A method for joining two metallic, tubular joining members to one another, the method including arranging two metallic, tubular joining members with respect to one another in an overlapping or end-face manner, and joining the joining members by material bond along a joining zone of the joining members. In the joining, a chain of joining spots extending in the circumferential direction of the joining members is produced in the joining zone, wherein successive joining spots in the chain overlap, wherein, in the joining, the joining spots are produced by means of TIG pulse welding with an arc time of up to 100 ms, preferably of up to 50 ms, wherein an arc of a welding pulse of the TIG pulse welding is extinguished after the arc time has been reached. A corresponding welding apparatus is also described.

Systems and methods for initiating and/or terminating a GMAW-P welding process are disclosed. A welding-type power supply may include a power conversion circuitry configured to convert input power to welding-type power, and a controller configured to control the power conversion circuitry based on a plurality of operating parameters. In examples, the systems and methods disclosed herein implement pulsed cycles with one or more increased output parameters (such as current, pulse width, etc.) in order to jump start a pulsed welding cycle at a cold start (i.e. at initiation of a welding process), and thereby prevent a ball forming and remaining on the end of an electrode wire as the welding process continues. In a similar manner, a pulsed cycle with one or more increased parameters can be used to terminate the welding process, also preventing the ball forming and remaining on the electrode wire.

A three stage power source for an electric arc welding process comprising an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal and converts the first DC output signal to a second DC output signal of the second stage; and a third stage to convert the second DC output signal to a welding output for welding wherein the input stage and the second stage are assembled into a first module within a first housing structure and the third stage is assembled into a second module having a separate housing structure connectable to the first module with long power cables. The second module also includes wire feeding systems and electronics.

A pulse welding period alternately includes a first peak period in which a first peak current whose peak value is a first current value is caused to flow through a welding wire and a base period in which a base current having a second current value is caused to flow through the welding wire. During the base period, a second peak current whose peak current value is a sum of a second current value and a third current value and is smaller than the first current value is superimposed on the base current at a second pulse frequency. A second peak period in which the second peak current is caused to flow once is shorter than the first peak period. During the first peak period, a droplet is transferred from the welding wire toward a base material.

Disclosed example welding power supplies comprise: power conversion circuitry configured to convert input power to welding power; an input device configured to receive a plurality of instances of an input; and control circuitry configured to: calculate a frequency of the plurality of instances of the input; and control the power conversion circuitry to output the welding power as a series of pulses having a pulse frequency determined based on the calculated frequency.

An arc welding system providing improved molten metal droplet transfer. The system includes a welding power source having a welding power supply, a welding waveform generator, and a controller. Two fluxed cored welding wire electrodes are connected to the power source and are powered by the same welding output voltage and current produced by the power source. A feedback circuit is connected to the power source to provide an adaptive response to maintain an average welding output voltage. The controller controls the waveform generator and the power supply to superimpose welding current pulses onto a welding waveform of a CV flux cored arc welding process, that uses CO.sub.2 as a shielding gas, to generate a modified waveform of a modified CV flux cored arc welding process. The current pulses are superimposed in time to form molten metal droplets between ends of the two electrodes during the modified welding process.

A method and apparatus for providing welding type power is disclosed. The output is cyclical, and is a controlled voltage output during the background and/or peak and a controlled current output during the transition up and/or down. During the controlled current portion the output is responsive to output voltage.

A three stage power source for an electric arc welding process comprising an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal and converts the first DC output signal to a second DC output signal of the second stage; and a third stage to convert the second DC output signal to a welding output for welding wherein the input stage and the second stage are assembled into a first module within a first housing structure and the third stage is assembled into a second module having a separate housing structure connectable to the first module with long power cables. The second module also includes wire feeding systems and electronics.

A welding power supply including power conversion circuitry adapted to receive a primary source of power, to utilize one or more power semiconductor switches to chop the primary source of power, and to convert the chopped power to a welding output is provided. The provided welding power supply includes a pulse width modulated (PWM) digital controller including gate drive circuitry that generates a PWM output signal that controls the switching of the one or more power semiconductor switches. The PWM output signal includes a duty cycle term corrected for one or more sources of error in the welding system.

A power supply for welding, cutting and similar operations includes a dual two-switch forward converter. The converter has two inverter circuits coupled in parallel but controlled to provide output power in an interleaved fashion. To avoid walking of the circuits (which could result in different duty cycles and imbalance of the load sharing), control signals are determined and applied to a first of the inverter circuits, and on times of the first circuit is monitored, such as by augmenting a counter to determine the number of clock cycles the first circuit is on. The same duration is then used for commanding output from the second inverter circuit. The duty cycles of both circuits is thus ensured to be the same regardless of changes in the total output power.