Determining patterns in the generation of magnetic fields when using different contact welding techniques

Abstract

The object of this study is the quantitative characteristics of magnetic fields induced during electric contact welding in various ways: contact point, arc-butt, capacitor point, contact-butt continuous, and pulsating fusion. The problem to be solved is the lack of necessary information regarding the electromagnetic safety of these welding techniques. A description of the proposed methodological approaches to determining the levels of magnetic fields, their measurement tools, and methods for assessing their impact on the welder's body is given. Based on the analysis and processing of the acquired oscillograms and spectrograms of magnetic fields, their quantitative characteristics were measured. To determine the general level of the polyfrequency magnetic field arising at contact welding, the proposed generalized indicator of the level of the magnetic field was used. It was established that during contact point welding by a stationary machine, the level of the magnetic field exceeds the maximum permissible value at the workplace in the range of 50–1000 Hz at a distance of 0.3 m from the welding electrodes. When manually welding in this way, the magnetic field level exceeds the permissible level in the frequency bands of 5–50, 50–1000 Hz directly near the electrical cable. Capacitor spot welding with direct current is characterized by exceeding the maximum permissible MP at the workplace in the high-frequency range of 1000–10000 Hz. During arc-butt welding, no excess of the maximum permissible levels of the magnetic field was detected at the workplace. It is shown that the spectral composition and magnitude of the magnetic field signal is determined by the welding technique and the initial parameters of power supplies. Orimani results can be used in the field of welding production and labor protection.