Abstract: Based on the law of the conservation of energy and Fouriers law, the mathematical odels respectively considering the effect of resistance heat and the heat transferred through the weld pool on the hotwire temperature distribution were developed. And then based on the superposition principle the mathematical model of quasistate temperature distribution of hotwire heated by resistance energy  was  developed. The   accuracy   of  the   mathematical   model   was  validated   by comparing   the   result   of   calculating   from   the   mathematical  model  with   the   experimental  result from the literature. The impact of current density, wire feeding speed, wire extension on temperature  distribution   of   hot-wire  was elaborately  discussed.   The  results   show  that  the mathematical model has high accuracy to effectively analyze the process of wire heated   by  resistance   energy.   The  larger the current  density  or   wire  extension  is,  the   higher  the temperature in different positions on the wire extension is, however, the bigger the wire feeding speed is, the higher the preheating temperature is. In some certain cases, the matching relations  among current density, wire feeding speed and wire extension can be concluded.

Key words: resistance heat, heat transferred from the weld pool, superposition principle, temperature distribution, analytical mathematical model