Heat treatment method for obtaining high durability of martensite heat-resistant steel

The invention relates to a heat treatment method for obtaining high durability of martensite heat-resistant steel, belonging to the technical field of heat-resistant steel. The method adopts a double tempering heat treatment technique. The method comprises the following steps: heating 9-12% Cr steel to 1050-1150 DEG C to perform austenization, keeping the temperature for 30-120 minutes, cooling with water to room temperature; and keeping the temperature at 650-750 DEG C for 0.5-2 hours, heating to 750-780 DEG C, keeping the temperature for 1-3 hours, and cooling in air to room temperature. The method is used for preparing 9-12% Cr steel and a large-caliber boiler tube thereof. The initial size of the precipitated phase is obviously finer than that of the precipitated phase treated by the traditional heat treatment process, and the quantity is higher. The precipitated phase can effectively fix dislocation and lath boundary in the long-time service process, maintain the strengthening effect on the dislocation and lath for a long time, enhance the enduring creep property, thereby further enhancing the service temperature of the 9-12% Cr heat-resistant steel.