In a consumable electrode-type arc welding in which pulse welding and short-circuit welding are alternately repeated, a welding current is controlled such that a welding current immediately before shifting from the pulse welding to the short-circuit welding is lower than a base current in a pulse.

There is provided an arc welding control method for 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 upon starting the welding. The forward feeding is continued during a transient welding period from a time point at which the welding wire comes in contact with a base material and conduction of welding current is started to a time point at which convergence on a steady welding period is performed. The transient welding period is terminated at the short-circuiting period. The forward/reverse feeding control is started from the reverse feeding period after the termination of the transient welding period.

A method and apparatus for welding is disclosed. The output is preferably a cyclical CV MIG output, and each cycle is divided into segments. An output parameter is sampled a plurality of times within one or more of the segments. The CV output is controlled within the at least one segment in response to the sampling. The parameter is output power, a resistance of the load, an output current, an output voltage, or functions thereof in various embodiments. The control loop is preferably a PI or PID loop. The loop may be applied only within a window. The set point may be taught or fixed. The system can be used to weld with a controlled arc length.

Provided is an arc welding control method for performing control in an arc period, the control including: first control of increasing welding current (Ia) to first current value (I1) in a range from 200 A to 300 A inclusive at first gradient (S1) and maintaining welding current (Ia) at first current value (I1) for first period (T1); second control of reducing welding current (Ia) from first current value (I1) to second current value (I2) at second gradient (S2) and maintaining welding current (Ia) at second current value (I2) for second period (T2); third control of increasing welding current (Ia) from second current value (I2) to third current value (I3) higher than first current value (I1) at third gradient (S3); and fourth control that is started to reduce welding current (Ia) from third current value (I3) within 0.5 ms after welding current (Ia) reaches third current value (I3) under the third control.

A method for encoding information includes specifying a digital value and providing a symbol (28, 70, 80, 90, 100) comprising a plurality of polygons (72, 82, 92, 94, 102) meeting at a common vertex (74, 84, 96, 98, 104) and having different, respective colors selected so as to encode the specified digital value.

A method for welding a zinc coated steel sheet is provided. The method for welding a zinc coated steel sheet of the present invention is a method for welding a zinc coated steel sheet by using a welding material, wherein when welding, the welding current is 150-300 A, a shielding gas is a mixed gas of Ar+10-30% CO2, and the welding polarity is alternately altered so that the welding polarity fraction defined by relational equation 1 satisfies the range of 0.25-0.35.

A welding system includes a power source configured to generate power and deliver the power to a welding torch. The power is provided in accordance with an electrode negative pulse welding regime that includes a cyclic peak, followed by a stabilization phase, then a return to a background level. The stabilization phase has a generally parabolic current shape, and is performed in a current-closed loop manner until a transition point. Resulting weld performance is improved, with a globular-like transfer mode, reduced shorts and enhanced arc stability.

A welding system and method provide for generating a controlled waveform for welding power output, the waveform comprising a plurality of successive peak phases followed by a short circuit between a welding wire electrode and an advancing weld puddle. Each then present peak phase is regulated based upon at least the immediately preceding short circuit to control the short circuit that will occur following the then present peak phase. Some embodiments permit regulating at least one waveform phase based upon at least the immediately preceding short circuit to control the next short circuit that will occur, and regulating at least one short response phase based upon at least the immediately preceding short circuit to control the next short circuit that will occur.

An arc welding system of a consumable electrode type comprises: a wire feeding device that feeds welding wire from a wire feeding source to a welding torch; and a power supply device that supplies electric power between the welding wire fed to the welding torch and a base material, the system being configured to weld the base material by arc generated by the supplied electric power. The wire feeding device is provided with: an intermediate wire feeding source that is disposed between the wire feeding source and the welding torch and is configured to temporarily accommodate the welding wire fed from the wire feeding source and to feed the accommodated welding wire to the welding torch; a pull-out feeding part that feeds the welding wire at the wire feeding source to the intermediate wire feeding source; and a push-out feeding part that feeds the welding wire accommodated in the intermediate wire feeding source to the welding torch.

An arc welding or additive manufacturing system includes a wire feeder, a torch, a wire electrode driven through the torch by the wire feeder, and an arc generation power supply operatively connected to the torch to deliver a pulse waveform to the wire electrode during a deposition operation. The pulse waveform includes a series of current pulses and interleaved background current portions such that each current pulse is separated from a prior current pulse by a prior background current portion and separated from a subsequent current pulse by a subsequent background current portion. During each current pulse a molten droplet is projected from a tip of the wire electrode followed by an axial spray of molten metal away from the tip of the wire electrode before the subsequent background current portion occurs.