Abstract:The effect of annealing process on the microstructure and mechanical properties of Ф7mm thin-walled inner-grooved copper tube was studied by means of metallographic observation, mechanical property test and statistical analysis. The results showed that the Φ7mm thin-walled inner grooved copper tube annealed at 440℃ and 460℃, the microstructure of the copper tube was small and uniform. With the increase of the annealing temperature, the elongation and tensile strength of the copper tube increase at first and then decrease, the production of 7 mm thin-walled copper tubes with internal thread was carried out by annealing at 460℃ for 37 minutes. The inner grains of the tubes were fine and uniform, and the tubes had higher tensile strength, higher hardness and higher elongation, the microstructure and comprehensive mechanical properties of copper tube are the best.