A large amount of heat is generated during the electromagnetic railgun launching

and theheat seriously affects the life and launch efficiency of the railgun. In order to study the variation of the temperature field of the armature rails and its contact surfaces

we put forward a method of analyzing joule heating and its temperature under the electromagnetic-heat-temperature transient coupling field. The joule heating and temperature characteristics of the armature and rails were also studied. Through the finite element numerical simulation of the three-dimensional railgun model

the electromagnetic feature of armature and rails under the pulse waveform current was analyzed firstly. Afterwards

the corresponding temperatures of the armature/rail and their interfaces were also studied. The results show that the maximum current density and temperature of the armature appear at the inner inflection point

and its temperature can reach2 000 ℃. The maximum current density and the temperature of the interfaces distribute on the outer edges

and the joule heat has little effect on the temperature rise of the contact surfaces

which is far from reaching of the melting points of the armature and rails. Therefore

Joule heat plays an important role in the temperature rise of the edge position of the armature/rail contact surfaces

but does not melt most of the material on the contact surface.