Abstract: A welding wire feed method and apparatus involves feeding a welding wire in a conduit cable to a workpiece, while maintaining it normally in one plane in the form of a sine curve in the conduit cable.

Abstract: The extent of shielding function of an arc atmosphere is measured by the concentration of nitrogen oxide in the arc atmosphere. The concentration of nitrogen oxide in the arc atmosphere is measured by a nitrogen oxide measuring device. The measured value is indicated by an indicator. When the measured value exceeds a predetermined reference value, an alarm device is operated or a welding operation is stopped. Either a supply of shielding gas which forms an arc atmosphere is controlled, or a flow of fume is controlled through a fume exhaust device, as a function of the measured value.