Processes in Spark Gap during Contact Butt Welding of Rails

In equipment for the contact butt welding of rails, innumerable parameters (input factors) affect the quality of the welded joint. That prevents complete selection of the optimal welding conditions. By studying the processes in the spark gap (the formation of microcontacts, increase or decrease in t...

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Bibliographic Details
Published in:Steel in translation 2022-04, Vol.52 (4), p.369-374
Main Authors: Shevchenko, R. A., Yur’ev, A. B., Kozyrev, N. A., Mikhno, A. R.
Format: Article
Language:English
Subjects:
Butt welding
Canonical forms
Chemistry and Materials Science
Electric contacts
Frequency distribution
Histograms
Materials Science
Normal distribution
Probability distribution functions
Rails
Spark gaps
Statistical analysis
Welded joints
Welding current
Welding machines
Welding parameters
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Description
Summary:In equipment for the contact butt welding of rails, innumerable parameters (input factors) affect the quality of the welded joint. That prevents complete selection of the optimal welding conditions. By studying the processes in the spark gap (the formation of microcontacts, increase or decrease in their cross-sectional area, and the explosion of existing microcontacts), the heat released in welding may be determined, and its uniformity may be assessed. On that basis, a smaller set of factors affecting the quality of the weld may be selected. Extensive statistical data are used in studying the processes in the spark gap during the contact butt welding of rails of type R65 and category DT350 on a K1000 welding machine. Analysis shows that there is no relation between the welding current and the plate motion in the welding machine. The welding current is assumed to be randomly distributed; it varies as a result of the formation, existence, and explosion of numerous brief electrical contacts. Analysis of the frequency distribution shows that the spark gap’s resistance does not conform to a normal distribution. As the sample is enlarged, deviation from normal form increases. Visually, the histogram corresponds to a gamma distribution. On the basis of a gamma distribution, the welding current in contact butt welding is simulated. The results will be used to model the thermal processes and to predict the structure of the seam and the thermal-influence zone in the welding of rails.
ISSN:0967-0912
1935-0988
DOI:10.3103/S0967091222040118