Abstract:

The copper conductor primary short circuited melted marks will change to some extent after being affected by high temperature in fire. With the help of synchronous thermal analysis technology (TG-DSC), the heating temperature is accuratelycontrolled, the O₂/N₂ atmosphere changes in the fire are simulated, the types and initial temperatures of various physical and chemical reactions of the melted marks are analyzed according to the TG-DSC curve, and assisted in judging the causes of the tissue changes. The results show that the melting point of the primary short circuited melted mark is 1 062 ℃, then the mark will melt and lose its characteristic structure. In the fire atmosphere, when the heating temperature reaches 850 ℃, the oxidation reaction will occur, and the black oxide particles and the outer ring oxidation belt will be produced. With the increasing of temperature, the annular oxidation zone will be thickened and the black oxide particles will concentrate to the grain boundary. The research results have certain theoretical reference for the accurate inspection and identification of the copper conductor primary short circuited melted marks and the analysis of its heat process in fire.

Key words:

identification of fire evidence, primary short circuited melted mark, thermal analysis, physical and chemical reaction changes, oxide