WO2019186797A1 - フラックス入りワイヤの製造方法、フラックス入りワイヤ、及び溶接継手の製造方法 - Google Patents
フラックス入りワイヤの製造方法、フラックス入りワイヤ、及び溶接継手の製造方法 Download PDFInfo
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- WO2019186797A1 WO2019186797A1 PCT/JP2018/012872 JP2018012872W WO2019186797A1 WO 2019186797 A1 WO2019186797 A1 WO 2019186797A1 JP 2018012872 W JP2018012872 W JP 2018012872W WO 2019186797 A1 WO2019186797 A1 WO 2019186797A1
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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
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
- B23K35/0255—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in welding
- B23K35/0261—Rods, electrodes, wires
- B23K35/0266—Rods, electrodes, wires flux-cored
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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
- B23K35/24—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
- B23K35/3073—Fe as the principal constituent with Mn as next major 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
- B23K35/368—Selection of non-metallic compositions of core 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/40—Making wire or rods for soldering or welding
- B23K35/404—Coated rods; Coated 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/40—Making wire or rods for soldering or welding
- B23K35/406—Filled tubular wire or rods
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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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- 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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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
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- 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
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
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- 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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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
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- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
Definitions
- the present invention relates to a flux cored wire manufacturing method, a flux cored wire, and a welded joint manufacturing method.
- a weather-resistant steel material that has been exposed to an atmospheric corrosive environment after being used for a long time generally has a protective rust layer formed on its surface. Since the rust layer shields the corrosion-resistant steel material from corrosive substances from the outside, the corrosion of the weather-resistant steel material after the formation of the rust layer is suppressed, and the weather resistance is exhibited. Therefore, weathering steel is used for structures such as bridges as steel that can be used as it is without being painted.
- the coating film is damaged by the coating film deterioration, and the steel material directly under the coating film scratched part is directly exposed to the corrosive environment. It shows the corrosion form in which the coating swells like a bump. Since the scratches on the coating film further progressively expand due to the progress of the corrosion form, the corrosion of the structure continues to progress. Therefore, in an environment where the amount of incoming salt is large, it is about 10 for the purpose of extending the life of the structure. Repainting is often performed on painted steel every year. Since such a repair process takes a lot of man-hours, several technical proposals have been made for corrosion-resistant steel materials that can reduce the maintenance cost by extending the coating life and greatly extending the repair coating interval. .
- Patent Document 1 discloses a bridge that can be used as a minimum maintenance material even in an environment where the amount of incoming salt is large, such as a beach area or an area where snow melting salt is sprayed, and has excellent weather resistance and paint peeling resistance. Steel is disclosed.
- the coating film is prone to mechanical damage, and even in a corrosive environment that is susceptible to both SO 4 2 ⁇ and Cl ⁇ , the life of the coating film is extended and the coating film is peeled off.
- Corrosion-resistant steel materials for holding coal and ore carriers that can prevent corrosion are disclosed.
- the surplus is the outermost layer of the weld metal, and the coating applied to the area of the surplus is different from the surface of the coating applied to the surrounding smooth base material during use of the welded joint. It is more susceptible to collisions with objects and mechanical friction relatively frequently. Further, since the surplus itself is convex and has a complicated shape, the thickness of the surplus coating film tends to be thinner than the thickness of the coating film of the surrounding base material in the painting work. For these reasons, the surfacing surface tends to cause peeling of the coating film, and therefore tends to be the starting point of the corrosion form in which progressive coating destruction proceeds early from the start of use of the steel structure.
- Patent Document 3 discloses a sea salt that is suitable for welding high Ni-based high weathering steel, provides good welding workability, particularly good slag removability, and does not impair the corrosion resistance of the base material.
- a gas shielded arc welding wire that imparts corrosion resistance to the weld metal.
- Patent Document 3 it is difficult to obtain the effect of extending the coating life of the structure including the weld metal.
- Patent Document 4 Patent Document 5, and Patent Document 6, for example, have been proposed as flux-cored wires for gas shield arc welding having excellent corrosion resistance.
- Patent Literature 4 when the flux-cored wire for gas shielded arc welding proposed in Patent Literature 4, Patent Literature 5 and Patent Literature 6 is applied to horizontal fillet welding, pits are generated and bead shape, bead appearance, slag There is a problem that welding workability such as peelability is poor. Moreover, the effect of improving the corrosion resistance of the weld metal has been obtained by examining conventional chemical components such as containing Cu, Cr and Ni, but the effect of extending the coating life of the structure including the weld metal is obtained. It is not done.
- the weld metal obtained by the welding materials described in Patent Documents 3 to 6 has a problem that it is easy to induce peeling of the coating film and becomes a starting point of the corrosion form in an environment with a large amount of flying salt. .
- the thickness of the coating applied to the surplus, the outermost layer of the welded joint, is the thickness of the coating applied to the surrounding flat base material due to the complex shape of the surplus convex This is because it tends to be thinner than the above.
- Japanese Unexamined Patent Publication No. 2008-163374 Japanese Unexamined Patent Publication No. 2007-262555 Japanese Unexamined Patent Publication No. 2003-311471 Japanese Unexamined Patent Publication No. 2000-102893 Japanese Unexamined Patent Publication No. 2000-288781 Japanese Unexamined Patent Publication No. 2004-230456
- the present invention provides welding workability, weldability, weatherability of the welded portion, and coating even in the case of horizontal fillet welding of corrosion resistant steel used in environments with a large amount of incoming salt such as bridges, harbor structures and beach areas. It aims at providing the manufacturing method of the flux cored wire from which the weld metal which is excellent in corrosion resistance and excellent in mechanical performance is obtained, the core wire, and the manufacturing method of a welded joint.
- excellent welding workability means that the amount of spatter generated is small and the bead shape, bead appearance and slag peelability are excellent.
- excellent weldability means that no pits are generated and hot cracks do not occur.
- being excellent in mechanical performance means being excellent in tensile strength and toughness.
- a method for manufacturing a flux-cored wire according to an aspect of the present invention is a method for manufacturing a flux-cored wire in which a flux is filled in a steel outer shell, Filling the inside of the steel sheet with flux while forming the steel sheet into a circle; Joining both ends of the steel sheet to form a steel pipe; Rolling and annealing the steel pipe to obtain the flux-cored wire;
- the chemical composition of the flux-cored wire is a mass% with respect to the total mass of the flux-cored wire, C: 0.03-0.10%, Si: 0.40 to 0.85%, Mn: 1.5 to 3.5% P: 0.020% or less, S: 0.020% or less, Cu: 0.03 to 0.70%, Sn: 0.05-0.30%, Mg: 0.05 to 0.50%, Al: 0.05 to 0.50%, Ti oxide: 1.50 to less than 4.60% in terms of TiO 2 , Si oxide: 0.30 to 1.00% in terms of Si
- the element symbol in the formula 1 indicates the content of the element related to each element symbol in mass% with respect to the total mass of the flux-cored wire.
- the chemical composition of the flux-cored wire is expressed in mass% with respect to the total mass of the flux-cored wire. Mo: 0 to 0.040% W: 0 to 0.010%, It may be.
- the chemical composition of the flux-cored wire is expressed in mass% with respect to the total mass of the flux-cored wire. Cu: 0.05 to 0.70%, It may be.
- the chemical composition of the flux-cored wire is at least in mass% with respect to the total mass of the flux-cored wire. Any one of the following may be satisfied.
- the joining may be caulking.
- the joining may be welding.
- a flux cored wire according to another aspect of the present invention is a flux cored wire manufactured by the flux cored wire manufacturing method according to any one of [1] to [6].
- a method for manufacturing a welded joint according to another aspect of the present invention uses a flux-cored wire manufactured by the flux-cored wire manufacturing method according to any one of [1] to [6] above. A step of welding.
- the corrosion resistance used in an environment with a large amount of incoming salt such as a bridge, a harbor structure, and a beach area.
- a weld metal excellent in welding workability, weldability, weather resistance of the welded portion and paint corrosion resistance, and excellent in mechanical performance can be obtained.
- the present inventors have made various types of flux-cored wires (hereinafter sometimes abbreviated as “wires”) and examined the details.
- the present inventors investigated the influence of the chemical composition in the wire (hereinafter sometimes referred to as “chemical component”) regarding the corrosion resistance in a corrosive environment with a large amount of scattered salt.
- chemical component the chemical composition in the wire
- the present inventors have improved the bead shape and bead appearance by adjusting the amount of Ti oxide, Si oxide, Zr oxide, Al, Fe oxide, Al oxide and fluorine compound in the wire.
- the slag peelability is improved by adjusting the total amount of Si oxide, Zr oxide, Al, Fe oxide, Na compound and K compound in the wire.
- pit resistance and reduction of spatter generation are improved by adjusting the Ti oxide, Si oxide, and Mg contents in the wire, and the mechanical performance includes C, Si, and Mn in the wire. It was found that adjusting the amount makes it better.
- the present inventors have found that in order to improve the corrosion resistance of the weld metal in a corrosive environment with a large amount of scattered salt, it is necessary to consider the interaction of the above-described elements. Specifically, the present inventors, unless the content ratio as an alloy component of Sn (and Sb) and Mo and W is within a predetermined range, particularly in an environment where the amount of incoming salt is high, It was found that when the coating film was damaged due to the deterioration of the coating film described above, it was difficult to suppress the corrosion depth just below the coating film scratched part, and the coating peel resistance was reduced.
- FIG. 4 is a cross-sectional view of the flux-cored wire 10 at the manufacturing stage
- FIG. 5 is a cross-sectional view of the flux-cored wire 10 manufactured by caulking.
- the manufacturing method of the wire 10 according to the present embodiment in which the flux 12 is filled in the steel outer shell 11 includes a step of filling the steel plate 13 with the flux 12 while forming the steel plate 13 into a circular shape (see FIG. 4). And a step of joining the both ends of the steel plate 13 to form a steel pipe, and a step of rolling and annealing the steel pipe to obtain the wire 10. Rolling and annealing are performed to reduce the diameter of the wire 10 to such an extent that it can be used as a welding material and to soften the wire 10.
- the chemical composition of the steel plate 13 is substantially the same as the chemical composition of the steel outer shell 11.
- the joining means is not particularly limited, for example, caulking or welding.
- the flux-cored wire 10 manufactured by welding shown in FIG. 6 is a so-called seamless wire having a welded portion 15 but no seam 14. Seamless wire can be used for further heat treatment with the aim of reducing the amount of hydrogen in the wire, and since the amount of moisture absorption after production is small, diffusible hydrogen in the weld metal can be reduced and crack resistance improved. This is preferable.
- FIG. 6 is a cross-sectional view of the flux cored wire 10 manufactured by welding.
- the method of manufacturing the flux cored wire 10 includes the step of plating the outer surface of the steel outer shell 11 and / or the steel outer shell 11.
- a step of applying a lubricant to the outer surface may be further included.
- the plating is, for example, copper plating.
- the lubricant is, for example, vegetable oil or PTFE oil.
- the chemical composition of the steel outer skin 11 and the flux 12 is controlled within a predetermined range.
- the component contained in the steel outer shell 11 and the flux 12 melts during welding to form a weld metal, a part is oxidized and discharged out of the weld metal as slag. Therefore, it is considered that the components described below have the same effect regardless of whether they are included in the steel outer shell 11 or the flux 12. For the above reason, in the manufacturing method according to the present embodiment, it is not necessary to distinguish between the chemical composition of the steel outer shell 11 and the chemical composition of the flux 12.
- a chemical composition (component) existing in the form of an oxide or fluoride is defined as a slag component
- a chemical composition (component) existing as a single metal or alloy is defined as an alloy component.
- C, P, and S are not metal elements, but are included in the alloy components in the present embodiment for convenience.
- the action of the oxide is considered to be the same as the action of Al and Bi as the alloy components, so that the oxide is substantially handled as the alloy component.
- the content of elements described below is the content of elements present as alloy components.
- the alloy component can be included in both the steel outer shell 11 and the flux 12, the slag component is usually included only in the flux 12.
- the diameter and filling rate of the flux-cored wire 10 to be manufactured refers to the ratio of the mass of the flux 12 to the total mass of the flux-cored wire 10).
- the design value (target value) of the chemical composition of the flux-cored wire 10 is determined in advance.
- the steel plate 13 which is a raw material for the steel outer shell, one having a specific chemical composition is usually used.
- the chemical composition of the steel outer shell 11 can be ascertained from a document indicating the chemical composition (for example, the analysis result of the chemical composition of the steel plate 13, the inspection certificate or catalog of the steel manufacturer).
- the design value (target value) of the chemical composition of the flux 12 can be determined from the filling rate, the chemical composition of the steel outer skin 11 and the design value (target value) of the chemical composition of the flux cored wire 10.
- a document for example, a raw material manufacturer
- the chemical composition of the raw material of the flux 12 which refers to both the raw material of the slag component and the raw material of the metal component
- the flux 12 is produced by blending the raw materials of the flux 12 selected by the above procedure at the blending ratio determined by the above procedure.
- the flux-cored wire 10 having the chemical composition of the design value can be manufactured using the flux 12 thus manufactured and the steel plate 13 described above.
- the flux-cored wire 10 is plated, it is necessary to control the chemical composition of the steel outer skin 11 and the flux 12 according to the chemical composition of plating and the thickness of plating.
- the unit “%” for the chemical composition indicates mass% relative to the total mass of the flux-cored wire 10 (the total mass of the steel outer sheath 11 and the flux 12) unless otherwise specified.
- the total mass of the flux-cored wire 10 is the total mass of the steel outer skin 11 and the flux 12.
- the mass of the plating is the steel outer skin 11. Is included in the mass.
- the mass of the lubricant applied to the outer surface of the steel outer skin 11 is not included in the total mass of the flux cored wire 10.
- C is an element contained in the wire in order to obtain the strength and toughness of the weld metal required for the welded structure.
- C can be contained in the metal powder containing a trace amount of iron alloys such as Fe—Si, Fe—Mn, and Fe—Si—Mn in the flux 12 in addition to the components contained in the steel outer shell 11. If the C content is less than 0.03%, the strength and toughness of the weld metal are lowered. On the other hand, if the C content exceeds 0.10%, the strength of the weld metal increases, and the toughness of the weld metal decreases. Therefore, the C content is 0.03 to 0.10%. Preferably, the lower limit of the C content is 0.04% or 0.05%.
- the upper limit of the C content is 0.09% or 0.08%.
- C may exist as a component of the steel outer shell 11 and as a component of metal powder and alloy powder in the flux 12. That is, by controlling the C content of the steel outer shell 11 and the C content of the flux 12, the flux-cored wire 10 having the C content can be manufactured.
- Si is an element that acts as a deoxidizer, and is an element contained in the wire in order to ensure the strength and toughness of the weld metal.
- Si can be contained in the metal Si, Fe—Si, Fe—Si—Mn, and the like in the flux 12 in addition to the components contained in the steel outer shell 11. If the Si content is less than 0.40%, pits are generated due to insufficient deoxidation. Further, when the Si content is less than 0.40%, the strength and toughness of the weld metal are lowered. On the other hand, if the Si content exceeds 0.85%, the strength of the weld metal increases, and the toughness of the weld metal decreases. Therefore, the Si content is set to 0.40 to 0.85%.
- the lower limit of Si content is 0.55% or 0.65%.
- the upper limit of Si content is 0.75% or 0.70%.
- Si can exist as a component of the steel outer shell 11 and a component of alloy powder such as metal Si, Fe—Si, Fe—Si—Mn in the flux 12. That is, by controlling the Si content of the steel outer skin 11 and the Si content of the flux 12, the flux-cored wire 10 having the Si content can be manufactured.
- Mn is an element that acts as a deoxidizer and is an element contained in the wire to ensure the strength and toughness of the weld metal. If the Mn content is less than 1.5%, deoxidation is insufficient and pits are generated. Further, if the Mn content is less than 1.5%, the strength and toughness of the weld metal also decrease. On the other hand, if the Mn content exceeds 3.5%, the strength of the weld metal increases, and the toughness of the weld metal decreases. Therefore, the Mn content is 1.5 to 3.5%.
- the lower limit of the Mn content is 2.4% or 2.6%.
- the upper limit of the Mn content is 3.0% or 2.8%.
- Mn can exist as a component of the steel outer shell 11 and a component of alloy powder such as metal Mn, Fe—Mn, Fe—Si—Mn in the flux 12. That is, by controlling the Mn content of the steel outer shell 11 and the Mn content of the flux 12, the flux-cored wire 10 having the Mn content can be manufactured.
- P and S are elements that may adversely affect the mechanical properties of the weld metal and may impair the corrosion resistance of the weld metal. Therefore, the lower limit of the contents of P and S is 0%. However, since it takes a lot of cost to completely remove P and S from the material of the wire, P and S may be contained within a range that does not impair the properties of the weld metal. In the flux cored wire 10 according to the present embodiment, 0.020% or less of P and 0.020% or less of S are allowed. The upper limit value of P or S may be 0.015%, 0.010%, or 0.005%. The lower limit value of P or S may be 0.001%, 0.002%, or 0.005%. By controlling the P content and S content of the steel outer skin 11 and the P content and S content of the flux 12 as in the case of C and Si, the P content and S content of the flux are contained. The wire 10 can be manufactured.
- Cu is an element having an effect of improving the corrosion resistance of the weld metal.
- the Cu content is less than 0.03%, the corrosion resistance of the weld metal is poor.
- the Cu content exceeds 0.70%, the effect of improving the corrosion resistance of the weld metal is saturated.
- the toughness of a weld metal will fall. Therefore, the Cu content is 0.03 to 0.70%.
- the lower limit of the Cu content is 0.05%, 0.15%, 0.17%, or 0.20%.
- the upper limit of Cu content is 0.35%, 0.32%, or 0.30%.
- Cu improves the weather resistance and paint peel resistance of weld metal is that Cu reduces the reaction rate of the dissolution reaction (corrosion reaction) of the weld metal itself containing Cu, and welds containing Cu.
- corrosion reaction corrosion reaction
- corrosion products generated on the surface (excess parts, etc.) exhibit a characteristic fine and dense structure, thereby preventing corrosion, which inhibits permeation of water, oxygen, chloride ions, etc. This is to form a high rust layer.
- Cu may exist as a component of the steel outer shell 11 itself, a plating component of the steel outer shell 11, or metal Cu in the flux 12. That is, the flux-cored wire 10 having the Cu content can be manufactured by controlling the Cu content of the steel outer shell 11, the Cu content of the plating, and the Cu content of the flux 12.
- Sn is an element having an effect of improving the corrosion resistance of the weld metal.
- the corrosion resistance is poor.
- the Sn content is 0.05 to 0.30%.
- the lower limit of the Sn content is 0.10% or 0.12%.
- the upper limit of the Sn content is 0.25%, 0.20%, or 0.18%.
- Sn may be contained as a component of the steel outer shell 11 or may be contained as a metal Sn or Sn compound in the flux 12.
- the reason why Sn improves the weather resistance and paint peel resistance of the weld metal is that the metal Sn in the weld metal elutes as tin ions (II) (Sn 2+ ) and is exposed to the environment, that is, acid chloride. This is because it exhibits an inhibitory action in a physical solution and suppresses corrosion at the anode whose pH is lowered. Further, the metal Sn in the weld metal also has an action of reducing iron (III) ions (Fe 3+ ) (2Fe 3+ + Sn 2+ ⁇ 2Fe 2+ + Sn 4+ ), thereby suppressing the corrosion promoting action of Fe 3+ and the incoming salt content. This is because the weather resistance in an environment with a lot of water is improved.
- Mg is an element having an effect of preventing the generation of pits by acting as a strong deoxidizer.
- the Mg content is less than 0.05%, there is no effect as a deoxidizer and pits are generated.
- the Mg content exceeds 0.50%, the arc becomes rough and the amount of spatter generated increases. Therefore, the Mg content is 0.05 to 0.50%.
- the lower limit of the Mg content is 0.15%, 0.18%, or 0.20%.
- the upper limit of Mg content is 0.35%, 0.30%, or 0.25%.
- the Mg content of the general steel outer skin 11 is almost 0%. For this reason, Mg is often present in the wire as an alloy powder of metal Mg, Al—Mg, etc. in the flux 12. In other words, the flux-cored wire 10 having the Mg content can be manufactured by mainly controlling the Mg content of the flux 12.
- Al 0.05 to 0.50%
- Al is an element that acts as a deoxidizer, and increases the viscosity of the slag by becoming an Al oxide in the molten slag, thereby suppressing the receding of the molten pool during horizontal fillet welding and sufficient slag encapsulation. It is an element having the function of maintaining the property. If the Al content is less than 0.05%, the bead shape becomes convex, and an undercut occurs in the upper leg portion. On the other hand, if the Al content exceeds 0.50%, the bead shape is not smooth, and the toe end of the bead is swollen.
- the Al content is set to 0.05 to 0.50%.
- the lower limit of the Al content is 0.07%, 0.10%, or 0.15%.
- the upper limit of the Al content is 0.25% or 0.20%.
- Al may exist as a component of the steel outer shell 11 or as metal Al powder, Fe—Al alloy powder, Al—Mg alloy powder, etc. in the flux 12. That is, the flux-cored wire 10 having the Al content can be manufactured mainly by controlling the Al content of the steel outer skin 11 and the Al content of the flux 12. Moreover, in order to make the Al content of the flux-cored wire 10 within the above range, the steel outer shell 11 having the Al content and the flux 12 having the Al content may be used.
- Ti oxide 1.50 to less than 4.60% in terms of TiO 2
- Ti oxide which is a slag component, has the effect of encapsulating the entire bead with slag uniformly.
- Ti oxide has the effect of stabilizing the arc duration and reducing the amount of spatter generated.
- the TiO 2 equivalent value of the Ti oxide is less than 1.50%, the amount of slag generated is insufficient and the beads cannot be encapsulated uniformly, and the slag is baked onto the bead surface, resulting in poor bead appearance. Further, when the TiO 2 converted value of Ti oxides is less than 1.50%, there is no effect of stabilizing the arc, also increases spatter. On the other hand, if the TiO 2 equivalent value of the Ti oxide is 4.60% or more, the amount of spatter is reduced due to the stabilization of the arc, but the slag becomes thicker due to the increased viscosity of the slag, and the bead stops. The end is swelled.
- the TiO 2 equivalent value of the Ti oxide is 1.50 to less than 4.60%.
- the lower limit of the TiO 2 conversion value of the Ti oxide is 2.50%, 2.80%, or 3.00%.
- the upper limit of the TiO 2 conversion value of the Ti oxide is 4.30%, 4.00%, 3.70%, or 3.50%.
- the Ti oxide may exist mainly as rutile, titanium oxide, titanium slag, illuminite, sodium titanate, potassium titanate, etc. in the flux 12. For this reason, the flux-cored wire 10 having the Ti oxide content can be manufactured mainly by controlling the Ti oxide content of the flux 12.
- the TiO 2 equivalent value of the Ti oxide refers to all Ti oxides contained in the wire (for example, TiO 2, Ti 2 O 3 , Ti 3 O 5 , sodium titanate, potassium titanate, etc.) when regarded as a 2, a percentage by weight relative to the total mass of the wire TiO 2. Therefore, the converted value of TiO 2 is obtained by measuring the total mass of only Ti obtained by excluding O from the mass of the Ti oxide and substituting this total Ti amount into the following equation.
- TiO 2 equivalent value (mass% with respect to the total wire mass of Ti forming the Ti oxide) ⁇ (formula amount of TiO 2 ) / (atomic weight of Ti)
- SiO 2 conversion value of Si oxide, ZrO 2 conversion value of Zr oxide, Fe converted value of FeO oxides, Al 2 O 3 conversion value of Al oxides obtained by a similar calculation.
- Si oxide 0.30 to 1.00% in terms of SiO 2
- Si oxide which is a slag component has the effect
- SiO 2 equivalent value of the Si oxide is less than 0.30%, the slag encapsulation state is poor and the slag peelability is poor, and the bead shape and bead appearance are also poor.
- the SiO 2 equivalent value of the Si oxide exceeds 1.00%, the amount of spatter generated increases. Further, if the SiO 2 equivalent value of the Si oxide exceeds 1.00%, pits and gas grooves are likely to be generated.
- the SiO 2 equivalent value of the Si oxide is 0.30 to 1.00%.
- the lower limit value of the Si oxide in terms of SiO 2 is 0.50% or 0.60%.
- the upper limit value of the Si oxide in terms of SiO 2 is 0.90% or 0.80%.
- the Si oxide can exist mainly as silica sand, zircon sand, feldspar, sodium silicate, potassium silicate and the like in the flux 12. Therefore, the flux-cored wire 10 having the Si oxide content (0.30 to 1.00% in terms of SiO 2 ) is mainly controlled by controlling the Si oxide content of the flux 12. Can be manufactured.
- Zr oxide 0.10 to 0.50% in terms of ZrO 2
- Zr oxide which is a slag component, has the effect of increasing the slag encapsulation by horizontal fillet welding and smoothing the bead shape.
- the ZrO 2 conversion value of the Zr oxide is less than 0.10%, the bead shape is not smooth, but becomes a convex bead shape, resulting in poor slag removability.
- the ZrO 2 conversion value of the Zr oxide exceeds 0.50%, the bead shape tends to be convex. Therefore, the ZrO 2 conversion value of the Zr oxide is set to 0.10 to 0.50%.
- the lower limit of the ZrO 2 converted value of the Zr oxide is 0.15% or 0.20%.
- the upper limit of the ZrO 2 conversion value of the Zr oxide is 0.40% or 0.30%.
- the Zr oxide can exist mainly as zircon sand, zirconium oxide or the like in the flux 12 and may be contained in a small amount in the above-described Ti oxide. Therefore, the flux-cored wire 10 having the Zr oxide content (0.10 to 0.50% in terms of ZrO 2 ) is mainly controlled by controlling the Zr oxide content of the flux 12. Can be manufactured.
- Fe oxides such as FeO and Fe 2 O 3 have the effect of adjusting the viscosity and solidification temperature of the molten slag, have the effect of eliminating the swelling of the bead toes and improving the compatibility with the lower plate. . If the FeO equivalent value of the Fe oxide is less than 0.10%, the bead toe portion swells, and the bead toe shape becomes poor.
- the FeO equivalent value of the Fe oxide is set to 0.10 to 1.00%.
- the lower limit of the FeO equivalent value of the Fe oxide is 0.20%, 0.30%, or 0.40%.
- the upper limit of the FeO equivalent value of Fe oxide is 0.80%, 0.70%, or 0.60%.
- the Fe oxide is mainly present in the flux 12.
- Al oxide when constituting molten slag, has the effect of preventing undercut on the upper leg side of the fillet bead by improving the slag encapsulation.
- Al 2 O 3 equivalent value of the Al oxide is less than 0.05%, an undercut tends to occur on the upper leg side of the fillet bead.
- Al 2 O 3 equivalent value of the Al oxide exceeds 0.50%, a bead shape in which the bead toe portion on the lower leg side of the fillet bead swells is formed. Accordingly, Al 2 O 3 conversion value of Al oxide, and 0.05 to 0.50%.
- the lower limit value of the Al oxide converted to Al 2 O 3 is 0.10%, 0.15%, or 0.20%.
- the upper limit of the terms of Al 2 O 3 value of Al oxide 0.35%, 0.30%, or 0.25%.
- the Al oxide is present mainly as a component such as alumina or feldspar in the flux 12. For this reason, mainly by controlling the content of the Al oxide in the flux 12, the flux-cored wire having the content of the Al oxide (0.05 to 0.50% in terms of Al 2 O 3 ). 10 can be manufactured.
- Na compound and K compound not only act as an arc stabilizer, but also act as a slag forming agent to suppress a sudden viscosity increase in the solidification process of molten slag and improve pit resistance, thereby forming a smooth bead shape.
- the Na compound and the K compound may exist as a solid component of water glass composed of sodium silicate and potassium silicate in the flux, and as a fluorine compound such as sodium fluoride and potassium silicate fluoride.
- the total of Na 2 O converted value and K 2 O converted value of Na compound and K compound is less than 0.050%, large spatters frequently occur, pits and gas grooves are likely to occur, and the bead has a rough surface. The bead shape and the bead appearance are poor. On the other hand, if the total of Na 2 O converted value and K 2 O converted value of Na compound and K compound exceeds 0.200%, the slag peelability, bead shape and bead appearance become poor, and the amount of spatter generated increases. Therefore, the total of Na 2 O equivalent value and K 2 O equivalent value of Na compound and K compound is 0.050 to 0.200%.
- the lower limit of the total of Na 2 O converted value and K 2 O converted value of Na compound and K compound is 0.080% or 0.100%.
- the upper limit of the total of Na 2 O converted value and K 2 O converted value of Na compound and K compound is 0.150% or 0.120%.
- the content of the Na compound and K compound in the normal steel outer shell 11 is approximately 0%. For this reason, mainly by controlling the content of the Na compound and the K compound in the flux 12, the content of the Na compound and the K compound (the total of the Na 2 O converted value and the K 2 O converted value is 0.050) ⁇ 0.200%) flux-cored wire 10 can be manufactured.
- Na 2 O values of Na compounds when all the Na compound contained in the wire is considered to be Na 2 O, by mass% with respect to Na 2 O of the total wire mass.
- the K 2 O conversion value of K compound when all of the K compound contained in the wire is considered to be K 2 O, by mass% with respect to K 2 O in the total mass of the wire.
- K 2 O conversion value of terms of Na 2 O values and K compounds of Na compound is calculated by the same means as TiO 2 converted value of the above-described Ti oxide.
- the fluorine compound which is a slag component, has the effect of increasing the directivity of the arc to form a stable molten pool, the function of adjusting the viscosity of the slag to smooth the bead shape, and the effect of improving pit resistance.
- the fluorine compound may exist as magnesium fluoride, cryolite, sodium fluoride, potassium silicofluoride or the like in the flux 12.
- the content of the fluorine compound in the normal steel outer skin 11 is almost 0%. Therefore, the flux-cored wire 10 having the fluorine compound content (0.02 to 0.20% in terms of F) can be manufactured mainly by controlling the fluorine compound content of the flux 12. it can.
- the F-converted value of the fluorine compound is less than 0.02%, the arc becomes unstable and the conformability of the lower leg portion on the lower plate side becomes poor. If the F-converted value of the fluorine compound is less than 0.02%, pits are likely to occur. On the other hand, if the F-converted value of the fluorine compound exceeds 0.20%, the slag viscosity decreases and a thin slag that is difficult to remove remains on the upper leg of the bead, resulting in poor slag peelability and a bead shape that is convex. Become. Therefore, the F converted value of the fluorine compound is 0.02 to 0.20%.
- the lower limit of the F-converted value of the fluorine compound is 0.03% or 0.05%.
- the upper limit of the F-converted value of the fluorine compound is 0.15%, 0.10%, or 0.07%.
- the F-converted value of the fluorine compound is the total amount of the content of F contained in all the fluorine compounds in the wire in mass% with respect to the total mass of the wire.
- the steel outer shell 11 and the flux 12 are required to contain the above elements and compounds, but the elements and compounds described below are further included as necessary. Can be contained. However, even when the optional components listed below are not included, the method for manufacturing the flux-cored wire 10 according to the present embodiment can achieve the problem, so the lower limit of the content of the optional components is 0%. is there.
- Bi has the effect of improving the slag removability, giving the bead surface a gloss, and improving the appearance of the bead, and therefore, Bi may be included in the wire 10.
- Bi may exist as a metal Bi or oxidized Bi in the flux 12 in addition to the components contained in the steel outer sheath.
- the sum of Bi converted values of the metal Bi and Bi oxide in the flux 12 is set to 0.035% or less.
- the upper limit of the total Bi converted value of the metal Bi and Bi oxide is 0.030% or 0.025%.
- the lower limit of the total of Bi conversion value of metal Bi and Bi oxide shall be 0.005%, 0.010%, or 0.015%. preferable.
- the steel plate 13 containing Bi is very expensive. Therefore, the flux-cored wire 10 having the Bi content and the Bi oxide content can be manufactured mainly by controlling the Bi content and the Bi oxide content of the flux 12. Further, in order to keep the Bi content and the Bi oxide content of the flux-cored wire 10 within the above ranges, the chemical composition (Bi and Bi oxide: 0 to 0.035% in total of Bi conversion values) A steel outer shell 11 and a flux 12 having the above-described chemical composition (Bi and Bi oxide: 0 to 0.035% in total of Bi conversion values) may be used.
- the Bi-converted value is a total value of mass% with respect to the total mass of Bi wire existing as a metal or alloy and mass% with respect to the total mass of Bi wire in Bi oxide (for example, Bi 2 O 3 ). Since Bi present as a metal or an alloy and Bi oxide have the same effect, in the method for manufacturing the flux cored wire 10 according to the present embodiment, the content of Bi present as a metal or an alloy, and Bi oxide Both contents are controlled as Bi converted values.
- Ni, Ti, and B may be contained in the wire 10 in order to ensure the toughness of the weld metal at a low temperature.
- the Ni content exceeds 2.50%, hot cracking tends to occur. Therefore, the Ni content is 2.50% or less.
- the upper limit of the Ni content is 2.30%, 2.00%, or 1.50%.
- the lower limit of the Ni content is preferably set to 0.10% or 0.20%.
- the Ti content exceeds 0.30%, the slag is seized on the bead surface, the bead appearance becomes poor, and the amount of spatter generated increases. Furthermore, if the Ti content exceeds 0.30%, the toughness of the weld metal also decreases. Moreover, when B content exceeds 0.010%, it will become easy to produce a high temperature crack. Therefore, the Ti content is set to 0.30% or less, and the B content is set to 0.010% or less.
- the upper limit of Ti content is 0.25% or 0.20%.
- the upper limit of the B content is 0.008% or 0.005%.
- Ni can be contained in the components of the steel outer shell 11, metal Ni in the flux 12, Fe—Ni, and the like.
- Ti and B may be contained in the wire 10 in order to ensure the low temperature toughness of the weld metal.
- Ti can exist as a component of the steel outer shell 11 and as a component of metal Ti or Fe—Ti in the flux 12.
- B may be present as a component of the steel outer shell 11 and a component such as Fe—B or Fe—Mn—B in the flux 12. That is, mainly by controlling the Ni content, Ti content and B content of the steel outer shell 11, and the Ni content, Ti content and B content of the flux 12, the Ni content, Ti
- the flux-cored wire 10 having the B content and the B content can be manufactured.
- the chemical composition Ni: 0 to 2.50%, Ti: 0 to 0.30%, B : 0-0.010%) steel outer shell 11 and the above-mentioned chemical composition (Ni: 0-2.50%, Ti: 0-0.30%, B: 0-0.010%) flux 12 May be used.
- Ni 0.10 to 2.50%
- Ti 0.03-0.30%
- B 0.002% to 0.010%
- Mo has the effect of improving the strength of the weld metal, it may be included in the wire 10.
- the Mo content exceeds 0.400%, particularly when the coating film scratches occur in an environment with a large amount of incoming salt, the average corrosion depth just below the coating film scratching part is due to competition with the ionization of Sn. Can not be suppressed. Therefore, the upper limit of the Mo content is preferably 0.400%.
- the minimum of Mo content into 0.010%.
- a preferable upper limit of the Mo content is 0.300%, 0.100%, or 0.040%.
- Mo may be present in the wire 10 as an alloy powder such as a component of the steel outer shell 11, metal Mo in the flux 12, or Fe—Mo. That is, mainly by controlling the Mo content of the steel outer shell 11 and the Mo content of the flux 12, the flux-cored wire 10 having the Mo content can be manufactured. Further, in order to keep the Mo content of the flux-cored wire 10 within the above range, the steel outer shell 11 having the Mo content (that is, 0 to 0.400%) and the Mo content (that is, 0 to 0). .400%) flux 12 may be used.
- W may be included in the wire 10 because it contributes to improving the strength of the weld metal.
- the W content exceeds 0.200%, particularly when the coating film scratches occur in an environment where the amount of incoming salt is high, the average corrosion depth directly below the coating film scratching part is due to competition with the ionization of Sn. Can not be suppressed. Therefore, the upper limit of the W content is 0.200%.
- a preferable upper limit of the W content is 0.150%, 0.100%, or 0.010%. Note that W may be present in the wire 10 as a component of the steel outer shell 11 or as an alloy powder such as metal W in the flux 12.
- the flux-cored wire 10 having the W content can be manufactured. Further, in order to keep the W content of the flux-cored wire 10 within the above range, the steel outer shell 11 having the W content (that is, 0 to 0.200%) and the W content (that is, 0 to 0). .200%) flux 12 may be used.
- Cr 0 to 0.500%
- Cr may be contained in the wire because it contributes to improving the strength of the weld metal.
- the upper limit of the Cr content is preferably 0.500%.
- a preferable upper limit of the Cr content is 0.100% or 0.050%.
- Cr may be present in the wire as a component of the steel outer shell 11 or as an alloy powder of an alloy powder such as metal Cr or Fe—Cr in the flux 12.
- the flux-cored wire 10 having the Cr content can be manufactured mainly by controlling the Cr content of the steel outer skin 11 and the Cr content of the flux 12. Further, in order to keep the Cr content of the flux-cored wire 10 within the above range, the steel outer shell 11 having the Cr content (that is, 0 to 0.500%) and the Cr content (that is, 0 to 0). .500%) flux 12 may be used.
- Nb may be contained in the wire 10 because it contributes to improving the strength of the weld metal by precipitation strengthening. However, if the Nb content exceeds 0.300%, Nb forms coarse precipitates and the toughness of the weld metal decreases. Therefore, the upper limit value of the Nb content is 0.300%. The upper limit value of the Nb content may be 0.250% or 0.200%. In order to acquire the above-mentioned effect, it is good also considering the lower limit of Nb content as 0.050% or 0.100%. Nb may be present in the wire 10 as a component of the steel outer shell 11 or as an alloy powder of an alloy powder such as metal Nb or Fe—Nb in the flux 12.
- the flux-cored wire 10 having the Nb content can be manufactured.
- the steel outer shell 11 having the Nb content (that is, 0 to 0.300%) and the Nb content (that is, 0 to 0) are used. .300%) flux 12 may be used.
- V may be included in the wire 10 because it contributes to improving the strength of the weld metal.
- the V content is 0.300% or less.
- the V content is preferably set to 0.010% or more.
- the upper limit of the preferable V content is 0.200% or 0.100%.
- V may be present in the wire 10 as a component of the steel outer shell 11 or as an alloy powder of an alloy powder such as metal V or Fe—V in the flux 12.
- the flux-cored wire 10 having the V content can be manufactured mainly by controlling the V content of the steel outer skin 11 and the V content of the flux 12. Further, in order to keep the V content of the flux-cored wire 10 within the above range, the steel outer shell 11 having the V content (that is, 0 to 0.300%) and the V content (that is, 0 to 0). .300%) flux 12 may be used.
- N 0 to 0.0080% Since N is an element that impairs the toughness and the like of the weld metal, it is most preferable that N is not included in the wire 10 at all. Therefore, the lower limit of the N content is 0%. However, since a large amount of cost is required to completely remove N from the material of the wire, N may be contained within a range that does not impair various properties of the weld metal. In the flux cored wire 10 according to the present embodiment, N of 0.0080% or less is allowed. The upper limit of the N content may be 0.0070%, 0.0060%, or 0.0050%.
- the steel outer shell 11 having the N content (that is, 0 to 0.0080%) and the V content (that is, 0 to 0.0080). %) Flux 12 may be used.
- Ca and REM have the effect of improving the ductility and toughness of the weld metal by changing the form of sulfides and oxides.
- the Ca content may be 0.0002% or more, and the REM content may be 0.0002% or more.
- Ca and REM are elements that increase the amount of sputtering and impair the weldability. Therefore, the upper limit of Ca content is 0.0050%, and the upper limit of REM content is 0.0050%.
- the upper limit of the Ca content may be 0.0040% or 0.0030%.
- the upper limit of the REM content may be 0.0040% or 0.0030%.
- Ca and REM may exist in the wire 10 as a component of the steel outer shell 11 or as a Ca compound or a REM compound in the flux 12. That is, mainly by controlling the Ca content and REM content of the steel outer skin 11 and the Ca content and REM content of the flux 12, the flux-cored wire 10 having the above Ca content and REM content is manufactured. can do. Further, since the Ca content and the REM content of the flux-cored wire 10 are within the above ranges, the Ca content (that is, 0 to 0.0050%) and the REM content (that is, 0 to 0.0050%). ) And the flux 12 having the Ca content (that is, 0 to 0.0050%) and the REM content (that is, 0 to 0.0050%) may be used.
- Sb is an element that imparts weather resistance and paint peel resistance to the weld metal in the same manner as Sn. Therefore, the Sb content may be 0.0010% or 0.0020%. However, if the Sb content exceeds 0.0050%, the toughness of the weld metal decreases due to segregation of Sb at the grain boundaries of the weld metal. Therefore, the upper limit of the Sb content is set to 0.0050%. The upper limit value of the Sb content may be 0.0040% or 0.0030%. Sb may be present in the wire 10 as a component of the steel outer shell 11 or as an alloy powder of an alloy powder such as metal Sb or Sb compound in the flux 12.
- the flux-cored wire 10 having the Sb content can be manufactured.
- the steel outer shell 11 having the Sb content (that is, 0 to 0.0050%) and the Sb content (that is, 0 to 0) are used. .0050%) flux 12 may be used.
- the total content of Sn and Sb needs to exceed the total content of Mo and W.
- the total content of Sn and Sb is less than or equal to the total content of Mo and W, especially in an environment with a large amount of incoming salt, when the coating film is damaged due to coating film deterioration, This is because it is difficult to suppress the average corrosion depth, and the coating peel resistance is lowered.
- the above-mentioned requirement can be said in other words that the index X obtained by substituting the contents of Sn, Sb, Mo, and W into the following formula is greater than zero.
- the components of the flux-cored wire 10 are preferably controlled so that the index X is 0.05 or more, 0.08 or more, or 0.10 or more.
- the balance of the chemical composition of the wire 10 is Fe and impurities.
- Fe exists as a component of the steel outer shell 11 and a component in the flux 12 (Fe powder, Fe alloy powder (eg, Fe—Mn alloy powder, Fe—Si alloy powder, etc.)).
- Fe powder is used for adjustment of components other than Fe, and its content may be 0% with respect to the total mass of the wire if not necessary.
- the upper limit of the Fe powder content may be 10.0% or less with respect to the total mass of the wire.
- Impurities are raw materials such as ore or scrap, or components mixed in due to various factors in the manufacturing process when manufacturing the wire industrially, and have an adverse effect on the manufacturing method of the wire according to the present embodiment. It means what is allowed in the range not given.
- the wire according to the present embodiment may contain O as an impurity in addition to O constituting the oxide, but such O is allowed if the content is 0 to 0.080%.
- all the O contents including the above-described Ti oxide, Si oxide, Zr oxide, Fe oxide, Al oxide, Na compound, K compound, fluorine compound, and O constituting the Bi oxide. The amount is usually 0.5 to 6.0%.
- the filling rate (ratio of the total mass of the flux to the total mass of the wire) is not particularly limited, but is 8 to 20% with respect to the total mass of the wire from the viewpoint of productivity. It is preferable to do this.
- the diameter of the wire is not particularly limited, but is preferably 1.0 to 2.0 mm in consideration of convenience during welding.
- the flux cored wire 10 according to another aspect of the present invention is the flux cored wire 10 obtained by the above-described method for manufacturing the flux cored wire 10 according to the present embodiment.
- the method for manufacturing a welded joint according to another aspect of the present invention includes the step of welding using the flux-cored wire 10 manufactured by the method for manufacturing the flux-cored wire 10 according to this embodiment described above. Is the method.
- the flux-cored wire 10 according to the present embodiment contains Cu and Sn, and the Sn content, the Sb content, the W content, and the Mo content satisfy the above-described formula 1, so the flux according to the present embodiment
- the manufacturing method of the cored wire 10 and the welded joint provides a weld metal having excellent corrosion resistance and mechanical performance in the welding of corrosion resistant steel used in environments where corrosive substances are present, such as a large amount of incoming salt. It is done.
- the flux-cored wire 10 according to this embodiment has an alloy component within the above-described predetermined range, according to the flux-cored wire 10 and the welded joint according to this embodiment, excellent pit resistance can be obtained.
- the amount of spatter is small, cracks are not generated during welding, the welding workability is good, such as the bead shape, the bead appearance, and the slag peelability are excellent, so that the welding efficiency can be improved and the quality of the welded portion can be improved.
- the use of the flux-cored wire 10 and the welded joint manufacturing method according to the present embodiment is not particularly limited, but structural steel materials that require corrosion resistance of the weld metal, in particular, harbor facilities, bridges, building / civil engineering structures and tanks, It is particularly suitable to be applied to the manufacture of steel structures such as ships / marine structures, railways and containers.
- the material of the steel material to which the manufacturing method of the flux cored wire 10 and the welded joint according to the present embodiment is not particularly limited, and may be a normal steel material such as carbon steel or low alloy steel. Weather resistant steel or low alloy steel containing Ni, Sn and the like is more advantageous from the viewpoint of weather resistance and paint corrosion resistance.
- the form of welding in which the flux-cored wire 10 according to the present embodiment is provided and the form of welding included in the method for manufacturing a welded joint according to the present embodiment are not particularly limited, but are preferably gas shielded arc welding. Also, no pits are generated, welding workability such as bead shape, bead appearance and slag peelability is good, and the coating life of the structure including the weld metal is extended. It is preferable.
- Elements such as Ti, Si, Na, and Ca contained in the flux-cored wire 10 are in the form of metal or alloy, oxide, fluoride, and carbonate in the flux-cored wire 10. This is because it is not easy to determine whether it exists. For example, it is difficult to separate Si (metal Si) existing as a metal or an alloy and Si existing as an oxide (SiO 2 ). This is because a method for performing wet analysis by selectively dissolving only metal Si has not been established. Further, when fluoride is contained in the flux 12, fluorine released from the flux 12 may damage the analytical instrument.
- the manufacturing method of the flux cored wire 10 includes a step of annealing the steel wire in which the flux 12 is encapsulated, and this annealing may change the composition of the non-metallic substance of the flux 12 to an unexpected one. It is.
- Table 1-1 to Table 1-4 are design values, and indicate mass% with respect to the total mass of the flux-cored wire (the total mass of the steel outer sheath and the flux). Further, when manufacturing the flux-cored wire, the content of each compound was controlled based on an analysis report, certificate or catalog of the chemical composition of the raw material of the flux. In Tables 1-1 to 1-4, the balance “bal.” Indicates that the balance of the chemical composition is Fe and impurities.
- a survey of welding workability was conducted.
- a horizontal fillet welding test was conducted with an automatic welder using a T-shaped fillet specimen.
- the specimen is a steel grade SM490B specified in JIS G 3106: 2008, a plate thickness of 12 mm, a specimen length of 600 mm, and an inorganic zinc primer on the steel plate surface to have a thickness of 20 to 25 ⁇ m in order to promote the generation of pits. Painted on.
- the welding conditions were the welding conditions shown in Table 2, and simultaneous welding was performed twice on both sides, and the bead shape, bead appearance, slag peelability, number of pits generated, and spatter generation amount were examined.
- the bead shape As for the bead shape, it was confirmed by visual observation whether the bead surface was flat or the bulge was not too large, and the case where the bead shape was too large was defined as “bad”.
- the appearance of the bead was determined by visual inspection to determine whether a bead breakage, bead constriction, or perforation due to a void had occurred due to arc instability. The case where no bead breakage or the like occurred was defined as “good”.
- the slag peelability is defined as “very good” when the slag is peeled off regardless of the hit by the chisel, and the slag is peeled off by hitting with the chisel (the slag does not peel off without hitting by the chisel).
- the case was determined as “good”, and the case where slag remained on the bead after hitting with a chisel was determined as “bad”.
- the pit resistance was defined as “good” when the amount of pits generated was 1 / m or less, and “bad” when the number of pits exceeded 1 / m.
- Spatter scattered during welding was collected and the mass of the spatter was measured.
- the amount of spatter generated is “high” when the sputter mass per minute is 1.5 g or more, and “slightly high” when 1.0 to 1.5 g (1.0 g or more and less than 1.5 g). "And less than 1.0 g was" less ".
- the temperature of the impact test was 0 ° C. However, impact tests at 0 ° C. and ⁇ 40 ° C. were performed on the weld metal obtained from the wire containing one or more of Ni, Ti, and B.
- the acceptance criteria for the mechanical properties of the weld metal were 510 to 660 MPa in tensile strength in the tensile test, and the impact energy was determined to be acceptable when the absorbed energy at a test temperature of 0 ° C. was 60 J or more.
- the weld metal obtained from wires containing at least one of Ti, B, and Ni has a test temperature of ⁇ 40.
- the case where the absorbed energy at 0 ° C. was 60 J or more was regarded as acceptable.
- a case where slag entrainment, blowhole, poor penetration, and crater cracking were not observed was regarded as acceptable.
- a sample for producing a corrosion test piece (thickness 3 mm ⁇ width 60 mm ⁇ length 150 mm) is deep from the surface of the base metal 1 so that the weld metal 2 is at the center.
- the sample was taken from a sampling position 3 of 1 mm, the surface was shot blasted, and then heated and dried at a furnace temperature of 80 ° C. to obtain a corrosion test piece material.
- paint A Choinese Paint Co., Ltd. Van No. # 200
- Paint B Tinto Paint Co., Ltd. Neo Gosei Primer HB
- a corrosion test piece was prepared by coating with a thickness of 200 to 350 ⁇ m. As shown in FIG. 2, a cross-cut 4 was applied to the corrosion test piece so as to straddle the weld metal 2, thereby producing a corrosion test piece 5 simulating a coating film scratch. For the crosscut 4, a scratch ridge that reaches from the top of the coating film to the underlying steel surface was applied with a cutter knife so that the rectangular dimension with the crosscut as a diagonal line was 100 mm long side ⁇ 40 mm short side. Thereafter, the corrosion resistance of the obtained corrosion test piece 5 was evaluated in accordance with SAE (Society of Automotive Engineers) J2334 test.
- SAE Society of Automotive Engineers
- the SAE J2334 test will be described.
- the SAE J2334 test is wet (50 ° C., 100% RH, 6 hours), salt adhesion (room temperature, 0.25 hour aqueous solution immersion (pH 8, 0.5 mass% NaCl, 0.1 mass% CaCl 2 , 0 0.075 mass% NaHCO 3 )) and drying (60 ° C., 50% RH, 17.75 hours) are accelerated tests conducted under dry and wet conditions with one cycle (total 24 hours).
- An outline of one cycle of the SAE J2334 test is shown in FIG.
- This corrosion test is a test that simulates a severe corrosive environment in which the amount of incoming salt exceeds 1 mdd. After 80 cycles of the SAE J2334 test, the area ratio of coating film peeling and swelling of each test piece was measured. In addition, coating adhesion was evaluated as a test reflecting the long-term paint corrosion resistance of actual structures. Paste two rows of transparent adhesive tapes with a width of 20 mm, cut to a long side length of 100 mm, over the entire area corresponding to the rectangle with the cross cut as a diagonal, and within 5 minutes after attaching the tape. It was separated at 4.0 to 8.0 seconds at an angle close to 60 °.
- the tape peeling rate obtained by dividing the coating film area peeled off by the tape peeling operation by the coating film area remaining immediately after 80 cycles of the SAE J2334 test was determined. Thereafter, the remaining coating film on the surface and the generated rust layer were removed, and after measuring the corrosion depth of the paint film ridge, the average corrosion depth was calculated.
- the case where the coating film peeling and swelling area ratio was less than 50% and the average corrosion depth of the coating film scratched part was less than 0.50 mm was regarded as acceptable.
- a tape peeling rate of 0 to less than 20% was judged as “very good”, 20% or more and less than 40% was judged as “good”, and 40% or more was judged as “bad”.
- wire No. which is an example of the present invention.
- the O content other than O constituting the compound such as an oxide is 0 to 0.080%, and the total O content including the oxide and other compounds is 0.5 to 6 0.0%.
- Wire No. containing an appropriate amount of Bi 3 to 5, 12, 13, and 15 to 22 had very good slag peelability. Further, a wire No. containing an appropriate amount of one or two of Ti and B is used. 6-8, Wire No. containing appropriate amount of Ni Wire Nos. 9 to 13, 19 to 23, and one or two of Ti and B and an appropriate amount of Ni. In Nos. 14 to 16 and 18, the absorbed energy of the weld metal at ⁇ 40 ° C. was as good as 60 J or more.
- the wire No. No. 24 had a small TiO 2 conversion value, so that the amount of slag produced was insufficient and the beads could not be encapsulated uniformly, the slag was seized, and the bead appearance was “bad”. Moreover, there was much spatter generation amount. Furthermore, since the ZrO 2 conversion value was small, the bead shape was not smooth, but became a convex bead shape, and the slag peelability was “bad”.
- Wire No. No. 25 had a large TiO 2 conversion value, so that the slag was thick and pits were generated, the viscosity of the slag was increased, and the toe portion of the bead was swollen. Further, since C is small, the tensile strength of the deposited metal and the absorbed energy at 0 ° C. were low.
- Wire No. No. 26 had a large TiO 2 conversion value and a small SiO 2 conversion value, so the slag encapsulation state was poor, and the slag peelability, bead shape and bead appearance were poor. Further, since the amount of C is large, the tensile strength of the weld metal becomes excessively high, resulting in a decrease in ductility. Therefore, the absorbed energy at 0 ° C. is low. Wire No. No. 27 has a large SiO 2 equivalent value, so the amount of spatter generated increased and pits were also generated. Moreover, since the ZrO 2 conversion value was large, the bead shape was convex.
- Wire No. 28 the FeO equivalent value was small, so the shape of the bead toe portion was poor. Further, since the amount of Si was small, pits were generated, and the tensile strength of the deposited metal and the absorbed energy at 0 ° C. were low. Wire No. No. 29 has a large FeO conversion value, so the slag encapsulation state was poor, the slag peelability was poor, the bead toe swelled, and the bead shape and bead appearance were also “bad”. Moreover, since the amount of Sn was large, crater cracks occurred.
- Wire No. No. 30 had a small equivalent value of Al 2 O 3, so an undercut occurred on the upper leg side, and the bead shape was “bad”. Further, the amount of Si was excessive, the tensile strength of the deposited metal was high, and the absorbed energy at 0 ° C. was low due to the decrease in ductility. Wire No. No. 31 had a large Al 2 O 3 converted value, so that the bead toe portion swelled, the conformability deteriorated, and the bead shape was “bad”. Moreover, pits were generated because the amount of Mg was small.
- Wire No. 32 the amount of Cu was excessive, and the absorbed energy of the weld metal at 0 ° C. was low. Further, since the amount of Al was small, the bead became convex and an undercut occurred in the upper leg portion. Wire No. Since No. 33 had a large amount of Al, the bead shape was not smooth and the toe portion swelled, and even in the molten slag, solidification unevenness occurred and the slag peelability was “bad”. Further, since the amount of Mg was large, the arc became rough and the amount of spatter was large. Further, since the amount of Mn is large, the tensile strength of the weld metal is high, and the absorbed energy at 0 ° C. is low due to the decrease in ductility.
- Wire No. No. 34 had a small amount of Sn, so that the area ratio of coating film peeling and swelling of the deposited metal was large, and the average corrosion depth of the scratches on the coating film was also deep. Further, since the Bi-converted value was large, the bead appearance was “bad”. Wire No. No. 35 had a large sum of Na 2 O converted value and K 2 O converted value, so that the amount of spatter was large, and the slag peelability, bead shape and bead appearance were “bad”. Further, since the amount of Mn was small, pits were generated, and the tensile strength of the deposited metal and the absorbed energy at 0 ° C. were low.
- Wire No. No. 36 had a small amount of Cu, so that the area ratio of peeling and swelling of the deposited metal film was large, and the average corrosion depth of the scratched part of the coating film was also deep. Further, since the F conversion value was small, the conformability of the lower leg portion on the lower plate side was poor, the bead shape was “bad”, and pits were generated. Furthermore, since the amount of B is large, crater cracks occurred. Wire No. No. 37 had a small amount of Sn, so that the area ratio of coating film peeling and swelling of the deposited metal was large, and the average corrosion depth of the coating film scratch was also deep. Moreover, since the F conversion value was large, the viscosity of the slag was lowered, the bead shape was convex, and the slag peelability was “bad”.
- Wire No. In No. 38 pits occurred because the Mg amount was small. Further, since the amount of Ti was large, the amount of spatter was large, slag was seized on the bead surface, and the bead appearance was “bad”. Wire No. In No. 39, since the total of Na 2 O converted value and K 2 O converted value was small, the arc became unstable, a large amount of spatter was generated, the bead shape and bead appearance became “bad”, and pits were also generated. Moreover, since the amount of Ni was large, crater cracks occurred.
- Wire No. 40 the index X was 0 or less, the average corrosion depth just below the scratched part of the weld metal coating film was deep, and the coating film adhesion was “bad”.
- Wire No. No. 41 has an index X of 0 or less, a large area ratio of peeling and swelling of the coating film of the weld metal, a large average corrosion depth just below the scratched part of the coating film, and a poor coating adhesion. It was.
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Abstract
Description
[1] 本発明の一態様に係るフラックス入りワイヤの製造方法は、鋼製外皮の内部にフラックスが充填されたフラックス入りワイヤの製造方法であって、
鋼板を円形に成形しながら、前記鋼板の内部にフラックスを充填する工程と、
前記鋼板の両端を接合して鋼管とする工程と、
前記鋼管に圧延及び焼鈍を施して、前記フラックス入りワイヤを得る工程と、
を備え、
前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの全質量に対する質量%で、
C:0.03~0.10%、
Si:0.40~0.85%、
Mn:1.5~3.5%、
P:0.020%以下、
S:0.020%以下、
Cu:0.03~0.70%、
Sn:0.05~0.30%、
Mg:0.05~0.50%、
Al:0.05~0.50%、
Ti酸化物:TiO2換算値で1.50~4.60%未満、
Si酸化物:SiO2換算値で0.30~1.00%、
Zr酸化物:ZrO2換算値で0.10~0.50%、
Fe酸化物:FeO換算値で0.10~1.00%、
Al酸化物:Al2O3換算値で0.05~0.50%、
Na化合物及びK化合物の合計:Na2O換算値及びK2O換算値の合計で0.050~0.200%、
弗素化合物:F換算値で0.02~0.20%、
Bi及びBi酸化物の合計:Bi換算値で0~0.035%、
Ni:0~2.50%、
Ti:0~0.30%、
B:0~0.010%、
Mo:0~0.400%、
W:0~0.200%、
Cr:0~0.500%、
Nb:0~0.300%、
V:0~0.300%、
N:0~0.0080%、
Ca:0~0.0050%、
REM:0~0.0050%、
Sb:0~0.0050%、
残部:Fe及び不純物であり、
Sn含有量、Sb含有量、W含有量、及びMo含有量が以下の式1を満たす。
Sn+Sb>Mo+W :式1
ただし、前記式1における元素記号は、各元素記号に係る元素の含有量を、前記フラックス入りワイヤの前記全質量に対する質量%で示すものである。
[2] 上記[1]に記載のフラックス入りワイヤの製造方法では、前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの前記全質量に対する質量%で、
Mo:0~0.040%
W:0~0.010%、
であってもよい。
[3] 上記[1]または[2]に記載のフラックス入りワイヤの製造方法では、前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの前記全質量に対する質量%で、
Cu:0.05~0.70%、
であってもよい。
[4] 上記[1]~[3]のいずれか一項に記載のフラックス入りワイヤの製造方法では、前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの前記全質量に対する質量%で、少なくとも下記のいずれかひとつを満たしてもよい。
Ni:0.10~2.50%
Ti:0.03~0.30%
B:0.002~0.010%
[5] 上記[1]~[4]のいずれか一項に記載のフラックス入りワイヤの製造方法では、前記接合がかしめであってもよい。
[6] 上記[1]~[4]のいずれか一項に記載のフラックス入りワイヤの製造方法では、前記接合が溶接であってもよい。
[7] 本発明の別の態様に係るフラックス入りワイヤは、上記[1]~[6]のいずれか一項に記載のフラックス入りワイヤの製造方法によって製造されるフラックス入りワイヤである。
[8] 本発明の別の態様に係る溶接継手の製造方法は、上記[1]~[6]のいずれか一項に記載のフラックス入りワイヤの製造方法によって製造されるフラックス入りワイヤを用いて溶接する工程を備える。
先ず、本発明者らは、飛散塩分量が多い腐食環境での耐食性について、ワイヤ中の化学組成(以下、「化学成分」という場合もある。)の影響を調査した。この結果、フラックス入りワイヤの化学成分として、Cu及びSnを添加することにより、飛散塩分量が多い腐食環境での耐食性を向上させることが可能であるという知見を得た。
Cは、溶接構造物に要求される溶接金属の強度及び靭性を得るためにワイヤ中に含有される元素である。Cは、鋼製外皮11に含まれる成分の他、フラックス12中のFe-Si、Fe-Mn及びFe-Si-Mn等の鉄合金が微量含有する金属粉に含まれ得る。C含有量が0.03%未満では、溶接金属の強度及び靭性が低下する。一方、C含有量が0.10%を超えると、溶接金属の強度が高くなることにより、溶接金属の靭性が低下する。従って、C含有量は0.03~0.10%とする。好ましくは、C含有量の下限値は0.04%、又は0.05%である。好ましくは、C含有量の上限値は0.09%、又は0.08%である。 なお、Cは、鋼製外皮11の成分、及びフラックス12中の金属粉及び合金粉の成分として存在し得る。つまり、鋼製外皮11のC含有量およびフラックス12のC含有量を制御することにより、前記のC含有量のフラックス入りワイヤ10を製造することができる。
Siは、脱酸剤として作用する元素であり、且つ溶接金属の強度及び靭性を確保するためにワイヤ中に含有される元素である。Siは、鋼製外皮11に含まれる成分の他、フラックス12中の金属Si、Fe-Si及びFe-Si-Mn等に含まれ得る。Si含有量が0.40%未満では、脱酸不足によりピットが発生する。また、Si含有量が0.40%未満では、溶接金属の強度及び靭性が低下する。一方、Si含有量が0.85%を超えると、溶接金属の強度が高くなることにより、溶接金属の靭性が低下する。従って、Si含有量は0.40~0.85%とする。好ましくは、Si含有量の下限値は0.55%、又は0.65%である。好ましくは、Si含有量の上限値は0.75%、又は0.70%である。
なお、Siは、鋼製外皮11の成分、及びフラックス12中の金属Si、Fe-Si、Fe-Si-Mn等の合金粉の成分として存在し得る。つまり、鋼製外皮11のSi含有量およびフラックス12のSi含有量を制御することにより、前記のSi含有量のフラックス入りワイヤ10を製造することができる。
Mnは、脱酸剤として作用する元素であるとともに、溶接金属の強度及び靭性を確保するためにワイヤ中に含有される元素である。Mn含有量が1.5%未満では、脱酸不足となり、ピットが発生する。また、Mn含有量が1.5%未満では、溶接金属の強度及び靭性も低下する。一方、Mn含有量が3.5%を超えると、溶接金属の強度が高くなることにより、溶接金属の靭性が低下する。従って、Mn含有量は、1.5~3.5%とする。好ましくは、Mn含有量の下限値は2.4%、又は2.6%である。好ましくは、Mn含有量の上限値は3.0%、又は2.8%である。
なお、Mnは、鋼製外皮11の成分、及びフラックス12中の金属Mn、Fe-Mn、Fe-Si-Mn等の合金粉の成分として存在し得る。つまり、鋼製外皮11のMn含有量およびフラックス12のMn含有量を制御することにより、前記のMn含有量のフラックス入りワイヤ10を製造することができる。
[S:0.020%以下]
P及びSは、溶接金属の機械的特性に悪影響を与え、また、溶接金属の耐食性を損なう場合がある元素であるので、ワイヤに一切含まれないことが最も好ましい。従って、P及びSの含有量の下限値は0%である。しかしながら、P及びSをワイヤの材料から完全に除去するためには多くの費用を必要とするので、溶接金属の諸特性を損なわない範囲内でP及びSが含有されてもよい。本実施形態に係るフラックス入りワイヤ10では、0.020%以下のP、及び0.020%以下のSが許容される。P又はSの上限値を0.015%、0.010%、又は0.005%としてもよい。P又はSの下限値を0.001%、0.002%、又は0.005%としてもよい。
前記のCおよびSiと同様に、鋼製外皮11のP含有量およびS含有量並びにフラックス12のP含有量およびS含有量を制御することにより、前記のP含有量およびS含有量のフラックス入りワイヤ10を製造することができる。
Cuは、溶接金属の耐食性を向上させる作用を有する元素である。Cu含有量が0.03%未満では、溶接金属の耐食性が劣る。一方、Cu含有量が0.70%を超えると、溶接金属の耐食性が向上される効果は飽和する。また、Cu含有量が0.70%を超えると、溶接金属の靭性が低下する。従って、Cu含有量は、0.03~0.70%とする。好ましくは、Cu含有量の下限値は0.05%、0.15%、0.17%、又は0.20%である。好ましくは、Cu含有量の上限値は0.35%、0.32%、又は0.30%である。
なお、Cuは、鋼製外皮11自体の成分、鋼製外皮11のめっき成分、又はフラックス12中の金属Cu等として存在し得る。つまり、鋼製外皮11のCu含有量、めっきのCu含有量およびフラックス12のCu含有量を制御することにより、前記のCu含有量のフラックス入りワイヤ10を製造することができる。
Snは、溶接金属の耐食性を向上させる効果を有する元素である。Sn含有量が0.05%未満では、耐食性が劣る。一方、Sn含有量が0.30%を超えると、高温割れが生じ易くなる。従って、Sn含有量は、0.05~0.30%とする。好ましくは、Sn含有量の下限値は0.10%、又は0.12%である。好ましくは、Sn含有量の上限値は0.25%、0.20%、又は0.18%である。
なお、Snは、鋼製外皮11の成分として含有されてもよいし、フラックス12中の金属Sn又はSn化合物として含有されてもよい。主に、鋼製外皮11のSn含有量およびフラックス12のSn含有量を制御することにより、前記のSn含有量のフラックス入りワイヤ10を製造することができる。
Mgは、強脱酸剤として作用することによって、ピット発生を防止する効果を有する元素である。Mg含有量が0.05%未満であると、脱酸剤としての効果が無く、ピットが発生する。一方、Mg含有量が0.50%を超えると、アークが荒くなりスパッタ発生量が多くなる。従って、Mg含有量は、0.05~0.50%とする。好ましくは、Mg含有量の下限値は0.15%、0.18%、又は0.20%である。好ましくは、Mg含有量の上限値は0.35%、0.30%、又は0.25%である。
一般的な鋼製外皮11のMg含有量は殆ど0%である。このため、Mgは、フラックス12中の金属Mg、Al-Mg等の合金粉末としてワイヤに存在することが多い。つまり、主にフラックス12のMg含有量を制御することにより、前記のMg含有量のフラックス入りワイヤ10を製造することができる。
Alは、脱酸剤として作用する元素であるとともに、溶融スラグ中でAl酸化物となることによってスラグの粘性を高めて、水平すみ肉溶接時に溶融プールの後退を抑制して十分なスラグ被包性を保持する作用を有する元素である。Al含有量が0.05%未満では、ビード形状が凸状になり、上脚部にアンダーカットが発生する。一方、Al含有量が0.50%を超えると、ビード形状に滑らかさがなくなることにより、ビードの止端部が膨らんだ形状となる。また、Al含有量が0.50%を超えると、溶融スラグの凝固むらが生じてスラグ剥離性が不良となる。従って、Al含有量は、0.05~0.50%とする。好ましくは、Al含有量の下限値は0.07%、0.10%、又は0.15%である。好ましくは、Al含有量の上限値は0.25%、又は0.20%である。
なお、Alは、鋼製外皮11の成分、又はフラックス12中の金属Al粉、Fe-Al合金粉、Al-Mg合金粉などとして存在し得る。つまり、主に、鋼製外皮11のAl含有量およびフラックス12のAl含有量を制御することにより、前記のAl含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のAl含有量を上記範囲内とするため、前記のAl含有量の鋼製外皮11および前記のAl含有量のフラックス12を使用してもよい。
スラグ成分であるTi酸化物は、ビード全体を均一にスラグで被包させる作用を有する。また、Ti酸化物は、アークの持続を安定させ、スパッタ発生量を低減させる効果を有する。
なお、Ti酸化物は、主に、フラックス12中のルチル、酸化チタン、チタンスラグ、イルミナイト、チタン酸ソーダ、チタン酸カリ等として存在し得る。このため、主に、フラックス12のTi酸化物の含有量を制御することにより、前記のTi酸化物の含有量のフラックス入りワイヤ10を製造することができる。
(TiO2換算値)=(Ti酸化物を形成するTiのワイヤ全質量に対する質量%)×(TiO2の式量)/(Tiの原子量)
なお、Si酸化物のSiO2換算値、Zr酸化物のZrO2換算値、FeO酸化物のFe換算値、Al酸化物のAl2O3換算値も、同様の計算により得られる。
スラグ成分であるSi酸化物は、溶融スラグの粘性を高め、スラグ剥離性を改善する作用を有する。Si酸化物のSiO2換算値が0.30%未満では、スラグ被包状態が悪くスラグ剥離性が不良になり、ビード形状及びビード外観も不良になる。一方、Si酸化物のSiO2換算値が1.00%を超えると、スパッタ発生量が多くなる。さらに、Si酸化物のSiO2換算値が1.00%を超えると、ピット及びガス溝等が発生し易くなる。従って、Si酸化物のSiO2換算値は、0.30~1.00%とする。好ましくは、Si酸化物のSiO2換算値の下限値は0.50%、又は0.60%である。好ましくは、Si酸化物のSiO2換算値の上限値は0.90%、又は0.80%である。
なお、Si酸化物は、主に、フラックス12中の珪砂、ジルコンサンド、長石、珪酸ソーダ、珪酸カリ等として存在し得る。このため、主に、フラックス12のSi酸化物の含有量を制御することにより、前記のSi酸化物の含有量(SiO2換算値で0.30~1.00%)のフラックス入りワイヤ10を製造することができる。
スラグ成分であるZr酸化物は、水平すみ肉溶接でスラグ被包性を高めてビード形状を平滑にする作用を有する。Zr酸化物のZrO2換算値が0.10%未満では、ビード形状が平滑にならず、凸状のビード形状となり、スラグ剥離性が不良となる。一方、Zr酸化物のZrO2換算値が0.50%を超えると、ビード形状が凸状になりやすい。従って、Zr酸化物のZrO2換算値は、0.10~0.50%とする。好ましくは、Zr酸化物のZrO2換算値の下限値は0.15%、又は0.20%である。好ましくは、Zr酸化物のZrO2換算値の上限値は0.40%、又は0.30%である。
なお、Zr酸化物は、主に、フラックス12中のジルコンサンド、酸化ジルコニウム等として存在し得るものであり、また、上述のTi酸化物に微量含有される場合もある。このため、主に、フラックス12のZr酸化物の含有量を制御することにより、前記のZr酸化物の含有量(ZrO2換算値で0.10~0.50%)のフラックス入りワイヤ10を製造することができる。
FeO、Fe2O3等のFe酸化物は、溶融スラグの粘性及び凝固温度を調整する作用を有し、ビード止端部の膨らみを無くし、下板とのなじみ性を良好にする作用を有する。Fe酸化物のFeO換算値が0.10%未満であると、ビード止端部が膨らむことによって、ビード止端部の形状が不良になる。一方、Fe酸化物のFeO換算値が1.00%を超えると、スラグ被包状態が悪くなり、スラグ剥離性が不良でビード止端部が膨らみ、ビード形状及びビード外観も不良となる。従って、Fe酸化物のFeO換算値は、0.10~1.00%とする。好ましくは、Fe酸化物のFeO換算値の下限値は0.20%、0.30%、又は0.40%である。好ましくは、Fe酸化物のFeO換算値の上限値は0.80%、0.70%、又は0.60%である。
なお、Fe酸化物は主にフラックス12に存在する場合が多く、主に、フラックス12のFe酸化物の含有量を制御することにより、前記のFe酸化物の含有量(FeO換算値で0.10~1.00%)のフラックス入りワイヤ10を製造することができる。
Al酸化物は、溶融スラグを構成した場合、スラグ被包性を良好にすることにより、すみ肉ビードの上脚側のアンダーカットを防止する作用を有する。Al酸化物のAl2O3換算値が0.05%未満では、すみ肉ビードの上脚側にアンダーカットが生じやすくなる。一方、Al酸化物のAl2O3換算値が0.50%を超えると、すみ肉ビードの下脚側のビード止端部が膨らんだビード形状となる。従って、Al酸化物のAl2O3換算値は、0.05~0.50%とする。好ましくは、Al酸化物のAl2O3換算値の下限値は0.10%、0.15%、又は0.20%である。好ましくは、Al酸化物のAl2O3換算値の上限値は0.35%、0.30%、又は0.25%である。
なお、Al酸化物は、主にフラックス12中のアルミナ、長石等の成分として存在する場合が多い。このため、主に、フラックス12のAl酸化物の含有量を制御することにより、前記のAl酸化物の含有量(Al2O3換算値で0.05~0.50%)のフラックス入りワイヤ10を製造することができる。
Na化合物及びK化合物には、アーク安定剤としての作用だけではなく、スラグ形成剤として溶融スラグの凝固過程の急激な粘性増加を抑えて耐ピット性を高めることによって、平滑なビード形状にする作用がある。Na化合物及びK化合物は、フラックス中の珪酸ソーダ及び珪酸カリ等からなる水ガラスの固質成分、弗化ソーダや珪弗化カリ等の弗素化合物として存在し得る。
通常の鋼製外皮11のNa化合物及びK化合物の含有量はほぼ0%である。このため、主にフラックス12のNa化合物及びK化合物の含有量を制御することにより、前記のNa化合物及びK化合物の含有量(Na2O換算値及びK2O換算値の合計で0.050~0.200%)のフラックス入りワイヤ10を製造することができる。
スラグ成分である弗素化合物は、アークの指向性を高めて安定した溶融プールにする作用を有するとともに、スラグの粘性を調整してビード形状を平滑にする作用並びに耐ピット性を良好にする作用を有する。弗素化合物は、フラックス12中の弗化マグネシウム、氷晶石、弗化ソーダや珪弗化カリ等として存在し得る。通常の鋼製外皮11の弗素化合物の含有量はほぼ0%である。このため、主にフラックス12の弗素化合物の含有量を制御することにより、前記の弗素化合物の含有量(F換算値で0.02~0.20%)のフラックス入りワイヤ10を製造することができる。
なお、弗素化合物のF換算値とは、ワイヤ中のすべての弗素化合物に含まれるFの、ワイヤ全質量に対する質量%での含有量の総量である。
Biは、スラグ剥離性を向上させ、ビード表面に光沢を出し、ビード外観を良好にする作用を有するので、ワイヤ10に含まれても良い。Biは、鋼製外皮に含まれる成分の他、フラックス12中の金属Biや酸化Bi等として存在し得る。しかし、金属Bi及びBi酸化物のBi換算値の合計が0.035%を超えると、ビード上部のスラグが流れて、ビード全面をスラグで被包することができなくなり、ビード外観が不良となる。従って、フラックス12中の金属Bi及びBi酸化物のBi換算値の合計は、0.035%以下とする。好ましくは、金属Bi及びBi酸化物のBi換算値の合計の上限値は0.030%、又は0.025%である。なお、スラグ剥離性を向上させる効果を得るためには金属Bi及びBi酸化物のBi換算値の合計の下限値は、0.005%、0.010%、又は0.015%とすることが好ましい。
[Ti:0~0.30%]
[B:0~0.010%]
Ni、Ti及びBは、溶接金属の低温における靭性を確保するためにワイヤ10中に含有させてもよい。しかし、Ni含有量が2.50%を超えると、高温割れが生じやすくなる。従って、Ni含有量は、2.50%以下とする。好ましくは、Ni含有量の上限値は2.30%、2.00%、又は1.50%である。なお、溶接金属の低温における靭性を確保するためには、Ni含有量の下限値を0.10%、又は0.20%とすることが好ましい。
Ni:0.10~2.50%
Ti:0.03~0.30%
B:0.002%~0.010%
Moは溶接金属の強度を向上させる効果を有するので、ワイヤ10中に含まれてもよい。しかし、Mo含有量が0.400%を超えると、特に飛来塩分量が多い環境下において塗膜傷が生じた場合、Snのイオン化と競合することで塗膜傷部直下の平均腐食深さが抑制できなくなる。したがって、Mo含有量の上限は0.400%とすることが好ましい。また、溶接金属の強度を向上させる効果を得るためには、Mo含有量の下限を0.010%とすることが好ましい。好ましいMo含有量の上限値は、0.300%、0.100%、又は0.040%である。
なお、Moは、鋼製外皮11の成分、フラックス12中の金属Mo、Fe-Mo等の合金粉末としてワイヤ10に存在し得る。つまり、主に、鋼製外皮11のMo含有量およびフラックス12のMo含有量を制御することにより、前記のMo含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のMo含有量を前記範囲内とするため、前記のMo含有量(つまり、0~0.400%)の鋼製外皮11および前記のMo含有量(つまり、0~0.400%)のフラックス12を使用してもよい。
Wは、溶接金属の強度向上に寄与することからワイヤ10中に含まれても良い。しかし、W含有量が0.200%を超えると、特に飛来塩分量が多い環境下において塗膜傷が生じた場合、Snのイオン化と競合することで塗膜傷部直下の平均腐食深さが抑制できなくなる。したがって、W含有量の上限は0.200%とする。好ましいW含有量の上限値は、0.150%、0.100%、又は0.010%である。
なお、Wは、鋼製外皮11の成分として、または、フラックス12中の金属W等の合金粉末としてワイヤ10に存在し得る。つまり、主に、鋼製外皮11のW含有量およびフラックス12のW含有量を制御することにより、前記のW含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のW含有量を前記範囲内とするため、前記のW含有量(つまり、0~0.200%)の鋼製外皮11および前記のW含有量(つまり、0~0.200%)のフラックス12を使用してもよい。
Crは、溶接金属の強度向上に寄与することからワイヤ中に含まれても良い。しかし、Cr含有量が0.500%を超えると、特に飛来塩分量が多い環境下において塗膜傷が生じた場合、Snのイオン化と競合することで塗膜傷部直下の腐食深さが抑制できなくなる。したがって、Cr含有量の上限は0.500%とすることが好ましい。好ましいCr含有量の上限値は、0.100%、又は0.050%である。
なお、Crは、鋼製外皮11の成分として、または、フラックス12中の金属Cr、Fe-Cr等の合金粉末の合金粉末としてワイヤに存在し得る。つまり、主に、鋼製外皮11のCr含有量およびフラックス12のCr含有量を制御することにより、前記のCr含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のCr有量を前記範囲内とするため、前記のCr含有量(つまり、0~0.500%)の鋼製外皮11および前記のCr含有量(つまり、0~0.500%)のフラックス12を使用してもよい。
Nbは、析出強化により溶接金属の強度向上に寄与することからワイヤ10中に含まれても良い。しかし、Nb含有量が0.300%を超えると、Nbが粗大な析出物を形成して溶接金属の靭性が低下する。したがって、Nb含有量の上限値は0.300%とする。Nb含有量の上限値を0.250%、又は0.200%としてもよい。上述の効果を得るために、Nb含有量の下限値を0.050%、又は0.100%としてもよい。
なお、Nbは、鋼製外皮11の成分として、または、フラックス12中の金属Nb、Fe-Nb等の合金粉末の合金粉末としてワイヤ10に存在し得る。つまり、主に、鋼製外皮11のNb含有量およびフラックス12のNb含有量を制御することにより、前記のNb含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のNb含有量を前記範囲内とするため、前記のNb含有量(つまり、0~0.300%)の鋼製外皮11および前記のNb含有量(つまり、0~0.300%)のフラックス12を使用してもよい。
Vは、溶接金属の強度向上に寄与することからワイヤ10中に含まれても良い。しかし、V含有量が0.300%を超えると、溶接金属の強度が過剰に高くなり、溶接金属の靭性が低下する。したがって、V含有量は0.300%以下とする。溶接金属の強度を向上させる効果を得るためには、V含有量を0.010%以上とすることが好ましい。好ましいV含有量の上限値は、0.200%、又は0.100%である。
なお、Vは、鋼製外皮11の成分として、または、フラックス12中の金属V、Fe-V等の合金粉末の合金粉末としてワイヤ10に存在し得る。つまり、主に、鋼製外皮11のV含有量およびフラックス12のV含有量を制御することにより、前記のV含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のV含有量を前記範囲内とするため、前記のV含有量(つまり、0~0.300%)の鋼製外皮11および前記のV含有量(つまり、0~0.300%)のフラックス12を使用してもよい。
Nは、溶接金属の靱性等を損なわせる元素であるので、ワイヤ10に一切含まれないことが最も好ましい。従って、N含有量の下限値は0%である。しかしながら、Nをワイヤの材料から完全に除去するためには多くの費用が必要とされるので、溶接金属の諸特性を損なわない範囲内でNが含有されてもよい。本実施形態に係るフラックス入りワイヤ10では、0.0080%以下のNが許容される。N含有量の上限値を0.0070%、0.0060%、又は0.0050%としてもよい。フラックス入りワイヤ10のN含有量を前記範囲内とするため、前記のN含有量(つまり、0~0.0080%)の鋼製外皮11および前記のV含有量(つまり、0~0.0080%)のフラックス12を使用してもよい。
[REM:0~0.0050%]
Ca及びREMは、硫化物及び酸化物の形態を変化させることで溶接金属の延性及び靭性を向上させる効果を有する。この効果を得るために、Ca含有量を0.0002%以上としてもよく、REM含有量を0.0002%以上としてもよい。一方、Ca及びREMは、スパッタ量を増大させ、溶接性を損なう元素でもある。従って、Ca含有量の上限値は0.0050%であり、REM含有量の上限値は0.0050%である。Ca含有量の上限値を0.0040%、又は0.0030%としてもよい。REM含有量の上限値を0.0040%、又は0.0030%としてもよい。
なお、CaおよびREMは、鋼製外皮11の成分として、または、フラックス12中のCa化合物またはREM化合物としてワイヤ10に存在し得る。つまり、主に、鋼製外皮11のCa含有量およびREM含有量並びにフラックス12のCa含有量およびREM含有量を制御することにより、前記のCa含有量およびREM含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のCa含有量およびREM含有量を前記範囲内とするため、前記のCa含有量(つまり、0~0.0050%)およびREM含有量(つまり、0~0.0050%)の鋼製外皮11および前記のCa含有量(つまり、0~0.0050%)およびREM含有量(つまり、0~0.0050%)のフラックス12を使用してもよい。
Sbは、Snと同様に耐候性及び耐塗装剥離性を溶接金属に付与する元素である。従って、Sb含有量を0.0010%、又は0.0020%としてもよい。しかしながら、Sb含有量が0.0050%を超えると、溶接金属の粒界へのSbの偏析により、溶接金属の靭性が低下する。従って、Sb含有量の上限値は0.0050%とする。Sb含有量の上限値を0.0040%、又は0.0030%としてもよい。
なお、Sbは、鋼製外皮11の成分として、または、フラックス12中の金属SbまたはSb化合物等の合金粉末の合金粉末としてワイヤ10に存在し得る。つまり、主に、鋼製外皮11のSb含有量およびフラックス12のSb含有量を制御することにより、前記のSb含有量のフラックス入りワイヤ10を製造することができる。また、フラックス入りワイヤ10のSb有量を前記範囲内とするため、前記のSb含有量(つまり、0~0.0050%)の鋼製外皮11および前記のSb含有量(つまり、0~0.0050%)のフラックス12を使用してもよい。
本実施形態に係るフラックス入りワイヤ10の製造方法において、Sn及びSbの合計含有量は、Mo及びWの合計含有量を超える必要がある。Sn及びSbの合計含有量がMo及びWの合計含有量以下である場合、特に飛来塩分量が多い環境下においては、塗膜劣化によって塗膜傷が生じた場合に、塗膜傷部直下の平均腐食深さの抑制が困難であり、耐塗装剥離性が低下するからである。なお、上述の要件は、Sn、Sb、Mo、及びWの含有量を以下の式に代入して得られる指数Xが0超である、と換言することができる。この指数Xが0.05以上、0.08以上、又は0.10以上となるように、フラックス入りワイヤ10の成分が制御されることが好ましい。
JIS G 3141:2011で規定されるSPCCを鋼製外皮として使用してフラックスを充填後、縮径して(外皮の軟化および脱水素のため中間焼鈍を1回実施)、表1-1~表1-4に示す成分(数値はワイヤの全質量に対する質量%で示す)を有し、充填率13.5%、ワイヤ径1.2mmの鋼製外皮に貫通した隙間が無いシームレスタイプのフラックス入りワイヤを各種試作した。ただし、A21はかしめによって製造した。なお、表1-1~表1-4に記載の値は、設計値であり、フラックス入りワイヤの全質量(鋼製外皮とフラックスとの合計の質量)に対する質量%を示す。また、フラックス入りワイヤの製造の際には、フラックスの原料の化学組成の分析報告書、証明書またはカタログなどに基づいて、各化合物の含有量を制御した。なお、表1-1~表1-4中の残部「bal.」は、化学組成の残部がFe及び不純物であることを示す。
ビード外観は、目視により、アーク不安定に起因したビード切れ、ビードくびれ、ボイドによる穴あきが生じたか否かを判断し、これらビード切れ等が生じた場合を「不良」とした。これらビード切れ等が生じなかった場合を「良好」とした。
スラグ剥離性は、たがねによる打撃によらずスラグが剥離した場合を「非常に良好」とし、(たがねによる打撃なしではスラグが剥離せず)たがねによる打撃によりスラグが剥離した場合を「良好」とし、たがねによる打撃の後もビード上にスラグが残留した場合を「不良」とした。
耐ピット性は、ピット発生量が1個/m以下の場合を「良好」とし、1個/m超の場合を「不良」とした。
溶接中に飛散するスパッタを捕集し、スパッタの質量を測定した。スパッタ発生量は、1分間の時間あたりのスパッタ質量が1.5g以上の場合を「多い」とし、1.0~1.5g(1.0g以上、1.5g未満)の場合を「やや多い」とし、1.0g未満の場合を「少ない」とした。
SAE J2334試験の80サイクル後に、各試験片の塗膜剥離及び膨れの面積率を計測した。また、実構造物の長期にわたる塗装耐食性能を反映する試験として塗膜密着性の評価を行った。クロスカットを対角線とする長方形に相当する領域の全面に対し、長方形の長辺長さ100mmに切りだした幅20mmの透明付着テープをお互いに重ならないように2列貼付け、テープ付着後5分以内に60°に近い角度にて4.0~8.0秒で引き離した。テープによる引き剥がし操作にて剥離した塗膜面積を、SAE J2334試験の80サイクル直後に残存していた塗膜面積にて除して得られたテープ剥離率を求めた。その後、表面の残存塗膜と生成した錆層を除去し、塗装被膜疵部の腐食深さを測定後、平均腐食深さを算出した。
耐候性・耐塗装剥離性の評価は、塗膜剥離及び膨れ面積率が50%未満、かつ、塗膜傷部の平均腐食深さが0.50mm未満の場合を合格とした。また、塗膜密着性の評価は、テープ剥離率が0~20%未満を「非常に良好」とし、20%以上40%未満を「良好」とし、40%以上を「不良」と判定した。
i)溶接作業性の各評価項目にて「不良」の評価がないこと(スパッタ発生量については「多い」を「不良」とし、「やや多い」および「少ない」は「不良」としない。)。
ii)X線透過試験は「欠陥なし」の評価であること。
iii)溶着金属試験で「合格」の判定であること。
iv)溶接部の耐食性評価試験において「合格」の判定であること。(ただし、「塗膜密着性」の評価は、溶着金属の耐食性のみならず鋼材の塗装耐食性の影響も受ける可能性があることから、総合評価の判断に含めないこととした。)
本発明例であるワイヤNo.1~24は、TiO2換算値、SiO2換算値、ZrO2換算値、FeO換算値、Al2O3換算値、C、Si、Mn、Cu、Al、Sn、Mg、Na2O換算値とK2O換算値の合計及びF換算値が適量であるので、ビード形状、ビード外観及びスラグ剥離性が「不良」ではなく、ピットの発生が少なく、スパッタ発生量が「多い」ではなく、X線透過試験で欠陥(クレータ割れ)が無く、溶着金属の引張強さ及び吸収エネルギーも合格判定基準値以上であった。また、耐食性評価試験結果も良好であり、合格判定基準値以上であった。なお、本発明例であるワイヤNo.1~23は、酸化物等の化合物を構成するO以外のO含有量が0~0.080%であり、酸化物等の化合物を含めた、全てのOの含有量は0.5~6.0%であった。
また、Ti及びBの1種又は2種を適量含むワイヤNo.6~8、Niを適量含むワイヤNo.9~13、および19~23及びTi及びBの1種又は2種とNiを適量含むワイヤNo.14~16および18は、-40℃における溶着金属の吸収エネルギーが60J以上と良好であった。
ワイヤNo.27は、SiO2換算値が大きいので、スパッタ発生量が多くなり、ピットも発生した。また、ZrO2換算値が大きいので、ビード形状が凸状であった。
ワイヤNo.29は、FeO換算値が大きいので、スラグ被包状態が悪くスラグ剥離性が不良となり、ビード止端部が膨らみビード形状及びビード外観も「不良」であった。また、Sn量が多いのでクレータ割れが発生した。
ワイヤNo.31は、Al2O3換算値が大きいので、ビード止端部が膨らみ、なじみ性が悪くなり、ビード形状が「不良」であった。また、Mg量が少ないのでピットが発生した。
ワイヤNo.33は、Al量が多いので、ビード形状に滑らかさがなくなり、止端部が膨らんだ形状となり、溶融スラグにおいても凝固むらが生じてスラグ剥離性が「不良」であった。また、Mg量が多いので、アークが荒くなり、スパッタ発生量も多かった。さらに、Mn量が多いので、溶着金属の引張強さが高く、延性低下に起因して0℃での吸収エネルギーが低値であった。
ワイヤNo.35は、Na2O換算値とK2O換算値の合計が大きいので、スパッタ発生量が多く、スラグ剥離性、ビード形状及びビード外観が「不良」であった。また、Mn量が少ないので、ピットが発生し、溶着金属の引張強さ及び0℃での吸収エネルギーが低値であった。
ワイヤNo.37は、Sn量が少ないので、溶着金属の塗膜剥離及び膨れの面積率が大きく、塗膜傷部の平均腐食深さも深かった。また、F換算値が大きいので、スラグの粘性が低下し、ビード形状が凸状で、スラグ剥離性も「不良」であった。
ワイヤNo.39は、Na2O換算値とK2O換算値の合計が少ないので、アークが不安定になり大粒のスパッタ発生量が多く、ビード形状及びビード外観が「不良」となり、ピットも発生した。また、Ni量が多いので、クレータ割れが生じた。
ワイヤNo.41は、指数Xが0以下となり、溶着金属の塗膜剥離及び膨れの面積率が大であるとともに、塗膜傷部直下の平均腐食深さが深く、塗膜密着性も「不良」であった。
2 溶着金属
3 腐食試験片の採取位置
4 クロスカット
5 腐食試験片
10 フラックス入りワイヤ
11 鋼製外皮
12 フラックス
13 鋼板
14 継ぎ目
15 溶接部
Claims (8)
- 鋼製外皮の内部にフラックスが充填されたフラックス入りワイヤの製造方法であって、
鋼板を円形に成形しながら、前記鋼板の内部にフラックスを充填する工程と、
前記鋼板の両端を接合して鋼管とする工程と、
前記鋼管に圧延及び焼鈍を施して、前記フラックス入りワイヤを得る工程と、
を備え、
前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの全質量に対する質量%で、
C:0.03~0.10%、
Si:0.40~0.85%、
Mn:1.5~3.5%、
P:0.020%以下、
S:0.020%以下、
Cu:0.03~0.70%、
Sn:0.05~0.30%、
Mg:0.05~0.50%、
Al:0.05~0.50%、
Ti酸化物:TiO2換算値で1.50~4.60%未満、
Si酸化物:SiO2換算値で0.30~1.00%、
Zr酸化物:ZrO2換算値で0.10~0.50%、
Fe酸化物:FeO換算値で0.10~1.00%、
Al酸化物:Al2O3換算値で0.05~0.50%、
Na化合物及びK化合物の合計:Na2O換算値及びK2O換算値の合計で0.050~0.200%、
弗素化合物:F換算値で0.02~0.20%、
Bi及びBi酸化物の合計:Bi換算値で0~0.035%、
Ni:0~2.50%、
Ti:0~0.30%、
B:0~0.010%、
Mo:0~0.400%、
W:0~0.200%、
Cr:0~0.500%、
Nb:0~0.300%、
V:0~0.300%、
N:0~0.0080%、
Ca:0~0.0050%、
REM:0~0.0050%、
Sb:0~0.0050%、
残部:Fe及び不純物であり、
Sn含有量、Sb含有量、W含有量、及びMo含有量が以下の式1を満たす
ことを特徴とするフラックス入りワイヤの製造方法。
Sn+Sb>Mo+W :式1
ただし、前記式1における元素記号は、各元素記号に係る元素の含有量を、前記フラックス入りワイヤの前記全質量に対する質量%で示すものである。 - 前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの前記全質量に対する質量%で、
Mo:0~0.040%、
W:0~0.010%
であることを特徴とする請求項1に記載のフラックス入りワイヤの製造方法。 - 前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの前記全質量に対する質量%で、
Cu:0.05~0.70%、
であることを特徴とする請求項1又は2に記載のフラックス入りワイヤの製造方法。 - 前記フラックス入りワイヤの化学組成が、前記フラックス入りワイヤの前記全質量に対する質量%で、少なくとも下記のいずれかひとつを満たすことを特徴とする請求項1~3のいずれか一項に記載のフラックス入りワイヤの製造方法。
Ni:0.10~2.50%
Ti:0.03~0.30%
B:0.002~0.010% - 前記接合がかしめであることを特徴とする請求項1~4のいずれか一項に記載のフラックス入りワイヤの製造方法。
- 前記接合が溶接であることを特徴とする請求項1~4のいずれか一項に記載のフラックス入りワイヤの製造方法。
- 請求項1~6のいずれか一項に記載のフラックス入りワイヤの製造方法によって製造されるフラックス入りワイヤ。
- 請求項1~6のいずれか一項に記載のフラックス入りワイヤの製造方法によって製造されるフラックス入りワイヤを用いて溶接する工程を備える溶接継手の製造方法。
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