Abstract: Mechanical properties of the friction weld drill rod, which is guaranteed with the rational welding technology and the rational heat treatment technology, must meet the requirements of profession standards.It is studied how to judge the cause of products being not up to standard.The effect of heat treatment technology on mechanical properties of the welded dill rods is analyzed.The results show that during the normal welding technology the yield intensity lower than that of profession standards, the impact ductility much higher than normal and the lower hardness in the heat treatment area are due to incorrect quench or temper technology.It can be corrected by revising quench or temper technology.