Welding equipment for metallic materials and method for welding metallic materials

• US 10,189,112 B2
• Filed: 06/12/2015
• Issued: 01/29/2019
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: National Institute for Materials Science, Neturen Company Limited
• Original Assignee: National Institute for Materials Science, Neturen Company Limited
• Inventors: Kanai, Takahiko, Hatta, Munehisa, Ikuta, Fumiaki, Kawasaki, Kazuhiro, Nakanishi, Eizaburo, Yoshida, Tsuyoshi, Nagai, Kotobu, Hayakawa, Masao, Itagaki, Takehiko
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): Samuels, Lawrence
• Application Number:
  US14/738,364
• Publication Number:
  US 20150306696A1
• Time in Patent Office: 1,327 Days
• Field of Search: 219660, 219 9122, 219 861, 219 912, 2191171, 219108-110, 219137 PS
• CPC Class Codes: B23K 11/115 by means of two electrodes placed opposite one another on both sides of the welded parts
• CPC Class Codes: B23K 11/24 Electric supply or control circuits therefor
• CPC Class Codes: B23K 11/241 Electric supplies B23K11/248 takes precedence
• CPC Class Codes: B23K 11/26 Storage discharge welding
• CPC Class Codes: B23K 11/312 for several electrodes
• CPC Class Codes: B23K 13/08 Electric supply or control circuits therefor
• CPC Class Codes: B23K 2101/18 Sheet panels
• CPC Class Codes: B23K 2103/04 Steel or steel alloys

Abstract

A welding equipment for metallic materials capable of performing heat treatment such as tempering based on partial heating in spot welding is provided. The welding equipment sandwiches metallic materials with a pair of electrodes, and heats different regions of the metallic materials by energization, with the pair of electrodes maintained at the same position with respect to the metallic materials. The welding equipment includes a first heating means connected to the pair of electrodes for heating and welding the internal region of the circle defined by projecting the cross-sectional area of the axis of the electrodes on the metallic materials by applying power having a low first frequency, a second heating means for heating a ring-shaped region along the circle by applying power having a second frequency that is higher than the first frequency, and an energization control unit for independently controlling the first and the second heating means.

Claims

1. A method for spot-welding metallic materials by sandwiching the metallic materials with respective tips of a pair of electrodes opposing to each other and energizing the metallic materials, wherein:

a spot-welding power source is connected to the pair of electrodes for supplying a spot-welding power to the pair of electrodes to heat and spot-weld a prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes, the spot-welding power being either AC electric power having a first frequency or DC electric power, and

a high-frequency power source is connected to the pair of electrodes for supplying AC electric power having a second frequency to the pair of electrodes to heat a region of the metallic materials different from the prescribed region,

the method comprising;

a first step for heating and spot-welding the prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes by a first energization applying, via said spot-welding power source, the AC electric power having the first frequency or the DC electric power to the pair of electrodes; and

a second step for heating said region different from the prescribed region in the first step by a second energization applying, via the high-frequency power source, the AC electric power having the second frequency to the pair of electrodes that are maintained at the same position as in the first step,

wherein the spot-welding power source and the high-frequency power source are respectively connected to the pair of electrodes in parallel,

wherein the first frequency is lower than the second frequency, and

wherein the heating time in the first step and that in the second step are independently controlled.

2. The spot-welding method for metallic materials according to claim 1, wherein

the inside of the prescribed region of the metallic materials is heated by the AC electric power having the first frequency or the DC electric power,

a proximity of the prescribed region of the metallic materials is heated by the AC electric power having the second frequency, and

the heating by the spot-welding power source in the first step and that by the high-frequency power source in the second step are independently controlled.

3. The spot-welding method for metallic materials according to claim 2, wherein

the prescribed region heated by the AC electric power having the first frequency or the DC electric power is an internal area of a circle defined by projecting contacting area of the opposing tips of the pair of electrodes on the metallic materials, and

the different region heated by the AC electric power having the second frequency is a ring-shaped area along a circumference of said prescribed region of the metallic materials.

4. The spot-welding method for metallic materials according to claim 3, wherein the ring-shaped are undergoes either resistance heating induction heating or both resistance heating and induction heating by the AC electric power having the second frequency.

9. The spot-welding method for metallic materials according to claim 1,

wherein an inductance for blocking current is connected between the spot-welding power source and the pair of electrodes,

wherein a capacitor for blocking current is connected between the high-frequency power source and the pair of electrodes,

wherein the inductance blocks high-frequency current supplied from the high-frequency power source to the pair of electrodes so as to prevent the high-frequency current from flowing into the spot-welding power source, and

wherein the capacitor blocks current supplied from the spot-welding power source to the pair of electrodes so as to prevent the current from the spot-welding power source from flowing into the high-frequency power source.

5. A method for spot-welding metallic materials using a pair of electrodes having respective tips opposing to each other, wherein:

a spot-welding power source is connected to the pair of electrodes for supplying a spot-welding power to the pair of electrodes to heat and spot-weld a prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes, the spot-welding power being either AC electric power having a first frequency or DC electric power, and

a high-frequency power source is connected to the pair of electrodes for supplying AC electric power having a second frequency to the pair of electrodes,

the method comprising;

a first step for sandwiching the metallic materials with the tips of the pair of electrodes;

a second step for heating and spot-welding the prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes by applying, via said spot-welding power source, the AC electric power having the first frequency or the DC electric power to the pair of electrodes; and

a third step for heating the welded prescribed region of the metallic materials or a region different from the prescribed region by applying, via the high-frequency power source, the AC electric power having the second frequency to the pair of electrodes,

wherein the spot-welding power source and the high-frequency power source are respectively connected to the pair of electrodes in parallel,

wherein the first frequency is lower than the second frequency, and

wherein the heating time in the second step and that in the third step are independently controlled.

10. The spot-welding method for metallic materials according to claim 5,

wherein an inductance for blocking current is connected between the spot-welding power source and the pair of electrodes,

wherein a capacitor for blocking current is connected between the high-frequency power source and the pair of electrodes,

wherein the inductance blocks high-frequency current supplied from the high-frequency power source to the pair of electrodes so as to prevent the high-frequency current from flowing into the spot-welding power source, and

wherein the capacitor blocks current supplied from the spot-welding power source to the pair of electrodes so as to prevent the current from the spot-welding power source from flowing into the high-frequency power source.

6. A method for spot-welding metallic materials using a pair of electrodes having respective tips opposing to each other, wherein

a spot-welding power source is connected to the pair of electrodes for supplying a spot-welding power to the pair of electrodes to heat and spot-weld a prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes, the spot-welding power being either AC electric power having a first frequency or DC electric power, and

a high-frequency power source is connected to the pair of electrodes for supplying AC electric power having a second frequency to the pair of electrodes,

the method comprising;

sandwiching the metallic materials with the tips of the pair of electrodes;

a welding step for heating and spot-welding the prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes by applying, via said spot-welding power source, the AC electric power having the first frequency or the DC electric power to the pair of electrodes; and

a heat-treating step for heating the welded prescribed region of the metallic materials or a region different from the prescribed region by applying, via the high-frequency power source, the AC electric power having the second frequency to the pair of electrodes,

wherein the spot-welding power source and the high-frequency power source are respectively connected to the pair of electrodes in parallel,

wherein the first frequency is lower than the second frequency,

wherein the heating time in the welding step and that in the heat treating step are independently controlled, and

wherein a power of the AC electric power having the second frequency is controlled.

7. The method for spot-welding metallic materials according to claim 6, wherein before ending applying the AC electric power having the first frequency or the DC electric power in the welding step, applying the AC electric power having the second frequency to the pair of electrodes in the heat-treating step starts.

11. The spot-welding method for metallic materials according to claim 6,

wherein an inductance for blocking current is connected between the spot-welding power source and the pair of electrodes,

wherein a capacitor for blocking current is connected between the high-frequency power source and the pair of electrodes,

wherein the inductance blocks high-frequency current supplied from the high-frequency power source to the pair of electrodes so as to prevent the high-frequency current from flowing into the spot-welding power source, and

wherein the capacitor blocks current supplied from the spot-welding power source to the pair of electrodes so as to prevent the current from the spot-welding power source from flowing into the high-frequency power source.

8. A method for spot-welding metallic materials using a pair of electrodes having respective tips opposing to each other, wherein:

a spot-welding power source is connected to the pair of electrodes for supplying a spot-welding power to the pair of electrodes to heat and spot-weld a prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes, the spot-welding power being either AC electric power having a first frequency or DC electric power, and

a high-frequency power source is connected to the pair of electrodes for supplying AC electric power having a second frequency to the pair of electrodes to heat a region of the metallic materials different from the prescribed region,

the method comprising;

sandwiching the metallic materials with the tips of the pair of electrodes;

a welding step for heating the prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes by applying, via said spot-welding power source, the AC electric power having the first frequency or the DC electric power to the pair of electrodes; and

a heating step for heating a region different from the prescribed region of the metallic materials by applying, via the high-frequency power source, the AC electric power having the second frequency to the pair of electrodes,

wherein the spot-welding power source and the high-frequency power source are respectively connected to the pair of electrodes in parallel,

wherein the first frequency is lower than the second frequency,

wherein a heating time in the welding step and that in the heating step are independently controlled, and

wherein the welding step and the heating step at least partially overlap with each other such that the AC electric power having the second frequency in the heating step is superimposed to the AC electric power having the first frequency or the DC electric power applied to the pair of electrodes in the heating step by controlling the heating time and a power of the AC electric power having the second frequency in the heating step.

12. The spot-welding method for metallic materials according to claim 8,

wherein an inductance for blocking current is connected between the spot-welding power source and the pair of electrodes,

wherein a capacitor for blocking current is connected between the high-frequency power source and the pair of electrodes,

wherein the inductance blocks high-frequency current supplied from the high-frequency power source to the pair of electrodes so as to prevent the high-frequency current from flowing into the spot-welding power source, and

wherein the capacitor blocks current supplied from the spot-welding power source to the pair of electrodes so as to prevent the current from the spot-welding power source from flowing into the high-frequency power source.