Title of invention: Welding material for austenitic heat-resistant steel, weld metal and welded structure, and method of manufacturing weld metal and welded structure
Technical field
[0001]
　TECHNICAL FIELD The present invention relates to a welding material for austenitic heat-resistant steel, a weld metal and a welded structure, and a method for manufacturing a weld metal and a welded structure.
Background technology
[0002]
　Conventionally, ASME T91 steel has been widely used as a superheater tube material for an exhaust heat recovery boiler. However, from the viewpoint of reducing the environmental load, the steam temperature is being raised. Since ASME T91 has a low Cr content, it has insufficient steam oxidation resistance and insufficient creep strength. Therefore, for example, there is a movement to apply austenitic stainless heat-resistant steel used in superheater tubes of coal-fired power generation boilers as disclosed in Patent Documents 1 and 2 to the high temperature portion of the superheater tubes. is there.
[0003]
　When these austenitic stainless heat-resisting steels are used as a structure, they are generally assembled by welding, and the welding materials used therefor are also disclosed, for example, in Patent Documents 3 and 4. ing.
Prior art documents
Patent literature
[0004]
Patent Document 1: Japanese Patent Laid-Open No. 2003-268503
Patent Document 2: Japanese Patent Laid-Open No. 2013-44013
Patent Document 3: Japanese Patent Laid-Open No. 6-142980 Japanese Patent
Document 4: Japanese Patent Laid-Open No. 2015-110240
Summary of the invention
Problems to be Solved by the Invention
[0005]
　By the way, an exhaust heat recovery boiler rarely operates continuously like a coal-fired power generation boiler, and it is common to stop and operate according to the required power generation amount.For example, it operates only in the daytime when there is a large demand for electricity. , At night, the car is stopped. As a result, the member such as the superheater tube used is repeatedly heated and cooled.
[0006]
　In this way, when heating and cooling to a high temperature are repeated, thermal shock occurs due to the temperature difference in the superheater pipe including the welded portion. Therefore, it is also necessary for the constituent members to have excellent properties against thermal shock, that is, shock properties after being subjected to repeated thermal cycles. In particular, since the shape and material of the welded portion containing the weld metal are discontinuous, this often causes a problem.
[0007]
　The weld metal obtained by using the welding material as disclosed in the above-mentioned Patent Documents 3 and 4 can surely obtain excellent creep rupture strength, but the impact when subjected to repeated thermal cycles. It has been clarified that sufficient performance may not be obtained depending on the size or structure of the member without considering the characteristics, and there is room for improvement.
[0008]
　The present invention provides a welding material for austenitic heat-resistant steel that can obtain a weld metal having sufficient impact properties even after repeating high-temperature heating and cooling, a weld metal using the same, and a welded structure having the weld metal. , And a method for manufacturing the above-mentioned weld metal and welded structure.
Means for solving the problem
[0009]
　The present invention has been made to solve the above problems, and has as its gist a welding material for austenitic heat-resistant steel, a weld metal and a welded structure, and a method for manufacturing a weld metal and a welded structure.
[0010]
　(1) Chemical composition in mass %,
　C: 0.06 to 0.14%,
　Si: 0.10 to 0.40%,
　Mn: 2.0 to 4.0%,
　P: 0.020% Hereinafter,
　Cu: 2.0 to 4.0%,
　Ni: 15.0 to 19.0%,
　Cr: 16.0 to 20.0%,
　Mo: 0.50 to 1.50%,
　Nb: 0. 30 to 0.60%,
　N: 0.10 to 0.30%,
　Al: 0.030% or less,
　O: 0.020% or less,
　S: 0 to 0.0030%,
　Sn: 0 to 0.0030 %,
　Bi:0 to 0.0030%,
　Zn:0 to 0.0030%,
　Sb:0 to 0.0030%,
　As:0 to 0.0030%,
　V:0 to 0.50%,
　Ti:0 ~0.50%,
　Ta:0~0.50%,
　Co:0~2.0%,
　B:0~0.020%,
　Ca:0~0.020%,
　Mg: 0 to 0.020%,
　REM: 0 to 0.06%,
　balance: Fe and impurities.
　Two or more kinds selected from S, Sn, Bi, Zn, Sb and As are selected from the following (i)
　Welding material for austenitic heat-resisting steel , contained in a range satisfying the formula .
　　0.0005≦S+Sn+Bi+Zn+Sb+As≦0.0030 (i)
　However, the element symbol in the above formula represents the content (% by mass) of each element contained in the steel.
[0011]
　(2) The chemical composition is% by mass,
　V: 0.01 to 0.50%,
　Ti: 0.01 to 0.50%,
　Ta: 0.01 to 0.50%,
　Co: 0.01 -2.0%,
　B: 0.001-0.02%,
　Ca: 0.001-0.02%,
　Mg: 0.001-0.02%, and
　REM: 0.001-0.06% The 　welding material for austenitic heat-resistant steel according to (1) above
　, containing at least one selected from the following
.
[0012]
　(3) Used for welding a base material made of austenitic heat-resistant steel,
　the chemical composition of the base material is% by mass,
　C: 0.05 to 0.15%,
　Si: 0.10 to 0.30% ,
　Mn: 0.1 to 1.0%,
　P: 0.040% or less,
　S: 0.010% or less,
　Cu: 2.0 to 4.0%,
　Ni: 7.0 to 11.0%,
　Cr: 16.0 to 20.0%,
　Mo: 0.03 to 0.80%,
　Nb: 0.30 to 0.60%,
　N: 0.05 to 0.20%,
　Al: 0.030% Below,
　O: 0.020% or less,
　V: 0 to 0.10%,
　Ti: 0 to 0.10%,
　Co: 0 to 1.0%,
　W: 0 to 0.50%,
　B: 0 to 0.005%,
　Ca:0 to 0.010%,
　Mg:0 to 0.010%,
　REM:0 to 0.10%,
　balance: Fe and impurities,
　The welding material for austenitic heat-resistant steel according to (1) or (2) above.
[0013]
　(4) A weld metal comprising the base material according to (3) above and the welding material for austenitic heat resistant steel according to any one of (1) to (3) above.
[0014]
　(5) A welded structure having the weld metal according to (4) above.
[0015]
　(6) A weld metal is produced by welding the base metal according to (3) above with the welding material for austenitic heat resistant steel according to any one of (1) to (3) above. A method for manufacturing a weld metal.
[0016]
　(7) Manufacture of a welded structure in which the base material described in (3) above is welded using the welding material for austenitic heat resistant steel according to any one of (1) to (3) above. Method.
Effect of the invention
[0017]
　According to the present invention, a welding material for austenitic heat-resistant steel that can obtain a weld metal having sufficient impact properties even after repeating high temperature heating and cooling, a weld metal using the same, and a weld having the weld metal It is possible to provide a structure and a method for manufacturing the weld metal and the welded structure described above.
Brief description of the drawings
[0018]
FIG. 1 is a schematic cross-sectional view showing the shape of a plate material that is groove processed in an example.
MODE FOR CARRYING OUT THE INVENTION
[0019]
　The present inventors have conducted various studies on the impact characteristics of the weld metal subjected to high temperature heating and cooling in order to obtain a weld metal having sufficient impact characteristics even after repeated high temperature heating and cooling. As a result, the following findings have been obtained.
[0020]
　(A) When the contents of S, Sn, Bi, Zn, Sb and As in the weld metal increase, the toughness decreases remarkably.
[0021]
　(B) Columnar crystal boundaries come to be mixed on the fracture surface after the impact test, and when the contents of S, Sn, Bi, Zn, Sb and As increase, the ratio increases.
[0022]
　(C) The proportion of columnar crystal boundaries mixed in the fracture surface tends to be saturated when high temperature heating and cooling are repeated a plurality of times.
[0023]
　From these matters, the following conclusions were reached. That is, S, Sn, Bi, Zn, Sb and As contained in the weld metal are solidified and segregated during the solidification of the weld, and are also columnar in the process of repeatedly heating to and cooling from high temperature. It segregates to the crystal boundaries, causing the columnar crystal boundaries to become brittle. Therefore, it is considered that when the content of S, Sn, etc. is increased, the impact characteristics are deteriorated and the ratio of columnar crystal boundaries on the fracture surface is increased.
[0024]
　Then, as a result of examining the preventive measures, the present inventors have found that it is effective to reduce the contents of S, Sn, Bi, Zn, Sb and As as much as possible.
[0025]
　However, although it has been confirmed that when these elements are extremely reduced, the required impact characteristics are certainly obtained after being subjected to high temperature heating and cooling, the penetration is insufficient, that is, the so-called backside wave forming ability is extremely low. It turned out to deteriorate. In order to solve this, increasing the welding heat input is one method. However, increasing the heat input increases the solidification cracking susceptibility during welding.
[0026]
　Then, as a result of studying to solve this problem, it was repeated by adding two or more kinds selected from S, Sn, Bi, Zn, Sb and As in a total amount of 0.0005 to 0.0030%. It was found that it is possible to increase the penetration depth while ensuring the impact characteristics after heating and cooling. This is because these elements affect convection in the weld pool during welding and promote heat transfer in the vertical direction, or evaporate from the weld pool surface and ionize in the arc to form a current path, It was thought to be due to increasing the current density of the arc.
[0027]
　The present invention has been made based on the above findings. Hereinafter, each requirement of the present invention will be described in detail.
[0028]
　(A) Chemical composition of welding material The
　reasons for limiting each element are as follows. In addition, in the following description, "%" regarding the content means "mass %".
[0029]
　C: 0.06 to 0.14%
　C is an austenite-forming element, which enhances the structural stability of the weld metal at high temperatures and produces fine carbides to contribute to the securing of creep strength. However, when C is excessively contained, carbides are coarsely and largely deposited, which rather lowers the creep strength and impairs impact properties. Therefore, the C content is 0.06 to 0.14%. The C content is preferably 0.07% or more, more preferably 0.08% or more. The C content is preferably 0.13% or less, more preferably 0.12% or less.
[0030]
　Si: 0.10 to 0.40%
　Si is contained as a deoxidizer, but when it is contained in excess, it increases the solidification cracking susceptibility during welding. However, if the Si content is excessively reduced, the deoxidizing effect cannot be sufficiently obtained, the cleanliness of the welding material is deteriorated, and the manufacturing cost is increased. Therefore, the Si content is set to 0.10 to 0.40%. The Si content is preferably 0.15% or more, more preferably 0.20% or more. Further, the Si content is preferably 0.35% or less, more preferably 0.30% or less.
[0031]
　Mn: 2.0 to 4.0%
　Mn suppresses the scattering of nitrogen from the surface of the molten pool by lowering the nitrogen activity of the molten metal during welding, and indirectly the tensile strength and creep strength of the weld metal. Contribute to securing. However, if Mn is excessively contained, embrittlement is caused. Therefore, the Mn content is set to 2.0 to 4.0%. The Mn content is preferably 2.2% or more, more preferably 2.5% or more. The Mn content is preferably 3.8% or less, more preferably 3.5% or less.
[0032]
　P: 0.020% or less
　P is contained as an impurity, segregates in the final solidified portion during solidification of the weld metal, lowers its melting point, and increases solidification cracking susceptibility. Therefore, the P content needs to be 0.020% or less. The P content is preferably 0.015% or less, more preferably 0.010% or less. The lower limit of the P content does not have to be set in particular, that is, the content may be 0%, but the extreme reduction leads to an increase in the manufacturing cost of the welding material. Therefore, the P content is preferably 0.0005% or more, more preferably 0.001% or more.
[0033]
　Cu: 2.0 to 4.0%
　Cu is an element effective for ensuring the structural stability of the weld metal at high temperatures and precipitating as a Cu-rich phase to improve the creep strength. However, when Cu is contained in excess, the Cu-rich phase is excessively precipitated and the impact properties are impaired. Therefore, the Cu content is set to 2.0 to 4.0%. The Cu content is preferably 2.3% or more, more preferably 2.5% or more. Further, the Cu content is preferably 3.8% or less, and more preferably 3.5% or less.
[0034]
　Ni: 15.0 to 19.0%
　Ni secures the structural stability of the weld metal at high temperatures and contributes to the improvement of creep strength. However, Ni is an expensive element, and a large amount of Ni causes an increase in the manufacturing cost of the welding material. In addition, if Ni is contained excessively, the nitrogen solubility of the molten metal during welding is lowered, and conversely the creep strength is impaired. Therefore, the Ni content is set to 15.0 to 19.0%. The Ni content is preferably 15.5% or more, and more preferably 16.0% or more. Further, the Ni content is preferably 18.5% or less, and more preferably 18.0% or less.
[0035]
　Cr: 16.0 to 20.0%
　Cr is contained to secure the oxidation resistance and corrosion resistance of the weld metal at high temperatures. However, if Cr is contained excessively, the stability of the weld metal structure at high temperature is impaired, and the creep strength is lowered. Therefore, the Cr content is set to 16.0 to 20.0%. The Cr content is preferably 16.5% or more, more preferably 17.0% or more. Further, the Cr content is preferably 19.5% or less, and more preferably 19.0% or less.
[0036]
　Mo: 0.50 to 1.50%
　Mo is an element that forms a solid solution in the matrix and contributes to the improvement of the creep strength of the weld metal. However, even if it is contained excessively, the effect is saturated, and the stability of the structure of the weld metal at high temperature is deteriorated, and rather the creep strength is deteriorated. Therefore, the Mo content is 0.50 to 1.50%. The Mo content is preferably 0.60% or more, more preferably 0.80% or more. Further, the Mo content is preferably 1.40% or less, and more preferably 1.20% or less.
[0037]
　Nb: 0.30 to 0.60%
　Nb precipitates in the grains as fine carbides, nitrides or carbonitrides during use at high temperatures and contributes to the improvement of the creep strength of the weld metal. However, if it is contained excessively, a large amount of carbonitride precipitates and coarsely precipitates, leading to a decrease in creep strength and creep ductility. Therefore, the Nb content is set to 0.30 to 0.60%. The Nb content is preferably 0.32% or more, more preferably 0.35% or more. Further, the Nb content is preferably 0.58% or less, more preferably 0.55% or less.
[0038]
　N: 0.10 to 0.30%
　N enhances the structural stability of the weld metal at high temperature, and forms a solid solution or finely precipitates in the grains as a nitride, which greatly contributes to the improvement of creep strength. To do. However, if it is contained in excess, a large amount of nitride is precipitated during use at high temperature, leading to a decrease in creep ductility. Therefore, the N content is set to 0.10 to 0.30%. The N content is preferably 0.12% or more, more preferably 0.15% or more. Further, the N content is preferably 0.28% or less, more preferably 0.25% or less.
[0039]
　Al: 0.030% or less
　Al is contained as a deoxidizing agent, but if contained in a large amount, the cleanliness is significantly impaired, and the workability of the welding material and the ductility of the weld metal are reduced. Therefore, the Al content is 0.030% or less. The Al content is preferably 0.025% or less, more preferably 0.020% or less. It is not necessary to set a lower limit for the Al content, that is, the Al content may be 0%, but an extreme reduction causes an increase in the manufacturing cost of the welding material. Therefore, the Al content is preferably 0.0005% or more, more preferably 0.001% or more.
[0040]
　O: 0.020% or less
　O (oxygen) is contained as an impurity, but when contained in a large amount, it deteriorates the workability of the welding material and the ductility of the weld metal. Therefore, the O content is 0.020% or less. The O content is preferably 0.015% or less, more preferably 0.010% or less. Note that it is not necessary to set a lower limit for the O content, that is, the O content may be 0%, but an extreme reduction causes an increase in the manufacturing cost of the material. Therefore, the O content is preferably 0.0005% or more, and more preferably 0.0010% or more.
[0041]
　S: 0 to 0.0030%
　Sn: 0 to 0.0030%
　Bi: 0 to 0.0030%
　Zn: 0 to 0.0030%
　Sb: 0 to 0.0030%
　As: 0 to 0.0030%
　S, Sn, Bi, Zn, Sb and As are not only solidified and segregated during solidification of welding, but also welded in the course of repeated heating to high temperature and cooling from high temperature when, for example, a welded structure including weld metal is used. It segregates to the columnar crystal boundaries of the metal, resulting in deterioration of impact properties. On the other hand, these elements are effective elements for increasing the penetration depth during welding, and particularly for preventing the penetration failure during the initial layer welding.
[0042]
　In order to achieve both impact properties and weldability after repeated heating and cooling, it is necessary to contain two or more selected from these elements within the range that satisfies the following formula (i). The value on the left side of the formula (i) is preferably 0.0008, and more preferably 0.0010. Further, the value on the right side of the expression (i) is preferably 0.0028, and more preferably 0.0025.
　　0.0005≦S+Sn+Bi+Zn+Sb+As≦0.0030 (i)
　However, the element symbol in the above formula represents the content (% by mass) of each element contained in the steel.
[0043]
　The lower limit of the content of each element is not particularly limited, but the content of any one of the above elements is set to 0.0001% or more within the range satisfying the above formula (i). Is preferable, 0.0002% or more is more preferable, and 0.0003% or more is further preferable.
[0044]
　In the chemical composition of the welding material of the present invention, in addition to the above elements, one or more selected from V, Ti, Ta, Co, B, Ca, Mg and REM is further contained in the range shown below. Good. The reasons for limiting each element will be described.
[0045]
　V: 0 to 0.50%
　V combines with C and/or N and precipitates in the grains as fine carbides, nitrides or carbonitrides, and contributes to the creep strength at high temperatures. May be included. However, if it is contained excessively, a large amount of carbonitrides are deposited, which causes a decrease in creep ductility. Therefore, the V content is 0.50% or less. The V content is preferably 0.45% or less, and more preferably 0.40% or less. When it is desired to obtain the above effects, the V content is preferably 0.01% or more, more preferably 0.02% or more.
[0046]
　Ti: 0 to 0.50%
　Similar to V, Ti precipitates in the grains as fine carbides, nitrides or carbonitrides and contributes to the creep strength at high temperatures. Therefore, Ti may be contained if necessary. .. However, if it is contained excessively, a large amount of carbonitrides are deposited, which causes a decrease in creep ductility. Therefore, the Ti content is 0.50% or less. The Ti content is preferably 0.45% or less, more preferably 0.40% or less. In order to obtain the above effects, the Ti content is preferably 0.01% or more, more preferably 0.02% or more.
[0047]
　Ta: 0 to 0.50%
　Like V and Ti, Ta also precipitates in the grains as fine carbides, nitrides or carbonitrides and contributes to the creep strength at high temperatures. Good. However, if it is contained excessively, a large amount of carbonitrides are deposited, which causes a decrease in creep ductility. Therefore, the Ta content is 0.50% or less. The Ta content is preferably 0.45% or less, more preferably 0.40% or less. In order to obtain the above effect, the Ta content is preferably 0.01% or more, more preferably 0.02% or more.
[0048]
　Co: 0 to 2.0%
　Like Ni and Cu, Co enhances the structural stability of the weld metal at high temperatures and contributes to the improvement of creep strength, so it may be contained if necessary. However, since it is an extremely expensive element, excessive inclusion causes a significant cost increase. Therefore, the Co content is 2.0% or less. The Co content is preferably 1.5% or less, more preferably 1.0% or less. In order to obtain the above effect, the Co content is preferably 0.01% or more, and more preferably 0.02% or more.
[0049]
　B: 0 to 0.020%
　B is an element effective in improving creep strength by segregating to the columnar crystal boundaries of the weld metal during high temperature use, strengthening grain boundaries and finely dispersing grain boundary carbides. Therefore, it may be contained if necessary. However, if it is contained excessively, solidification cracking susceptibility during welding is increased. Therefore, the B content is 0.020% or less. The B content is preferably 0.018% or less, more preferably 0.015% or less. When it is desired to obtain the above effects, the B content is preferably 0.001% or more, and more preferably 0.002% or more.
[0050]
　Ca: 0 to 0.020% Since
　Ca has an effect of improving hot workability at the time of manufacturing a welding material, it may be contained if necessary. However, if it is contained in excess, it combines with oxygen, significantly deteriorating the detergency and conversely degrading the hot workability. Therefore, the Ca content is 0.020% or less. The Ca content is preferably 0.015% or less, more preferably 0.010% or less. When it is desired to obtain the above effects, the Ca content is preferably 0.0005% or more, more preferably 0.001% or more.
[0051]
　Mg: 0 to 0.020%
　Similar to Ca, Mg has an effect of improving hot workability at the time of manufacturing a welding material, and thus may be contained if necessary. However, if it is contained in excess, it combines with oxygen, significantly deteriorating the detergency and conversely degrading the hot workability. Therefore, the Mg content is 0.020% or less. The Mg content is preferably 0.015% or less, more preferably 0.010% or less. In order to obtain the above effect, the Mg content is preferably 0.0005% or more, more preferably 0.001% or more.
[0052]
　REM: 0 to 0.06%
　Like Ca and Mg, REM has an effect of improving hot workability at the time of manufacturing a welding material, and thus may be contained if necessary. However, if it is contained in excess, it combines with oxygen, significantly deteriorating the detergency and conversely degrading the hot workability. Therefore, the REM content is 0.06% or less. The REM content is preferably 0.05% or less, more preferably 0.04% or less. In order to obtain the above effects, the REM content is preferably 0.001% or more, more preferably 0.002% or more.
[0053]
　Here, REM refers to a total of 17 elements of Sc, Y and lanthanoid, and the content of the REM means the total content of these elements.
[0054]
　In the chemical composition of the welding material of the present invention, the balance is Fe and impurities. Here, the "impurity" is a component that is mixed in by raw materials such as ore and scrap when manufacturing steel industrially, and various factors of the manufacturing process, and is allowed within a range that does not adversely affect the present invention. Means something.
[0055]
　(B) Method for manufacturing weld metal The weld metal according to the
　present invention is produced by welding a base material of austenitic heat-resistant steel using the above-mentioned welding material (filler material). The welding method for obtaining the above-mentioned weld metal is not particularly limited, but examples thereof include TIG welding, MIG welding, covered arc welding, submerged arc welding, and laser welding.
[0056]
　The preferable composition of the base material of the austenitic heat-resistant steel is not particularly limited. For example, the chemical composition of the base material is C: 0.05 to 0.15%, Si: 0.10 to 0.30%, Mn: 0.1 to 1.0%, P: 0. 040% or less, S: 0.010% or less, Cu: 2.0 to 4.0%, Ni: 7.0 to 11.0%, Cr: 16.0 to 20.0%, Mo: 0.03. To 0.80%, Nb: 0.30 to 0.60%, N: 0.05 to 0.20%, Al: 0.030% or less, O: 0.020% or less, V: 0 to 0. 10%, Ti:0 to 0.10%, Co:0 to 1.0%, W:0 to 0.50%, B:0 to 0.005%, Ca:0 to 0.010%, Mg: 0 to 0.010%, REM: 0 to 0.10%, balance: Fe and impurities are preferable.
[0057]
　The chemical composition of the base material is, in mass %, V: 0.01 to 0.10%, Ti: 0.01 to 0.10%, Co: 0.01 to 1.0%, W: 0.01. To 0.50%, B: 0.0002 to 0.005%, Ca: 0.0005 to 0.010%, Mg: 0.0005 to 0.010%, and REM: 0.0005 to 0.10. %, one or more selected from
[0058]
　Although there is no particular limitation on the method for producing the base material and the welding material (filler material), hot forging, hot rolling, heat treatment and It can be manufactured by sequentially performing machining.
[0059]
　(C) Welded Structure The welded structure according to the
　present invention is a structure having the above-mentioned weld metal. For example, a welded structure is composed of a weld metal and a base material. That is, it is manufactured by welding the above base material using the welding material according to the present invention. The base material is made of metal and is preferably a steel material, more preferably stainless steel, and further preferably an austenitic heat-resistant steel. The specific shape of the welded structure and the specific mode (welding posture) of welding for obtaining the welded structure are not particularly limited.
[0060]
　Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.
Example 1
[0061]
　A plate material (base material) having a plate thickness of 15 mm, a width of 50 mm, and a length of 100 mm was formed from an ingot obtained by melting and casting steel having the chemical composition shown in Table 1 by hot forging, hot rolling, heat treatment and machining. A plate material having a plate thickness of 4 mm, a width of 200 mm and a length of 500 mm was produced. Further, using the above plate material having a plate thickness of 4 mm, a cut filler having a 2 mm square and a length of 500 mm was produced by machining. Using these, various performance evaluation tests shown below were performed.
[0062]
[table 1]

[0063]
　
　A groove shape having the shape shown in FIG. 1 was applied to the longitudinal end portion of the base material. After that, two base materials having a groove formed therein were butted against each other, and butt welding was performed by TIG welding using a cut filler obtained from the same plate material as each parent material as a filler material. With a heat input of 9 kJ/cm, two weld joints were produced for each base material. Of the obtained welded joints, the one in which the back bead was formed over the entire length of the welding line was determined to have good back-wave forming ability, and was designated as "pass". On the other hand, if some of the two welded joints had no back bead formed, it was determined to be “fail”.
[0064]
　
　Subsequently, using a cut filler obtained from the same plate material as each base material as a filler material, lamination welding was performed by manual TIG welding in the groove. The heat input was 9 to 15 kJ/cm, and two welded joints were produced for each base material.
[0065]
　After that, after repeating a heating and cooling cycle of “room temperature→650° C.×108 hours→room temperature” five times for one welded joint, three full size Charpy impact test pieces having V notches in the weld metal were taken. Then, a Charpy impact test was performed at room temperature. And the thing which the average value of absorbed energy is 27 J or more was made into "pass", and the thing below 27 J was made into "fail".
[0066]
　
　Further, a round bar creep rupture test piece was sampled from the remaining one body of the welded joint so that the weld metal was at the center of the parallel portion, and the target rupture time of the base metal was about 1000 hours 650. A creep rupture test was conducted under the conditions of 216° C. and 216 MPa. Then, the case where the breaking time was 90% or more of the target breaking time of the base material was defined as “pass”.
[0067]
　The results are summarized in Table 2.
[0068]
[Table 2]

[0069]
　As can be seen from Table 2, Test Nos. using Steels A to F satisfying the requirements of the present invention as both the base metal and the filler metal. In Nos. 1 to 6, the back wave forming ability required for producing a welded joint was obtained, and the impact characteristics after repeating high temperature heating and cooling were excellent.
[0070]
　On the other hand, the steels G and H, which are comparative examples, exceeded the upper limit of the formula (i), so that the test Nos. In Nos. 7 and 8, the impact properties were poor after repeated high temperature heating and cooling. Further, since Steels I and J were below the lower limit of the formula (i), the test Nos. In Nos. 9 and 10, a sufficient penetration depth was not obtained, and the back-wave forming ability was poor.
Example 2
[0071]
　A plate material (base material) having a plate thickness of 15 mm, a width of 50 mm, and a length of 100 mm is formed from an ingot obtained by melting and casting steel having the chemical composition shown in Table 3 by hot forging, hot rolling, heat treatment and machining. It was made. Using this, various performance evaluation tests shown below were performed.
[0072]
[Table 3]

　
　A groove having the shape shown in FIG. 1 was applied to the end portion in the longitudinal direction of the base material. After that, two base materials having a groove formed therein were butted against each other, and a cut filler obtained from a plate material of steel A was used as a filler metal, and laminated welding was performed by manual TIG welding in the groove. The heat input was 9 to 15 kJ/cm, and two welded joints were produced for each base material.
[0073]
　After that, after repeating a heating and cooling cycle of “room temperature→650° C.×108 hours→room temperature” five times for one welded joint, three full size Charpy impact test pieces having V notches in the weld metal were taken. Then, a Charpy impact test was performed at room temperature. And the thing which the average value of absorbed energy is 27 J or more was made into "pass", and the thing below 27 J was made into "fail".
[0074]
　
　Further, a round bar creep rupture test piece was sampled from the remaining one body of the welded joint so that the weld metal was at the center of the parallel portion, and the target rupture time of the base metal was about 1000 hours 650. A creep rupture test was conducted under the conditions of 216° C. and 216 MPa. Then, the case where the breaking time was 90% or more of the target breaking time of the base material was defined as “pass”.
[0075]
　The results are summarized in Table 4.
[0076]
[Table 4]

[0077]
　As can be seen from Table 4, the test No. in which the chemical composition of the welding material satisfies the requirements of the present invention. In Nos. 11 to 14, the result was that the backside wave forming ability required when producing the welded joint was obtained and the impact characteristics were excellent after repeated high temperature heating and cooling.
[0078]
　As described above, it is understood that the necessary weldability, weld crack resistance, and excellent creep strength can be obtained only when the requirements of the present invention are satisfied.
Industrial availability
[0079]
　According to the present invention, a welding material for austenitic heat-resistant steel that can obtain a weld metal having sufficient impact properties even after repeating high temperature heating and cooling, a weld metal using the same, and a weld having the weld metal It is possible to provide a structure and a method for manufacturing the weld metal and the welded structure described above.
The scope of the claims
[Claim 1]
　The chemical composition is% by mass,
　C: 0.06 to 0.14%,
　Si: 0.10 to 0.40%,
　Mn: 2.0 to 4.0%,
　P: 0.020% or less,
　Cu : 2.0 to 4.0%,
　Ni: 15.0 to 19.0%,
　Cr: 16.0 to 20.0%,
　Mo: 0.50 to 1.50%,
　Nb: 0.30 to 0 % .60%,
　N: 0.10 to 0.30%,
　Al: 0.030% or less,
　O: 0.020% or less,
　S: 0 to 0.0030%,
　Sn: 0 to 0.0030%,
　Bi : 0 to 0.0030%,
　Zn: 0 to 0.0030%,
　Sb: 0 to 0.0030%,
　As: 0 to 0.0030%,
　V: 0 to 0.50%,
　Ti: 0 to 0. 50%,
　Ta:0 to 0.50%,
　Co:0 to 2.0%,
　B:0 to 0.020%,
　Ca:0 to 0.020%,
　Mg: 0 to 0.020%,
　REM: 0 to 0.06%,
　balance: Fe and impurities.
　Two or more kinds selected from S, Sn, Bi, Zn, Sb and As are selected from the following (i)
　Welding material for austenitic heat-resisting steel , contained in a range satisfying the formula .
　　0.0005≦S+Sn+Bi+Zn+Sb+As≦0.0030 (i)
　However, the element symbol in the above formula represents the content (% by mass) of each element contained in the steel.
[Claim 2]
　The chemical composition is% by mass,
　V: 0.01 to 0.50%,
　Ti: 0.01 to 0.50%,
　Ta: 0.01 to 0.50%,
　Co: 0.01 to 2.
　% 0,
　B: 0.001 ~ 0.02%,
　Ca: 0.001 ~ 0.02%, Mg: 0.001 ~ 0.02%, and
　REM: 0.001 ~ 0.06%,
　selected from The
　welding material for austenitic heat-resistant steel according to claim 1 , containing at least one of the following.
[Claim 3]
　It is used for welding a base material made of austenitic heat resistant steel, and
　the chemical composition of the base material is
　C: 0.05 to 0.15%,
　Si: 0.10 to 0.30%,
　Mn: 0.1 to 1.0%,
　P: 0.040% or less,
　S: 0.010% or less,
　Cu: 2.0 to 4.0%,
　Ni: 7.0 to 11.0%,
　Cr: 16 0.0 to 20.0%,
　Mo: 0.03 to 0.80%,
　Nb: 0.30 to 0.60%,
　N: 0.05 to 0.20%,
　Al: 0.030% or less,
　O : 0.020% or less,
　V: 0 to 0.10%,
　Ti: 0 to 0.10%,
　Co: 0 to 1.0%,
　W: 0 to 0.50%,
　B: 0 to 0.005 %,
　Ca: 0 to 0.010%,
　Mg: 0 to 0.010%,
　REM: 0 to 0.10%,
　balance: Fe and impurities,
　The welding material for austenitic heat resistant steels according to claim 1 or 2.
[Claim 4]
　A weld metal comprising the base material according to claim 3 and the welding material for austenitic heat resistant steel according to any one of claims 1 to 3.
[Claim 5]
　A welded structure comprising the weld metal according to claim 4.
[Claim 6]
　A weld metal is produced by welding the base metal according to claim 3 with the welding material for austenitic heat resistant steel according to any one of claims 1 to 3. Production method.
[Claim 7]
　A method for manufacturing a welded structure, comprising welding the base material according to claim 3 with the welding material for austenitic heat-resistant steel according to any one of claims 1 to 3.