# US 6,723,956 B2 · Pulsed-arc welding process and device

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- Number: US 6,723,956 B2
- Document ID: US6723956B2
- Status: Granted
- Kind: B2
- Application number: 10/023,870
- Filed: 2001-12-21
- Published: 2002-09-19
- Granted: 2004-04-20
- Earliest claimed: 2000-12-21
- Assignees: L'Air Liquide - Societe Anonyme a Directoire et Conseil de Surveillance pour l'Etude Exploitation des Procedes Georges Claude; La Soudure Autogene Francaise
- Inventors: Francis Briand; Christophe Mas; Georges Caillibotte; Jean-Pierre Eyschen
- Web page: https://patentgrep.com/patent/US6723956B2

## CPC

- B23K 9/09: Arrangements or circuits for arc welding with pulsed current or voltage
- B23K 9/1056: {by using digital means (B23K9/1068 takes precedence)}
- 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

## Abstract

Process for the arc welding in pulsed mode of one or more workpieces made of carbon steel, stainless steel, aluminum or aluminum alloy, with the use of a gas shield, in which an electric arc welding torch is supplied with at least one consumable wire at a wire feed speed (Vwire) and the consumable wire is subjected to current pulses, in order to melt the end of the consumable wire in which, for a given pulse frequency, a wire feed speed (Fwire), a mean current (Imean) value and an rms current (Irms) value are chosen, so as to detach one drop of molten metal per current pulse and to obtain a low degree of spatter.

## Claims

### Claim 1

Process for the arc welding in pulsed mode of one or more workpieces made of carbon steel, stainless steel, aluminum or aluminum alloy, with the use of a gas shield, in which an electric arc welding torch is supplied with at least one consumable wire at a wire feed speed (Vwire) and the consumable wire is subjected to current pulses, in order to melt the end of the consumable wire and to detach a drop of molten metal by a current impulse, and in which, for a given pulse frequency, a wire feed speed (Vwire), a mean current (Imean) value and an rms current (Irms) value such that:
Imean=A1Vwire+B1, where 5<A1<45 and 0<B1<50
and
Irms=A2Vwire+B2, where 5<A2<45 and 40<B2<100,
where Imean and Irms are expressed in amps and Vwire is expressed in m/min, are chosen, and wherein:
the wire feed speed (Vwire) is between 1 and 20 m/min; the pulse frequency is between 20 and 300 Hz; and
the ratio (Irms/Imean) of the rms current Irms) value to the mean current Imean) value is between 1.05 and 2.

### Claim 2 (depends on 1)

Process according to claim 1, wherein the workpiece or workpieces to be welded are made of carbon steel and the mean current (Imean) value and the rms current (Irms) value, such that:
Imean=A1Vwire+B1, where 20<A1<40 and 0<B1<30
and
Irms=A2Vwire+B2, where 19<A2<39 and 40<B2<100,
where Imean and Irms are expressed in amps and Vwire is expressed in m/min, are chosen.

### Claim 3 (depends on 1)

Process according to claim 1, wherein the workpiece or workpieces to be welded are made of stainless steel and the mean current (Imean) value and the rms current (Irms) value, such that:
Imean=A1Vwire+B1, where 10<A1<40 and 0<B1<40
and
Irms=A2Vwire+B2, where 9<A2<39 and 40<B2<100,
where Imean and Irms are expressed in amps and Vwire is expressed in m/min, are chosen.

### Claim 4 (depends on 1)

Process according to claim 1, wherein the workpiece or workpieces to be welded are made of aluminum or aluminum alloy and the mean current (Imean) value and the rms current (Irms) value, such that:
Imean=A1Vwire+B1, where 5<A1<30 and 0<B1<20
and
Irms=A2Vwire+B2, where 5<A2<25 and 40<B2<65,
where Imean and Irms are expressed in amps and Vwire is expressed in m/min, are chosen.

### Claim 5 (depends on 1)

Process according to claim 1, wherein the wire feed speed (Vwire) is between 2 and 15 m/min.

### Claim 6 (depends on 1)

Process according to claim 1, wherein the pulse frequency is between 50 and 200 Hz.

### Claim 7 (depends on 1)

Process according to claim 1, wherein the ratio (Irms/Imean) of the rms current (Irms) value to the mean current (Imean) value is between 1.1 and 1.8.

### Claim 8 (depends on 1)

Process according to claim 1, wherein the workpiece or workpieces to be welded are made of carbon steel and the ratio (Irms/Imean) of the rms current (Irms) value to the mean current (Imean) value is between 1.05 and 2.

### Claim 9 (depends on 1)

Process according to claim 1, wherein the workpiece or workpieces to be welded are made of stainless steel and the ratio (Irms/Imean) of the rms current (Irms) value to the mean current (Imean) value is between 1.05 and 2.

### Claim 10 (depends on 1)

Process according to claim 1, wherein the workpiece or workpieces to be welded are made of aluminum or aluminum alloy and the ratio (Irms/Imean) of the rms current (Irms) value to the mean current (Imean) value is between 1.05 and 2.

### Claim 11 (depends on 1)

Process according to claim 1, wherein the gas shield consists of a gas or gas mixture selected from the group consisting of helium, argon, carbon dioxide, oxygen, nitrogen and hydrogen and the consumable wire has a diameter of between 0.6 mm and 2.2 mm.

### Claim 12 (depends on 1)

Process according to claim 1, wherein the welding is of the pulsed MIG or pulsed MAG type and the wire is a solid wire or a flux-cored wire.

### Claim 13 (depends on 1)

Pulsed arc welding device, capable of implementing a process according to claim 1, comprising:
frequency selection means for setting, adjusting or selecting a pulse frequency;
wire speed selection means for setting, adjusting or selecting a wire feed speed (Vwire)
means for determining the mean current (Imean) and rms current (Irms) values making it possible to determine or calculate at least one mean current (Imean) value and at least one rms current (Irms) value such that:
Imean=A1Vwire+B1, where 5<A1<45 and 5<B1<50
and
Irms=A2Vwire+B2, where 5<A2<45 and 45<B2<110,
where Imean and Irms are expressed in amps and Vwire is expressed in m/min; and
current adjustment means for adjusting the welding current in response to the determination or calculation of the mean current (Imean) and rms current (Irms) values by the means for determining the mean current (Imean) and rms current (Irms) values; and
optionally at least one welding current generator.

### Claim 14 (depends on 13)

Welding unit comprising at least one device according to claim 13, at least one welding torch, at least one source of welding wire and at least one source of shielding gas.