JPH1110390A - Flux cored wire for electrogas arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux cored wire for electrogas arc welding of high efficiency capable of forming welding part having excellent welding workability and mechanical properties in the welding of weather resisting sheet. SOLUTION: The flux filling rate is 20-30% against the whole weight of wire. The component of whole of the wire is 0.02-0.10% C (including C in the outer crust), 0.10-1.00% Si (including Si in the outer crust), 1.80-3.00% Mn (including Mn in the outer crust), 0.15-0.80% Cu, 0.10-1.00% Ni, 0.25-1.00% Cr, 0.10-0.50% Ti, 0.001-0.020% B, 0.10-1.00% total amount of one side or both sides of metal Mg and metal Ca, 0.10-1.00% total amount of metal fluoride (expressed in terms of F) and 0.15-1.0 in the ratio (Cu+Ni+Cr)/(Si+Mn). The metal fluoride preferably contains CaF2 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly efficient flux cored wire for electrogas arc welding.
The present invention relates to a flux cored wire for electrogas arc welding suitable for welding a weather-resistant steel sheet having good welding workability and mechanical properties (tensile performance, impact performance).

[0002]

2. Description of the Related Art As a technique for improving welding workability and mechanical properties of an electrogas arc welded part, Japanese Patent Application Laid-Open No.
There is a flux-cored wire disclosed in Japanese Patent No. 259894 and Japanese Patent Application Laid-Open No. 60-152393.

[0003] However, these prior arts disclose.
Flux cored wire for electrogas arc welding
Ears are mild steel and 490-570 N / mm^Two Class high tension
It is an effective means for welding steel and is required for weatherable steel sheets.
Good welding work when Cu, Ni and Cr are added
Properties and mechanical properties have not yet been obtained. Immediately
In addition, electro gas arc welding flash
Boxed wire has not been put to practical use (development).

[0004] As a welding wire for a weather-resistant steel sheet, a submerged arc welding wire is known (Japanese Patent Laid-Open No. 1-3).
1993). However, compared with this submerged arc welding, electrogas arc welding has a heat input about three times as large, and if welding is performed with such a large heat input, Cu, Ni
And the base material of the weather-resistant steel sheet to which Cr is added is severely deteriorated.
For this reason, it has not been possible to apply the conventional flux cored wire for electrogas arc welding to the weatherable steel sheet as it is to perform electrogas arc welding.

[0005]

However, the application of weather-resistant steel plates to bridge webs and the like has recently been studied for the purpose of maintenance-free after welding. In this case, there is a strong demand for the use of electrogas arc welding, which has a large heat input and very high welding efficiency, and therefore, there is a need for the development of an electrogas arc wire for a weather-resistant steel sheet.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in view of the above-mentioned problems, and is a highly efficient electrogas arc welding capable of forming a weld having good welding workability and mechanical properties in welding a weather-resistant steel sheet. It is an object of the present invention to provide a flux cored wire.

[0007]

The flux-cored wire for electrogas arc welding according to the present invention has a flux filling rate of 20 to 30% based on the total weight of the wire, and the composition of the entire wire is C (in the outer sheath). Including C):
0.02 to 0.10%, Si (including Si in outer skin): 0.10 to 1.00%, Mn (including Mn in outer skin): 1.80 to 3.00%, Cu: 0 .15 to 0.80%, Ni: 0.10 to 1.00%, Cr:
0.25 to 1.00%, Ti: 0.10 to 0.50
%, B: 0.001 to 0.020%, one or both of metal Mg and metal Ca: 0.10 to 1.00 in total amount
%, Metal fluoride (converted value of F amount): 0.10 to 1.00
%, (Cu + Ni + Cr) / (Si + Mn) ratio: 0.1
5 to 1.0.

It is preferred that the metal fluoride contains CaF ₂ .

The above (Cu + Ni + Cr) / (Si
+ Mn) ratio is preferably 0.55 to 0.80.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the reason for adding each component and the reason for limiting the composition of the flux cored wire for electrogas arc welding of the present invention will be described. In addition,
The composition (%) of each component in the present invention is a ratio of the weight to the total weight of the wire including the outer coat and the flux.

C: 0.02 to 0.10% (C in outer skin)
If C is less than 0.02%, the hardenability is insufficient, and the toughness and tensile performance of the weld are deteriorated. On the other hand, when C exceeds 0.10%, the amount of fumes and spatters increases, the strength of the welded portion becomes too high, the toughness is reduced, and hot cracking is likely to occur. For this reason, the C content including the outer skin is made 0.02 to 0.10%, preferably 0.04 to 0.07%.

Si: 0.10 to 1.00% (in the outer skin
If the content of Si is less than 0.10%, the tensile strength and ductility of the welded portion decrease. Conversely, when Si exceeds 1.00%, slag does not easily flow and arc instability occurs, and the tensile strength of the welded portion becomes excessively high, toughness is deteriorated, and hot cracking is liable to occur. Therefore, the amount of Si is set to 0.10 to 1.00%, preferably 0.20 to 0.80%. As a Si source for adjusting the amount of Si, Fe
-Si and alloys such as Fe-Si-Mn, and K ₂ Si
There are fluorides and oxides such as F _6. In the case of a Si compound, the value converted to Si is within the above range. When added as a Si compound, the content is preferably 0.2% or less based on the total weight of the wire in terms of Si.

Mn: 1.80 to 3.00% (in the hull
If Mn is less than 1.80%, the slag flows easily, so that the weld metal is liable to melt down or sag, and
The hardenability is insufficient, and the toughness and tensile performance of the weld metal deteriorate. On the other hand, when Mn exceeds 3.00%, slag becomes difficult to flow, causing arc instability, too high tensile strength, deteriorating toughness, and easily causing hot cracking. For this reason, the Mn content is set to 1.80 to 3.00%, preferably 2.00 to 2.50%. Examples of the Mn source include metal Mn and alloys such as Fe-Mn and Fe-Si-Mn.

Cu: 0.15 to 0.80%, Ni:
0.10 to 1.00%, Cr: 0.25 to 1.00
% Cu, Ni and Cr are mainly added as flux components in the wire in order to obtain good weather resistance. Cu is less than 0.15%, Ni is less than 0.10%, Cr is 0.2
If it is less than 5%, good weather resistance cannot be obtained. Cu is 0.8
If the content exceeds 0%, the content of Ni exceeds 1.00%, and the content of Cr exceeds 1.00%, the tensile strength becomes too high and the crack resistance deteriorates. C
As the u source, there is metal Cu. As the Ni source, there is an alloy such as Ni-Mg other than metal Ni. As a Cr source, in addition to metallic Cr, Fe—Cr and Fe—Si—Cr
And other alloys.

The individual addition amounts of Si, Mn, Cu, Ni, and Cr are in the above-mentioned ranges. However, in order to have good welding workability, (Cu + Ni + C
r) / (Si + Mn) ratio also needs to be properly adjusted.

Ti: 0.10 to 0.50%, B: 0.
When 001 to 0.020% of Ti and B are added in combination, the structure becomes finer and the toughness is enhanced. When Ti is less than 0.10% or B is less than 0.001%, the toughness strengthening mechanism is not exhibited, and the toughness of the obtained weld is low. On the other hand, when Ti is 0.
If it exceeds 05% or B exceeds 0.020%, the strength becomes excessive, the toughness is deteriorated, and hot cracking is liable to occur. Therefore, Ti is 0.10 to 0.50%,
Preferably, it is 0.20 to 0.40%. B is set to 0.001 to 0.020%, preferably 0.005 to 0.015%. Examples of the Ti source include metal Ti and alloys such as Fe-Ti. Examples of the B source include alloys such as Fe-B and Fe-Si-B, and oxides such as special glass.

One or both of metal Mg and metal Ca:
Since 0.10 to 1.00% by weight of metal Mg and metal Ca are strong deoxidizing agents, the addition thereof can reduce the oxygen content of the weld metal and improve the toughness. If one or both of the metal Mg and the metal Ca is less than 0.10% in total, the toughness is not improved due to insufficient deoxidation of the weld metal. On the other hand, when the total amount of one or both of the metal Mg and the metal Ca exceeds 1.00%, the welding workability deteriorates, and the amount of spatters increases, and the arc becomes unstable. Therefore, the content of one or both of Mg and Ca is set to 0.10 to 1.00%, preferably 0.30 to 0.70% in total.

As the metal Mg source, in addition to Mg, Ni-
There are alloys such as Mg, Fe-Si-Mg and Al-Mg. As the metal Ca source, there is an alloy such as Ca-Si.
In some cases, CaF ₂ is contained as the following metal fluoride, but Ca in this fluoride is not included in the metal Ca.

Metal fluoride (value converted into F amount): 0.10 to
1.00% metal fluoride is added to increase the basicity of the slag to reduce the amount of oxygen in the weld metal and to stabilize the arc. If the amount of the metal fluoride is less than 0.10% in terms of F, the oxygen amount of the weld metal is not reduced, the toughness is deteriorated, and the arc becomes unstable. When the amount of the metal fluoride exceeds 1.00%, since the vapor pressure is high, the amount of fume generated increases, and the welding workability deteriorates. Therefore, the amount of metal fluoride is
0.10 to 1.00%, preferably 0.30 to 0.1%.
70%. As the metal fluoride source, LiF, N
aF, K ₂ SiF ₆ and CaF ₂ .

(Cu + Ni + Cr) / (Si + Mn)
Ratio: 0.15 to 1.0 As a flux-cored wire for electrogas arc welding suitable for welding a weather-resistant steel sheet as the object of the present invention, C
u, Ni and Cr are essential components. However, if Cu, Ni, and Cr are simply added to the conventional flux cored wire for electrogas arc welding, the tensile strength of the welded portion becomes too high, toughness and crack resistance deteriorate, and slag peelability deteriorates. In order to solve such problems, it is necessary to lower the tensile strength by adding other components, and to increase the toughness and crack resistance. However, since C is often added from the shell metal, its content is not limited. Is not easy to lower. Further, Ti and B are indispensable for securing the toughness of the welded portion in large heat input welding.

Under the above-mentioned technical background, the present inventors set the (Cu + Ni + Cr) / (Si + Mn) ratio from 0.15 to 0.15 in order to obtain a weld having good welding workability and mechanical properties. It has been found that setting the range of 1.0 is effective. That is, when the amount of Cu, Ni and / or Cr is large, the amount of Si and / or Mn is increased, and
If u, Ni and / or Cr are small, the amount of Si and / or Mn is reduced accordingly. In this manner, a weld metal having an appropriate tensile strength, excellent toughness and crack resistance can be obtained, and has sufficient slag removability.

If the (Cu + Ni + Cr) / (Si + Mn) ratio is less than 0.15, the slag becomes difficult to flow, an undercut occurs on the bead surface, and the tensile strength becomes too high, and the toughness and crack resistance deteriorate. Also, C
The value of u + Ni + Cr is too low and (Cu + Ni + Cr)
When the / (Si + Mn) ratio is small, the weather resistance is poor. Further, the (Cu + Ni + Cr) / (Si + Mn) ratio is 1.0
If it exceeds slag, the slag will seize and the slag removability will be poor. Furthermore, when the above ratio exceeds 1.0, slag flows easily, and the molten metal drops or sags, making it impossible to perform sound welding. And Cu + Ni
+ Cr is too high and (Cu + Ni + Cr) / (Si
When the (+ Mn) ratio is large, the tensile strength increases, and the toughness and crack resistance deteriorate.

This (Cu + Ni + Cr) / (Si + M)
n) The ratio is preferably between 0.55 and 0.80%.

Flux filling rate: 20 to 30% If the flux filling rate is less than 20%, the spatter increases and the current density decreases, so that high efficiency construction cannot be achieved. On the other hand, when the flux filling rate exceeds 30%, the thickness of the outer skin metal becomes thin, so that the wire strength becomes insufficient and the wire may be broken during welding.

[0025] As the metal fluoride CaF ₂ is essential metal fluoride to, by the addition of CaF ₂ in the range of the metal fluorides, it is possible to obtain an improvement in slag removability, easily further flow slag It has the effect of.

[0026]

EXAMPLES The effects of the examples of the present invention will be described below in comparison with comparative examples. Table 1 below shows the composition (% by weight based on the total weight of the skin) of the mild steel skin used. Table 2 below shows welding conditions, and Tables 3 to 11 show wire compositions (% by weight based on the total weight of the wires). The test results are shown in Tables 12 to 17 below. Table 1 below
◎, 欄, and × in the remarks columns 2 to 17 indicate comprehensive judgment, ◎ indicates extremely good, ○ indicates good, and × indicates poor. Further, in each table, "actual" indicates an example of the present invention, and "ratio" indicates a comparative example.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

[Table 5]

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

[Table 8]

[0035]

[Table 9]

[0036]

[Table 10]

[0037]

[Table 11]

[0038]

[Table 12]

[0039]

[Table 13]

[0040]

[Table 14]

[0041]

[Table 15]

[0042]

[Table 16]

[0043]

[Table 17]

As is clear from Tables 3 to 17, Comparative Examples 1, 6, 7, 12, 13, 18, 19, and 2
2,23,28,29,34,35,40,41,4
Nos. 4, 45 and 48 were inferior in any of arc stability, spatter generation amount, fume generation amount, bead appearance / shape, slag peeling property, tensile strength and impact absorption energy VE-5. In contrast, in the embodiment of the present invention,
These properties were all excellent, and the overall evaluation was ◎ or ○.

[0045]

As described above, according to the present invention,
The composition of each component such as Cu, Ni, and Cr in the wire is defined within a predetermined range, and (Cu + Ni + Cr) / (Si +
Since the Mn) ratio was set to 0.15 to 1.0, when this wire was used to perform electrogas arc welding on a weather-resistant steel sheet, the welding workability was excellent, the tensile strength was moderate, and the toughness was low. Excellent welds can be obtained.

Claims (3)

[Claims] A flux filling rate is 20 to 30% based on the total weight of the wire, and the composition of the entire wire is C
(Including C in the outer skin): 0.02 to 0.10%, Si
(Including Si in outer skin): 0.10 to 1.00%, M
n (including Mn in the hull): 1.80 to 3.00%,
Cu: 0.15 to 0.80%, Ni: 0.10 to 1.00%, Cr: 0.25 to 1.00%, Ti:
0.10 to 0.50%, B: 0.001 to 0.02
0%, one or both of metal Mg and metal Ca: 0.10 to 1.00% in total, metal fluoride (converted value of F amount):
0.10 to 1.00%, (Cu + Ni + Cr) / (S
(i + Mn) ratio: 0.15 to 1.0. A flux cored wire for electrogas arc welding. 2. The flux cored wire for electrogas arc welding according to claim 1, wherein the metal fluoride contains CaF ₂ . 3. The (Cu + Ni + Cr) / (Si + M)
The flux-cored wire for electrogas arc welding according to claim 1 or 2, wherein n) ratio is 0.55 to 0.80.