method for producing a mixed flux for submerged arc welding, comprising: a welding flux of a bond flux used for submerged arc welding; and a molten flux solidified and ground by a trunk cooling method. And a mixture type flux for submerged arc welding in which the content of the welding slag of the bond flux is mechanically mixed at a ratio of 10 to 90% by mass of the total amount,
The method is characterized in that the welding slag of the bond flux is collected, charged simultaneously with the cullet of the molten flux solidified by the dry cooling method, and coarsely pulverized, dried, pulverized, adjusted in particle size and adjusted in bulk density.

The method for producing a mixed flux for submerged arc welding according to claims 5, 6 and 7 of the present invention is a method for solidifying a weld flux of a bond flux used for submerged arc welding and a welding slag of a molten flux using a dry cooling method. A mixed flux for submerged arc welding in which a molten flux that has been pulverized and pulverized is mechanically mixed at a ratio such that the content of the welding slag of the bond flux is 10 to 90 mass% of the total amount, and the welding of the bond flux is performed. Collect slag and welding slag of molten flux,
The method is characterized in that the molten flux is solidified by the dry cooling method and is injected at the same time as the cullet, and coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment are performed.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present inventors can apply welding slag generated after submerged arc welding, particularly butt welding from thin steel plate to thick steel plate and downward fillet welding, in order to recycle welding slag of bond flux which is difficult to recycle. In addition, as a result of intensive experiments and researches on a mixed flux for submerged arc welding, which is less likely to cause component segregation of the mixed material of the flux, (1) a welding slag of a bond flux and a welding slag of a molten flux or a dry cooling method (2) welding slag of bond flux, welding slag of molten flux or molten flux solidified and pulverized by dry cooling method. It was found that it was effective to reduce the bulk density difference of

The present invention has been made from this point of view. The welding slag of the bond flux is recovered, subjected to magnetic separation and pulverization, and the particle size is adjusted. And mechanically mixing with a molten flux solidified and pulverized by a welding slag or a dry cooling method. As a result, a mixed flux for submerged arc welding, which is applicable to butt welding from thin steel plate to thick steel plate and downward fillet welding, prevents component bias of the flux, and has excellent slag peelability and bead shape. can get.

The mixed flux for submerged arc welding of the present invention is a flux obtained by mechanically mixing a welding slag of a bond flux and a welding slag of a molten flux. Bond flux is generally mixed with flux raw material powders such as silicon oxide, limestone, manganese oxide, fluorite, and magnesium oxide, granulated using a binder such as water glass, and then fired at about 400 to 540 ° C. Manufactured. This bond flux can be added with a carbonate that generates CO _{2 in} an arc, an alloying element, and a deoxidizer, thereby easily reducing the hydrogenation of the weld metal and improving the mechanical performance. . The welding slag of this bond flux contains one derived from the decomposition of carbonate, or an oxide that has a deoxidizing effect, and has a significantly different chemical composition from the unused flux. Therefore, it is difficult to reuse the welding slag of the bond flux as it is as the bond flux. However, the bond flux welding slag
Because it is melted by arc heat and is glassy,
It has low moisture absorption, its chemical composition is also effective as a slag forming agent, and it can be expected to be recycled as a raw material for mixed flux. Then, the present inventors collected welding slag of the bond flux, and after magnetic separation pulverization, adjusted the particle size and tried welding as a flux for submerged arc welding. Then, it was recognized that the welding slag of the bond flux lacked arc stability at the time of welding, generated a pock mark, had a narrow bead width, and had a deep penetration. This is (MgO mass%) / chemical component of the bond flux.
This is considered to be due to the high ratio of (SiO ₂ mass%). Therefore, stable welding workability and bead shape cannot be obtained only with the welding slag of the bond flux.

On the other hand, the molten flux is produced by melting, cooling and pulverizing raw materials for melting such as silicon oxide, limestone, manganese oxide, fluorite and magnesium oxide in an electric furnace or the like. This molten flux is glassy because it has once melted the raw material, has almost no moisture absorption, and has good welding workability from low current range to medium current range, that is, from thin steel plate to middle steel plate. is there. The components of the welding slag have substantially the same composition as the unused flux, and it is relatively easy to reuse the welding slag of the molten flux, and there are many practical examples as described above. However, the molten flux has poor welding workability in a high current region, that is, a thick steel plate, and thus the thickness and heat input are limited.

Based on these findings, the present inventors have found that although welding slag of bond flux alone cannot provide stable welding workability and bead shape, the bead shape is narrow and the penetration shape is deep. Utilizing and mechanically mixing the welding slag of the bond flux and the welding slag of the molten flux, the submerge improves not only the workability of welding thin steel sheets to medium steel sheets but also the workability of welding thick steel sheets. It has been found that a mixed flux for arc welding can be obtained. Further, it has been found that the same effect can be obtained by using a molten flux solidified and pulverized by a dry cooling method instead of the welding slag of the molten flux.

In the mixed flux for submerged arc welding of the present invention, the content of the welding slag of the bond flux used for submerged arc welding is 10% with respect to the total amount.
To 90% by mass. When the welding slag content of the added bond flux is less than 10% by mass, the welding slag of the bond flux cannot be effectively reused. On the other hand, the welding slag content of the bond flux is 90% by mass.
When it exceeds, the moisture absorption resistance is deteriorated, and a pock mark is easily generated. Therefore, the welding slag content of the bond flux is set to 10 to 90% by mass. In consideration of the component adjustment of the mixed flux, the content of the welding slag in the bond flux is preferably 10 to 70% by mass.

The mixed flux for submerged arc welding (hereinafter referred to as "mixed flux") has a particle diameter of 2.36 mm or less, that is, particles having a particle diameter of 2.36 mm or less occupy almost 100%, and have a bulk density of 1.36 mm. 30 to 1.90
The particle size and the bulk density are adjusted so as to obtain a mixed flux of g / cc. When a mixed flux containing particles having a particle diameter of more than 2.36 mm is used, the bead width is narrow, the wave is coarse, and the welding workability is deteriorated. In particular, in large heat input welding of thick steel plates, blow-up becomes remarkable. The bulk density varies depending on the mixing ratio, the particle size configuration, and the like.
If it is less than 0 g / cc, the blow-up at the time of welding becomes remarkable, and welding workability deteriorates. On the other hand, the bulk density is 1.90 g
If it exceeds / cc, undercuts are likely to occur, and the slag removability also deteriorates.

Further, the chemical composition of the mixed flux for submerged arc welding is SiO ₂ : 15 to 55% by mass,
Al ₂ O ₃ : 2 to 25% by mass, MnO: 2 to 40% by mass, MgO: 4 to 30% by mass, CaO: 30% by mass
And CaF ₂ : 20% by mass or less, and (MgO 2
The components are adjusted so that (mass%) / (SiO ₂ mass%) ≦ 1.

The composition ratio of the mixed flux for submerged arc welding is (MgO mass%) / (SiO ₂ mass%) ≦
Must be 1. This is because the workability during welding and the stabilization of the bead shape are most importantly affected. Further, the present inventors have studied the welding slag of the bond flux used for the submerged arc welding as the raw material of the mixed flux, the welding slag of the molten flux, and the MgO / SiO of the molten flux solidified and pulverized by the dry cooling method. _With respect to the _two composition ratios, it has been found that the welding workability is further improved by controlling the composition ratio in an appropriate range.

The composition ratio of MgO / SiO ₂ is closely related to the melting point of the molten slag, and the higher the composition ratio of MgO / SiO ₂ , the higher the melting point. As described above (paragraph 0030), the flux of the present invention utilizes the property that the bead shape of the weld slag of the bond flux is narrow and the penetration shape is deep. Therefore, in order to utilize this characteristic, it is necessary to use MgO / SiO ₂ of the welding slag of the bond flux.
Preferably, the composition ratio is 0.7 or more.

On the other hand, the welding slag of the molten flux and the molten flux solidified and pulverized by the trunk cooling method have the effect of easily becoming a molten slag in the flux of the present invention and having an effect of expanding the bead shape. By the arc heat generated at the time of welding, first, the molten slag which is solidified and crushed by the welding slag of the molten flux or the dry cooling method becomes molten slag, and the molten slag makes it easier to melt the slag of the bond flux having a high melting point. Therefore, a molten pool that has been solidified and pulverized by the welding slag of the molten flux or the stem-type cooling method and pulverized to form a molten pool that is stably and appropriately widened, and a bead shape with deep penetration due to the effect of the welding slag of the bond flux. can get. Therefore, the molten flux slag and M of the molten flux solidified and pulverized by the dry cooling method are used.
The gO / SiO ₂ composition ratio is preferably 0.5 or less.

The reasons for adding the chemical components of the mixed flux of the present invention and the reasons for limiting the composition will be described below.

SiO ₂ : 15 to 55% by mass SiO ₂ is an acidic component and is effective in adjusting the viscosity and melting point of slag. When the content of SiO ₂ is less than 15%, the viscosity of the slag at the time of melting is insufficient, which causes the meandering of beads and the occurrence of undercut. On the other hand, SiO
_If the content of ₂ exceeds 55%, the oxygen content in the weld metal increases, and the toughness deteriorates.

Al ₂ O ₃ : 2 to 25% by mass Al ₂ O ₃ is also an effective component for adjusting the viscosity and melting point of the slag. If the content of Al ₂ O ₃ is less than 2%, the viscosity of the slag at the time of melting is insufficient, undercutting is likely to occur, and the slag removability also deteriorates. on the other hand,
If the content of Al ₂ O ₃ exceeds 25%, the viscosity of the slag becomes too high, resulting in a convex bead.

MnO: 2 to 40% by mass MnO is also an effective component for adjusting the viscosity and melting point of slag. If the content of MnO is less than 2%, the viscosity of the slag at the time of melting is insufficient, undercutting is likely to occur, and the slag removability also deteriorates. On the other hand, MnO
If the content exceeds 40%, the amount of oxygen in the weld metal increases, and the toughness deteriorates.

MgO: 4 to 30% by mass MgO is a basic component and has an effect of reducing the amount of oxygen in the weld metal. If the content of MgO is less than 4%, the amount of oxygen in the weld metal increases, and the toughness deteriorates. On the other hand, if the content of MgO exceeds 30%, the arc tends to be unstable, the meandering of the bead and the grain become coarse, and the appearance of the bead deteriorates.

CaO: 30% by mass or less CaO is also a basic component and has an effect of reducing the amount of oxygen in the weld metal, and is therefore effective in improving the toughness of the weld metal part. However, when the content of CaO exceeds 30%, the slag removability deteriorates, the moisture absorption resistance deteriorates, and a pock mark easily occurs.

CaF ₂ : 20% by mass or less CaF ₂ is also a basic component and has an effect of reducing the amount of oxygen in the weld metal, and is therefore extremely effective in improving the toughness of the weld metal portion. However, when the content of CaF ₂ is 20%
If it exceeds 300, the arc tends to be unstable, the meandering of the bead and the wave become coarse, and the bead appearance deteriorates.

In addition to the above components, TiO ₂ may be contained in an amount of 20% by mass or less. TiO ₂ is an acidic component, and is an effective component for adjusting the viscosity and melting point of slag. Further, TiO ₂ is reduced during melting and yields in the weld metal, which is effective in improving toughness. However, when the content of TiO ₂ exceeds 20%, the slag removability is rapidly deteriorated.
If there is no requirement for toughness, it may not be added.

( MgO mass%) / (SiO ₂ mass%) ≦
1 MgO and SiO ₂ define each composition as described above,
In addition, (MgO mass%) in the mixed flux
The ratio of / (SiO ₂ mass%) is regulated to 1 or less. This is because (MgO mass%) / (SiO2) in the mixed flux
_This is because the ratio of ₂ mass%) has the most important effect on workability during welding and stabilization of the bead shape. When the ratio of (MgO mass%) / (SiO ₂ mass%) is more than 1, arc stability is deteriorated during welding, bead width is narrow, easily becomes penetration deep pear shaped bead. For this reason, Mg
The ratio of O mass% / SiO ₂ mass% is set to 1 or less.

The bond used for submerged arc welding
Lux welding slag and molten flux welding slag
The difference in bulk density between the welding slag of the bond flux and the welding slag of the molten flux used in submerged arc welding is preferably 0.50 g / cc or less. Generally, the bulk density of the bond flux is 0.70 to 1.3.
0 g / cc, but the bulk density is 1.30 to 1.9 because the weld slag of the bond flux is molten.
It becomes as high as 0 g / cc. In addition, the bulk density of the molten flux varies greatly depending on the cooling method, and is about 0.30 to 2.10 g / cc. However, since the welding slag was once melted, the bulk density was 1.00 to 2.00 g, almost the same as the welding slag of the bond flux.
/ Cc. The present invention is a flux obtained by mechanically mixing a welding slag of a bond flux and a welding slag of a molten flux having different component systems.If the flux is subjected to component deviation during welding due to vibration or the like, bead meandering, pock marks, etc. Occurs and welding workability deteriorates. Therefore, in order to prevent flux segregation, it is preferable that the difference in bulk density be 0.50 g / cc or less. The smaller the difference between these bulk densities, the less the possibility that component deviation occurs.

From the viewpoint of adjusting the composition of the mixed flux, instead of the welding slag of the molten flux,
The same effect can be obtained by using a molten flux solidified and pulverized by a dry cooling method capable of obtaining a bulk density of 1.00 to 2.00 g / cc. In this case, when using a molten flux solidified and pulverized by a dry cooling method instead of the welding slag of a molten flux, and a welding flux of the molten flux solidified and pulverized by a dry cooling method and a welding flux of the molten flux. In the case of using both, the difference in bulk density between the welding slag of the bond flux used for submerged arc welding and the welding slag of the molten flux solidified and pulverized by the dry cooling method is 0.50 g / cc or less, respectively, and The difference in the bulk density between the welding slag of the bond flux used for the submerged arc welding and the welding slag of the molten flux and the welding slag of the molten flux solidified and pulverized by the dry cooling method is 0.
It should be 50 g / cc or less.

The flux of the present invention can be manufactured by the manufacturing method according to claims 8 to 13.

In the method for producing a mixed type flux for submerged arc welding according to claim 1, 2 or 7 of the present application, as shown in FIG.
Coarse pulverization, drying (450 ° C. × 20 minutes), pulverization, particle size adjustment and bulk density adjustment are performed, while welding slag of the molten flux is recovered, coarse pulverization, drying (450 ° C. × 20 minutes), pulverization, particle size Adjustment and bulk density adjustment are performed, and these are mechanically mixed. In this case, the welding slag of the bond flux used for the submerged arc welding and the welding slag of the molten flux are mechanically mixed at a ratio where the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. I do.

Further, the method for producing a mixed flux for submerged arc welding according to claim 3, 4 or 7 of the present application is as follows.
As shown in FIG. 2, the welding slag of the bond flux is collected, coarsely pulverized, dried, pulverized, the particle size is adjusted, and the bulk density is adjusted. On the other hand, the cullet of the molten flux solidified by the dry cooling method is coarsely pulverized. , Pulverization, particle size adjustment and bulk density adjustment, and these are mechanically mixed. In this case, the welding slag of the bond flux used for the submerged arc welding and the molten flux crushed and pulverized by the stem-type cooling method are combined with the welding flux of the bonding flux having a content of 10 to 90% by mass of the total amount. Mix mechanically in proportions.

Further, the method for producing a mixed type flux for submerged arc welding according to claim 5, 6 or 7 of the present application is as follows.
As shown in FIG. 3, the welding slag of the bond flux is collected, coarse crushing, drying, crushing, particle size adjustment and bulk density adjustment are performed, and the welding slag of the molten flux is collected, coarse crushing, drying, crushing, particle size After the adjustment and bulk density adjustment, the cullet of the molten flux solidified by the dry cooling method is roughly pulverized, pulverized, adjusted in particle size and adjusted in bulk density, and mechanically mixed. In this case, the welding slag of the bond flux used for the submerged arc welding, the welding slag of the molten flux, and the molten flux solidified and pulverized by the dry cooling method are combined with the welding slag of the bond flux having a total content of 10%. To 90
The mixture is mechanically mixed at a ratio of mass%.

Another method for producing a mixed flux for submerged arc welding according to claim 1, 2 or 7 of the present invention is to collect welding slag of a bond flux and welding slag of a molten flux as shown in FIG. These are simultaneously introduced into a pulverizer, and coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment are performed. In this case, the welding slag of the bond flux used for the submerged arc welding and the welding slag of the molten flux are mechanically mixed at a ratio where the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. I do.

Another method for producing the mixed flux for submerged arc welding according to the third, fourth or seventh aspect of the present invention is as shown in FIG. 5, in which a welding slag of a bond flux is recovered, and this is subjected to a dry cooling method. The molten flux is solidified in the same manner as described above, and is introduced into a grinder at the same time as coarse crushing, drying, crushing, particle size adjustment and bulk density adjustment. In this case, the weld slag of the bond flux used for the submerged arc welding and the molten flux solidified and pulverized by the trunk cooling method, and the content of the weld slag of the bond flux is 10 to 90% by mass of the total amount. Mix mechanically in proportions.

Another method for producing a mixed flux for submerged arc welding according to claims 5, 6 and 7 of the present application is to collect welding slag of a bond flux and welding slag of a molten flux as shown in FIG. This is introduced into a pulverizer at the same time as the cullet of the molten flux solidified by the dry cooling method, and coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment are performed. In this case, the welding slag of the bond flux used for the submerged arc welding, the welding slag of the molten flux, and the molten flux solidified and pulverized by the dry cooling method are combined with the welding slag of the bond flux having a total content of 10%. Mechanically mixed at a ratio of up to 90% by mass.

In the coarse pulverizing step, it is necessary that the coarse pulverizing step has a size that can be put into a pulverizer for pulverizing to a target product particle size. The coarse crushing step uses a jaw crusher or a hammer mill. The drying step is performed for the purpose of removing the collected slag, which may contain moisture or foreign substances such as broom dust. In this drying step, for example, the raw materials are put into
By heating for about 20 minutes. In the pulverization step, a hammer mill or a rotary bar pulverizer can be used. In the particle size adjusting step, the pulverized raw material is sieved to remove, for example, those exceeding 2.36 mm. The bulk density is
It varies depending on the slag component system and particle size composition, and the bulk density of the mixed flux is also affected by the mixing ratio. When the particle diameter is uniform at around 500 μm, the bulk density is relatively high, and the bulk density tends to decrease as the overall particle diameter becomes smaller or the particle diameter increases. On the other hand, when various particle diameters are mixed, generally, the bulk density increases as the flux particles are closer to the closest packing. Bulk density tends to be high.

In the mixing step according to claims 8 to 10, mixing is carried out uniformly so as not to cause segregation. In this mixing step, for example, a fret mill or an Erich mixer can be used. In addition, if the crushability of the cullet between the welding slag of the bond flux used for submerged arc welding and the welding slag of the molten flux and the molten flux solidified by the dry cooling method are almost the same,
In the production method according to claims 11 to 13, a mixed flux equivalent to the mixed flux produced in claims 8 to 10 can be obtained. If necessary, a magnetic separation process may be performed for the purpose of removing wire scraps and the like.

The welding slag of the bond flux, the welding slag of the molten flux, and the cullet of the molten flux solidified by the trunk cooling method are not limited to one type, and may be two or more types. That is, two or more types of welding slag of the bond flux may be used, but when two or more types are used, the MgO / SiO ₂ composition ratio per weight when the total is used is limited to the range described in claim 7. You. Similarly, the welding slag of the molten flux and the cullet of the molten flux solidified by the stem-type cooling method may be used in the same manner, but two or more of them may be used. The composition ratio of MgO / SiO ₂ per weight is limited to the range described in claim 7.

[0058]

Next, the effects of the fluxes of the examples falling within the scope of the present invention will be described in comparison with comparative examples that fall outside the scope of the present invention.

First Example Table 1 below shows the composition of the welding slag of the bond flux, and Table 2 shows the composition of the welding slag of the molten flux and the molten flux of the dry cooling type. Using the test raw materials shown in Tables 1 and 2 having different particle sizes and bulk densities, mixed fluxes were produced by mechanical mixing. And Table 3 below
The fillet welding and the joint welding were performed on a steel sheet having the composition and thickness shown in Table 4 below using a wire for submerged arc welding having the composition shown in Table 4 below. The welding conditions are shown in FIGS.
And Tables 5 and 6. FIG. 7 shows a wire aiming position and electrode arrangement in fillet welding. 8 to 10 show the groove shape and electrode arrangement in joint welding. FIG. 8 shows the case where the thickness of the test steel plate is 12 mm, FIG. 9 shows the case where the thickness of the test steel plate is 20 mm, and FIG. Steel plate thickness is 32mm
This is the case. In addition, 1st side and 2nd si of Table 6
de is the welding condition for the surface to be welded first and the welding condition for the surface to be welded second with the front and back reversed. Tables 7 to 12 show the welding workability, weld metal performance, and segregation state when welding was performed under these welding conditions.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

[0065]

[Table 6]

[0066]

[Table 7]

[0067]

[Table 8]

[0068]

[Table 9]

[0069]

[Table 10]

[0070]

[Table 11]

[0071]

[Table 12]

The segregation state was determined by vibrating the flux for a certain period of time using a vibrator, sampling the upper layer and the lower layer, and measuring the fluctuation width of the flux component before and after the vibration. Regarding all of the chemical components contained in the flux of the present invention, when the fluctuation range before and after vibration was less than 30%, the evaluation was ◎, and when it was 30% or more, the evaluation was ○.

The mixed flux C1 shown in Tables 7 to 12
C18 to C18 are examples of the present invention, and C19 to C34 are comparative examples. In the fluxes C1 to C18 of the present invention, the welding workability was good in both the fillet welding and the joint welding, and the weld metal performance was also good. However, among the examples, the segregation was 30% for the mixed flux of Examples C3, C6, C8, and C9 in which the difference in bulk density between the weld slag of the bond flux and the weld slag of the molten flux exceeded 0.50 g / cc. (O) was recognized, and welding was performed with a mixed flux in which the flux was vibrated for a certain period of time using a vibrator. As a result, deterioration of welding workability due to flux component deviation was observed.

On the other hand, in the case of C19 in the comparative example, since the mixing ratio of the bond flux exceeded the range of the present invention and was 98%, a pock mark was generated. Comparative Example C20 was 2.3
It contains a particle size exceeding 6 mm, the bead width is narrow,
The waves became coarse, and the welding workability deteriorated. In particular, in the case of large heat input welding of a thick steel plate, blow-up became remarkable. Comparative Example C21 had a bulk density of less than 1.30 g / cc, markedly increased blowing during welding, and deteriorated welding workability. Comparative Example C22 had a bulk density of more than 1.90 g / cc,
Undercut occurred, and slag peelability also deteriorated. In Comparative Example C23, since the content of SiO ₂ was less than 15%, the viscosity of the slag at the time of melting was insufficient, and bead meandering and underpower occurred. In Comparative Example C24, since the content of SiO ₂ exceeded 55%, the amount of oxygen in the weld metal was increased, and the toughness was deteriorated. Comparative Example C25 was made of Al ₂ O ₃
Is less than 2%, the viscosity of the slag at the time of melting is insufficient, undercut occurs, and the slag removability is deteriorated. In Comparative Example C26, since the content of MnO was less than 2%, the viscosity of the slag at the time of melting was insufficient, undercut occurred, and the slag removability was deteriorated. Comparative Example C27
Since the MgO content was less than 4%, the oxygen content in the weld metal increased, and the toughness deteriorated. Comparative Example C28
Since the content of Al ₂ O ₃ exceeded 25%, the viscosity of the slag became too high, resulting in a convex bead. Comparative Example C2
In No. 9, since the content of MnO exceeded 40%, the amount of oxygen in the weld metal was increased, and the toughness was deteriorated. Comparative Example C3
In the case of No. 0, since the content of MgO exceeded 30%, the arc was likely to be unstable, the meandering of the bead and the grain became coarse, and the bead appearance was deteriorated. In Comparative Example C31, since the content of CaO exceeded 30%, a pock mark occurred, and the slag removability was also deteriorated. Comparative Example C31
Since the content of MnO was less than 2%, the viscosity of the slag at the time of melting was insufficient, undercut occurred, and the slag removability was deteriorated. In Comparative Example C32, since the content of CaF ₂ exceeded 20%, the arc was likely to be unstable, the meandering of the bead and the grain became coarse, and the bead appearance was deteriorated. Comparative Example C33 had a ratio of (MgO) / (SiO ₂ ) of more than 1, lacked arc stability at the time of welding, had a narrow bead width, and was a deep pear-shaped bead having a penetration shape.

Second Embodiment Next, a second embodiment of the present invention will be described. Table 13 below shows the composition of the welding slag of the bond flux, and Table 14 shows the composition of the welding slag of the molten flux and the molten flux of the dry cooling type. Using the test raw materials shown in Tables 13 and 14 having different particle sizes and bulk densities, mixed fluxes were produced by mechanical mixing. Note that B1 to B9
And B12 are welding slags of molten flux,
Reference numerals 10, B11 and B13 are dry cooling type molten fluxes.

[0076]

[Table 13]

[0077]

[Table 14]

Then, a steel plate having a composition and a plate thickness shown in Table 3 was subjected to fillet welding and joint welding using a wire for submerged arc welding having a composition shown in Table 4.
The welding conditions are shown in FIGS. 7 to 10 and Tables 5 and 6 described above. The conditions of each figure and each table are as described in the above paragraph 00.
36 and 0049.

The evaluation results are shown in Tables 15 to 18 below.
You. The mixed fluxes D1 and D2 of the second embodiment are
In Examples of the present invention, D3 and D4 are Comparative Examples. Departure
The flux D1 of the embodiment is a welding of a bond flux.
Slag (A1), welding slag of molten flux (B
1) and a dry cooling type molten flux (B11)
Mechanically mixed with D1 and D2
The welding workability is good for both welding and joint welding.
The weld metal performance was also good. On the other hand, D3 in the comparative example
Is MgO / SiO of welding slag of bond flux₂
The composition ratio was less than 0.7, and insufficient penetration occurred. ratio
Comparative Example D4 is welding slag of molten flux (B12)
MgO / SiO₂The composition ratio exceeds 0.5,
The width has been reduced. Comparative Example D5 is a dry cooling type molten mold.
MgO / SiO of flux (B13) ₂The composition ratio is 0.
It exceeded 5 and the bead width narrowed. Comparative Example D6
Is MgO of the dry cooling type molten flux (B13)
/ SiO₂The composition ratio exceeds 0.5, and the molten type
M per weight when summed with flux welding slag
gO / SiO₂The composition ratio also exceeds 0.5 (total Mg
O / SiO₂= 0.51), narrow welding slag bead width
became. In addition, the welding slag of this molten flux
Per unit weight of the total cooling flux
MgO / SiO₂Is calculated as follows. Destination
From Tables 2 and 14, B8 is SiO 2₂Is 30%, M
gO is 7%, and B13 is SiO₂Is 15%, MgO
Is 9%. And, from Table 15, B8
10%, B13 60% (B8 1/7, B13 6 /
7). Therefore, when B8 and B13 are summed
SiO per weight₂Is 30 × (1/7) + 15 × (6
/7)=17.1 (%), MgO is 7 × (1/7) +9
× (6/7) = 8.7%. Therefore, MgO / Si
O ₂= 0.51.

[0080]

[Table 15]

[0081]

[Table 16]

[0082]

[Table 17]

[0083]

[Table 18]

[0084]

As described above, the mixed flux for submerged arc welding according to the present invention can be applied to butt welding and downward welding from thin steel plates to thick steel plates, and there is a possibility that flux component segregation may occur. And good slag releasability and bead shape can be obtained. This allows
Reuse of the welding slag becomes possible, and effective utilization of resources can be achieved.

[Brief description of the drawings]

FIG. 1 is a view showing a first manufacturing method of the present invention.

FIG. 2 is a view showing a second manufacturing method of the present invention.

FIG. 3 is a view showing a third manufacturing method of the present invention.

FIG. 4 is a view showing a fourth manufacturing method of the present invention.

FIG. 5 is a view showing a fifth manufacturing method of the present invention.

FIG. 6 is a view showing a sixth manufacturing method of the present invention.

FIG. 7 is a diagram showing a wire aiming position and electrode arrangement in fillet welding.

FIG. 8 is a diagram showing a groove shape and electrode arrangement when the thickness of a steel plate is 12 mm.

FIG. 9 is a diagram showing a groove shape and electrode arrangement when the thickness of a steel plate is 20 mm.

FIG. 10 is a view showing a groove shape and an electrode arrangement when a plate thickness of a steel plate is 32 mm.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kaoru Hase 100-1 Urakawachi, Miyama-shi, Fujisawa-shi, Kanagawa F-term in Kobe Steel, Ltd. Fujisawa Works (reference) 4E084 AA03 AA06 CA23 CA26 CA38 DA17

Claims (13)

[Claims] 1. The welding slag of the bond flux and the welding slag of the molten flux used in the submerged arc welding are mechanically combined with each other at such a ratio that the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. A mixed flux for mixed submerged arc welding,
The particle diameter is 2.36 mm or less and the bulk density is 1.30 to 1.
90 g / cc, SiO ₂ : 15 to 55% by mass,
Al ₂ O ₃ : 2 to 25% by mass, MnO: 2 to 40% by mass, MgO: 4 to 30% by mass, CaO: 30% by mass
Or less and CaF ₂ : 20% by mass or less, and (M
gO% by mass) / (submerged arc welding mixed flux, characterized by having a chemical composition satisfying SiO ₂ mass%) ≦ 1. 2. The difference between the bulk density of the welding slag of the bond flux used for the submerged arc welding and the bulk density of the welding slag of the molten flux is 0.50 g / c.
The mixed flux for submerged arc welding according to claim 1, wherein the flux is not more than c. 3. The welding slag of the bond flux used for the submerged arc welding and the molten flux solidified and pulverized by the dry cooling method, wherein the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. A mixed flux for submerged arc welding, which is mechanically mixed at a ratio, having a particle diameter of 2.36 mm or less, a bulk density of 1.30 to 1.90 g / cc, and Si
O ₂ : 15 to 55% by mass, Al ₂ O ₃ : 2 to 25% by mass, MnO: 2 to 40% by mass, MgO: 4 to 30%
% By mass, 30% by mass or less of CaO and 20% by mass or less of CaF ₂ , and (MgO mass%) / (SiO ₂
A mixed flux for submerged arc welding, having a chemical composition satisfying (mass%) ≦ 1. 4. The method according to claim 3, wherein the difference between the bulk density of the welding slag of the bond flux used for the submerged arc welding and the bulk density of the molten flux is 0.50 g / cc or less. Mixed flux for submerged arc welding. 5. The welding slag of the bond flux used for the submerged arc welding, the welding slag of the molten flux, and the molten flux solidified and pulverized by the dry cooling method, and the content of the welding slag of the bond flux is the total amount. It is a mixed flux for submerged arc welding that is mechanically mixed at a ratio of 10 to 90% by mass of, having a particle diameter of 2.36 mm or less, a bulk density of 1.30 to 1.90 g / cc, SiO ₂ : 15 to 55% by mass, Al ₂ O ₂ : 2 to 25% by mass, MnO: 2 to 40% by mass, MgO: 4 to 30% by mass, CaO: 30
Mass%, _CaF 2: 20 wt% or less, _TiO 2: 2
0% by mass or less, and (MgO mass%) / (Si
A mixed flux for submerged arc welding, having a chemical composition that satisfies (O ₂ mass%) ≦ 1. 6. The difference in bulk density between the welding slag of the bond flux used in the submerged arc welding and the welding slag of the molten flux and the molten flux solidified and pulverized by the dry cooling method is 0.50 g / cc or less. The mixed flux for submerged arc welding according to claim 5, wherein the flux is provided. 7. MgO / SiO per weight of welding slag of bond flux used for submerged arc welding
_{2 The} composition ratio is 0.7 or more, and the MgO / SiO ₂ composition ratio of the molten flux solidified and pulverized by welding slag or dry cooling method of the molten flux is 0.5 or less. Item 7. A mixed flux for submerged arc welding according to any one of Items 1 to 6. 8. The method for producing a mixed flux for submerged arc welding according to claim 1, 2 or 7, wherein the welding slag of the bond flux and the welding slag of the molten flux used for the submerged arc welding are bonded to each other. The welding slag content of the flux is 10 to 9 of the total amount
It is a mixed flux for submerged arc welding that is mechanically mixed at a ratio of 0% by mass, and collects welding slag of a bond flux and performs coarse pulverization, drying, pulverization, particle size adjustment, and bulk density adjustment. A method for producing a mixed type flux for submerged arc welding, comprising collecting welding slag of a molten type flux, performing coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment, and mechanically mixing these. 9. The method for producing a mixed flux for submerged arc welding according to claim 3, 4 or 7, wherein the welding flux of the bond flux used for the submerged arc welding is quenched and pulverized by a trunk cooling method. A mixed flux for submerged arc welding in which a mold flux is mechanically mixed at a rate such that the content of the welding slag of the bond flux is 10 to 90 mass% of the total amount, and the welding slag of the bond flux is recovered. , Coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment.On the other hand, the cullet of the molten flux solidified by the dry cooling method is coarsely pulverized, pulverized, particle size adjustment and bulk density adjustment, and these are machined. A method for producing a mixed type flux for submerged arc welding, comprising: mixing. 10. The method for producing a mixed flux for submerged arc welding according to claim 5,6, or 7,
The welding slag of the bond flux used for the submerged arc welding, the welding slag of the molten flux, and the molten flux solidified and pulverized by the dry cooling method are combined with the welding slag of the bond flux in an amount of 10 to 90% by mass of the total amount. It is a mixed type flux for submerged arc welding that is mechanically mixed at the following ratio, collects welding slag of bond flux, performs coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment, welding of molten flux Collect the slag, perform coarse grinding, drying, grinding, particle size adjustment and bulk density adjustment, and further perform coarse grinding, grinding, particle size adjustment and bulk density adjustment of the cullet of the molten flux solidified by the dry cooling method. And a method for producing a mixed flux for submerged arc welding, wherein the flux is mechanically mixed. 11. The method for producing a mixed flux for submerged arc welding according to claim 1, 2 or 7,
Submerged arc welding in which the welding slag of the bond flux and the welding slag of the molten flux used in the submerged arc welding are mechanically mixed at a ratio such that the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. Submerge, characterized in that welding flux of bond flux and welding slag of fusion flux are collected, fed simultaneously, and coarsely pulverized, dried, pulverized, adjusted in particle size and adjusted in bulk density. Manufacturing method of mixed flux for arc welding. 12. The method for producing a mixed flux for submerged arc welding according to claim 3, 4 or 7,
The welding slag of the bond flux used for the submerged arc welding and the molten flux solidified and pulverized by the stem-type cooling method are mechanically combined at a ratio where the content of the welding slag of the bond flux is 10 to 90% by mass of the total amount. A mixed flux for submerged arc welding mixed with the above, the welding slag of the bond flux is collected, and simultaneously injected with the cullet of the molten flux solidified by a dry cooling method, coarse pulverization, drying, pulverization, particle size adjustment and A method for producing a mixed flux for submerged arc welding, comprising adjusting a bulk density. 13. The method for producing a mixed flux for submerged arc welding according to claim 5,6, or 7,
The welding slag of the bond flux used for the submerged arc welding and the welding slag of the molten flux and the molten flux solidified and pulverized by the dry cooling method, the content of the welding slag of the bond flux is 10 to the total amount.
A mixed flux for submerged arc welding that is mechanically mixed at a ratio of 90% by mass, wherein welding slag of a bond flux and welding slag of a molten flux are collected and solidified by a dry cooling method. A method for producing a mixed type flux for submerged arc welding, wherein the mixed flux is charged simultaneously with a cullet and subjected to coarse pulverization, drying, pulverization, particle size adjustment and bulk density adjustment.