Disclosed is an arc welding control method of controlling a welding current in short-circuit arc welding of feeding a welding wire toward a base metal and alternating a short-circuit state and an arc state. The arc welding control method includes: executing, in the short-circuit state, a first increase in the welding current with a first slope, a first decrease in the welding current to a first bottom value after executing the first increase, a second increase in the welding current with a second slope after executing the first decrease, and a second decrease in the welding current to a second bottom value that is smaller than the first bottom value after executing the second increase to shift a state to the arc state.

A welding system is provided which utilizes a short arc welding method in which the waveforms have a positive polarity portion and negative portion to optimize heat input and provide heat and current control.

A method is provided for controlling arc welding including forward and reverse feeding periods alternately switched. By the method, a set of a short circuit period and an arc period is repeated, and the arc welding is controlled such that the reverse feeding period shifts to the forward feeding period when an arc occurs during the reverse feeding period, and that the forward feeding period shifts to the reverse feeding period when a short circuit occurs between the welding wire and the object during the forward feeding period. The reverse feeding period includes a reverse feeding deceleration period having a time length that is adjusted in accordance with the time length of the short circuit period.

A method is provided for controlling arc welding including forward and reverse feeding periods alternately switched. By the method, a set of a short circuit period and an arc period is repeated, and the arc welding is controlled such that the reverse feeding period shifts to the forward feeding period when an arc occurs during the reverse feeding period, and that the forward feeding period shifts to the reverse feeding period when a short circuit occurs between the welding wire and the object during the forward feeding period. The reverse feeding period includes a reverse feeding deceleration period having a time length that is adjusted in accordance with the time length of the short circuit period.

A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.

A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.

There is provided an arc welding control method of performing a forward/reverse feeding control of alternating a feeding rate of a welding wire between a forward feeding period and a reverse feeding period, and generating short-circuiting periods and arc periods to perform welding. The welding wire is fed forwardly at a time of staring the welding. The forward/reverse feeding control is started from the reverse feeding period of the welding wire after starting conduction of a welding current.

There is provided an arc welding control method of performing a forward/reverse feeding control of alternating a feeding rate of a welding wire between a forward feeding period and a reverse feeding period, and generating short-circuiting periods and arc periods to perform welding. The welding wire is fed forwardly at a time of staring the welding. The forward/reverse feeding control is started from the reverse feeding period of the welding wire after starting conduction of a welding current.

An example arc starting/stabilizing circuit includes: a pulse generator configured to generate voltage pulses having a first voltage; and a plurality of transformers configured to receive the voltage pulses and output the voltage pulses to a welding-type output circuit at a second voltage higher than the first voltage, wherein: each of the plurality of transformers comprises one primary winding turn, one secondary winding turn, and a core configured to magnetically couple the primary winding turn and the secondary winding turn; the primary winding turns of the plurality of transformers are coupled to the pulse generator to receive the voltage pulses; and the secondary winding turns of the plurality of transformers are coupled in series and are configured to conduct welding-type current in the welding-type output circuit.

An example arc starting/stabilizing circuit includes: a pulse generator configured to generate voltage pulses having a first voltage; and a plurality of transformers configured to receive the voltage pulses and output the voltage pulses to a welding-type output circuit at a second voltage higher than the first voltage, wherein: each of the plurality of transformers comprises one primary winding turn, one secondary winding turn, and a core configured to magnetically couple the primary winding turn and the secondary winding turn; the primary winding turns of the plurality of transformers are coupled to the pulse generator to receive the voltage pulses; and the secondary winding turns of the plurality of transformers are coupled in series and are configured to conduct welding-type current in the welding-type output circuit.