JPS63220996A - Filler metal for tig welding - Google Patents

Abstract

PURPOSE:To obtain filler metal with the satisfactory separating property of slag by allowing to contain the specific quantity of TiO2, CaF2, AlF3, Mn and Ti in a wire formed of the stainless steel skin and further, filling flux with a specific value of a simple substance or a compound of Bi therein. CONSTITUTION:The titled TIG welding filler metal uses a pipe or band steel as the skin and indicates the wire having a wire cross section such as a shape where the edge of the band steel is tucked in the inside, a shape where the end faces are butted to each other, etc., and the filling flux 8 is filled in the inside of the skin 7 which is formed tubularly from the pipe or the band steel of the stainless steel. The filling flux 8 contains, by weight, 3-12% TiO2, 0.05-5% AlF3, 0.5-2.5% Mn and 0.05-1.5% Ti and further, the total of the simple substance or the compound of B''i contains 0.001-0.5% expressed in terms of Bi. A satisfactory root pass reverse side beam is obtained in the TIG one-side welding of the stainless steels by a synergetic effect of these elements.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides TIG welding with excellent slag releasability within the groove in initial layer uranami welding by TIG welding without pack shielding gas. This relates to filler metals for use in other applications.

[Conventional technology]

For normal welding of stainless steel, multi-machine arc welding, MIG
Welding, T-G welding, and submerged arc welding are all applicable, but for single-sided welding of stainless steel, the TIG welding method, which stably forms a back bead P, is widely used for first-layer welding. ing.

To form the first layer of bead by TIG welding, it is necessary to flow argon gas not only on the front side but also on the back bead side to create a so-called pack shield to prevent oxidation from the atmosphere like the front bead. .

Pack shielding requires a large amount of argon gas and pack shielding equipment, which is time-consuming and costly. There is a demand for the provision of filler metals for G# welding, for example, JP-A-61-
This is proposed in Japanese Patent No. 154793.

The filler material is a composite wire surrounded by a metal sheath and filled with flux, and the back bead is encapsulated by the produced slag to achieve insulation from the outside air and to obtain a sound back bead. This allows particularly good welding in all positions.

[Problem that the invention seeks to solve]

By the way, in welding using the filler metal, the generated slag covers the back bead surface and blocks the atmosphere to obtain a healthy back bead, but the slag encapsulates the back bead. At the same time, the front bead is also covered. That is, the generated slag covers both the back and front sides. When performing multilayer welding, it is essential to remove slag, but in this case, the removability of slag has not always been satisfactory.

In view of these problems, the present invention has developed stainless steel T.
IG welding, especially in first-layer uranami welding that is performed without pack shielding gas, has a T with good peelability of the generated slag.
An object of the present invention is to provide a filler metal for IG welding.

[Means for solving problems]

That is, the present inventors added TiO2, TiO2,
CaF2, AlF3, Mn, Ti, B
By filling a flux containing an appropriate amount of i, the synergistic effect of these elements becomes remarkable, and the slag generated in TIG welding of stainless steel, especially in first-layer uranami welding without pack shield gas, is It was found that the releasability of the material was improved.

Also, by mixing the filling flux with a fixing agent,
The present invention was made based on the knowledge that when a pipe is used as an outer skin, the filler material can be filled evenly and uniformly, and a filler material of uniform quality can be obtained. Note that % used herein below means weight (wt) %.

The gist of the present invention is that in a wire formed with a stainless steel outer shell, based on the total weight of the wire, T i O2 3-12% CaF2 0.05-5% AtF3 0.05-596 Mn 0.5-2.5 % Ti 0.05-1.5
A filler metal for TIG welding characterized by being filled with a flux containing.

[For production]

Hereinafter, the present invention will be explained in detail along with its operation.

First, to describe the composition of the filler metal for TIG welding of the present invention, the alloying elements necessary to ensure corrosion resistance and mechanical properties at low and room temperatures as stainless steel in the welded part are mainly contained in the outer sheath that forms the wire. The slab forming agent added to ensure the integrity of the back pead in single-sided welding and the component that improves the removability of the generated slag are:
The wire is filled with an alloying component that makes up for the deficiency of the alloying element added to the wire jacket.

Next, the T I G% welding filler metal of the present invention refers to the embodiment shown in FIG. The shape with the steel ends folded inside (b), and the shape with the ends butted together (
It refers to a wire with a wire cross section such as C), which is made of a stainless steel pipe or steel band formed into a tubular shape and filled with a filling flux 8. It is the spirit of the present invention to create various shapes other than those shown in Figure 2, such as using a steel strip as an outer skin and making a tubular shape by overlapping the end faces of the steel strip, or making a tubular shape by folding the steel strip in a complicated manner. It does not harm the

Next, the range of the 7 lux components filled in the wire will be described.

It is essential that the filler metal melts to form a back bead, and that the slag produced at that time evenly covers the surface of the back bead.

T i O2 is a very effective slag forming agent in producing a slag that uniformly covers the back bead surface.

If the content is less than 3%, the encapsulation of the back bead surface is insufficient. On the other hand, if the content exceeds 12%, hard slag will be produced and it will take time to remove the slag. Ti
O2 is added in the form of rutile, white titanium, potassium titanate, illuminite, etc., but the effect is the same no matter which one is used.

CaF2 improves the fluidity of the slag and improves the encapsulation of the back bead surface. If the content is less than 0.05%, sufficient effects cannot be obtained. On the other hand, if the content exceeds 5%, the slag becomes too fluid, causing the slag to droop during welding in all positions, and the irritating odor becomes strong.

AtF3 improves the fluidity of the slag, improves the encapsulation of the back bead surface, and gives the slag an appropriate level of viscosity, which is effective in maintaining an appropriate balance between slag fluidity and viscosity in all position welding. be.

If the content is less than 0.05%, sufficient effects cannot be obtained. On the other hand, if the content exceeds 5%, the slag will flow too much, making it difficult to perform all-position welding.

fVl n is effective in imparting appropriate viscosity to the slag and maintaining a balance between fluidity and viscosity of the slag in all position welding. If the content is less than 0.5%, sufficient effects cannot be obtained. On the other hand, if the content exceeds 2.5%, the viscosity of the slag becomes too high, making welding difficult.

Ti is effective as a deoxidizing agent, and it was also found to be effective in improving the slag releasability of the surface bead when the groove angle is narrow. The effect is particularly remarkable when N is added to the outer skin. If the content is less than 0.05%, sufficient effects cannot be obtained. On the other hand, if the content exceeds 1.5%, the encapsulation of the slag becomes poor, making welding difficult.

Bi is effective in improving slag releasability. Fe-
When used in combination with Ti, there is a remarkable effect on improving the releasability of slag on the surface of the front bead when the groove angle is narrow. The effect is particularly remarkable when N is added to the outer skin. If the content is less than o.ooi%, sufficient effects cannot be obtained. On the other hand, if the content exceeds 0.5%, the fluidity of the slag will deteriorate and the mechanical performance of the weld metal will deteriorate. Note that Bi is metal Bi, Bi2O3, Bi
F3 is added, but the effect is the same even if one or more of these are used.

Since metal carbonates are thermally decomposed during welding, they generate spatter and inhibit the encapsulation of slag, so it is necessary not to include them.

TiO2, CaF2mA mentioned above as flux composition
In addition to tF3, Mn, Tt, and Bt, crushed sand, alumina, potassium feldspar, zirconium oxide, and magnesium oxide.

Wollastonite, Fe-At, Fe-8t, AL-M
g, Cr, Ni.

Even if it contains Mo, stainless steel powder, etc. as appropriate, its properties will not be impaired.

Next, let's talk about the stainless steel outer skin. One is the one made of austenitic stainless steel, which has a C[16
~28%, Ni5~22.5%, M.

4% or less, Mn 2.5% or less, Si 0.6% or less.

Cu: 2.5% or less, Nb: 1% or less 1[11% or less, and if necessary, N may be added to 0.5% or less.

The other type is austenitic and ferritic stainless steel with 3 to 12% Ni and Cr2.
3-28%, Mo 1-4%.

Si 1% or less, Mn 2% or less, N if necessary
It contains 0.5% or less. Note) When using ξ Eve as a case, outer diameter 5~15W1 wall thickness 0.2~
2. Also, when forming a case using steel band, it is best to use a steel band with a thickness of 0.1 to 1.0 m and a width of 5 to 12.5 m and form it to an outer diameter of 1.0 to 4 m. It's as expected.

Here, referring to an example of the means for manufacturing the filler metal for TIG welding of the present invention, for example, when forming a case into a tubular shape from a steel band, fill a U-shaped groove with mixed and stirred filling flux, and then The wire is formed into a shape, drawn to a predetermined wire diameter, and dried at 100 to 500° C. for 30 minutes or more if necessary. Also, if the case is /guib,
For filling the flux, mix and stir the filling flux.
If the filling flux is filled up to 100%, the filling will not be done smoothly, it will become uneven, or it will clog in the middle, making it impossible to fill, making it difficult to fill uniformly. The process is carried out smoothly and uniform filling is possible.

Potassium silicate, sodium silicate, lithium silicate, etc. can be used as the adhesive. It is sufficient to add the fixing agent in an amount of 1 to 2.5%. After filling, the wire is drawn to the specified wire diameter.
Drying is performed at 100 to 500° C. for 30 minutes or more, if necessary.

〔Example〕

The effects of the present invention will be described in more detail below with reference to Examples.

Table 1 shows the chemical composition of the rind.

Table 2 shows the composition of the filler metal based on the combination of the outer skin and the filling flux.

The shape and dimensions of the outer skin are as follows: filler metal symbol 4,5°6.7
,8,9,10,11,12,13,14,15゜27
, 28.29.30. and 31 is wall thickness 0.2 garden, lr
Using an outer skin made of g 8 vm steel strip with an outer diameter of 2 to 2.3 mφ, filler metal symbol &l, 2, 3, 16, 17, 18
゜19, 20.21.22.23.24.25. and 26 used a pipe with an outer diameter of 9Ialφ and a wall thickness of 1.0m.

Table 3 shows the chemical composition of the base material. The plate thickness is 10cm.

Table 4 shows the slag envelopment status of the back bead, the shape of the back bead, and the welding results obtained by performing TIG welding using the TIG filler metal in Table 2 and the base metal in Table 3 according to the procedure shown in Figure 1. The results of observations of workability and slag removability of the front bead surface within the groove are shown.

In addition, FIG. 1 is a drawing showing the welding procedure in the example, (a) is a perspective view, (b) is a front view, and in the drawing, 1 is a T-work G torch nozzle, 2 is a tungsten electrode, 3
4 indicates the filler metal for TIG welding, 4 indicates the arc, 5 indicates the base metal, 6 indicates the weld metal, and 1 indicates the welding direction.

The groove shape of the base material used in the test is as shown in Figure 3.
Plate thickness t = 10 m, groove angle θ = 80 root face f = 2 M, root gap g = 2
．． It is 5m.

Welding conditions were as follows: A TIG welding power source with DC droop characteristics was used as the power source, the power source characteristics were DC positive polarity, the electrode was a thoriated tungsten electrode 2.4+wφ, and the shielding gas was Ar.
, flow 1115/, /-.

Welding current: 150-200A, welding voltage: 10-12V
All welding positions were used, and the welding torch movement and filler metal insertion were performed manually.

The wire used was 2WφX 1000m.

The base material symbol f is used for filler metal symbols 1 to 14 and 15 to 26, and the base material symbol g is used for filler metal symbol 428.
1 For filler metal symbol A29, base metal symbol h1 For filler metal symbols 14 and 30, base metal symbol 11 Filler metal symbol iF
As for x 31 K, the test was conducted using the combination of base material symbol j.

Filler metal symbols 1-14 are comparative examples, 7fL15-3
1 is the present invention.

Filler metal symbol shop 1 has 3% TiO2 relative to the wire weight ratio.
The slag coverage of the back bead was poor, and the shape of the back bead P was poor.

In case 2, the T i 02 exceeded 12% relative to the wire weight ratio, resulting in a hard slag, and it took time to remove the slag from the front bead surface within the groove.

In A3, CaF2 was less than 0.05% based on the wire weight ratio, the slag coverage of the back bead was poor, and the shape of the back bead was poor.

In A4, the CaF2 content exceeded 5% relative to the wire weight ratio, the slag hung down in the upright position and the upward position, the encapsulability was poor, and the back bead shape was poor.

In &5, AtF3 was less than 0.05% with respect to the wire weight ratio, the slag envelopment of the back bead was poor, and the shape of the back bead was poor.

&6 has AtF3 exceeding 5% of the wire weight ratio, the slag flows too much in the upright position and the upward position, uneven encapsulation is observed, and the back bead has poor shape. It was seen.

In case No. 7, Mn was less than 0.5% based on the wire weight ratio, and the fluidity of the slag was uneven in the upright position and the upward position, resulting in poor welding workability.

In case No. 8, the Mn content exceeds 2.5% relative to the wire weight ratio, and the viscosity of the slag becomes too large in the vertical and upward positions, resulting in poor encapsulation and poor welding workability. is inferior.

In &9, the Ti content was less than 0.05% based on the wire weight ratio, and the slag removability of the front bead surface within the groove was poor.

In Flat No. 10, the Ti exceeded 1.5% with respect to the wire Nil ratio, the slag envelopment of the back bead was poor, and the shape of the back bead was poor.

The flat plate 11 has a Bi content of less than 0.001% based on the wire weight ratio, and the slag removability of the front bead surface in the groove is poor.

In A12, Bi exceeded 5% of the wire weight ratio, the fluidity of the slag was poor, and the slag encapsulation of the back bead was deteriorated.

A13 contains 0.7% metal carbonate based on the wire weight ratio.
However, the slag encapsulation of the back bead was poor and the shape of the back bead was poor. In addition, the occurrence of snow ξ ivy was observed.

No. 414 used an outer shell containing 0.134% N, and the Bi content was insufficient, resulting in extremely poor slag removal from the surface of the front bead within the groove.

On the other hand, those using TIG welding filler metals of Nos. 15 to 31 according to the present invention have good bead slag envelopment, bead shape, welding workability, and surface roughness within the groove. Slag removability from the bead surface was good in all position welding.

〔Effect of the invention〕

As explained above, the TIG filler material of the present invention contains TiO2, CaF2, AtF3, M in the filler material.
n, Ti.

By containing Bi within the specified range and not substantially containing metal carbonates, the synergistic effect of these elements makes it possible to weld stainless steel TIG piece 1II without using pack shield gas. In addition, a good initial layer long-wave bead can be obtained in all positions, and the slag on the surface of the bead in the groove can be easily peeled off, allowing efficient welding.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the welding procedure in the example, (a)
Id is a perspective view, and (b) is a front view. FIG. 2 is a diagram showing an aspect of the wire according to the present invention. (a) shows a case where a nozzle is used as the outer skin, and (b) shows a case where a steel strip is used as the outer skin, and the inside of the end portion t of the steel strip is used as the outer skin. (C) is a case where the steel strip is used as a steel strip and the end faces of the steel strip are butted. FIG. 3 is a sectional view showing the groove shape in the example. 1-TIG torch nozzle, 2-electrode, 3. ,,TI
G - Filler metal for welding, 4 - Arc, 5 - Base metal, 6 - Weld metal, 7 - Outer skin, 8... Filling flux, W... Welding direction, - plate thickness, θ - opening Tip angle, f-root face, g-root gap. Agent: Patent attorney Masamitsu Akizawa and one other person Figure 1 (a) <b) Figure 7.2 <(1) Cb)
(C) Figure 73

Claims (1)

[Claims] (1) In a wire formed with a stainless steel sheath, based on the total weight of the wire, TiO_23-12% CaF_20.05-5% AlF_30.05-5% Mn0.5-2.5% Ti0.05-1. 5% Furthermore, a filler for TIG welding characterized by being filled with a flux containing 0.001 to 0.5% of one or more of Bi alone or a compound in terms of Bi. Material.