Abstract: Following the special requirements for the seamless steel tube for semi-trailer axle purpose by the US market, the chemical composition, the manufacturing process and the heat treatment schedule are accordingly designed and determined, while testing and inspections are conducted to the as-hot rolled and as-heat treated seamless steel tubes for semi-trailer axle service for their properties and hardness.It is concluded that the following heat treatment schedule should be deemed as the best one to satisfy the requirements by the US market for the seamless steel tube for semi-trailer axle purpose.First the tube is held in the furnace at 750℃ for 3 minutes, then held for 6 minutes along with the temperature going up to 910℃, and water quenched.Afterwards, the tube is immediately tempered at 560℃, then held for 60 minutes, and finally, after leaving the furnace, air cooled.