A solid wire is for gas-shielded arc welding, using a shielding gas, and for galvanized steel sheet welding. The solid wire comprises, to the mass of the whole of the solid wire, predetermined amount of C, Si, Mn, P, S, O, and Cr, with the balance consisting Fe and inevitable impurities. The solid wire satisfies 1.0(percentage by mass of Si+that by mass of Mn)/{100(that by mass of S+that by mass of O}4.0 and 0.50percentage by mass of Mn/that by mass of Si2.00. The shielding gas is an Ar gas comprising 25 to 40% of CO.sub.2 gas. It is achieved to improve spatter-decreasing performance and pore-resisting performance (performance of restraining the generation of porosity defects, such as pits and blowholes).

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.

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 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.

An electric arc welder including a high speed switching power supply with a controller for creating high frequency current pulses with negative polarity components through the gap between a workpiece and a welding wire advancing toward the workpiece, where the pulses and a background current defining a series of weld cycles. A wave shape generator defines the shape of the pulses and the background current including a controlled ramp up and/or ramp down in each of said cycles, and a circuit to change the shapes of the pulses and/or background current in a repeating pattern in each of the weld cycles, including a negative current in at one of said pulses. The shape change in a cycle can be between first and second shapes or by a rhythmic AC modulation.

A method and apparatus for providing welding-type power includes an input circuit, a power circuit, and a controller. The input circuit receives input power and provides intermediate power. The power circuit has a power control input with at least one switch that responds to the control input. The power circuit receives the intermediate power and provides welding type output power. The controller has a set point input and a control output. The control output is connected to the power control input. The control circuit also includes a pwm module that responds to the user set point input and provided the control output. The pwm module can include a short duty cycle linearizing module. The pwm module can also include a short duty cycle charging ramp module.

A welder power supply and welding method are provided which welds in a DCEN state, but when a short circuit is detected the current waveform switches to an EP state and the short circuit is cleared while the electrode has a positive polarity.

A method is provided for controlling pulse arc welding. The method includes feeding a welding wire, and providing a number of currents such as: a peak rise current that rises from a value of a base current to a value of a peak current during a peak rise period; the peak current during a peak period; a peak fall current that falls from the value of the peak current to the value of the base current during a peak fall period; and the base current during a base period. The method also includes repeating the provision of the currents as one pulse cycle to perform welding. The welding wire is fed forward and backward repeatedly, and is fed backward at least during the base period.

An example welding-type power supply includes: power conversion circuitry configured to convert input power to welding-type power having at least one of an alternating current (AC) waveform or a pulse waveform; an interface configured to receive an input representative of a selected frequency of the AC waveform or the pulse waveform; and control circuitry configured to: determine an amperage parameter of the welding-type power; based on the amperage parameter, determine a range of frequencies of the AC waveform or the pulse waveform; control the interface to output an indication of the selected frequency with respect to the determined range of frequencies; and control the power conversion circuitry to output the welding-type power at the selected frequency and based on the amperage parameter.

A method and apparatus for providing welding-type power includes an input circuit, a power circuit, and a controller. The input circuit receives input power and provides intermediate power. The power circuit has a power control input with at least one switch that responds to the control input. The power circuit receives the intermediate power and provides welding type output power. The controller has a set point input and a control output. The control output is connected to the power control input. The control circuit also includes a pwm module that responds to the user set point input and provided the control output. The pwm module can include a short duty cycle linearizing module. The pwm module can also include a short duty cycle charging ramp module.