WO2012124529A1 - 耐焼戻し脆化特性に優れた溶接金属 - Google Patents
耐焼戻し脆化特性に優れた溶接金属 Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
- B23K35/308—Fe as the principal constituent with Cr as next major constituent
- B23K35/3086—Fe as the principal constituent with Cr as next major constituent containing Ni or Mn
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3026—Mn as the principal constituent
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/365—Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/18—Submerged-arc welding
- B23K9/186—Submerged-arc welding making use of a consumable electrodes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/23—Arc welding or cutting taking account of the properties of the materials to be welded
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/02—Iron or ferrous alloys
- B23K2103/04—Steel or steel alloys
Definitions
- the present invention relates to a weld metal used for welding a high-strength steel material such as Cr-Mo steel, and relates to a weld metal having improved temper embrittlement resistance and a welded structure including such a weld metal. It is.
- High-strength Cr-Mo steel and its weld metal parts used in boilers and chemical reaction vessels are used in high-temperature and high-pressure environments. Therefore, heat resistance (high-temperature strength) and SR cracking resistance as well as properties such as strength and toughness. It is necessary to have a high level of [no intergranular cracking during stress relief annealing (SR annealing)] and high resistance to temper embrittlement (less embrittlement during use in high-temperature environments). . Particularly in recent years, the heat input during welding has been increasing from the viewpoint of construction efficiency due to the increase in thickness due to the increase in the size of the equipment.
- the increase in welding heat input causes the structure of the weld metal part to become coarser and increases the toughness (resistance to The required toughness and tempering embrittlement resistance are at a higher level in order to deteriorate the tempering embrittlement characteristic).
- Patent Document 1 discloses that a weld metal having various properties can be obtained by specifying in detail the steel plate composition, the welding material composition, and the welding conditions.
- vTr 5.5 temperature at which the absorbed energy after SR annealing becomes 5.5 kgf ⁇ m
- SR annealing Stress Relief annealing
- vTr ′ 5.5 indicating the toughness after temper embrittlement treatment (step cooling) (temperature at which the absorbed energy after step cooling becomes 5.5 kgf ⁇ m) is ⁇ 41 ° C. at best. That is not enough.
- Patent Document 2 discloses to improve toughness, strength, and heat resistance by controlling the contents of C, Mn and Ni in relation to the core wire and the yield of the coating in the coated arc welding rod. Has been proposed. However, the tempering embrittlement resistance is not considered.
- Patent Documents 3 and 4 A technique that can realize a weld metal that is excellent in toughness, strength, temper embrittlement resistance and SR crack resistance by considering the components of solid wire and bond flux and welding conditions (heat input) (for example, has been proposed) Patent Documents 3 and 4).
- vTr 55 indicating toughness after SR annealing (temperature at which absorbed energy after SR annealing becomes 55 J)
- vTr ′ indicating toughness after temper embrittlement treatment (step cooling).
- Patent Document 5 proposes a technique for improving toughness, strength, and SR cracking resistance by controlling the amount of weld metal components, particularly impurity elements. However, the tempering embrittlement resistance is not considered.
- Patent Document 6 proposes to improve toughness and strength by controlling the core wire of the welding rod and the coating material component in the coated arc welding.
- tempering embrittlement resistance is not considered.
- the assumed welding heat input is small and the restrictions on construction are large.
- Patent Documents 7 and 8 it has also been proposed to improve toughness and strength by controlling the core wire and covering material component of the welding rod.
- the recommended welding condition is a welding current of about 140 to 190 A (core) according to Patent Document 7 that defines a weld metal by coated arc welding.
- the wire diameter is ⁇ 4.0 mm
- the heat input amount is about 2.0 to 3.6 kJ / mm in Patent Document 8 which defines the weld metal by submerged arc welding, which is sufficiently compatible with the increasing tendency of the welding heat input amount. It can not be said.
- the present invention has been made in view of the above circumstances, and its purpose is to exhibit excellent tempering embrittlement resistance even under welding conditions where the heat input is relatively large, as well as toughness, SR crack resistance, and strength.
- Another object of the present invention is to provide a weld metal excellent in characteristics such as the above, and a welded structure including such a weld metal.
- the weld metal according to the present invention capable of solving the above problems is C: 0.05 to 0.15% (meaning “mass%”; the same applies hereinafter), Si: 0.1 to 0.50%, Mn: 0.6 to 1.30%, Cr: 1.8 to 3.0%, Mo: 0.80 to 1.20%, V: 0.25 to 0.50%, Nb: 0.010 to 0.050%, N: 0.025% or less (excluding 0%), O: 0.020 to 0.060%, respectively, the balance is made of iron and inevitable impurities, and the equivalent circle diameter is 1 ⁇ m
- the number of super oxides is 2000 or less per 1 mm 2
- the equivalent circle diameter is 2 or less oxides of 100 or less per 1 mm 2
- the A value defined by the following formula (1) is 5.0.
- the weld metal of the present invention as other elements, (a) Cu: 1.0% or less (not including 0%) and / or Ni: 1.0% or less (not including 0%), ( b) B: 0.0050% or less (excluding 0%), (c) W: 0.50% or less (not including 0%), (d) Al: 0.030% or less (including 0%) And (e) Ti: 0.020% or less (not including 0%) and the like are also preferable, and the properties of the weld metal are further improved depending on the type of element to be included.
- the present invention also includes a welded structure including the above weld metal.
- the number of oxides of a predetermined size is specified, and the respective contents (mass%) of Cr, Mo, Nb and V present as compounds after stress relief annealing and Since the relationship between C and Mo in the weld metal is properly defined, the weld metal exhibits excellent tempering embrittlement resistance and excellent properties such as toughness, SR crack resistance, and strength. realizable.
- the chemical component composition of the weld metal is appropriately controlled, and the number of oxides having an equivalent circle diameter of more than 1 ⁇ m existing in the weld metal is 2000 or less per 1 mm 2 (2000 pieces / mm 2 or less), with oxides of 2 ⁇ m than a circle equivalent diameter is reduced to 1 mm 2 per 100 or less (100 / mm 2 or less), by controlling the a value defined by the following equation (1) 5.0 below It has been found that various properties including toughness and tempering embrittlement resistance can be combined.
- a value (100 ⁇ [C] ⁇ 6 ⁇ [insol.Cr] ⁇ 2 ⁇ [insol.Mo] ⁇ 24 ⁇ [insol.V] ⁇ 13 ⁇ [insol.Nb]) ⁇ ([Mo] ⁇ [insol] .Mo])
- [insol. Cr], [insol. Mo], [insol. Nb] and [insolV] indicate the respective contents (mass%) of Cr, Mo, Nb and V present as compounds in the weld metal after stress relief annealing, and [C] and [Mo] Each content (mass%) of C and Mo in a metal is shown.
- equivalent circle diameter refers to the diameter of a circle that is assumed to have the same area by paying attention to the size of the oxide particles observed on the observation surface of the optical microscope.
- each content (mass%) of Cr, Mo, Nb, and V which exists as a compound is calculated
- [C] and [Mo] show each content (mass%) of C and Mo in a weld metal, these quantity does not change before and after stress relief annealing.
- the tempering embrittlement resistance of a weld metal is evaluated based on how much the toughness has deteriorated as compared with a weld metal that has been subjected to a heat treatment called step cooling after SR annealing and is subjected to normal SR annealing.
- the present inventors have newly found that the fine carbide Mo 2 C precipitated during the step cooling causes toughness deterioration by hardening the weld metal by precipitation strengthening, and the A value defined by the above formula (1). By controlling the above, it was possible to suppress the precipitation of Mo 2 C, suppress the deterioration of toughness after step cooling, and realize a weld metal excellent in temper embrittlement resistance.
- the A value defined by the above equation (1) defines the requirements related to solid solution C and solid solution Mo that contribute to Mo 2 C precipitation during step cooling, and is Mo 2 C thermodynamically. It expresses the driving force of precipitation.
- the smaller the value A the smaller the amount of Mo 2 C precipitated. Therefore, in order to obtain a weld metal having excellent tempering embrittlement resistance, it is necessary to control the A value to a predetermined value or less. From such a viewpoint, the A value needs to be 5.0 or less, and when it exceeds 5.0, the amount of precipitation of Mo 2 C increases and the tempering embrittlement resistance deteriorates.
- This A value is preferably 4.5 or less, more preferably 4.0 or less, and even more preferably 3.5 or less.
- the weld metal of the present invention it is necessary to control the number of oxides having a predetermined size.
- the microstructure of the weld metal can be refined and the toughness can be improved.
- the number of oxides having an equivalent circle diameter of more than 1 ⁇ m is preferably 1500 pieces / mm 2 or less, more preferably 1200 pieces / mm 2 or less, and according to the present invention, the oxide is reduced to several hundred pieces / mm 2. it can. Further, the number of oxides having an equivalent circle diameter of more than 2 ⁇ m is preferably 60 / mm 2 or less, and more preferably 40 / mm 2 or less.
- C 0.05 to 0.15%
- C is an element necessary for ensuring the strength of the weld metal.
- the preferable lower limit of the C content is 0.07% or more, more preferably 0.09% or more, and the preferable upper limit is 0.13% or less, more preferably 0.12% or less.
- Si 0.1 to 0.50%
- Si is an element effective in improving workability during welding.
- the Si content is less than 0.1%, welding workability is deteriorated.
- the Si content is excessive, an excessive increase in strength or an increase in hard structure such as martensite is caused, leading to a decrease in toughness.
- the minimum with preferable Si content is 0.15% or more, More preferably, it is 0.17% or more, and a preferable upper limit is 0.40% or less, More preferably, it is 0.32% or less.
- Mn is an element effective in securing the strength of the weld metal.
- the content is less than 0.6%, the strength at room temperature is lowered and the SR crack resistance is also adversely affected.
- the Mn content is excessive, the high-temperature strength is lowered, so it is necessary to make it 1.30% or less.
- the minimum with preferable Mn content is 0.8% or more, More preferably, it is 1.0% or more, and a preferable upper limit is 1.2% or less, More preferably, it is 1.15% or less.
- Cr 1.8-3.0%
- the Cr content is lower than 1.8%, film-like coarse cementite is precipitated at the prior ⁇ grain boundaries, and the SR crack resistance is deteriorated.
- the Cr content is excessive, it causes coarsening of the carbide and causes a decrease in toughness, so it is necessary to make it 3.0% or less.
- the minimum with preferable Cr content is 1.9% or more, More preferably, it is 2.0% or more, and a preferable upper limit is 2.8% or less, More preferably, it is 2.6% or less.
- Mo 0.80 to 1.20%
- Mo is an element useful for ensuring the strength of the weld metal.
- the Mo content is lower than 0.80%, a predetermined strength cannot be obtained.
- the Mo content is excessive, the toughness is reduced by an excessive increase in strength, and solid solution Mo is increased after SR annealing, and fine Mo 2 C is precipitated during step cooling, thereby tempering embrittlement resistance. Since the characteristics deteriorate, it is necessary to be 1.20% or less.
- the minimum with preferable Mo content is 0.9% or more, More preferably, it is 0.95% or more, and a preferable upper limit is 1.15% or less, More preferably, it is 1.1% or less.
- V 0.25 to 0.50%
- MC carbide M is a carbide forming element
- the minimum with preferable V content is 0.27% or more, More preferably, it is 0.30% or more, and a preferable upper limit is 0.45% or less, More preferably, it is 0.40% or less.
- Nb is an element useful for forming carbide (MC carbide) and ensuring the strength of the weld metal.
- MC carbide carbide
- the minimum with preferable Nb content is 0.012% or more, More preferably, it is 0.015% or more, and a preferable upper limit is 0.040% or less, More preferably, it is 0.035% or less.
- N 0.025% or less (excluding 0%)
- N is an element useful for ensuring the creep strength of the weld metal.
- a preferable lower limit is 0.004% or more (more preferably 0.005% or more)
- a preferable upper limit is 0.020% or less (more preferably 0.018% or less). is there.
- O is an element useful for improving toughness by forming an oxide and contributing to refinement of the structure. In order to exhibit such an effect, it is necessary to contain 0.020% or more. However, when the O content becomes excessive and exceeds 0.060%, coarse oxides increase and the toughness is lowered by becoming the starting point of brittle fracture.
- the preferable lower limit of the O content is 0.025% or more (more preferably 0.028% or more), and the preferable upper limit is 0.050% or less (more preferably 0.045% or less).
- the contained elements specified in the present invention are as described above, and the balance is iron and unavoidable impurities, and the elements (for example, P, S) brought in as raw materials, materials, production facilities, etc. as the unavoidable impurities. Etc.) can be allowed to be mixed.
- the weld metal of the present invention as other elements, (a) Cu: 1.0% or less (not including 0%) and / or Ni: 1.0% or less (not including 0%), ( b) B: 0.0050% or less (excluding 0%), (c) W: 0.50% or less (not including 0%), (d) Al: 0.030% or less (including 0%) No), (e) Ti: 0.020% or less (not including 0%), and the like are preferably included, and the characteristics of the weld metal are further improved depending on the type of element to be included.
- the reason for setting the range when these elements are contained is as follows.
- Cu and Ni are effective elements for improving toughness by refining the structure.
- the content of Cu or Ni is preferably 1.0% or less. More preferably, each is 0.8% or less, and further preferably 0.5% or less.
- the preferable minimum for exhibiting the said effect is 0.05% or more (more preferably 0.1% or more) in any case.
- B 0.0050% or less (excluding 0%)
- B is an element effective in suppressing the formation of ferrite from the grain boundary and improving the strength of the weld metal.
- the B content is excessive, the SR cracking resistance is lowered, so 0.0050% or less is preferable. More preferably, it is 0.0040% or less (more preferably 0.0025% or less).
- the preferable minimum for exhibiting the said effect is 0.0005% or more (more preferably 0.0010% or more).
- W 0.50% or less (excluding 0%)
- W is an element effective for improving the strength of the weld metal.
- the content is preferably 0.50% or less. More preferably, it is 0.3% or less (more preferably 0.2% or less).
- the preferable minimum for exhibiting the said effect is 0.08% or more (more preferably 0.1% or more).
- Al 0.030% or less (excluding 0%)
- Al is an element effective as a deoxidizer.
- the content is preferably 0.030% or less. More preferably, it is 0.020% or less (more preferably 0.015% or less).
- the preferable minimum for exhibiting the said effect is 0.001% or more (more preferably 0.0012% or more).
- Ti 0.020% or less (excluding 0%)
- Ti is an element effective for improving the strength of the weld metal.
- 0.020% or less is preferable. More preferably, it is 0.015% or less (more preferably 0.012% or less).
- the preferable minimum for exhibiting the said effect is 0.005% or more (more preferably 0.008% or more).
- the welding method for obtaining the weld metal of the present invention is not particularly limited as long as it is an arc welding method.
- Submerged arc welding (SAW) which is frequently used when a chemical reaction vessel or the like is actually welded, Application of covered arc welding (SMAW) is preferred.
- the welding material component is naturally constrained by the required welding metal component, and in order to obtain a given oxide form, the welding conditions and the welding material component must be appropriately controlled.
- preferable welding conditions in SAW are a welding heat input of 2.5 to 5.0 kJ / mm and a preheating-pass temperature of about 190 to 250 ° C. during welding.
- the Mo content in the welding wire is 1.3% or less
- the V content is 0.36% or more
- the Nb content is 0.012% or more.
- the ratio of Mo content to the total content of V and Nb [Mo / (V + Nb)] is 2.8 or less
- the concentrations of the metal Ca and Al 2 O 3 in the bond flux are as follows (2 Control may be performed so as to satisfy the formula.
- the Mo content in the welding wire is preferably 1.2% or less, more preferably 1.1% or less.
- the V content in the welding wire is preferably 0.37% or more, more preferably 0.38% or more.
- the Nb content in the welding wire is preferably 0.018% or more, more preferably 0.020% or more. Further, the value of the ratio [Mo / (V + Nb)] is preferably 2.7 or less, more preferably 2.6 or less.
- the heat input in SAW is less than 2.5 kJ / mm, or if the preheating-pass temperature is below 190 ° C, the cooling rate during welding will increase and sufficient carbide will not be generated during cooling.
- the A value does not satisfy the predetermined range.
- the heat input exceeds 5.0 kJ / mm or the preheating-pass temperature exceeds 250 ° C., the weld metal structure becomes coarse, and as a result, the grain boundaries, which are the formation sites of carbides, decrease. The amount of carbide generated at the time decreases, and the A value does not satisfy the predetermined range.
- preferable welding conditions in SMAW are a welding heat input of 2.3 to 3.0 kJ / mm and a preheating-pass temperature of about 190 to 250 ° C. during welding.
- the Mo content of the core wire is 1.20% or less (preferably 1.1% or less, more preferably 1.0%) when manufacturing a welding rod. %)
- the V content of the coating agent is 0.85% or more (preferably 1.0% or more, more preferably 1.3% or more)
- the Nb content of the coating agent is 0.10% or more. (Preferably 0.11% or more, more preferably 0.13% or more), and the content of MgO in the coating agent may be 2.0% or more.
- the Mo content of the core wire, the V content of the coating agent, and the Nb content are important requirements for controlling the A value within an appropriate range. If these values are out of the above range, the solid content after SR annealing will be reduced. The amount of dissolved Mo and the amount of dissolved C increase, and the A value cannot be suppressed to 5.0 or less.
- the coating MgO has the effect of suppressing the formation of coarse oxides. Although the reason for this is not clear, it is considered that the formation of fine oxides is promoted by changing the balance between the deoxidizing element and the free element in the weld metal. In order to exert such effects, the MgO content of the coating agent is preferably 2.0% or more. The MgO content of the coating agent is preferably 2.1% or more, more preferably 2.2% or more.
- the heat input in SMAW is less than 2.3 kJ / mm or the preheating-pass temperature is less than 190 ° C, the cooling rate during welding increases and sufficient carbide is not generated during cooling.
- the A value does not satisfy the predetermined range.
- the heat input exceeds 3.0 kJ / mm or the preheating-pass temperature exceeds 250 ° C. the weld metal structure becomes coarse, and as a result, the grain boundaries, which are the formation sites of carbides, decrease. The amount of carbide generated at the time decreases, and the A value does not satisfy the predetermined range.
- a weld metal that exhibits excellent tempering embrittlement resistance and excellent properties such as toughness, SR crack resistance, and strength can be obtained.
- a welded structure with metal can be realized.
- Base material composition (mass%)] C: 0.12%, Si: 0.23%, Mn: 0.48%, P: 0.004%, S: 0.005%, Cu: 0.04%, Al: ⁇ 0.002%, Ni: 0.08%, Cr: 2.25%, Mo: 0.99%, V: 0.004%, Ti: 0.002%, Nb: 0.005% (the balance: iron and inevitable impurities)
- composition A (weight%) SiO 2: 8%, Al 2 O 3: 14%, MgO: 31%, CaF 2: 27%, CaO: 10%, Ca: 0.13%, others (CO 2, AlF 3 Etc.): 10%
- Composition B (wt%) SiO 2: 8%, Al 2 O 3: 14%, MgO: 31%, CaF 2: 27%, CaO: 10%, Ca: 0.08%, others (CO 2, AlF 3 Etc.): 10%
- composition a (mass%) C: 0.09%, Si: 0.15%, Mn: 0.49%, Cu: 0.04%, Ni: 0.03%, Cr: 2.31%, Mo: 1.10% (balance: iron and inevitable impurities)
- Composition b (mass%) C: 0.08%, Si: 0.18%, Mn: 0.50%, Cu: 0.03%, Ni: 0.03%, Cr: 2.28%, Mo: 1.22% (balance: iron and inevitable impurities)
- SR annealing treatment The obtained weld metal was heat-treated at 705 ° C. for 8 hours as an SR annealing treatment.
- the test material is heated, and when the temperature of the test material exceeds 300 ° C., the heating conditions are adjusted so that the rate of temperature rise is 55 ° C./hour or less.
- the material was heated until it reached 705 ° C.
- the rate of temperature rise and the rate of cooling are not defined in the temperature range where the temperature of the specimen is 300 ° C. or lower.
- FIG. 1 is a graph showing step cooling processing conditions with temperature on the vertical axis and time on the horizontal axis.
- step cooling heats a test material, and when the temperature of a test material exceeds 300 degreeC, heating conditions are set so that a temperature rise may be 50 degreeC / hour (50 degreeC / hour) or less. Adjust and heat the specimen until it reaches 593 ° C. and hold at that temperature for 1 hour. Then, in the same manner, hold at 538 ° C. for 15 hours, at 524 ° C. for 24 hours, and at 496 ° C. for 60 hours.
- the specimen is cooled at a temperature of 5.6 ° C. adjust. Further, the test piece held at 496 ° C. is cooled at 2.8 ° C./hour (2.8 ° C./hour) to 468 ° C. and held at this temperature for 100 hours. Then, the sample material is cooled so that the temperature drop is 28 ° C./hour (28 ° C./hour) or less until the temperature of the sample material becomes 300 ° C. or less. In this step cooling process, similarly to the SR annealing process, the temperature raising rate and the cooling rate are not defined in the temperature range where the temperature of the test material is 300 ° C. or lower.
- a tensile test piece (JIS Z3111 A2) was taken in the weld line direction based on FIG. 2 from a position 10 mm deep from the thickness surface of the weld metal subjected to SR annealing at 705 ° C. for 32 hours, and room temperature (25 C.), the tensile strength TS was measured in accordance with JIS Z 2241. The tensile strength TS> 600 MPa was evaluated as excellent in strength.
- a Charpy impact test piece (JIS Z31114 V-notch test piece) was taken from the center of the thickness of the weld metal subjected to SR annealing at 705 ° C. for 8 hours and perpendicular to the weld line direction based on FIG.
- the Charpy impact test was performed in the manner of 2242, and the temperature vTr 54 at which the average value of the absorbed energy of 3 times was 54 J was measured. It was evaluated that the toughness was excellent when vTr 54 was ⁇ 50 ° C. or lower.
- the temperature vTr ′ 54 at which the average value of absorbed energy was 54 J was measured in the same manner for the weld metal subjected to step cooling after the SR annealing treatment at 705 ° C. ⁇ 8 hours. It was evaluated that the toughness was excellent when vTr ′ 54 was ⁇ 50 ° C. or lower.
- SR crack resistance From the final pass (original part) of the weld metal, a ring crack specimen having a slit size of 0.5 mm was collected based on the following. When SR annealing treatment of 625 ° C. ⁇ 10 hours was performed and no cracks occurred in the vicinity of the notch bottom of all six test pieces (observation surface 3 ⁇ number of tests 2), the SR crack resistance was excellent (evaluation ⁇ ). The case where cracking occurred was evaluated as being inferior in SR cracking resistance (evaluation x).
- FIG. 4A shows the sampling position of the test piece
- FIG. 4B shows the shape of the test piece.
- the sample is taken from directly under the surface of the final bead so that the structure immediately below the U-notch is the original part, and the slit size (width) is 0.5 mm.
- the slit width is reduced to 0.05 mm, the slit portion is TIG welded, and a tensile residual stress is applied to the bottom of the notch.
- the test piece after TIG welding was subjected to SR annealing treatment at 625 ° C.
- test piece was divided into three equal parts as shown in FIG. 3)
- the cross section near the notch bottom
- optical microscope was observed with an optical microscope, and the occurrence of SR cracks was observed.
- Example 1 The chemical composition of the various welding wires (W1 to 44) used when forming the weld metal with SAW is shown in Tables 1 and 2 below together with the value of the ratio [(Mo / (V + Nb)].
- the chemical composition of the weld metal is shown in Tables 3 and 4 below along with the welding conditions (welding wire No., heat input conditions, flux used, preheating-pass temperature) and the A value.
- the results [number of oxides of each size, tensile strength TS, toughness (vTr 54 , vTr ′ 54 ), temper embrittlement resistance ( ⁇ vTr 54 ), SR crack resistance] are shown in Tables 5 and 6 below.
- No. 1 to 30 are examples satisfying the requirements defined in the present invention, exhibiting excellent tempering embrittlement resistance and excellent weld metal in characteristics such as toughness, SR cracking resistance and strength. Yes.
- No. 31 to 49 are examples that do not meet any of the requirements defined in the present invention, and any of the characteristics is inferior.
- No. No. 31 has a large A value due to heat input conditions (heat input is 2.4 kJ / mm), and the tempering embrittlement resistance is deteriorated.
- No. No. 32 has a large A value due to heat input conditions (heat input is 5.2 kJ / mm), and the tempering embrittlement resistance is deteriorated.
- the preheating-pass temperature is lower than the appropriate range, the A value is large, and the tempering embrittlement resistance is deteriorated.
- No. No. 34 has a preheating-pass temperature higher than the proper range and a large A value, and the tempering embrittlement resistance is deteriorated.
- No. 35 is an example using the composition B in which the concentrations of the metal Ca and Al 2 O 3 in the flux used do not satisfy the relationship of the above formula (2), the number of coarse oxides increases, and the toughness (vTr 54 , VTr ′ 54 ) has deteriorated.
- No. No. 36 has insufficient C content, and the strength is reduced.
- No. No. 37 has an excessive C content and a large A value, and deteriorates toughness (vTr 54 , vTr ′ 54 ), temper embrittlement resistance ( ⁇ vTr 54 ), and SR crack resistance.
- No. No. 38 has a high value of the ratio [Mo / (V + Nb)] in the welding wire (2.93), the Si content in the weld metal is excessive, the Mn content is insufficient, and the A value increases. As the strength decreases, the toughness (vTr 54 , vTr ′ 54 ), temper embrittlement resistance ( ⁇ vTr 54 ), and SR crack resistance all deteriorate.
- No. No. 39 has an excessive Mn content, and the toughness (vTr ′ 54 ) and the temper embrittlement resistance ( ⁇ vTr 54 ) are deteriorated.
- No. 40 the Ni content in the weld metal is excessive, the A value is large, and the toughness (vTr 54 , vTr ′ 54 ) and the temper embrittlement resistance ( ⁇ vTr 54 ) are deteriorated. .
- No. No. 41 has an excessive Cr content and an Mo content, an excessive Cu content, an increased A value, toughness (vTr 54 , vTr ′ 54 ), and temper embrittlement resistance. ( ⁇ vTr 54 ) has deteriorated.
- No. 42 the Mo content in the weld metal is insufficient and the Al content is excessive, the number of coarse oxides increases, the strength decreases, and the toughness (vTr 54 , vTr ′ 54 ). Has deteriorated. No.
- the V content in the weld metal is insufficient, the B content is excessive, the A value is large, the strength is reduced, and the toughness ( vTr ′ 54 ), tempering embrittlement resistance ( ⁇ vTr 54 ), and SR cracking resistance are degraded.
- No. No. 44 has excessive V content and W content in the weld metal, and toughness (vTr 54 , vTr ′ 54 ) is deteriorated.
- No. In No. 45 the Nb content and Ti content in the weld metal are excessive, and the toughness (vTr 54 , vTr ′ 54 ) and SR crack resistance are deteriorated.
- Example 2 The chemical composition of the various coating materials used when forming the weld metal with SMAW is shown in Table 7 below (Coating materials Nos. B1 to 24). The chemical composition of the formed weld metal is shown in Table 8 below together with the welding conditions (coating material No., heat input conditions, core wire type, preheating-pass temperature) and A value. Furthermore, evaluation characteristic results [number of oxides of each size, tensile strength TS, toughness (vTr 54 , vTr ′ 54 ), tempering embrittlement resistance ( ⁇ vTr 54 ), SR cracking resistance] of each weld metal are shown in the following table. 9 shows.
- No. 50 to 63 are examples satisfying the requirements defined in the present invention, exhibiting excellent tempering embrittlement resistance ( ⁇ vTr 54 ), and excellent weld metal in characteristics such as toughness, SR crack resistance, and strength. Is obtained.
- no. 64 to 77 are examples that do not meet any of the requirements defined in the present invention. Either property is inferior.
- No. No. 64 has a preheating-pass temperature lower than the proper range and a large A value, and has deteriorated toughness (vTr ′ 54 ) and tempering embrittlement resistance.
- No. 65 the preheat-pass temperature is higher than the appropriate range, the A value is large, and the toughness (vTr ′ 54 ) and the temper embrittlement resistance ( ⁇ vTr 54 ) are deteriorated.
- No. No. 66 has a large A value due to heat input conditions (amount of heat input is 2.1 kJ / mm), and toughness (vTr ′ 54 ) and temper embrittlement resistance ( ⁇ vTr 54 ) are deteriorated.
- No. No. 67 has a large A value due to heat input conditions (heat input is 3.2 kJ / mm), and toughness (vTr ′ 54 ) and temper embrittlement resistance ( ⁇ vTr 54 ) are deteriorated.
- No. No. 71 has an excessive Mn content and V content, and has deteriorated toughness (vTr 54 , vTr ′ 54 ) and tempering embrittlement resistance ( ⁇ vTr 54 ).
- No. No. 72 has excessive C content and Mo content, and has a large A value, and the toughness (vTr 54 , vTr ′ 54 ) and the tempering embrittlement resistance ( ⁇ vTr 54 ) are deteriorated. .
- No. No. 73 has a large A value due to the Nb content of the coating agent, and the tempering embrittlement resistance ( ⁇ vTr 54 ) is deteriorated.
- No. No. 74 has a large A value due to the V content of the coating, and the tempering embrittlement resistance ( ⁇ vTr 54 ) is deteriorated.
- No. No. 75 has an excessive Si content and an insufficient Nb content, and has a large A value, insufficient strength, toughness (vTr 54 , vTr ′ 54 ) and temper embrittlement resistance. ( ⁇ vTr54) has deteriorated.
- No. No. 76 has a large A value due to insufficient V content, and a coarse oxide is increased due to the MgO content in the coating, resulting in insufficient strength and toughness (vTr 54 , VTr ′ 54 ) and anti-temper embrittlement resistance ( ⁇ vTr 54 ).
- No. No. 77 has an excessive Nb content and B content, and has deteriorated toughness (vTr 54 , vTr ′ 54 ) and SR crack resistance.
- the weld metal of the present invention is useful for high-strength Cr—Mo steel used for boilers, chemical reaction vessels and the like.
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Abstract
Description
A値=(100×[C]-6×[insol.Cr]-2×[insol.Mo]-24×[insol.V]-13×[insol.Nb])×([Mo]-[insol.Mo])…(1)
但し、[insol.Cr],[insol.Mo],[insol.Nb]および[insolV]は、応力除去焼鈍後において溶接金属中に化合物として存在するCr,Mo,NbおよびVの夫々の含有量(質量%)を示し、[C]および[Mo]は、溶接金属中のCおよびMoの夫々の含有量(質量%)を示す。
A値=(100×[C]-6×[insol.Cr]-2×[insol.Mo]-24×[insol.V]-13×[insol.Nb])×([Mo]-[insol.Mo])…(1)
但し、[insol.Cr],[insol.Mo],[insol.Nb]および[insolV]は、応力除去焼鈍後において溶接金属中に化合物として存在するCr,Mo,NbおよびVの夫々の含有量(質量%)を示し、[C]および[Mo]は、溶接金属中のCおよびMoの夫々の含有量(質量%)を示す。
Cは、溶接金属の強度を確保する上で必要な元素である。C含有量が0.05%よりも低いと、所定の強度が得られない。しかしながら、C含有量が過剰になると、炭化物の粗大化を招くことで、靭性低下の原因となるので0.15%以下とする。C含有量の好ましい下限は0.07%以上であり、より好ましくは0.09%以上であり、好ましい上限は0.13%以下、より好ましくは0.12%以下である。
Siは、溶接時の作業性を良好にする上で有効な元素である。Si含有量が0.1%を下回ると、溶接作業性が劣化する。しかしながら、Si含有量が過剰になると、強度の過大な上昇、またはマルテンサイト等の硬質組織増加をもたらし、靭性低下を招くので、0.50%以下とする。尚、Si含有量の好ましい下限は0.15%以上であり、より好ましくは0.17%以上であり、好ましい上限は0.40%以下、より好ましくは0.32%以下である。
Mnは、溶接金属の強度を確保する上で有効な元素であり、その含有量が0.6%を下回ると、室温での強度が低下するほか、耐SR割れ性にも悪影響を及ぼす。しかしながら、Mn含有量が過剰になると、高温強度を低下させるので、1.30%以下とする必要がある。尚、Mn含有量の好ましい下限は0.8%以上であり、より好ましくは1.0%以上であり、好ましい上限は1.2%以下、より好ましくは1.15%以下である。
Cr含有量が1.8%よりも低くなると、旧γ粒界にフィルム状の粗大セメンタイトが析出するようになり、耐SR割れ性が劣化する。しかしながら、Cr含有量が過剰になると、炭化物粗大化を招くことで靭性低下の原因となるので、3.0%以下とする必要がある。尚、Cr含有量の好ましい下限は1.9%以上であり、より好ましくは2.0%以上であり、好ましい上限は2.8%以下、より好ましくは2.6%以下である。
Moは、溶接金属の強度を確保する上で有用な元素である。Mo含有量が0.80%よりも低いと、所定の強度が得られない。しかしながら、Mo含有量が過剰になると、強度の過大な上昇により靭性を低下させるとともに、SR焼鈍後の固溶Moの増加をもたらし、ステップクーリング時に微細Mo2Cが析出することで耐焼戻し脆化特性が劣化するので、1.20%以下とする必要がある。尚、Mo含有量の好ましい下限は0.9%以上であり、より好ましくは0.95%以上であり、好ましい上限は1.15%以下、より好ましくは1.1%以下である。
Vは、炭化物(MC炭化物:Mは炭化物形成元素)を形成して、溶接金属の強度を確保する上で有用な元素である。V含有量が0.25%を下回ると、所定の強度が得られない。しかしながら、V含有量が過剰になると、強度の過大な上昇を招き靭性を低下させるので、0.50%以下とする必要がある。尚、V含有量の好ましい下限は0.27%以上であり、より好ましくは0.30%以上であり、好ましい上限は0.45%以下、より好ましくは0.40%以下である。
Nbは、炭化物(MC炭化物)を形成して、溶接金属の強度を確保する上で有用な元素である。Nb含有量が0.010%を下回ると、所定の強度が得られない。しかしながら、Nb含有量が過剰になると、強度の過大な上昇を招き靭性を低下させるので、0.050%以下とする必要がある。尚、Nb含有量の好ましい下限は0.012%以上であり、より好ましくは0.015%以上であり、好ましい上限は0.040%以下、より好ましくは0.035%以下である。
Nは、溶接金属のクリープ強度を確保する上で有用な元素であるが、N含有量が過剰になると、強度の過大な上昇を招き靭性を低下させるので、0.025%以下とする必要がある。尚、上記効果を発揮させる上で好ましい下限は、0.004%以上(より好ましくは0.005%以上)であり、好ましい上限は0.020%以下(より好ましくは0.018%以下)である。
Oは、酸化物を形成し、組織微細化に寄与することで靭性を向上させるのに有用な元素である。こうした効果を発揮させるためには、0.020%以上含有させる必要がある。しかしながら、O含有量が過剰になって0.060%を超えると、粗大な酸化物が増加し、脆性破壊の起点となることでかえって靭性は低下する。尚、O含有量の好ましい下限は0.025%以上(より好ましくは0.028%以上)であり、好ましい上限は0.050%以下(より好ましくは0.045%以下)である。
CuおよびNiは、組織微細化による靭性向上に有効な元素である。しかしながら、これらの元素の含有量が過剰になると、強度が過大となって靭性が低下するので、CuまたはNiの含有量は、夫々1.0%以下とすることが好ましい。より好ましくは、夫々0.8%以下、更に好ましくは0.5%以下である。尚、上記効果を発揮させるための好ましい下限は、いずれも0.05%以上(より好ましくは0.1%以上)である。
Bは、粒界からのフェライト生成を抑制し、溶接金属の強度を向上させるのに有効な元素である。しかしながら、B含有量が過剰になると、耐SR割れ性を低下させるので、0.0050%以下とすることが好ましい。より好ましくは0.0040%以下(更に好ましくは0.0025%以下)である。尚、上記効果を発揮させるための好ましい下限は、0.0005%以上(より好ましくは0.0010%以上)である。
Wは、溶接金属の強度を向上させるのに有効な元素である。しかしながら、W含有量が過剰になると、粒界に析出する炭化物を粗大化させ、靭性に悪影響を及ぼすので、0.50%以下とすることが好ましい。より好ましくは0.3%以下(更に好ましくは、0.2%以下)である。尚、上記効果を発揮させるための好ましい下限は、0.08%以上(より好ましくは0.1%以上)である。
Alは、脱酸剤として有効な元素である。しかしながら、Al含有量が過剰になると、酸化物粗大化を招き靭性に悪影響を及ぼすので、0.030%以下とすることが好ましい。より好ましくは0.020%以下(更に好ましくは、0.015%以下)である。尚、上記効果を発揮させるための好ましい下限は、0.001%以上(より好ましくは0.0012%以上)である。
Tiは、溶接金属の強度を向上させるのに有効な元素である。しかしながら、Ti含有量が過剰になると、MC炭化物の析出強化が促進されることによる粒内強化の著しい上昇をもたらし、耐SR割れ性を低下させるので、0.020%以下とすることが好ましい。より好ましくは0.015%以下(更に好ましくは、0.012%以下)である。尚、上記効果を発揮させるための好ましい下限は、0.005%以上(より好ましくは0.008%以上)である。
17/9×([Ca]/[Al2O3])≧0.015…(2)
但し、[Ca]、[Al2O3]は、夫々ボンドフラックスに含まれる金属Ca、Al2O3の濃度(質量%)である。
[母材組成(質量%)]
C:0.12%、Si:0.23%、Mn:0.48%、P:0.004%、S:0.005%、Cu:0.04%、Al:<0.002%、Ni:0.08%、Cr:2.25%、Mo:0.99%、V:0.004%、Ti:0.002%、Nb:0.005%(残部:鉄および不可避的不純物)
溶接方法:サブマージアーク溶接(SAW)
母材板厚:25mm
開先角度:10°(V字型)
ルート間隔:25mm
溶接姿勢:下向き
ワイヤ径:4.0mmφ(ワイヤ組成は下記表1、2に示す)
入熱条件(AC-ACタンデム)
ア)2.4kJ/mm(L:440A-25V/T:480A-27V,10mm/秒)
イ)2.6kJ/mm(L:480A-25V/T:500A-28V,10mm/秒)
ウ)3.7kJ/mm(L:580A-30V/T:600A-32V,10mm/秒)
エ)4.8kJ/mm(L:440A-25V/T:480A-27V,5mm/秒)
オ)5.2kJ/mm(L:480A-25V/T:500A-28V,5mm/秒)
但し、L:Leading wire(先行電極)、T:Trailing wire(後行電極)
予熱-パス間温度:180~260℃
積層方法:1層2パス(計6層)
組成A(質量%) SiO2:8%、Al2O3:14%、MgO:31%、CaF2:27%、CaO:10%、Ca:0.13%、その他(CO2、AlF3等):10%
組成B(質量%) SiO2:8%、Al2O3:14%、MgO:31%、CaF2:27%、CaO:10%、Ca:0.08%、その他(CO2、AlF3等):10%
溶接方法:被覆アーク溶接(SMAW)
母材板厚:20mm
開先角度:20°(V字型)
ルート間隔:19mm
溶接姿勢:下向き
心線径:5.0mmφ(被覆剤の組成は下記表7に示す)
入熱条件
カ)2.1kJ/mm(210A-27V,2.7mm/秒)
キ)2.3kJ/mm(215A-27V,2.5mm/秒)
ク)2.7kJ/mm(215A-27V,2.2mm/秒)
ケ)3.0kJ/mm(220A-27V,2.0mm/秒)
コ)3.2kJ/mm(225A-28V,2.0mm/秒)
予熱-パス間温度:180~260℃
積層方法:1層2パス(計8層)
組成a(質量%) C:0.09%、Si:0.15%、Mn:0.49%、Cu:0.04%、Ni:0.03%、Cr:2.31%、Mo:1.10%(残部:鉄および不可避的不純物)
組成b(質量%) C:0.08%、Si:0.18%、Mn:0.50%、Cu:0.03%、Ni:0.03%、Cr:2.28%、Mo:1.22%(残部:鉄および不可避的不純物)
(SR焼鈍処理)
得られた溶接金属に、SR焼鈍処理として705℃で8時間の熱処理を実施した。SR焼鈍処理は、供試材を加熱し、供試材の温度が300℃を超えると、昇温速度が毎時55℃(55℃/時)以下となるように加熱条件を調整し、供試材の温度が705℃に到達するまで加熱した。そして、705℃で8時間保持した後、供試材の温度が300℃以下になるまで、冷却速度が55℃/時以下となるように供試材を冷却した。尚、このSR焼鈍処理において、供試材の温度が300℃以下の温度域では、昇温速度および冷却速度は規定しない。
SR焼鈍処理後の供試材に脆化促進処理としてのステップクーリングを実施した。図1は、温度を縦軸にとり、時間を横軸にとって、ステップクーリング処理条件を示すグラフである。図1に示すように、ステップクーリングは、供試材を加熱し、供試材の温度が300℃を超えると、温度上昇が毎時50℃(50℃/時)以下となるように加熱条件を調整して、供試材の温度を593℃に到達するまで加熱し、その温度で1時間保持する。その後、同様の要領で、538℃で15時間、524℃で24時間、496℃で60時間保持するが、これらの冷却段階においては毎時5.6℃の温度で試験片が冷却される様に調整する。更に、496℃で保持された試験片を、毎時2.8℃(2.8℃/時)で冷却して468℃とし、この温度で100時間保持する。そして、供試材の温度が300℃以下となるまで、温度降下が毎時28℃(28℃/時)以下となる様に供試材を冷却する。尚、このステップクーリング処理において、SR焼鈍処理と同様に、供試材の温度が300℃以下の温度域では、昇温速度および冷却速度は規定しない。
(円相当直径が1μm超の酸化物の個数、および円相当直径が2μm超の酸化物の個数)
上記で705℃×8時間のSR焼鈍処理を施した溶接金属の最終パス中央部を鏡面研磨し、倍率:1000倍で0.037μm2の画像を4枚撮影し、撮影した酸化物のサイズ、個数密度を画像解析ソフト(「Image-Pro Plus」Media Cybernetics社製)により算出し、円相当直径が1μm超または円相当直径が2μm超の酸化物を選択したうえで(円相当直径が2μm超の酸化物の個数は、円相当直径が1μm超の酸化物の個数にも含まれる)、それらの個数を算出した。
705℃×8時間のSR焼鈍処理を施した溶接金属の板厚中心部を、10体積%アセチルアセトン-1体積%テトラメチルアンモニウムクロライド-メタノール溶液により電解抽出し、フィルター孔径:0.1μmのフィルターで濾過して残渣を得た後、この残渣をICP発光分析にかけ、化合物として存在するCr,Mo,NbおよびVの含有量を求めた。
705℃×32時間のSR焼鈍処理を施した溶接金属の板厚表面から10mm深さの位置より、図2に基づき溶接線方向に引張試験片(JIS Z3111 A2号)を採取し、室温(25℃)において、JIS Z 2241の要領で、引張強度TSを測定した。引張強度TS>600MPaを強度に優れると評価した。
705℃×8時間のSR焼鈍処理を施した溶接金属の板厚中央部より、図3に基づき溶接線方向に垂直にシャルピー衝撃試験片(JIS Z31114号Vノッチ試験片)を採取し、JIS Z 2242の要領で、シャルピー衝撃試験を実施し、3回の吸収エネルギーの平均値が54Jとなる温度vTr54を測定した。vTr54が-50℃以下のときに靭性に優れると評価した。また705℃×8時間のSR焼鈍処理後にステップクーリングを施した溶接金属について、同様の要領で、吸収エネルギーの平均値が54Jとなる温度vTr’54を測定した。vTr’54が-50℃以下のときに靭性に優れると評価した。
上記で測定したvTr54とvTr’54の差ΔvTr54が5℃以下のときに[ΔvTr54=vTr’54-vTr54≦5℃]、耐焼戻し脆化特性靭性に優れると評価した。尚、ΔvTr54が負の値となる場合には、「0℃」として表示した。これは、焼戻脆化がほとんど生じない優れた溶接金属である。
溶接金属の最終パス(原質部)より、スリットサイズ=0.5mmのリング割れ試験片を下記に基づき採取した。625℃×10時間のSR焼鈍処理を施し、試験片6個(観察面3×試験数2)とも、ノッチ底部近傍に割れが発生しなかった場合を耐SR割れ性に優れる(評価○)と評価し、割れが発生した場合を耐SR割れ性に劣る(評価×)と評価した。
SAWで溶接金属を形成したときに用いた各種溶接ワイヤ(W1~44)の化学成分組成を、比[(Mo/(V+Nb)]の値と共に、下記表1、2に示す。また形成された溶接金属の化学成分組成を、溶接条件(溶接ワイヤNo.、入熱条件、使用フラックス、予熱-パス間温度)およびA値と共に、下記表3、4に示す。更に、各溶接金属の評価特性結果[各大きさの酸化物個数、引張強度TS、靭性(vTr54、vTr’54)、耐焼戻し脆化特性(ΔvTr54)、耐SR割れ性]を下記表5、6に示す。
SMAWで溶接金属を形成したときに用いた各種被覆剤の化学成分組成を、下記表7に示す(被覆剤No.B1~24)。また形成された溶接金属の化学成分組成を、溶接条件(被覆剤No.、入熱条件、心線種類、予熱-パス間温度)およびA値と共に、下記表8に示す。更に、各溶接金属の評価特性結果[各大きさの酸化物個数、引張強度TS、靭性(vTr54、vTr’54)、耐焼戻し脆化特性(ΔvTr54)、耐SR割れ性]を下記表9に示す。
本出願は、2011年3月11日出願の日本特許出願(特願2011―054648)に基づくものであり、その内容はここに参照として取り込まれる。
Claims (3)
- C :0.05~0.15%(「質量%」の意味。以下同じ)、
Si:0.1~0.50%、
Mn:0.6~1.30%、
Cr:1.8~3.0%、
Mo:0.80~1.20%、
V :0.25~0.50%、
Nb:0.010~0.050%、
N :0.025%以下(0%を含まない)、
O :0.020~0.060%を夫々含有し、
残部が鉄および不可避的不純物からなり、
円相当直径で1μm超の酸化物が1mm2当り2000個以下であると共に、円相当直径で2μm超の酸化物が1mm2当り100個以下であり、且つ下記(1)式で規定されるA値が5.0以下であることを特徴とする耐焼戻し脆化特性に優れた溶接金属。
A値=(100×[C]-6×[insol.Cr]-2×[insol.Mo]-24×[insol.V]-13×[insol.Nb])×([Mo]-[insol.Mo])…(1)
但し、[insol.Cr],[insol.Mo],[insol.Nb]および[insolV]は、応力除去焼鈍後において溶接金属中に化合物として存在するCr,Mo,NbおよびVの夫々の含有量(質量%)を示し、[C]および[Mo]は、溶接金属中のCおよびMoの夫々の含有量(質量%)を示す。 - 更に他の元素として、下記元素の少なくとも一つを含むことを特徴とする請求項1記載の溶接金属。
Cu:1.0%以下(0%を含まない)
Ni:1.0%以下(0%を含まない)
B :0.0050%以下(0%を含まない)
W :0.50%以下(0%を含まない)
Al:0.030%以下(0%を含まない)
Ti:0.020%以下(0%を含まない) - 請求項1または2に記載の溶接金属を備えた溶接構造体。
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EP12757293.1A EP2684638A4 (en) | 2011-03-11 | 2012-03-05 | WELDING METAL HAVING SUPERIOR FEATURES OF WELDING FRAGILIZATION RESISTANCE |
CN201280010005.1A CN103402696B (zh) | 2011-03-11 | 2012-03-05 | 耐回火脆化特性优异的焊缝金属 |
US13/982,757 US20130315661A1 (en) | 2011-03-11 | 2012-03-05 | Weld metal highly resistant to temper embrittlement |
KR1020137023928A KR101554405B1 (ko) | 2011-03-11 | 2012-03-05 | 내 템퍼링 취화 특성이 우수한 용접 금속 |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013077356A1 (ja) * | 2011-11-21 | 2013-05-30 | 株式会社神戸製鋼所 | 耐焼戻し脆化特性に優れた溶接金属 |
WO2014119197A1 (ja) * | 2013-02-04 | 2014-08-07 | 株式会社神戸製鋼所 | 高強度2.25Cr-1Mo-V鋼用サブマージアーク溶接ワイヤおよび溶接金属 |
WO2014119189A1 (ja) * | 2013-02-04 | 2014-08-07 | 株式会社神戸製鋼所 | 被覆アーク溶接棒 |
WO2014119785A1 (ja) * | 2013-02-04 | 2014-08-07 | 株式会社神戸製鋼所 | 溶接金属および溶接構造体 |
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JP6181947B2 (ja) | 2013-03-07 | 2017-08-16 | 株式会社神戸製鋼所 | 溶接金属 |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02182378A (ja) | 1989-01-09 | 1990-07-17 | Kawasaki Steel Corp | 高強度Cr―Mo鋼のサブマージアーク溶接施工法 |
JPH02220797A (ja) | 1989-02-21 | 1990-09-03 | Kobe Steel Ltd | Cr―Mo系低合金鋼用被覆アーク溶接棒 |
JPH06328292A (ja) | 1993-05-24 | 1994-11-29 | Kobe Steel Ltd | 高強度Cr−Mo鋼用サブマージアーク溶接方法 |
JPH08150478A (ja) | 1994-09-30 | 1996-06-11 | Kobe Steel Ltd | 高強度Cr−Mo鋼用サブマージアーク溶接方法及び溶接金属 |
JPH09192881A (ja) * | 1995-11-08 | 1997-07-29 | Kobe Steel Ltd | 高強度Cr−Mo鋼の溶接金属及びサブマージアーク溶接方法 |
JP2000301378A (ja) | 1999-04-21 | 2000-10-31 | Sumikin Welding Ind Ltd | 高強度Cr−Mo鋼の溶接方法及び溶接材料並びに溶接鋼構造物 |
JP2002263883A (ja) | 2001-03-13 | 2002-09-17 | Nkk Corp | 低合金耐熱鋼用被覆アーク溶接棒 |
JP2007090399A (ja) * | 2005-09-29 | 2007-04-12 | Nippon Steel Corp | 低酸素系サブマージアーク溶接用溶融型フラックス |
JP2008229718A (ja) | 2007-02-19 | 2008-10-02 | Kobe Steel Ltd | 高強度Cr−Mo鋼の溶接金属 |
JP2009106949A (ja) | 2007-10-26 | 2009-05-21 | Kobe Steel Ltd | 高強度Cr−Mo鋼の溶接金属 |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006225718A (ja) * | 2005-02-17 | 2006-08-31 | Kobe Steel Ltd | 低温靭性および耐SR割れ性に優れた高強度Cr−Mo鋼用溶着金属 |
US8101029B2 (en) * | 2007-02-19 | 2012-01-24 | Kobe Steel, Ltd. | Weld metal of high-strength Cr-Mo steel |
JP5607002B2 (ja) * | 2011-02-02 | 2014-10-15 | 株式会社神戸製鋼所 | 耐水素脆化感受性に優れた溶接金属 |
-
2011
- 2011-03-11 JP JP2011054648A patent/JP5685116B2/ja not_active Expired - Fee Related
-
2012
- 2012-03-05 BR BR112013023082A patent/BR112013023082A2/pt not_active Application Discontinuation
- 2012-03-05 CN CN201280010005.1A patent/CN103402696B/zh not_active Expired - Fee Related
- 2012-03-05 US US13/982,757 patent/US20130315661A1/en not_active Abandoned
- 2012-03-05 WO PCT/JP2012/055595 patent/WO2012124529A1/ja active Application Filing
- 2012-03-05 KR KR1020137023928A patent/KR101554405B1/ko active IP Right Grant
- 2012-03-05 EP EP12757293.1A patent/EP2684638A4/en not_active Withdrawn
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02182378A (ja) | 1989-01-09 | 1990-07-17 | Kawasaki Steel Corp | 高強度Cr―Mo鋼のサブマージアーク溶接施工法 |
JPH02220797A (ja) | 1989-02-21 | 1990-09-03 | Kobe Steel Ltd | Cr―Mo系低合金鋼用被覆アーク溶接棒 |
JPH06328292A (ja) | 1993-05-24 | 1994-11-29 | Kobe Steel Ltd | 高強度Cr−Mo鋼用サブマージアーク溶接方法 |
JPH08150478A (ja) | 1994-09-30 | 1996-06-11 | Kobe Steel Ltd | 高強度Cr−Mo鋼用サブマージアーク溶接方法及び溶接金属 |
JPH09192881A (ja) * | 1995-11-08 | 1997-07-29 | Kobe Steel Ltd | 高強度Cr−Mo鋼の溶接金属及びサブマージアーク溶接方法 |
JP2000301378A (ja) | 1999-04-21 | 2000-10-31 | Sumikin Welding Ind Ltd | 高強度Cr−Mo鋼の溶接方法及び溶接材料並びに溶接鋼構造物 |
JP2002263883A (ja) | 2001-03-13 | 2002-09-17 | Nkk Corp | 低合金耐熱鋼用被覆アーク溶接棒 |
JP2007090399A (ja) * | 2005-09-29 | 2007-04-12 | Nippon Steel Corp | 低酸素系サブマージアーク溶接用溶融型フラックス |
JP2008229718A (ja) | 2007-02-19 | 2008-10-02 | Kobe Steel Ltd | 高強度Cr−Mo鋼の溶接金属 |
JP2009106949A (ja) | 2007-10-26 | 2009-05-21 | Kobe Steel Ltd | 高強度Cr−Mo鋼の溶接金属 |
Non-Patent Citations (1)
Title |
---|
See also references of EP2684638A4 |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013077356A1 (ja) * | 2011-11-21 | 2013-05-30 | 株式会社神戸製鋼所 | 耐焼戻し脆化特性に優れた溶接金属 |
JP2013128982A (ja) * | 2011-11-21 | 2013-07-04 | Kobe Steel Ltd | 耐焼戻し脆化特性に優れた溶接金属 |
US9505087B2 (en) | 2011-11-21 | 2016-11-29 | Kobe Steel, Ltd. | Weld metal having excellent temper embrittlement resistance |
CN105008088A (zh) * | 2013-02-04 | 2015-10-28 | 株式会社神户制钢所 | 焊接金属和焊接结构体 |
WO2014119785A1 (ja) * | 2013-02-04 | 2014-08-07 | 株式会社神戸製鋼所 | 溶接金属および溶接構造体 |
JP2014147970A (ja) * | 2013-02-04 | 2014-08-21 | Kobe Steel Ltd | 被覆アーク溶接棒 |
CN104955609A (zh) * | 2013-02-04 | 2015-09-30 | 株式会社神户制钢所 | 涂药焊条 |
CN104955607A (zh) * | 2013-02-04 | 2015-09-30 | 株式会社神户制钢所 | 高强度2.25Cr-1Mo-V钢用埋弧焊丝及焊接金属 |
WO2014119189A1 (ja) * | 2013-02-04 | 2014-08-07 | 株式会社神戸製鋼所 | 被覆アーク溶接棒 |
EP2952285A4 (en) * | 2013-02-04 | 2016-06-22 | Kobe Steel Ltd | UNDERPULSE WELDING WIRE FOR HIGH-WALL 2.25CR-1MO-V STEEL AND WELDING METAL |
EP2952286A4 (en) * | 2013-02-04 | 2016-07-06 | Kobe Steel Ltd | WELDING METAL AND WELDED STRUCTURE |
WO2014119197A1 (ja) * | 2013-02-04 | 2014-08-07 | 株式会社神戸製鋼所 | 高強度2.25Cr-1Mo-V鋼用サブマージアーク溶接ワイヤおよび溶接金属 |
CN105008088B (zh) * | 2013-02-04 | 2017-06-09 | 株式会社神户制钢所 | 焊接金属和焊接结构体 |
KR101764040B1 (ko) | 2013-02-04 | 2017-08-01 | 가부시키가이샤 고베 세이코쇼 | 피복 아크 용접봉 |
US9879335B2 (en) | 2013-02-04 | 2018-01-30 | Kobe Steel, Ltd. | Weld metal and welded structure |
CN104955607B (zh) * | 2013-02-04 | 2018-03-09 | 株式会社神户制钢所 | 高强度2.25Cr‑1Mo‑V钢用埋弧焊丝及焊接金属 |
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US20130315661A1 (en) | 2013-11-28 |
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KR20130122683A (ko) | 2013-11-07 |
JP5685116B2 (ja) | 2015-03-18 |
BR112013023082A2 (pt) | 2016-12-06 |
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