WO2014167772A1 - インダイレクトスポット溶接方法 - Google Patents
インダイレクトスポット溶接方法 Download PDFInfo
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- WO2014167772A1 WO2014167772A1 PCT/JP2014/001257 JP2014001257W WO2014167772A1 WO 2014167772 A1 WO2014167772 A1 WO 2014167772A1 JP 2014001257 W JP2014001257 W JP 2014001257W WO 2014167772 A1 WO2014167772 A1 WO 2014167772A1
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- electrode
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- current value
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- pressure
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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
- B23K11/00—Resistance welding; Severing by resistance heating
- B23K11/10—Spot welding; Stitch welding
- B23K11/11—Spot welding
-
- 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
- B23K11/00—Resistance welding; Severing by resistance heating
- B23K11/10—Spot welding; Stitch welding
- B23K11/11—Spot welding
- B23K11/115—Spot welding by means of two electrodes placed opposite one another on both sides of the welded parts
-
- 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
- B23K11/00—Resistance welding; Severing by resistance heating
- B23K11/30—Features relating to electrodes
-
- 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
- B23K11/00—Resistance welding; Severing by resistance heating
- B23K11/30—Features relating to electrodes
- B23K11/31—Electrode holders and actuating devices therefor
- B23K11/314—Spot welding guns, e.g. mounted on robots
- B23K11/315—Spot welding guns, e.g. mounted on robots with one electrode moving on a linear path
-
- 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
-
- 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
- B23K35/0205—Non-consumable electrodes; C-electrodes
-
- 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
-
- 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
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/18—Sheet panels
Definitions
- the present invention presses a welding electrode against a metal plate on one surface side against a member obtained by superimposing two metal plates, and the metal plate on the other surface side is spaced from the welding electrode.
- the present invention relates to an indirect spot welding method in which a power supply terminal is attached, and welding is performed by energizing between the welding electrode and the power supply terminal.
- the present invention relates to an indirect spot welding method capable of obtaining a suitable nugget even when energization between metal plates other than the welded portion of the overlapped member, that is, a so-called shunt current is large.
- resistance spot welding mainly direct spot welding
- indirect spot welding has been used.
- FIG. 1A shows the direct spot welding method.
- a current is applied while pressing a pair of electrodes 3 and 4 from above and below between the two stacked metal plates 1 and 2, and the resistance heating of the metal plates is used.
- This is a method for obtaining the welded portion 5.
- Each of the electrodes 3 and 4 includes pressurization control devices 6 and 7 and a current control device 8, which are configured to control the applied pressure and the current value to be energized.
- the two metal plates 21 and 22 are pressed against each other while pressing the electrode 23 against one metal plate 21 and against the other metal plate 22.
- the weld is a meteorite shape formed through a state of being completely melted between metal plates as obtained by direct spot welding. Often required to be a nugget. Therefore, among the above-described welding methods, when there is a space and an opening that sandwiches the metal plate from above and below is obtained, the direct spot welding method is used.
- the stacked metal plates are pressurized by the electrode only from one direction, and the opposite side is in a hollow state without support. Yes. Therefore, it is not possible to apply a high applied pressure directly under the electrodes as in the direct spot welding method in which the electrodes are sandwiched from both sides. In addition, since the electrode sinks into the metal plate during energization, the contact state between the electrode and the metal plate and between the metal plate and the metal plate changes.
- Patent Document 1 as a welding electrode that can be applied to indirect spot welding and can obtain a weld portion having a predetermined strength, “a substantially conical tip shape is provided, and the tip angle of the cone is 120 degrees or more”. Describes a resistance welding electrode having a conical surface of 165 degrees and a flat portion having a diameter of 1.5 to 3 mm at the center of the tip of the cone.
- Patent Document 1 regarding the welded portion welded according to the technique disclosed in the same document, “when the metal structure of the overlapped portion of the metal plates 11 and 12 is observed, the metal in the overlapped portion of the metal plates 11 and 12 is Compared to conventional ordinary nuggets, there are many events that are formed by melting and recrystallizing finely and partly, which is the case of joining in the so-called diffusion bonding state, May be joined by different events ”(paragraph [0038] of the document 1). That is, the welded part obtained by using the welding electrode described in Patent Document 1 is not necessarily a nugget formed in a meteorite shape after being completely melted like a nugget found in direct spot welding. There was a problem.
- the current spot welding part management standards in transportation equipment manufacturers often require the welded part to be a meteorite-shaped nugget. For this reason, even a welded portion having a predetermined joint strength does not satisfy the management standard unless a meteorite-shaped nugget formed through a completely melted state is obtained. Accordingly, there is a need for an indirect spot welding method that can more stably obtain a meteorite-shaped nugget even when current flowing between metal plates other than the welded portion, that is, a so-called diversion is large.
- the shape of the electrode tip of the welding electrode is related to the thickness of the metal plate serving as a reference for the nugget diameter with respect to the stacked metal plates used for welding. That is, the thickness of the metal plate serving as a reference for the nugget diameter is the thickness of the thinner metal plate of the member obtained by superimposing two metal plates.
- the current value during energization and its time are finely controlled, or the applied pressure and time during energization are finely controlled. It is more effective to finely control the current value, the electrode pressing force, and the time. The present invention is based on the above findings.
- the gist configuration of the present invention is as follows. (1) Pressing a welding electrode against a metal plate on one surface side of the member against a member obtained by superimposing two metal plates, and welding the metal plate on the other surface side of the member
- the electrode tip portion of the welding electrode includes a leading edge of the welding electrode, and a radius of curvature r 1 (within a radius R (mm) centered on the leading edge when viewed from the leading edge side.
- the current value to be energized is constant from the start to the end of energization,
- the welding electrode pressure is divided into two time zones t 1 and t 2 from the start of energization. After the first time zone t 1 is pressurized with the pressure F 1 , the next time zone t 2 is The indirect spot welding method according to (1), wherein pressurization is performed with a pressurizing force F 2 lower than F 1 .
- the welding electrode pressure and the current value to be energized are divided into two time zones t 1 and t 2 from the start of energization, and the first time zone t 1 is pressurized with the pressure F 1 and the current After energizing at the value C 1 , in the next time zone t 2 , pressurizing at a pressure F 2 lower than F 1 and energizing at a current value C 2 higher than C 1.
- Direct spot welding method
- the welding electrode pressure is divided into two time zones t F1 and t F2 from the start of energization.
- the first time zone t F1 after pressurizing with the pressure F 1 , the next time zone t In F2 , pressurization is performed with a pressure F 2 lower than F 1 .
- the current value to be energized is divided into two time zones t C1 and t C2 from the start of energization independently of the time zones t F1 and t F2, and in the first time zone t C1 , the current value C 1
- the indirect spot welding method according to (1) wherein after energization, energization is performed at a current value C 2 higher than C 1 in the next time zone t C2 .
- the present invention since a welding electrode having an electrode tip having an appropriate shape is used, even when energization between metal plates other than the welded portion, so-called shunt current is large, the molten state between the metal plates is maintained. The meteorite-type nugget formed through the process can be obtained more stably.
- a member obtained by superimposing two metal plates is pressed against a metal plate on one surface side of the member while pressing a welding electrode, and the other surface side of the member is A power supply terminal is attached to the metal plate at a position separated from the welding electrode, and welding is performed by energizing between the welding electrode and the power supply terminal.
- a member on which metal plates are overlapped is placed on a concave metal jig, a ground electrode is attached to the lower part of the jig, and the overlapped metal plates are integrated.
- FIG. 2 shows the shape of the electrode tip of the welding electrode in one embodiment of the method of the present invention.
- the electrode tip 30 of the welding electrode includes the leading edge of the welding electrode and has a radius of curvature r 1 (mm) located within a circle having a radius R (mm) centered on the leading edge when viewed from the leading edge.
- a two-stage dome shape composed of a first curved surface 31 and a second curved surface 32 having a radius of curvature r 2 (mm) located around the first curved surface, which are expressed by equations (1) to Satisfy (3).
- the electrode tip 30 has a two-stage dome shape, and the first curved surface 31 has a larger radius of curvature than the second curved surface 32, thereby causing a phenomenon that the electrode sinks into the metal plate during energization.
- a high current density can be maintained between the stacked metal plates directly under the electrodes.
- the first curved surface 31 a curved surface having a larger radius of curvature than the second curved surface 32, a sufficient contact area between the electrode and the metal plate can be secured at the start of energization, and the current density becomes excessive. Problems such as molten metal scattering from the metal plate on the side in contact with the electrode can be solved.
- the second curved surface 32 is a curved surface having a smaller radius of curvature than the first curved surface 31. Therefore, an increase in the contact area between the electrode and the metal plate is suppressed when the electrode sinks into the metal plate during energization and the second curved surface 32 starts to contact the metal plate in addition to the first curved surface 31. be able to.
- one of the characteristic configurations of the present invention is a nugget among members formed by superimposing metal plates for welding with a radius R (mm) that defines the boundary between the first curved surface 31 and the second curved surface 32. It is limited by an integral multiple of the square root of the plate thickness t (mm) of the metal plate serving as a reference for the diameter.
- the thickness t of the metal plate serving as a reference for the nugget diameter is a thickness of a thinner metal plate in spot welding of a member in which two metal plates are overlapped. When two sheets have the same thickness, the thickness is the same.
- the required value of the nugget diameter is defined by an integral multiple of the square root of the thickness of the thinner plate.
- the radius R is an appropriate size, the increase of the nugget diameter to the range exceeding the radius R can be suppressed in the process of increasing the contact area between the electrode and the metal plate during welding. A good nugget diameter can be obtained.
- the radius R is set to a smaller plate. It should be limited to an integral multiple of the square root of the plate thickness.
- the radius R is less than 2 ⁇ t (mm)
- the contact area between the electrode and the metal plate is suppressed in an extremely small range at the start of energization. Therefore, the current density becomes excessive, and the metal on the side where the electrode contacts Problems such as molten metal splashing from the plate occur.
- the radius R exceeds 6 ⁇ t (mm)
- the electrode sinks into the metal plate during energization as described above, and the second curved surface 32 in addition to the first curved surface 31 also starts to contact the metal plate. At this time, the effect of suppressing an increase in the contact area between the electrode and the metal plate cannot be sufficiently obtained. Therefore, the radius R (mm) is limited to the range of the following formula (1).
- t is the plate thickness (mm) of the thin metal plate described above.
- the radius R is more preferably in the range of 3 ⁇ t ⁇ R ⁇ 5 ⁇ t (mm).
- the radius of curvature r 1 (mm) of the first curved surface 31 With respect to the radius of curvature r 1 (mm) of the first curved surface 31, by setting r 1 to 30 mm or more, a sufficient contact area between the electrode and the metal plate can be secured at the start of energization, and the current density is excessive. Thus, it is possible to eliminate problems such as molten metal scattering from the metal plate on the side in contact with the electrode. Therefore, the radius of curvature r 1 (mm) is limited to the range of the following formula (2). 30 ⁇ r 1 (2) Moreover, in order to more reliably obtain the above-described effects, it is more preferable that r 1 is 40 mm or more.
- the first curved surface can also be made a flat surface by assuming that the radius of curvature is infinite.
- the radius of curvature r 2 (mm) of the second curved surface 32 when r 2 is less than 6 mm, the electrode sinks excessively into the metal plate during energization, unnecessarily deforms the weld between the metal plates, and cracks. This is not preferable.
- the radius of curvature r 2 (mm) is limited to the range of the following formula (3). 6 ⁇ r 2 ⁇ 12 (3) In order to more reliably obtain the above-described effects, it is more preferable that the curvature radius r 2 (mm) is in the range of 8 ⁇ r 2 ⁇ 10.
- the electrode radius at the lower end of the electrode tip 30 of the welding electrode can be set to 8 mm, for example, as shown in FIG. 2, and can be appropriately determined to be about 4.0 to 12.5 mm.
- the first curved surface 31 and the second curved surface 32 constituting the distal end portion 30 of the welding electrode satisfy the above-described equations (1) to (3).
- the current density between the metal plates can be made appropriate. Therefore, even if energization between the metal plates other than the welded portion, that is, a so-called diversion is large, a meteorite-shaped nugget formed through a molten state between the metal plates can be obtained more stably.
- the metal plate used by this invention is not specifically limited, For example, a metal plate made from steel can be used. Further, the plate thickness t of the thinner metal plate targeted by the present invention is about 0.5 to 1.8 mm, and the total plate thickness of the members laminated with the metal plates is about 1 to 4 mm.
- the time zone from the start of energization to the end of energization, the control of the applied pressure F, and the current value C are not particularly limited, and can be appropriately selected.
- the energization time can be about 0.06 to 0.60 s
- the applied pressure F is about 100 to 1500 N
- the current value C is about 4 to 12 kA.
- control of the time zone from the start of energization to the end of energization, the applied pressure F, and the current value C is not limited.
- the energizing time is divided to control the welding electrode pressure and current value. Is more preferable.
- FIGS. 3A and 3B show the basic relationship between the energization time and the applied pressure and the energization time and the current value, respectively, in another preferred embodiment according to the present invention. By performing such control, a more remarkable effect can be obtained.
- a preferable relationship between the energization time and the applied pressure and a relationship between the energization time and the current value in the embodiment will be described below.
- the time zone from the start of energization is divided into two simultaneously or independently, and the welding electrode pressure F or energization is conducted in each time zone. It is preferable to control one of the current values C or both the applied pressure F and the current value C.
- the divided time zones are t 1 and t 2, and both the pressing force F and the current value C are controlled independently.
- T F1 and t F2 are time zones for dividing the applied pressure F
- t C1 and t C2 are time zones for dividing the current value C
- the applied pressure in each time zone is F 1 , F 2 and the current value.
- C 1 and C 2 are denoted by C 1 and C 2 .
- This time zone t 1 is a time zone in which energization is started while pressing the metal electrode on which the welding electrodes are overlapped, and the formation of the melted portion is started from the heat generated by the contact resistance between the metal plates.
- the pressing force F 1 is too low, the contact area between the electrode and the metal plate becomes extremely small, the current density increases excessively, the metal plate surface melts and scatters, and the surface shape is significantly impaired. Will occur. Therefore, it is preferable to select the pressurizing force F 1 as appropriate so that such a problem does not occur.
- the current value C 1 needs to be a current value high enough to start melting due to heat generation between the metal plates, but if it is too high, the metal plate surface melts and scatters as described above. Not only does the shape become poor and the appearance is remarkably impaired, but there is also a problem that the joint strength is reduced. Therefore, it is preferable to select appropriately so that such a problem does not occur.
- This time zone t 2 is a stage in which the melted portion that has been formed in the time zone t 1 is further grown.
- the metal plate around the electrode softens due to heat generated by energization, and when indirect spot welding is performed in a hollow state where the opposite side of the electrode is not supported, the tip of the electrode sinks into the metal plate when the metal plate softens.
- the contact area between the electrode and the metal plate, or between the metal plate and the metal plate increases, and the current density decreases. Therefore, heat generation sufficient for growing nuggets cannot be obtained. Therefore, in this time zone t 2 , it is preferable that the applied pressure F 2 is set lower than the applied pressure F 1 to suppress the electrode tip from sinking into the metal plate.
- the current value C 2 is preferably set to a current value higher than the current value C 1 , and the current density is preferably prevented from decreasing due to the increase in the contact area due to the sinking of the electrode.
- the current value is too high, the molten metal scatters from the surface of the metal plate on the opposite side of the electrode and melts away, resulting in a problem that not only the appearance is significantly impaired but also the joint strength is lowered. Therefore, it is preferable to appropriately select the current value C 2 so that such a problem does not occur.
- the preferred embodiment in which the energization is divided into two time zones and both the applied pressure F and the current value C are controlled at the same time has been described.
- only the applied pressure is controlled.
- the above-described time zones t 1 and t 2 it is possible to obtain a further effect by making the pressure F 2 lower than F 1 and the current value C 2 higher than C 1. it can.
- the applied pressure F is divided into time zones t F1 and t F2 from the start of energization, and the applied pressure F 2 is made lower than F 1 , while the current value C is separated from the time zones t F1 and t F2.
- the current value C 2 is made higher than C 1 by dividing into time zones t C1 and t C2 from the start of energization.
- the energization times in the time zones t 1 and t 2 are t 1 : It is preferable to set 0.02 to 0.30 s and t 2 : about 0.10 to 0.60 s.
- the applied pressure in each of the time zones t 1 and t 2 is respectively F 1 : 300 to 2000 N, F 2 : about 100 to 1500 N, and the current values are C 1 : 2.0 to 10.0 kA, C 2 : 2 respectively. It is preferably about 5 to 12.0 kA.
- the current values C 1 and C 2 are constant, and when the applied pressure F 2 is lower than F 1 , the constant current value is preferably about 2.5 to 10 kA.
- the pressing force F is set to t F1 : 0.02 to 0.30 s, t F2 : 0.10 to 0.60 s.
- F 1 is about 300 to 2000 N and F 2 is about 100 to 1500 N
- the current value C is t C1 : 0.02 to 0.30 s
- t Preferably, C2 is about 0.10 to 0.60 s, C 1 is about 2.0 to 10.0 kA, and C 2 is about 2.5 to 12.0 kA in each of the time zones t C1 and t C2 .
- the indirect spot welding method was implemented with the configuration shown in FIG.
- Tensile strength to be chemical components shown in Table 1 SPC270 steel plates of 270 MPa or more were combined as an upper steel plate and a lower steel plate to produce a member composed of two superposed steel plates.
- the plate thickness of the upper steel plate is 1.0 mm
- the plate thickness of the lower steel plate is 1.2 mm.
- This member is placed on a concave metal jig as shown in FIG. 4, the support interval is set to 30 mm, a ground electrode is attached to the lower part of the jig, and pressure is applied from above with a welding electrode. Went.
- both ends of the upper and lower steel plates stacked as described above are restrained on a jig by clamping, and the upper steel plate and the lower steel plate are brought into close contact with each other, thereby making it easy to cause a shunt between the steel plates when energized.
- the conditions under which nuggets were hardly formed immediately below the electrodes were set.
- a DC inverter type power supply was used for welding.
- the electrode used for welding is made of chromium copper alloy, and the electrode tip of the welding electrode includes the leading edge of the welding electrode and has a radius R (mm) centered on the leading edge when viewed from the leading edge.
- R, r 1 and r 2 composed of a first curved surface having a radius of curvature r 1 (mm) extending within a circle and a second curved surface having a radius of curvature r 2 (mm) extending around the first curved surface. It is a stepped dome shape.
- R, r 1 and r 2 are shown in Table 2, respectively.
- Table 2 also shows the electrode radius at the lower end of the electrode tip of the welding electrode.
- Table 2 shows the conditions of the time zone from the start of energization to the end of energization and the applied pressure and current value in each time zone during welding. Under the conditions described in Table 2, no. Indirect spot welding was tried from 1 to 16.
- the electrode pressure is divided into two time zones t F1 and t F2 from the start of energization, while the energizing current value is started independently of the time zones t F1 and t F2.
- the pressure F and the current value C were independently controlled by dividing into two time zones t C1 and t C2 .
- Table 3 shows the results of investigating the nugget diameter, nugget thickness, nugget thickness / diameter, and appearance defects of each joint when welding with the electrode shape and the energization pattern shown in Table 2.
- the nugget diameter is the length of the melted portion formed between the upper steel plate and the lower steel plate on the overlap line in the cross section cut around the welded portion.
- the nugget thickness was the maximum thickness of the melted portion formed between the upper steel plate and the lower steel plate in the cross section cut at the center of the weld.
- the nugget thickness / diameter is obtained by dividing the above-described nugget thickness by the nugget diameter. If the nugget diameter is 4 mm or more and the nugget thickness / diameter is 0.22 or more, it can be determined as a suitable nugget.
- the plate thickness of the upper steel plate is 1.0 mm
- the plate thickness of the lower steel plate is 0.7 mm
- the electrode shape of the welding electrode the time zone from the start of energization to the end of energization, and the applied pressure and current value in each time zone Indirect spot welding was performed under the same conditions as in Example 1 except that the conditions of No. 1 were as shown in Table 4. Tried from 1 to 6.
- Table 5 shows the results of investigating the nugget diameter, nugget thickness, nugget thickness / diameter and appearance defects of each joint when welding with the electrode shape and energization pattern shown in Table 4.
- the nugget diameter and the nugget thickness in Table 5 are as described in the first embodiment. If the nugget diameter is 3.4 mm or more and the nugget thickness / diameter is 0.20 or more, it can be determined as a suitable nugget.
- No. 1 was obtained by performing indirect spot welding using a welding electrode satisfying the requirements of the present invention for a thickness of 0.7 mm of the thinner steel plate.
- any of Nos. 2 to 5 it is possible to obtain a molten nugget having a sufficient nugget diameter and a sufficient thickness with respect to this diameter even under a condition in which the nugget is difficult to be formed directly under an intentionally set electrode. In addition, no appearance defects were observed.
- no. In 6 the nugget diameter was insufficient and the nugget thickness / diameter was less than 0.20. No. In 1, the formation of nuggets was not observed, and further burn-out occurred.
- the present invention since a welding electrode having an electrode tip having an appropriate shape is used, even when energization between metal plates other than the welded portion, so-called shunt current is large, the molten state between the metal plates is maintained. The meteorite-type nugget formed through the process can be obtained more stably.
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Abstract
Description
いずれのスポット溶接も、重ね合わせた少なくとも2枚の金属板を溶接により接合する点では変わりはない。
図1(A)は、ダイレクトスポット溶接法を示したものである。この溶接は、同図に示すとおり、重ね合わせた2枚の金属板1,2を挟んでその上下から一対の電極3,4を加圧しつつ電流を流し、金属板の抵抗発熱を利用して、溶接部5を得る方法である。なお、電極3,4はいずれも、加圧制御装置6,7および電流制御装置8を備えており、これらによって加圧力と通電する電流値が制御できる仕組みになっている。
a)上述のとおり、インダイレクトスポット溶接では、ダイレクトスポット溶接のように電極直下の重ね合わせた金属板間に溶接部を形成するための十分な発熱が得難く、ナゲットが形成されにくい。特に、溶接部以外での金属板間の通電、所謂分流が大きな場合においては、ナゲット形成がさらに困難となる。
b)上記の問題を解決するには、通電中に電極が金属板に沈み込んでいく現象が生じても、電極直下の重ね合わせた金属板間で高い電流密度が維持できるよう、電極先端部を適切な形状とした溶接電極を用いる必要がある。
c)上記溶接電極の電極先端部の形状は、溶接に供する重ね合わせた金属板に関し、ナゲット径の基準となる金属板の板厚に関連する。すなわち、ナゲット径の基準となる金属板の板厚とは、2枚の金属板を重ね合わせた部材の、より薄い方の金属板の板厚である。
d)上記の形状とした溶接電極を用いることに加えて、通電中の電流値およびその時間を細かく制御する、または通電中の電極の加圧力およびその時間を細かく制御する、さらには通電中の電流値と電極の加圧力およびその時間を細かく制御することがより有効である。
本発明は、上記の知見に立脚するものである。
(1)2枚の金属板を重ね合わせた部材に対し、前記部材の一方の面側の金属板に溶接電極を加圧しながら押し当て、前記部材の他方の面側の金属板には前記溶接電極と離隔した位置に給電端子を取り付け、前記溶接電極と前記給電端子との間で通電して溶接を行うインダイレクトスポット溶接方法において、
前記溶接電極の電極先端部は、前記溶接電極の最先端を含み、該最先端側から見て該最先端を中心とした半径R(mm)の円の範囲内に位置する曲率半径r1(mm)の第1の曲面と、該第1の曲面の周囲に位置する曲率半径r2(mm)の第2の曲面とから構成される2段のドーム形状であって、下記(1)~(3)式を満足することを特徴とするインダイレクトスポット溶接方法。
記
2√t≦R≦6√t ・・・(1)
30≦r1 ・・・(2)
6≦r2≦12 ・・・(3)
ただし、tは前記部材のうち、薄い方の金属板の板厚(mm)である。
前記溶接電極の加圧力に関しては、通電開始から2つの時間帯t1,t2に区分し、最初の時間帯t1では加圧力F1で加圧したのち、次の時間帯t2では、F1よりも低い加圧力F2で加圧する上記(1)に記載のインダイレクトスポット溶接方法。
前記通電する電流値に関しては、時間帯tF1,tF2とは独立して、通電開始から2つの時間帯tC1,tC2に区分し、最初の時間帯tC1では、電流値C1で通電したのち、次の時間帯tC2では、C1よりも高い電流値C2で通電する上記(1)に記載のインダイレクトスポット溶接方法。
本発明に従うインダイレクトスポット溶接方法では、2枚の金属板を重ね合わせた部材に対し、この部材の一方の面側の金属板に溶接電極を加圧しながら押し当て、上記部材の他方の面側の金属板には上記溶接電極と離隔した位置に給電端子を取り付け、上記溶接電極と上記給電端子との間で通電して溶接を行う。図4を用いて実施例に後述するように、金属板を重ね合わせた部材を凹形状の金属製治具の上に配置し、治具下部にアース電極を取り付け、重ね合わせた金属板を一方向からのみ溶接電極により加圧し、その反対側は支持の無い中空の状態とする場合には、金属製治具およびアース電極を組み合わせたものが給電端子に相当する。
一般に、2枚の金属板を重ね合わせた部材からなる板組みでは、より薄い方の板の板厚の平方根の整数倍によりナゲット径の要求値が規定される。一方、半径Rが適正な大きさの場合は、溶接中に電極と金属板との接触面積が増大していく過程において、半径Rを超えた範囲へのナゲット径の増大を抑制することができ、良好なナゲット径を得ることができる。また、このとき、半径Rとナゲット径には相関関係があるため、任意の板組みにおいて要求されるナゲット径を得るに際して、適正な半径Rを設定するためには、半径Rをより薄い板の板厚の平方根の整数倍で限定してやればいい。
2√t≦R≦6√t(mm) ・・・(1)
ここで、tは既述の薄い方の金属板の板厚(mm)である。
また、上記作用効果をより確実に得るためには、半径Rは、3√t≦R≦5√t(mm)の範囲であることがより好ましい。
30≦r1 ・・・(2)
また、上記作用効果をより確実に得るために、r1を40mm以上とすることがより好ましい。曲率半径を無限大とみなして、第1の曲面を平坦面とすることもできる。
6≦r2≦12 ・・・(3)
また、上記作用効果をより確実に得るために、曲率半径r2(mm)を、8≦r2≦10の範囲とすることがより好ましい。
この時間帯t1は、溶接電極を重ね合わせた金属板に加圧しながら押し当てつつ、通電を開始し、金属板間の接触抵抗による発熱から溶融部の形成を始める時間帯である。重ね合わせた金属板を一方向からのみ溶接電極により加圧し、その反対側は支持の無い中空の状態でインダイレクトスポット溶接を行う際には、加圧力F1を、両側から電極で挟むダイレクトスポット溶接法のような高い加圧力とすることができない。しかし、加圧力F1が低すぎると、電極と金属板との間の接触面積が極度に小さくなり、電流密度が過度に上昇して金属板表面が溶融飛散し、表面形状が著しく損なわれる不具合が発生する。従って、加圧力F1は、かような不具合が生じないよう、適宜選択することが好ましい。
この時間帯t2は、時間帯t1で形成が始まった溶融部をさらに成長させていく段階である。しかしながら、通電による発熱で電極周辺の金属板が軟化し、電極の反対側は支持の無い中空の状態でインダイレクトスポット溶接を行う際には、金属板が軟化すると電極先端部が金属板に沈み込み、電極-金属板間、金属板-金属板間の接触面積が増大し電流密度が低下する。そのため、ナゲットを成長させるに十分な発熱が得られない。従って、この時間帯t2では、加圧力F2を加圧力F1よりも低い加圧力とし、電極先端部が金属板に沈み込むのを抑えることが好ましい。
すなわち、上記の時間帯t1,t2において、電流値C1,C2は一定とし、加圧力F2をF1より低くする方法でも、同様の効果を得ることができる。しかしながら、前述したとおり、上記の時間帯t1,t2において、加圧力F2をF1より低くし、かつ電流値C2をC1より高くすることによって、より一層の効果を得ることができる。
なお、時間帯t1,t2において、電流値C1,C2は一定とし、加圧力F2をF1より低くする場合、一定電流値は2.5~10kA程度とすることが好ましい。
表1に示す化学成分になる引張強さ:270MPa以上のSPC270鋼板を、上鋼板、下鋼板として組み合わせて、重ね合わせた2枚の鋼板からなる部材を作製した。上鋼板の板厚は1.0mmであり、下鋼板の板厚は1.2mmである。この部材を、図4に示すような凹形状の金属製治具の上に配置し、支持間隔を30mmとし、治具下部にアース電極を取り付け、上方から溶接電極で加圧し、上記部材の溶接を行った。また、上記のように重ねた上鋼板、下鋼板の両端をクランプにより治具上で拘束し、上鋼板、下鋼板間を密着させることにより、通電時に鋼板間で分流を起こりやすくさせ、意図的に電極直下にナゲットが形成されにくい条件を設定した。
溶接に際しては、直流インバータ式の電源を使用した。また、溶接に使用した電極はクロム銅合金を材質としており、溶接電極の電極先端部は、溶接電極の最先端を含み、最先端側から見て最先端を中心とした半径R(mm)の円の範囲内に延在する曲率半径r1(mm)の第1の曲面と、第1の曲面の周囲に延在する曲率半径r2(mm)の第2の曲面とから構成される2段のドーム形状である。これら、R,r1,r2の寸法を表2にそれぞれ示す。また、溶接電極の電極先端部下端の電極半径についても表2にそれぞれ示す。さらに、溶接の際の、通電開始から通電終了までの時間帯と、それぞれの時間帯での加圧力および電流値との条件を表2に示す。表2に記載の条件で、No.1~16までインダイレクトスポット溶接を試行した。
さらに、以下の基準で総合評価を行った。
○:ナゲット径4mm以上、ナゲット厚さ/径が0.22以上で、かつ外観不具合がないもの
×:ナゲット径4mm未満、ナゲット厚さ/径が0.22未満または外観不具合ありのうち、1つでも条件を満たすもの
これに対し、本発明要件を満足しない溶接電極を用いたNo.7では、ナゲット厚さ/径が0.22未満を満たさなかった。また、No.9,11では、ナゲット径が不十分であった。さらにNo.1,8,10,12,13では、いずれもナゲットの形成が観察されず、さらに溶け落ちが発生した。
さらに、以下の基準で総合評価を行った。
○:ナゲット径3.4mm以上、ナゲット厚さ/径が0.20以上で、かつ外観不具合がないもの
×:ナゲット径3.4mm未満、ナゲット厚さ/径が0.20未満または外観不具合ありのうち、1つでも条件を満たすもの
これに対し、本発明要件を満足しない溶接電極を用いたNo.6では、ナゲット径が不十分であり、かつナゲット厚さ/径が0.20未満であった。また、No.1では、ナゲットの形成が観察されず、さらに溶け落ちが発生した。
3,4 電極
5 溶接部
6,7 加圧制御装置
8 電流制御装置
21,22 金属板
23 溶接電極
24 給電端子
25 溶接部
30 電極先端部
31 第1の曲面
32 第2の曲面
Claims (4)
- 2枚の金属板を重ね合わせた部材に対し、前記部材の一方の面側の金属板に溶接電極を加圧しながら押し当て、前記部材の他方の面側の金属板には前記溶接電極と離隔した位置に給電端子を取り付け、前記溶接電極と前記給電端子との間で通電して溶接を行うインダイレクトスポット溶接方法において、
前記溶接電極の電極先端部は、前記溶接電極の最先端を含み、該最先端側から見て該最先端を中心とした半径R(mm)の円の範囲内に位置する曲率半径r1(mm)の第1の曲面と、該第1の曲面の周囲に位置する曲率半径r2(mm)の第2の曲面とから構成される2段のドーム形状であって、下記(1)~(3)式を満足することを特徴とするインダイレクトスポット溶接方法。
記
2√t≦R≦6√t ・・・(1)
30≦r1 ・・・(2)
6≦r2≦12 ・・・(3)
ただし、tは前記部材のうち、薄い方の金属板の板厚(mm)である。 - 前記通電する電流値については通電開始から終了まで一定にし、
前記溶接電極の加圧力に関しては、通電開始から2つの時間帯t1,t2に区分し、最初の時間帯t1では加圧力F1で加圧したのち、次の時間帯t2では、F1よりも低い加圧力F2で加圧する請求項1に記載のインダイレクトスポット溶接方法。 - 前記溶接電極の加圧力および前記通電する電流値に関して、通電開始から2つの時間帯t1,t2に区分し、最初の時間帯t1では加圧力F1で加圧し、かつ電流値C1で通電したのち、次の時間帯t2では、F1よりも低い加圧力F2で加圧し、かつC1よりも高い電流値C2で通電する請求項1に記載のインダイレクトスポット溶接方法。
- 前記溶接電極の加圧力に関して、通電開始から2つの時間帯tF1,tF2に区分し、最初の時間帯tF1では、加圧力F1で加圧したのち、次の時間帯tF2では、F1よりも低い加圧力F2で加圧し、
前記通電する電流値に関しては、時間帯tF1,tF2とは独立して、通電開始から2つの時間帯tC1,tC2に区分し、最初の時間帯tC1では、電流値C1で通電したのち、次の時間帯tC2では、C1よりも高い電流値C2で通電する請求項1に記載のインダイレクトスポット溶接方法。
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JP2017124405A (ja) * | 2016-01-12 | 2017-07-20 | 新日鐵住金株式会社 | めっき鋼板の高周波抵抗溶接用の給電電極 |
TWI601588B (zh) * | 2015-10-21 | 2017-10-11 | Nippon Steel & Sumitomo Metal Corp | Resistance point welding method |
JP2020116629A (ja) * | 2019-01-28 | 2020-08-06 | ダイハツ工業株式会社 | インダイレクトスポット溶接方法 |
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US20170361392A1 (en) * | 2016-06-16 | 2017-12-21 | GM Global Technology Operations LLC | Multistep electrode weld face geometry for weld bonding aluminum to steel |
KR20200086730A (ko) * | 2017-12-19 | 2020-07-17 | 닛폰세이테츠 가부시키가이샤 | 저항 스폿 용접 조인트의 제조 방법 |
KR101988769B1 (ko) * | 2017-12-22 | 2019-09-30 | 주식회사 포스코 | 스폿 용접용 전극 |
CN112916992A (zh) * | 2019-12-06 | 2021-06-08 | 中国科学院上海光学精密机械研究所 | 用于焊接高强度钢的电阻点焊电极及其焊接方法 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09122928A (ja) * | 1995-10-31 | 1997-05-13 | Suzuki Motor Corp | 抵抗溶接装置 |
JP2006198676A (ja) | 2004-12-24 | 2006-08-03 | Daihatsu Motor Co Ltd | 抵抗溶接用電極、及び、シリーズスポット溶接装置又はインダイレクトスポット溶接装置 |
US20090218323A1 (en) * | 2005-11-09 | 2009-09-03 | Hiroshi Abe | Spot welding method, method for judging shape of nugget, spot welding machine and spot welding electrode |
JP2010194609A (ja) * | 2009-01-29 | 2010-09-09 | Jfe Steel Corp | インダイレクトスポット溶接方法 |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN2785779Y (zh) | 2005-04-19 | 2006-06-07 | 中国国际海运集装箱(集团)股份有限公司 | 一种薄板点焊装置 |
JP2012011398A (ja) * | 2010-06-29 | 2012-01-19 | Daihatsu Motor Co Ltd | 抵抗溶接方法 |
JP5625597B2 (ja) * | 2010-08-04 | 2014-11-19 | Jfeスチール株式会社 | インダイレクトスポット溶接方法 |
JP5691395B2 (ja) | 2010-10-27 | 2015-04-01 | Jfeスチール株式会社 | インダイレクトスポット溶接方法 |
JP5803116B2 (ja) | 2011-01-31 | 2015-11-04 | Jfeスチール株式会社 | インダイレクトスポット溶接方法 |
JP5778942B2 (ja) * | 2011-02-16 | 2015-09-16 | 株式会社キーレックス | 片側スポット溶接装置 |
-
2014
- 2014-03-06 KR KR1020157026911A patent/KR101735234B1/ko active IP Right Grant
- 2014-03-06 CN CN201480020462.8A patent/CN105121087B/zh active Active
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09122928A (ja) * | 1995-10-31 | 1997-05-13 | Suzuki Motor Corp | 抵抗溶接装置 |
JP2006198676A (ja) | 2004-12-24 | 2006-08-03 | Daihatsu Motor Co Ltd | 抵抗溶接用電極、及び、シリーズスポット溶接装置又はインダイレクトスポット溶接装置 |
US20090218323A1 (en) * | 2005-11-09 | 2009-09-03 | Hiroshi Abe | Spot welding method, method for judging shape of nugget, spot welding machine and spot welding electrode |
JP2010194609A (ja) * | 2009-01-29 | 2010-09-09 | Jfe Steel Corp | インダイレクトスポット溶接方法 |
Non-Patent Citations (1)
Title |
---|
See also references of EP2985108A4 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI601588B (zh) * | 2015-10-21 | 2017-10-11 | Nippon Steel & Sumitomo Metal Corp | Resistance point welding method |
JP2017124405A (ja) * | 2016-01-12 | 2017-07-20 | 新日鐵住金株式会社 | めっき鋼板の高周波抵抗溶接用の給電電極 |
JP2020116629A (ja) * | 2019-01-28 | 2020-08-06 | ダイハツ工業株式会社 | インダイレクトスポット溶接方法 |
JP7245591B2 (ja) | 2019-01-28 | 2023-03-24 | ダイハツ工業株式会社 | インダイレクトスポット溶接方法 |
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