JPS58205696A - Stainless steel flux cored wire for gas shielded arc welding - Google Patents

Abstract

PURPOSE:To improve the slag removability, resistance to cracking, etc. in a weld zone, by using a fine hollow wire of stainless steel packed therein with a slag forming material and metallic powder of specific compsns. for a flux cored wire for gas shielded arc welding of stainless steel. CONSTITUTION:A wire contg. 0.001-0.1% S alone or various sulfides and sulfates in terms of S based on the weight of wire, 0.001-0.04% Bi alone or compds. such as Bi2O3, Bi(OH)3 or the like in terms of Bi, 1-10% rutile, ilmenite, etc. in terms of TiO2, 1-10% slilica sand or a silicate compd. in terms of SiO2 and >=45% metallic powder of Cr, Ni, etc. for controlling the components of molten metal and Si, Al, etc. as a deoxidizing agent in a hollow tube made of stainless steel or mild steel is used as a wire to be used in the stage of gas shielded arc welding of stainless steel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stainless steel welding material for gas-shielded arc welding, and more particularly to a stainless steel flux-cored shear wire that has excellent welding workability and productivity in gas-shielded arc welding. It is.

Stainless steel has excellent resistance to corrosion, corrosion, and oxidation.
Although it is widely used in various fields due to its heat resistance, manual welding using a coated arc welding rod is the main welding method, but there is a problem in that it is less efficient. As an alternative to this, MIG welding using solid wire is becoming popular.

However, although the MiG welding method using solid wire is superior in terms of efficiency, when applied to stainless steel, blowholes are likely to occur, and the spread of weld metal cannot be obtained in multilayer welding, resulting in poor fusion. There are problems in that the range of appropriate conditions is very narrow. Due to these factors, it has excellent efficiency and welding workability, making it easy to use! It is necessary to establish a welding method that is less likely to cause welding defects such as low holes and poor fusion.

As a means to solve the disadvantages of MIG welding using solid wire, a small diameter wire 1.6 containing flux is used.
A method of welding using wφ, 12■φ and flowing shield goss has been attracting attention.

Although the diameter of the flux-cored shear wire is reduced, arc welding protects the weld metal by both the slag shield by the embedded flux and the gas shield, so the weld metal spreads out and the bead Good shape! It is less likely to cause weld metal defects such as low holes and poor fusion, and enables highly efficient welding, and its demand has been increasing in recent years.

On the other hand, the outer skin of the stainless steel welding slacks choir is made of Cr-Nl' stainless steel, Cr stainless steel,
and mild steel are used; among these, Cr −
Since Ni stainless steel has very high work hardening properties, it is difficult to wire-draw it.

On the other hand, Cr stainless steel and mild steel have Cr-Ni
Stainless steel does not have particularly good work hardening properties, but the necessary alloying elements such as Cr + Ni must be supplied from the filling flux, which naturally results in a high filling rate. However, as the filling rate increases, it is unavoidable that wire drawability deteriorates as a natural result.

With the current method of manufacturing Flux Jin 9 wire, it is difficult to draw the wire even if you use the outer shell of the chair, so by drawing the wire from a small diameter of 2.5 φ or less, 161 φ, The current situation is that 12-φ flux-containing wires are produced, and the productivity is very low, and despite the high demand for such wires, it is not possible to stably supply them in large quantities.

In order to solve this problem, we conducted various studies in order to use thin flux-cored wires of 1.6 mm and 1.2 m + φ for wire drawing processing from large diameter wires of 3 mm or more.
It was found that heat treatment was necessary to soften the outer skin more than once, and a method for manufacturing wire with high productivity became possible.

However, it has been found that with existing slab agents, as the heat treatment resorption increases, the bath welding workability, especially the slag release performance, deteriorates. Regarding the releasability of slag, it has been disclosed in Japanese Unexamined Patent Publication No. 56-4393 that addition of bismuth oxide or the like is conventionally effective. When added to the wire, the slag releasability is certainly improved. However, it has been found that in the range where this effect becomes significant, the susceptibility to hot cracking of the weld metal increases and the bead shape becomes difficult to become uniform.

In view of the above-mentioned problems, the present inventors conducted numerous studies to improve this problem, and as a result, added a trace amount of Bi in addition to a trace amount of S to the existing slag agent [7, Addition of these elements] By numerically limiting the amount, these synergistic effects become noticeable,
The interfacial tension between the molten metal and the molten slag is reduced, and the slag releasability is significantly improved. Furthermore, a bead with a more beautiful appearance can be obtained, and other deterioration of welding workability, hot cracking susceptibility, and mechanical performance are reduced. A completely new finding that there is no deterioration was obtained.

The present invention was made based on the above knowledge, and the shield is made of Ar-02, Ar-CO2 mixture, and Carbon
To provide a novel stainless steel flux-cored wire which has excellent welding workability, especially slag peelability, in gas-shielded arc welding using only O2, and which provides excellent cracking resistance and mechanical properties in the welded part.

That is, the gist of the present invention is that the sum of one or more types of S as a single substance or compound is 0.001 to 0.001 or more in terms of the weight of the wire inside the outer sheath formed into a tubular shape of stainless steel or mild steel. 0.1%, the sum of one or more types of Bi alone or compounds is o, oo when converted to a single substance
t ~ 0.04%, 1 of titanium oxide calculated as TiO2
The total amount of seeds or two or more types is 1 to 10 yen, plus 5IO2
filled with a slag-forming material containing a total of 1 to 10 parts of one or more crushed sand or silicate compounds, and a filler powder consisting of a metal powder of 45 cm or less based on the weight of the wire. Stainless steel flux-cored wire for gas-shielded arc welding.

The present invention will be explained in detail below.

First of all, the flux wire wire as used in the present invention refers to a wire having a wire cross section as shown in FIG. It is filled with filler powder 2. It should be noted that the purpose of the present invention will not be impaired if the shape of the outer skin is a cylindrical shape other than that shown in FIG.

Next, regarding the range of ingredients in the slag formed into the wire, S improves the releasability of the slag and the bead shape and appearance. That is, it has a very high surface activity and lowers the interfacial tension between the molten metal and molten slag, thereby making the sipeed shape flat and improving the conformability of the bead toe. Furthermore, since the bead surface and the slag surface in contact with it are made smooth, the bead appearance becomes beautiful. In addition, by increasing the bonding force between the slags near the slag surface that contacts the bead surface and at the same time reducing the bonding force between the weld metal and the slag, the bead surface and toe become smooth, and the slag The peeling becomes better. However, if it is less than 0.001%, the above effect will not be observed, and if it exceeds 0.1%, the hot cracking susceptibility of the weld metal will increase. It was defined as 0.001 to well 0.1 in terms of a single substance. In particular, when Bi is added at the same time, the synergistic effect of both improves the slag releasability significantly.

Here, the compound S refers to sulfides such as zinc sulfide, lead sulfide, iron sulfide, sulfide steel, barium sulfide, calcium sulfide, manganese sulfide, etc., sulfuric acid such as aluminum sulfide, calcium sulfate, barium sulfate, iron sulfate, lead sulfate, etc. Refers to salt.

Next, when Bi is added, the melting point of the molten slag is lowered, the fluidity is improved, the interfacial tension is lowered, and the releasability of the slag is significantly improved, but if it is less than 0.001 inch, the above effects are not If it exceeds 0.04%, the hot cracking susceptibility of the weld metal increases and beads are not formed smoothly.

In addition, the Bi mino compound here is B I 205 , B
l (0H)3, B i F 5, BiCl3, B 1
B r 5, B115 '7.

Titanium oxide uniformly covers the weld metal, forms a slag with good followability, and improves the overall bead shape, but 1
If the diameter is less than 10mm, the effect will not be exhibited, and if the diameter exceeds 10mm, the slag cover will increase and the slag will lead in the groove, causing defects such as slag entrainment. 1 to 10% because it will actually impair the releasability of
limited to. Incidentally, the titanium oxide in the present study refers to rutile, illuminite, titanium white, titanium slag, potassium titanate, etc., and may be used singly or in combination.

Silica sand or silicate compounds form a slag with good encapsulation properties, and have good concentration and slag.

There is little occurrence of dark spots, and a stable arc condition can be obtained. However, a slag formed only from fine sand, silicate compounds, and titanium oxide has problems in terms of flaking, and by adding appropriate amounts of the aforementioned S and Bi'z, the slag can improve its encapsulation, followability, and slag.

This makes it possible to significantly improve the slag releasability without impairing the finish.

If the amount before addition of silica sand or silicate compound is less than 1%, the effect will be insufficient, and if it exceeds 10%, the slag will become hard and will cause sticking to the book, which will actually impair the releasability. Limit to 10%.

The silicate compound referred to here is potassium feldspar.

It refers to silicate compounds such as mica, talc, kaolin, potassium silicate, uy soda, and lithium silicate calculated by S+024, and is used alone or in combination. In addition to slag formations,
To adjust the composition of weld metal, Cr・Nt + Mn +
Nbr Mo I Cu, etc., and metal powder such as Sl, At, Ti, etc. are filled as a deoxidizing agent 1.

The welding metal component of the stainless steel flux-cored wire according to the present invention contains all the chemical components equivalent to the bath-depositing metal of the stainless steel flux-cored wire specified in AVi/SA 5.22-80, and is Even when a soft prisoner is used, it is sufficient to fill the metal powder in an amount of 45 inches or less relative to the weight of the wire, which is safe for component adjustment. Therefore, in the present invention, the metal powder content is specified to be 45% or less.

The outer skin is made of stainless steel or mild steel, but in the case of stainless steel, austenitic, stenite-ferrite thread, or ferritic stainless steel is used.
, 16-26% Cr, 3.5-22% Ni, furthermore 1.2-6% Mo, 1-2.5% Cu,
NO, 30% or less, NbO, 15% or less or 10xC
Contains 0.1% or less, 5% or less of Si, 10% or less of Mn, 0.040% or less of Po, and 0.30% or less of So. .

Austenitic ferritic stainless steel is N13
-6%, Cr23-28%, Mo 1-3% as main components, CO 0.08% or less, St 1% or less, Mn
It contains 1.5% or less, Po, 04i or less, and SO, 030% or less.

The ferrite type has 11.5 to 27.5% of Cr as a main component, and further contains 0.75 to 2.5% of Mo, Ato, 1
0 to 0,30%, Ti+Nb+Zr or a combination thereof, containing 8×(C factor×N%) to O, SO factor alone or in combination, and C0,12% or less, Si 1
% or less, Mn 1% or less, Po, 040% or less, S
It contains 30% or less of O,0'' and 25% or less of NO,0.

15+m, wall thickness 0.3-2 Nn, when forming the outer skin using a band, the molding size is 3-4 m, wall thickness 0.5-08
It is desirable to use one with a width of 9.5 to 12.5 mm.

Here, referring to an example of the means for manufacturing the stainless steel wire or wire-cored wire of the present invention, for example, a stainless steel or mild steel outer shell and a filler powder are prepared, the filler powder is initially filled inside the outer shell, and the outer shell is 8oo~1150℃ for Cr-Ni stainless steel, 780~85+1℃ for Cr stainless steel, and 600℃ for mild steel.
After performing intermediate heat treatment at ~70°C one or more times and drawing the wire to a predetermined diameter,
It should dry for more than a minute.

The effects of the present invention will be described in more detail below.

Example 1111111 Table 1 shows the chemical components of the stainless steel and mild steel used as the outer skin. The shape and dimensions of the outer skin are as follows: The flux-cored wire symbol is 1 to 20 mm, the wall thickness is 07 mm, and the width is 11 mm. 4,
Using a wire with an outer diameter of 13+l1llφ and a wall thickness of 1.42 mm, the flux-cored wire symbol 22 has an outer diameter of 14 mm.
, Noya Eve with a thickness of 1 mm was used.

Table 2 shows the composition of the flux-cored wire based on the combination of the outer skin and the filler powder.

Table 3 shows the chemical composition of the base material. Each plate thickness is 12x
and 30IIW+.

Table 4 shows the results of the horizontal fillet welding workability test conducted using the flux-cored wire shown in Table 2 and the base material shown in Table 3.
The results of a welding test in a narrow gap using a 9It thick plate, the chemical composition of Natsuki Kintsugi, and the results of a hot cracking susceptibility test are shown.

The welding conditions were the same for the horizontal fillet welding workability test and the thick and narrow groove welding workability test, with flux-cored wire symbols A1 to 12 using a wire diameter of 1.6 maφ, a welding current of 260A, and a welding voltage. 28v, welding speed 30 Crn/
min, flux-cored shear wires 13 to 22 use wire diameter 1.2mm, welding current 24 OA, welding voltage 26V, welding speed +30, yn/'min, power source is DC constant voltage, polarity is reverse polarity The welding workability test in a narrow gap in a thick plate was conducted by welding the groove shown in FIG. 2 with a gas flow rate of 20 #/min and a gas flow rate of 20 #/min.

In Fig. 2, the groove angle θ=20·W, the shape R of the groove bottom is a radius of 2 degrees, the root face is f=2 degrees, and the root groove at this time is in close contact and 1 degrees. Ta. b is a copper dopant and was used to form a good back peak of the first layer.

The chemical composition of the deposited metal was analyzed by taking a sample from the welded part at a position where the base metal was not mixed after welding the groove shown in Figure 2 (7).

The hot cracking susceptibility test was conducted after welding the first layer of the groove shown in Figure 2.
A dye penetrant test was conducted to investigate the presence or absence of cracks.

Footnote 1) Iron sulfide (836%) was used in 7 lux wire symbols 1, 2, 3, 4, 6, 7, 9, 10, 17° 18 and 22.

Calcium sulfide (844m) was used in flux-cored wire numbers A5.8 and 19.

Zinc sulfide (832%) flux-cored wire symbol A
11, 13 and 15.

Barium sulfide (819%) was used for flux-cored wire symbols A12 and 14.

Calcium sulfate (823%) was used in flux-cored wire code A 20.

Barium sulfate (814%) was used for 7 lux-cored wire symbol A21. 2) BizOs (Bt 90%) was used for flux-cored wire symbol AI, 2.3, 4, 5, 6, 11.13° 14.15, 16.17 and 22.

Bi2(OH)3 (Bi 89chi) with flux-cored wire symbol A 7 , 8.9110 , 12.18 ,
19.

20 and 21.

3) Rutile CTlO296'4) 'Flux-cored wire symbol 1, 2.3.4, 11.12.13゜1
Used on 9.20.21 and 22.

Titanium white (TiO□98%) was used with flux-cored wires symbols A5, 6 and 10VC.

Potassium titanate (TlO2 71%) was used in Fluxman 9 wire symbols A8, 9.14 and 15.

Ilbanite (TlO2 71%) tl-7 lux-cored wires were used for wires code 47, 16, 17 and 18.

4) Silica sand (510297chi) with flux-cored wire symbol A1.2, 3.6, 7.11.13, 16°18.2
0 and 22.

Potassium feldspar (5iO264To) k flux-cored shewire symbol A4,8. It was used for B and 10.

Mica (S 10247'4) was used in flux-cored shear symbols A5, 14 and 15.

Talc (510,225 fp) was used in flux man shewire symbols A9, 17 and 19.

Kaolin (SiO□81ch) was used for 7 lux cored wires symbols A 12 and 21.

Potassium silicate (510265%) was used for 7 lanox-filled wire symbol 〼21.

Sodium silicate (810270%) Used for k-flux wire symbol shop 22.

In addition, regarding the flux human shear wire symbol A21, 5% of the 5IO2 nasal exchange value of 8% relative to the wire weight was added as kaolin and 3% as potassium silicate.

In addition, for flux-cored choir symbol A22, 5
IO2 conversion: Of the jL value of 8tII, 5% was added as silica sand and 3% as sodium silicate.

Flux-cored wire symbol A1,2°3.8 of the present invention.
1O, 13, 14, 17, 18, 19°20.21 and 22 had good results in all test results of horizontal fillet welding workability test, thick plate narrow gap welding workability test, and hot cracking susceptibility test. The results were obtained. Among them, A18 is an example of dissimilar metal joint welding of stainless steel and mild steel, and it was in good condition with no cracks observed.

A4 shown as a comparative example has an S conversion value of 1@total exceeding 0°1, A7 has a Bi conversion value total of over 0.00cm, a 5 and 8i conversion value total of less than 0.0014, and Boiled 6 has an S conversion value of over 0.00cm. The total converted value is less than 0.001 cm, A9 has a total TiO2 converted value of more than 10, and All has a total SiO2 converted value of 10.
%, Section 12 has a total TiO2 conversion value of less than 1 Ti,
For A15, the total 810□ conversion value was less than 1%, and as shown in Table 4, welding workability was poor in both cases. A
No. 16 is an example in which S was not added to the filler powder, and the bead shape was poor and hot cracking was observed.

As explained above, the flux-cored 9 wire of the present invention is made by adding an appropriate amount of Bi in addition to an appropriate amount of S to the filler powder, and by limiting the amount of these elements added, the synergistic effect of both can be used to form steel eaves and plates. Regardless of the thickness or groove shape, welding workability, especially slag removability, is excellent, and a sound welded part can be obtained.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a flux-cored wire, Figure 2 is a diagram showing a cross section of a flux-cored wire;
The figure is a diagram showing a groove shape for a welding workability test in a thick plate groove. ■...Outer skin, 2...Filling, θ...Bevel angle 5 degrees,
R...radius of groove bottom, f...root-face,
b...Copper backing money. Patent applicant Nippon Steel Corporation 1 company, -IS- Agent Kazuo Ozeki, -, = 2.21, τ
Bu

Claims (1)

[Claims] Inside the outer shell made of stainless steel and mild steel molded into a tubular shape, the sum of one or more types of S alone or compounds is 0001 to 0.1 in terms of the weight of the wire.
%, the total of one or more types of Bi or compounds is 0001 to 0.04% in terms of Bi, Ti
The total of one or more titanium oxides converted to O2 is 1 to 10 Ti, and the total of one or more borax or silicate compounds converted to 5i02 is 1 to 10.
A stainless steel flux-cored wire for use in gas-shielded arc liquid contact, characterized in that it is filled with a filler powder consisting of a slag forming material containing 1% and a metal powder of 45 cm or less based on the weight of the wire.