JPH0788684A - Welding material for austenitic stainless steel and welding method - Google Patents

Abstract

PURPOSE:To provide a same metal base welding material and joint welding method excellent in toughness after aging and resistance to high-temp. corrosion in joint welding of austenitic stainless steel tubes, plates or the like which are used in a severe high-temp. corrosive environment. CONSTITUTION:This welding material is used for manufacturing a welded joint of the austenitic stainless steel excellent in resistance to high-temp. corrosion and contains the proper amount of C, Si, Mn, Cr, Ni, Mo, P, S and N, as necessary, either or both of >=1 kind of Nb, Ti and V or >=1 kind of Ca, Y, La and Ce. And, the value of deltaFe that is expressed by deltaFe=3(Cr+Mo+1.5Si+0.5Nb+Ti+0.9V)-2.8(Ni+0.5Mn+30C+30N)-19.8 is <=-7.3 for coated arc welding and <=-21.3 for TIG welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is excellent in post-aging toughness and high temperature corrosion resistance of austenitic stainless steel applied to boilers, chemical plant equipment, heating furnaces, etc. used in high temperature environments of 400 ° C. or higher. The present invention relates to a welding material and a joint welding method.

[0002]

2. Description of the Related Art At present, the number of boilers, chemical plant equipment, heating furnaces, etc. used at 400 ° C. or higher, which have severe high-temperature corrosiveness due to the inclusion of S, Cl, etc. in their high temperature environment, is increasing. High temperature austenitic stainless steel,
For example, SUS304, SUS321, SUS347,
SUS304HTB, SUS321HTB and SUS
In 347HTB, severe high temperature corrosion occurs, and there are problems such as unusable or short service life. High Cr, high Ni, low C, and high N of austenitic stainless steel are effective in these severe high temperature corrosive environments. However, in the welding, the characteristics of the welded joint made of the conventional welding material were problems such as hot cracking of the welded joint and deterioration of the toughness after aging of the welded joint as compared with the welded joint of the existing steel.

[0003]

From the viewpoint of solving the above problems, the present invention is an austenitic stainless steel excellent in high temperature corrosion resistance which is used in a severe high temperature corrosive environment containing S, Cl and the like. It is an object of the present invention to provide a joint metal welding material and a joint welding method, which have good weld hot crack resistance, excellent post-aging toughness and high temperature corrosion resistance in joint welding of pipes, plates and the like.

[0004]

The gist of the present invention is that in the production of austenitic stainless steel weld joints having excellent high-temperature corrosion resistance, the welding material is C;
0.001-0.03%, Si; 0.5% or less, Mn;
0.1-5.0%, Cr; 23.0-30.0%, N
i; 5.0 to 22.0%, Mo; 0.1 to 6.0%,
P; 0.04% or less, S; 0.005% or less, N;
2 to 0.5%, and if necessary, Nb;
0.05-0.6%, Ti; 0.02-0.3%, V;
One or more of 0.03 to 0.5%, and Ca: 0.00
05-0.05%, Y; 0.001-0.1%, La;
0.001 to 0.1%, Ce: 0.001 to 0.1%, including either or both of one or more kinds,
The value of δFe represented by the formula (2) is −7.3 or less for the welding rod for covered arc welding and −21.3 or less for the welding rod for TIG welding, and δFe = 3 (Cr + Mo + 1. 5Si + 0.5Nb + Ti + 0.9V) -2.8 (Ni + 0.5Mn + 30C + 30N) -19.8 (2) Austenitic stainless steel characterized by joint welding using an austenitic stainless steel with the balance being Fe and inevitable impurities. Welding material and its joint welding method.

[0005]

[Function] The reason for limiting the components of the welding material will be described below. Since C has a great effect on creep rupture strength and creep rupture elongation as a carbide forming element, the amount of C is the minimum amount necessary to form carbides of Cr, Nb, Ti and V effective for creep properties. Therefore, the lower limit of the C content of the welding material is set to 0.001%. On the other hand, the high temperature intergranular corrosion that occurs when Cl is contained in the high temperature corrosive environment is caused by the Cr deficient phase around it due to the precipitation of Cr carbide at the grain boundary, and low C is desirable from the high temperature intergranular corrosion resistance. Further, it is necessary to reduce the C content as much as possible in order to prevent hot cracking during welding. From the above viewpoints, the upper limit of the C content of the welding material is set to 0.03%.

Si is an element which exerts an important effect on the post-aging toughness and the suppression of high temperature intergranular corrosion in the present invention by reducing the content thereof. That is, the post-aging toughness and the high temperature intergranular corrosion resistance of a welded joint of austenitic stainless steel for high temperature are the grain boundary Cr due to aging or heating during use.
It may decrease due to carbide precipitation or σ phase precipitation. By reducing the amount of Si, the precipitation of grain boundary Cr carbide or the σ phase is suppressed, and both properties are improved. Therefore, the upper limit of the amount of Si in the welding material is set to 0.5%.

[0007] Mn is necessary for sufficient deoxidation to obtain a sound slab, fixes the S component contained as an impurity in steel, prevents hot brittleness, weldability, and hot working. Therefore, the lower limit was made 0.1% to improve the property. Further, although it is added from the viewpoint of structural stability, if the addition amount is too large, the oxidation resistance is impaired, so the upper limit was made 5.0%. Cr is an essential element for heat-resistant alloys because it improves high-temperature creep rupture strength, high-temperature corrosion resistance against sulfates, etc. and high-temperature oxidation resistance, and in particular, from the viewpoint of high-temperature corrosion resistance, the lower limit of the Cr content is 23%. It was set to 0.0%. However, if the amount of Cr is large, σ embrittlement easily occurs due to heating for a long time, so the upper limit was made 30.0%.

[0008] Ni is added to stabilize the austenite structure, and has the effect of improving the high temperature corrosion resistance against the high temperature corrosion environment containing Cl. The effect of stabilizing the structure is determined in particular by the interaction with the contents of C, N, Mn, Cr, Mo and Si, and a Ni content of 5.0% or more is required. The upper limit of Ni is set to 22.0% because if the Ni content increases, hot work hardening easily occurs and the hot workability deteriorates, and in terms of cost, if the Ni content increases, it becomes expensive. Therefore, the amount of Ni should be 5.0
It was limited to ~ 22.0%.

Since Mo is an element necessary for increasing the creep rupture strength by the solid solution hardening action and the precipitation hardening action, the lower limit was made 0.1%. However, adding a large amount of Mo
The upper limit of the amount added is set to 6.0% because it promotes the formation of phases and tends to cause embrittlement during long-term use. If a large amount of P is added, the weld cracking susceptibility becomes high and the precipitation during high temperature creep is promoted to promote embrittlement during creep, so the upper limit is 0.0.
It was 4%.

If S is added in a large amount, the weld cracking susceptibility becomes high and segregates at the grain boundaries to promote embrittlement of the grain boundaries during high temperature creep, so the upper limit was made 0.005%. N is
It is important as an austenite structure stabilizing element, and its addition also has the effect of reducing expensive Ni while stabilizing the austenite structure. Further, N enhances the creep rupture strength by its solid solution effect or the formation of nitrides. For these effects, the N content was set to 0.
It must be 2% or more. However, the amount of dissolved N is determined by the Cr content and the like, and the addition of too much causes bubbles in the steel material to deteriorate the soundness of the steel, so the upper limit of the amount of N was set to 0.5%. However, it is desirable that the N content in the welding material is 0.01 to 0.1% higher than the N content in the base metal within the above range in consideration of a decrease due to vaporization during welding.

Nb, Ti and V are charcoal and nitride forming elements and are effective in improving the creep rupture strength, so one or more kinds are added if necessary. The creep rupture strength becomes highest when the amount of carbon or nitride is finely dispersed by addition alone or in combination. Regarding the precipitation amount of carbon and nitride, the Nb amount is less than 0.05%, the Ti amount is less than 0.02%, and the V amount is 0.
If it is less than 03%, it is not sufficient, while the amount of Nb is 0.6%,
Nb and T with a Ti content of 0.3% and a V content of more than 0.5%
When i and V are added individually or in combination, carbon and nitride are aggregated and coarsened, and the creep rupture strength is reduced. In consideration of the above points, the amount of Nb is 0.05 to 0.6%, the amount of Ti is 0.02 to 0.3%, and the amount of V is 0.03 to 0.5%.

Ca, Y, La and Ce have a deoxidizing / desulfurizing action, and improve the hot workability and the creep rupture strength by reducing the grain boundary segregation of O and S.
Add as needed. The effect is Ca; 0.0005
%, Y; less than 0.001%, La; less than 0.001%, Ce; less than 0.001% is not sufficient, so Ca
Lower limit of 0.0005%, lower limit of Y 0.001%, L
The lower limit of a was 0.001%, and the lower limit of Ce was 0.001%. If the Ca content exceeds 0.05% and the Y, La, and Ce contents exceed 0.1%, the cleanliness of the steel decreases and the hot workability decreases, so the Ca content is 0.05% or less. Y
It is necessary that the amount be 0.1% or less, the La amount be 0.1% or less, and the Ce amount be 0.1% or less. For these reasons, the amount of Ca is 0.0005 to 0.05%, the amount of Y is 0.001 to 0.1%, and the amount of La is 0.001 to 0.
1% and the amount of Ce were 0.001-0.1%. In addition,
If necessary, one or more of Ca, Y, La, and Ce can be added to obtain the above effects. However, from the viewpoint of ensuring hot workability, the upper limit in the case of combined addition is Ca,
The total of Y, La, and Ce is preferably 0.2%.

Next, the restriction of the amount of δ-ferrite in the welding material component, which is the main constitution of the present invention, will be described. The value of δFe of the welding material component (Equation (1) or (2)) is -7.3 or less for the welding material for covered arc welding, TIG
In the case of a welding material for welding, the amount of δ-ferrite in the deposited metal after welding is 1% or less by actual measurement by limiting the content to -21.3 or less. On the other hand, the post-aging toughness of the welded joint has a clear correlation with the amount of δ-ferrite in the deposited metal,
Sufficient toughness (≧) when the ferrite content is less than 1%
20 J / cm ² ) can be maintained (Fig. 1). In the present invention,
As a reason for this, it was found that the δ-ferrite in the weld metal after welding caused a decrease in toughness due to a structural change to an embrittlement σ phase during aging, and to suppress it, the amount of δ-ferrite was set to 1% or less. It is based on the fact that reducing is effective.

For the above reasons, the value of δFe in the welding material component is limited to −7.3 or less for the welding material for covered arc welding and −21.3 or less for the welding material for TIG welding. Next, regarding austenitic stainless steel pipes and plates (base materials) having excellent high-temperature corrosion resistance and toughness after aging, for example, Japanese Patent Publication No. 4-30463 and Japanese Patent Publication No. 430463 proposed by the present inventors. There is one described in JP-A-31020. When the material of the component system specified in claims 9 to 16 containing these component systems is used as the base material, excellent hot corrosion resistance and post-aging toughness not only in the welded portion but also in the base material as described above. It is possible to obtain a welded joint having

[0015]

EXAMPLES Next, examples of the present invention will be described more specifically. Table 1, Table 2 (continued from Table 1) and Table 3, Table 4
Table 3 (continued) shows the chemical compositions of the welding material and base material of the present invention, and Tables 5 and 6 (continued in Table 5) and Tables 7 and 8 (continued in Table 7) show comparative examples. The chemical composition of the welding material and the base metal is shown.

Table 9 shows the measured values of the amount of δ-ferrite in the weld metal of the welded joint of the present invention as-welded, the toughness after aging of the weld metal and the high temperature intergranular corrosion depth u (μm). Table 10 shows the characteristics of the comparative example. The welding material was vacuum-melted at 45 kg, and after hot extrusion, cold drawing and solution heat treatment, a coated arc welding rod and a TIG welding wire were produced. The coated arc welding rod is φ3.2 x L
After cutting the wire rod to 350 mm, a so-called lime-based coating material containing lime and fluorite as main components was applied and used. The base material is vacuum-melted by 45 kg, and after hot rolling and solution heat treatment,
A welded joint was manufactured using the above welding material and a high temperature corrosion test was performed.

For the production of joints by covered arc welding, the first layer is DC 100A, 10V, and the welding speed is 80 mm / min.
After IG welding, AC 80A, 23V,
The welding was performed at a welding speed of about 150 mm / min. The joint production by TIG arc welding was performed at a DC of about 150 A and 10 V and a welding speed of about 100 mm / min.

Δ− of the weld metal of the welded joint as-welded
The amount of ferrite was measured with a ferrite meter. welding
The toughness after aging of the joint is welded after aging at 650 ° C for 500 hours.
0 ° C Charpy impact test of metal part (test piece; JIS4
No., 1/2 size). High temperature intergranular corrosion resistance
Evaluation is Na₂SO_Four+ K₂SO_Four+ NaCl synthetic ash
(Mixed molar ratio; 2: 2: 1), welded joint and base metal
W15 x L25 x t4mm cut out from (surface; 60
Apply to No. 0 emery polished skin) and mix gas (0.2% SO
₂+ 5% O₂+ 10% CO₂+ Bal. N₂) In airflow
550 ℃ × 100h heating, intergranular corrosion depth of vertical cross section of test piece
It was done by measuring the height.

Among the examples of the welding material of the present invention shown in Tables 1 and 2, S1 to S9 are welding materials for covered arc welding, and all steels have a δFe value of -7.3 or less. Among them, S1 to S3 are steels corresponding to claims 1 and 9, and S4,
S5 is steel containing at least one of Nb, Ti and V corresponding to claims 3 and 11, and S6 and S7 are claims 5 and 1.
A steel containing at least one of Ca, La and Ce corresponding to No. 3, S8 and S9 are Nb corresponding to claims 7 and 15.
And steel containing at least one of Ti and at least one of Ca and Y. Further, T1 to T9 are welding materials for TIG welding, and all steels have a δFe value of −21.3 or less. Among them, T1 to T3 are steels corresponding to claims 2 and 10, T4 is a steel containing Nb corresponding to claims 4 and 12, and T5 to T7 are Ca corresponding to claims 6 and 14. And steel containing at least one of Y, T8, T9
Is a steel containing at least one of Nb and V and at least one of Ca, Y, La and Ce corresponding to claims 8 and 16.

Next, among the examples of the base material of the present invention shown in Tables 3 and 4, B1 to B3 are steels corresponding to claims 9 and 10, and B4 to B6 are claims 11 and 12. Nb, T
Steel containing at least one of i and V, B7 to B10
Is Ca, Y, La and C corresponding to claims 13 and 14.
B is a steel containing at least one e, and B11 to B14 are steels containing at least one of Nb, Ti and V corresponding to claims 15 and 16 and at least one of Ca, Y, La and Ce. .

On the other hand, among the comparative examples of welding materials shown in Tables 5 and 6, HS1 to HS7 are welding materials for covered arc welding, of which HS1 to HS3 are comparative examples of claims 1 and 9. In comparison with the example of the present invention, HS1 has a high Si and HS2 has a high δ.
Fe and HS3 are high C and high δFe component systems. HS4
Is a comparative example of claims 3 and 11 and has a high δ as compared with the examples of the present invention.
It is a component system of Fe. HS5 and HS6 are claims 5 and 13.
In the comparative example, HS5 is a high δFe and HS6 is a low Cr component system. HS7 is a comparative example of claims 7 and 15 and has a high δF.
It is a component system of e. Next, HT1 to HT7 are welding materials for TIG welding, in which HT1 to HT3 are comparative examples of claims 2 and 10, and HT1 has a high S compared to the present invention example.
i, HT2, and HT3 are high δFe component systems. HT4
Is a comparative example of claims 4 and 12, and has a high C as compared with the examples of the present invention.
It is a component system of. HT5 and HT6 are comparative examples of claims 6 and 14, HT5 is a high δFe component, and HT6 is a low Cr component system. HT7 is a comparative example of claims 8 and 16 and is a high δFe component system.

Among the comparative examples of the base materials shown in Tables 7 and 8, HB1 to HB3 are comparative examples of claims 9 and 10. Compared with the examples of the present invention, HB1 has high Si and HB2 has high C. , HB3
Is a low Cr component system. HB4 is a comparative example of claims 11 and 12 and is a component system having a high C as compared with the examples of the present invention. H
B5 and HB6 are comparative examples of claims 13 and 14, and HB5 is a high Si and HB6 is a high C component system. HB7, HB8
Is a comparative example of claims 15 and 16, wherein HB7 is high Si, HB
No. 8 is a low Cr component system.

Next, among the examples of the present invention of the welded joint shown in Table 9, J1 to J10 are joints manufactured by the covered arc welding method. Among them, J1 to J3 are defined in claims 1 and 9 and J4,
J5 is claims 3 and 11, and J6 and J7 are claims 5 and 13.
In addition, J8 and J9 correspond to claims 7 and 15, respectively.
J10 is an example in which the welding material S1 corresponding to claim 1 is used for joint welding of the base material HB1 of the comparative example. Also, J11 ~
J20 is a joint manufactured by the TIG welding method. Among them, J11 to J13 are in claims 2 and 10, J14 is in claims 4 and 12, J15 to J17 are in claims 6 and 14, and J
18, J19 correspond to claims 8 and 16, respectively. J
20 is an example in which the welding material T1 corresponding to claim 2 is used for joint welding of the base material HB1 of the comparative example.

According to Table 9, the welded joints J1 to J1 of the present invention are shown.
In all of J20, the as-welded δ-ferrite amount measured value of the weld metal part is 1% or less, the toughness after aging of the weld metal part is 20 J / cm ² or more, and the high temperature grain boundary of the weld metal part is high. Corrosion depth is J of the example of the present invention for both welding material and base material.
1 to J9 and J11 to J19 are 0 μm, and J10 and J20 using the welding material of the present invention as the base material of the comparative example are 5 μm.
It is the following. That is, the welded joints J1 to J2 of the present invention example
It can be said that all of 0 are welded joints of austenitic stainless steel which are excellent in both toughness after aging and high temperature intergranular corrosion resistance.

On the other hand, among the comparative examples of welded joints shown in Table 10, HJ1 to HJ7 are joints manufactured by the covered arc welding method. Of these, HJ1 to HJ3 are claims 1,
9 and HJ4 are comparative examples for claims 3 and 11, HJ5 and HJ6 are claims 5 and 13, and HJ7 is for claims 7 and 15, respectively. HJ8 to HJ14 are joints manufactured by the TIG welding method. Among these, HJ8 to HJ1
0 for claims 2 and 10, HJ11 for claims 4 and 12,
HJ12 to HJ13 are comparative examples for claims 6 and 14, and HJ14 is a comparative example for claims 8 and 16, respectively.

According to Table 10, the welded joint HJ1 of the comparative example is shown.
It can be said that all of HJ14 have problems in at least one of the toughness after aging of the deposited metal portion and the high temperature intergranular corrosion resistance of the deposited metal portion and the base material. FIG. 1 shows the relationship between the toughness of the weld metal parts of the welded joints of the present invention example and the comparative example after aging for 500 hours at 550 ° C. and the as-welded δ-ferrite amount of the weld metal part. In the comparative example where the measured value exceeds 1%, the toughness after aging of the weld metal part is 20 J / cm.
It is less than ² . Moreover, the measured value of the amount of δ-ferrite is 1%.
Even in the following, when the welding material is the weld joints HJ1 and HJ8 using the high Si-based component systems HS1 and HT1, the toughness after aging of the weld metal part is less than 20 J / cm ² , and
High temperature intergranular corrosion exceeding 5 μm occurs in the deposited metal part. On the other hand, in the case of HJ6 and HJ13 of low Cr system or HJ11 of high C system, the measured value of δ-ferrite amount is 1% or less and the toughness after aging of the weld metal part is 20 J / cm ² or more. High temperature intergranular corrosion exceeding 10 μm occurs in the metal part.

Further, in the comparative weld joints HJ2, HJ9, HJ3 and HJ11 in which high P type HS2, high S type HT2 and high C type HS3 and HT4 were used as welding materials, welding hot cracking was observed. .

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

[Table 5]

[0033]

[Table 6]

[0034]

[Table 7]

[0035]

[Table 8]

[0036]

[Table 9]

1) Method for measuring δ-ferrite amount; measured by ferrite meter 2) Conditions for evaluating toughness after aging; 650 ° C., 500
h After aging, evaluated by Charpy impact test at 0 ° C 3) High temperature intergranular corrosion depth evaluation condition; Na ₂ SO ₄ + K
₂ SO ₄ + NaCl synthetic ash coating 0.2% SO ₂ + 5% O ₂ + 10% CO ₂ + bal. N
After heating in ₂ gas at 550 ° C for 100 hours, the vertical cross section is observed with an optical microscope. 4) High temperature intergranular corrosion depth u (μm) rating; ◎: u = 0, ○
= 0 <u ≦ 5, Δ: 5 <u ≦ 10, ×: 10 <u

[0038]

[Table 10]

1) Method for measuring δ-ferrite amount; measured by ferrite meter 2) Conditions for evaluating toughness after aging; 650 ° C., 500
h After aging, evaluated by Charpy impact test at 0 ° C 3) High temperature intergranular corrosion depth evaluation condition; Na ₂ SO ₄ + K
₂ SO ₄ + NaCl synthetic ash coating 0.2% SO ₂ + 5% O ₂ + 10% CO ₂ + bal. N
After heating in ₂ gas at 550 ° C for 100 hours, the vertical cross section is observed with an optical microscope. 4) High temperature intergranular corrosion depth u (μm) rating; ◎: u = 0, ○
= 0 <u ≦ 5, Δ: 5 <u ≦ 10, ×: 10 <u

[0040]

INDUSTRIAL APPLICABILITY According to the present invention, when welding austenitic stainless steel pipes, plates and the like having excellent high-temperature corrosion resistance used in a severe high-temperature corrosion environment containing S, Cl, etc., welding resistance It becomes possible to supply a common metal-based welding material and a joint welding method that have good hot cracking properties, excellent toughness after aging and high temperature corrosion resistance, and bring about an extremely useful effect industrially.

[Brief description of drawings]

FIG. 1 is a diagram showing the influence of the amount of δ-ferrite on the toughness after aging of a weld metal part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mizuo Sakakibara 3434 Shimada, Hikari-shi, Yamaguchi Prefecture Nippon Steel Co., Ltd. Hikari Steel Works (72) Inventor Tadao Ogawa 20-1 Shintomi, Futtsu-shi, Chiba Made by Shinnihon Iron & Steel Co., Ltd.Technical Development Headquarters (72) Inventor Toshiyuki Miyake 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Co., Ltd. Technical Development Headquarters (72) Inventor Masanobu Shinohara 717, Fukahori-cho, Nagasaki-shi, Nagasaki Prefecture No. 1 Sanryo Heavy Industries Co., Ltd. Nagasaki Research Institute (72) Inventor Toshiaki Nishio 5-717-1, Fukahori-cho, Nagasaki City, Nagasaki Sanryo Heavy Industry Co., Ltd. Nagasaki Research Institute (72) Makoto Nakamura Fukahori, Nagasaki City, Nagasaki Prefecture 5-717-1 Machi Choryo Engineering Co., Ltd.

Claims (16)

[Claims] 1. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: 0.2 to 0.5% is contained, and the value of δFe represented by the formula (1) is −7.3 or less, δFe = 3 (Cr + Mo + 1.5Si) -2. 8 (Ni + 0.5Mn + 30C + 30N) -19.8 (1) A welding material for covered arc welding of austenitic stainless steel, wherein the balance is Fe and inevitable impurities. 2. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: 0.2 to 0.5% is contained, and the value of δFe represented by the formula (1) is −21.3 or less, and δFe = 3 (Cr + Mo + 1.5Si) -2. 8 (Ni + 0.5Mn + 30C + 30N) -19.8 (1) A welding material for tungsten-inert-gas (hereinafter simply referred to as TIG) welding of austenitic stainless steel, wherein the balance is Fe and inevitable impurities. 3. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: containing 0.2 to 0.5%, further Nb: 0.05 to 0.6%, Ti: 0.02 to 0.3%, V: 0.03 to 0.5% Including one or more of them, and the value of δFe represented by the formula (2) is −7.3 or less, δFe = 3 (Cr + Mo + 1.5Si + 0.5Nb + Ti + 0.9V) −2.8 (Ni + 0.5Mn + 30C + 30N) ) -19.8 (2) Austenite characterized by the balance being Fe and inevitable impurities Metal arc welding welding systems stainless steel. 4. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: containing 0.2 to 0.5%, further Nb: 0.05 to 0.6%, Ti: 0.02 to 0.3%, V: 0.03 to 0.5% The value of δFe represented by the formula (2) is −21.3 or less, and δFe = 3 (Cr + Mo + 1.5Si + 0.5Nb + Ti + 0.9V) −2.8 (Ni + 0.5Mn + 30C + 30N) ) -19.8 (2) Austener characterized by the balance being Fe and inevitable impurities Preparative stainless steel welding material for TIG welding. 5. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: 0.2 to 0.5% is contained, further Ca: 0.0005 to 0.05%, Y: 0.001 to 0.1%, La; 0.001 to 0.1% , Ce; 0.001 to 0.1% inclusive, and the value of δFe represented by the formula (1) is −7.3 or less, δFe = 3 (Cr + Mo + 1.5Si) −2 .8 (Ni + 0.5Mn + 30C + 30N) -19.8 (1) The balance is Fe and inevitable impurities. Welding material for shielded metal arc welding Tenaito stainless steel. 6. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: 0.2 to 0.5% is contained, further Ca: 0.0005 to 0.05%, Y: 0.001 to 0.1%, La; 0.001 to 0.1% , Ce; 0.001 to 0.1% inclusive, and the value of δFe represented by the formula (1) is −21.3 or less, δFe = 3 (Cr + Mo + 1.5Si) −2 .8 (Ni + 0.5Mn + 30C + 30N) -19.8 (1) The balance is Fe and inevitable impurities. Welding for TIG welding of austenitic stainless steel. 7. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: containing 0.2 to 0.5%, further Nb: 0.05 to 0.6%, Ti: 0.02 to 0.3%, V: 0.03 to 0.5% 1 or more types among them, and Ca; 0.0005-0.05%, Y; 0.001-0.1%, La; 0.001-0.1%, Ce; 0.001-0.1 %, The value of δFe represented by the formula (2) is −7.3 or less, and δFe = 3 (Cr + Mo + 1.5Si + 0.5Nb + Ti + 0. 9V) -2.8 (Ni + 0.5Mn + 30C + 30N) -19.8 (2) A welding material for covered arc welding of austenitic stainless steel, wherein the balance is Fe and inevitable impurities. 8. A welding material for joint welding of austenitic stainless steel, wherein C: 0.001 to 0.03%, Si: 0.5% or less, Mn: 0.1 to 5% by weight. 0.0%, Cr; 23.0 to 30.0%, Ni; 5.0 to 22.0%, Mo; 0.1 to 6.0%, P; 0.04% or less, S; 0.005 % Or less, N: containing 0.2 to 0.5%, further Nb: 0.05 to 0.6%, Ti: 0.02 to 0.3%, V: 0.03 to 0.5% 1 or more types among them, and Ca; 0.0005-0.05%, Y; 0.001-0.1%, La; 0.001-0.1%, Ce; 0.001-0.1 %, The value of δFe represented by the formula (2) is −21.3 or less, and δFe = 3 (Cr + Mo + 1.5Si + 0.5Nb + Ti + 0). 9.9V) -2.8 (Ni + 0.5Mn + 30C + 30N) -19.8 (2) A welding material for TIG welding of austenitic stainless steel, wherein the balance is Fe and inevitable impurities. 9. In% by weight, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% A joint welding method for austenitic stainless steel, characterized in that the joint welding of the austenitic stainless steel containing Fe and inevitable impurities is carried out by covered arc welding using the welding material according to claim 1. 10. In wt%, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% A joint welding method for austenitic stainless steel, characterized in that the joint welding of austenitic stainless steel containing Fe and inevitable impurities in the balance is TIG-welded using the welding material according to claim 2. 11. In% by weight, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% Contained, and further contains one or more of Nb; 0.05 to 0.6%, Ti; 0.02 to 0.3%, V; 0.03 to 0.5%, the balance being Fe and unavoidable. A joint welding method for austenitic stainless steel, characterized in that covered arc welding of the austenitic stainless steel made of impurities is performed using the welding material according to claim 3. 12. In% by weight, C: 0.001-0.04%, Si: 0.6% or less, Mn: 0.1-5.0%, Cr: 23.0-30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% Contained, and further contains one or more of Nb; 0.05 to 0.6%, Ti; 0.02 to 0.3%, V; 0.03 to 0.5%, the balance being Fe and unavoidable. A joint welding method for austenitic stainless steel, characterized in that the joint welding of austenitic stainless steel made of impurities is performed by TIG welding using the welding material according to claim 4. 13. In% by weight, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% In addition, Ca; 0.0005-0.05%, Y; 0.001-0.1%, La; 0.001-0.1%, Ce; 0.001-0.1% A joint welding method for austenitic stainless steel, which comprises performing joint arc welding of the austenitic stainless steel containing at least one kind and the balance consisting of Fe and unavoidable impurities using the welding material according to claim 5. . 14. In% by weight, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% In addition, Ca; 0.0005-0.05%, Y; 0.001-0.1%, La; 0.001-0.1%, Ce; 0.001-0.1% A joint welding method for austenitic stainless steel, characterized in that the joint welding of austenitic stainless steel containing at least one kind and the balance consisting of Fe and unavoidable impurities is TIG-welded using the welding material according to claim 6. 15. In% by weight, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% Contained, and further Nb; 0.05 to 0.6%, Ti; 0.02 to 0.3%, V; 0.03 to 0.5%, and one or more of Ca; 0.0005 to 0.05%, Y; 0.001 to 0.1%, La; 0.001 to 0.1%, Ce; 0.001 to 0.1%, containing at least one kind, and the balance being Fe and unavoidable. Joint welding of austenitic stainless steel consisting of mechanical impurities is performed by covered arc welding using the welding material according to claim 7. Joint welding method of the scan steel. 16. In% by weight, C: 0.001 to 0.04%, Si: 0.6% or less, Mn: 0.1 to 5.0%, Cr: 23.0 to 30.0% Ni: 5.0 to 22.0%, Mo: 0.1 to 6.0%, P: 0.04% or less, S: 0.005% or less, N: 0.2 to 0.5% Contained, and further Nb; 0.05 to 0.6%, Ti; 0.02 to 0.3%, V; 0.03 to 0.5%, and one or more of Ca; 0.0005 to 0.05%, Y; 0.001 to 0.1%, La; 0.001 to 0.1%, Ce; 0.001 to 0.1%, containing at least one kind, and the balance being Fe and unavoidable. Joint welding of austenitic stainless steel consisting of mechanical impurities is performed by TIG welding using the welding material according to claim 8, austenitic stainless steel characterized by the following: Joint welding method.