1986 年 4 巻 4 号 p. 657-661
Formation of molten metal layer at weld interface was found to be detected in real time by measurement of effective time-integral value of weld voltage as monitoring parameter in upset welding of low carbon steel rod.
Upset weld quality can be assured by formation of uniform molten metal layer at weld interface at early period of welding and of weld interface larger than mother metal in sectional area at final period of welding. The molten metal layer can be formed by melting of the interface due to weld current, and, furthermore, it seems to be connected to effective time-integral value of weld voltage which is related to temperature rise at upset welds. It is experimentally confirmed that the uniform molten metal layer is formed over a certain value of effective time-integral value of weld voltage with no relation to edge angle, welding condition and so on for upset welding process of low carbon steel rod (20mm dia.) with prepared edge.