Metallographic Microcosmic Analysis on Primary Short Circuited Melted Bead of Copper Wire Heated in Different Temperature

In order to find the influences of heating temperature on the metallographic microcosmic of primary short circuited melted beads, the beads were heated at different temperatures for 30 min in a box-type resistance furnace before cooling by water or by air. Contrasting the microstructure of primary short circuited beads, the changing regularity of the microstructure of primary short circuited beads is drawn. With the increase of the temperature, metallographic microcosmic of the primary short circuited beads change from finely cylindrical crystal to isometric crystal. The conclusion can be used in physical evidence identification.