This paper deals with the modelling and identification of the heat exchange at the tool―workpiece interface in machining. A thermomechanical modelling has been established including heat balance equations of the tool―workpiece interface which take into account the heat generated by friction and the heat transfer by conduction due to the thermal contact resistance. The interface heat balance equations involve two coefficients: heat generation coefficient (HGC) of the frictional heat and heat transfer coefficient (HTC) of the heat conduction (inverse of the thermal contact resistance coefficient). Using experimental average heat flux in the tool, estimated for several cutting speeds, an identification procedure of the HGC―HTC couple, involved in the established thermomechanical FE-based modelling of the cutting process, has been proposed, which gives the numerical heat flux equal the measured one for each cutting speed. Using identified values of the HGC―HTC couple, evolution laws are proposed for the HGC as function of cutting speed, and then as function of sliding velocity at the tool―workpiece interface. Such laws can be implemented for instance in a Finite Element code for machining simulations.