Flashing Phenomena in Steel Sheets

Study on Flash Welding : Part 1

Abstract

The flash welding consists of the flashing and the upsetting actions, and has a number of variables for the processes. The purpose of this study in Part one is to examine the flashing phenomena in carbon steels and ferritic or austenitic stainless steel sheets in 1.2 mm thick. The flash welding was carried out using the constant rates of the platen acceleration and the secondary no load voltage of 12.2V and below. The following results were obtained.
1. The flashing current waveform in each half cycle consists basicaly of the three phases of bridge, flash and open. The ratio of these phases results in a nearly constant value at the early stage of the flashing process.
2. In the late stage the ratio of these phases in low carbon steel shows the same values as that in medium carbon steel, but a little difference from that in austenitic stainless steel.
3. The ratio of these phases and the numbers of flash in a unite time are remarkably affected by the variations of the size of specimen, platen speed, secondary no load voltage and electrical circuit constant of the welding equipment, and the remarkable firing of flash generates under the secondary no load voltage of about 6V.