The Cinemicroscopic Observation of Explosions between Contact Rods-in Connection with Flash Butt Welding

Abstract

Taking high speed motion pictures of the flashes generated in flash butt welding on mild steel Fe and Al, we could make the mechanism of the flash generation rather clear.
A very interesting phenomenon in flash generation we observed was, that a number of bubbles were produced by the passage of large electric current at one short-circuited bridge formed between two contact rods ; we concluded that the mechanism of this bubble generation was very much like that of an exploding wire, on which many researches are now proceeding in several countries.
Since the flashing is an explosive phenomenon due to more local heating around a short-circuited part, much more bubbles are generated than in the case of an exploding wire. This means a possibility in future of the research for metal explosion, using contact points between opposed surfaces.
Lastly, we found that many flashes were bubbles in the enlarged photographs of flashes that stick on glass surfaces. The auxiliary effect of CO₂ gas in the explosion of mild steel is also described.