CONNECTION OF AUTOMOBILE CONDUCTORS BY ULTRASONIC WELDING. FIRE HAZARD
https://doi.org/10.18322/PVB.2018.27.10.38-45
Abstract
Introduction. Nowadays ultrasonic welding of metals including conductors is widely used. The connection of copper conductors by ultrasound is based on high-frequency oscillations.
Materials and methods. Copper stranded conductors interconnected by ultrasonic welding were chosen as the materials for the study. The study of these samples was carried out in the laboratory by metallographic analysis.
Results and discussion. In case of a poor contact at the connection point, a large transient resistance may occur when an electric current passes through a given point and cause fire.
To establish the involvement of a poor adhesion to the occurrence of a fire, it is necessary to conduct metallographic studies of the compound. With qualitatively performed welding, fusion of individual sections of wires at the junction site is observed, while in the case of a “poor” connection, clearly defined boundaries are observed.
A very long exposure to ultrasound in the welding process on the connected conductors leads to a decrease in the plasticity of the conductor, which in turn leads to the fracture of the veins near the junction and, as a consequence, to the emergence of local current overload. Where the places of rupture after the fire are melted and smoked, indicates that the test conductor was damaged even before the ignition of the vehicle.
Conclusion. Thus, the possibility of vehicle combustion as a result of a poorly executed connection of conductors by ultrasonic welding is shown. It is noted that the fire can be caused by uncompleted welding (“non-fusion” of the conductors), or vice versa when an impact of ultrasonic waves on the conductors to be connected has been too long.
It is necessary to withdraw this connection directly at the seat of fire for further laboratory metallographic research.
About the Authors
Yu. N. Eliseev
Saint Petersburg University of State Fire Service of Emercom of Russia.
Russian Federation
Russian Federation
candidate of Technical Sciences, Leading Researcher of Research Center for Fire Examination.
Oktyabrskaya Emb., 35, Saint Petersburg, 193079.
T. P. Sysoeva
Saint Petersburg University of State Fire Service of Emercom of Russia.
Russian Federation
Russian Federation
Candidate of Technical Sciences, Leading Researcher of Research Center for Fire Examination.
Oktyabrskaya Emb., 35, Saint Petersburg, 193079.
S. V. Skodtaev
Saint Petersburg University of State Fire Service of Emercom of Russia.
Russian Federation
Russian Federation
Senior Researcher of Research Center for Fire Examination.
Oktyabrskaya Emb., 35, Saint Petersburg, 193079.
A. Yu. Pariyskaya
Saint Petersburg University of State Fire Service of Emercom of Russia.
Russian Federation
Russian Federation
Senior Researcher of Research Center for Fire Examination.
Oktyabrskaya Emb., 35, Saint Petersburg, 193079.
Ya. V. Roshchina
Saint Petersburg University of State Fire Service of Emercom of Russia.
Russian Federation
Russian Federation
Researcher of Research Center for Fire Examination.
Oktyabrskaya Emb., 35, Saint Petersburg, 193079.
E. V. Kalach
Voronezh Institute – Branch of Ivanovo Fire and Rescue Academy of State
Firefighting Service of Emercom of Russia.
Russian Federation
Russian Federation
Candidate of Technical Sciences, Docent, Associate Professor of Department of Natural Science Disciplines.
Krasnoznamennaya St., 231, Voronezh, 394052.
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Review
For citations:
Eliseev Yu.N., Sysoeva T.P., Skodtaev S.V., Pariyskaya A.Yu., Roshchina Ya.V., Kalach E.V. CONNECTION OF AUTOMOBILE CONDUCTORS BY ULTRASONIC WELDING. FIRE HAZARD. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2018;27(10):38-45. (In Russ.) https://doi.org/10.18322/PVB.2018.27.10.38-45
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