Manufacturing method of ferritic heat-resistant steel forged tee joint for ultra-supercritical power station boiler

Abstract

The invention relates to the technical field of forging hot working, and provides a manufacturing method of a ferritic heat-resistant steel forged tee joint for an ultra-supercritical power station boiler, which comprises the following steps: S1, weighing raw materials, smelting, casting and forming to obtain a steel billet; s2, the steel billet is heated and subjected to extrusion forming, and a forged tee joint blank is obtained; and S3, after the forged tee joint blank is subjected to first heat treatment, punching and second heat treatment, the ferritic heat-resistant steel forged tee joint for the ultra-supercritical power station boiler is obtained. In the step S2, heating is divided into first-section heating, second-section heating and third-section heating. According to the technical scheme, the problem that the mechanical property of the forged tee joint for the ultra-supercritical power station boiler is poor in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of forging hot processing, and in particular to a method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler. Background Art

[0002] In the construction and operation of ultra-supercritical power plant boilers, forged tees are critical pipe connection components, and their performance and quality are directly related to the safety and operational efficiency of the entire power plant boiler. As the power industry evolves towards higher efficiency and environmental protection, the operating temperatures and pressures of ultra-supercritical units continue to rise, placing more stringent requirements on the overall performance of forged tees. Traditional ferritic heat-resistant steel, due to its excellent high-temperature strength and oxidation resistance, is widely used in the manufacture of these components, but its manufacturing process still presents numerous challenges.

[0003] Traditional forging methods face challenges during the forming process, including low material utilization, long processing cycles, and high manufacturing costs. Furthermore, due to the difficulty in controlling process parameters, the mechanical properties of forged tees often fail to meet the high standards required of ultra-supercritical units. Insufficient tensile strength can cause component failure under high-temperature and high-pressure environments, seriously impacting the safe operation of power plant boilers. Especially under ultra-supercritical conditions of 630°C and above, forged tees require higher structural stability, which traditional processes struggle to achieve.

[0004] Therefore, it is urgent to propose an efficient, precise and economical manufacturing method. By optimizing the material composition and precisely controlling the process, the mechanical properties of the forged tee can be improved, which is of great significance for meeting the high standard requirements of high-temperature ultra-supercritical units for forged tees. Summary of the Invention

[0005] The present invention provides a method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler, which solves the problem of poor mechanical properties of the forged tee for an ultra-supercritical power station boiler in the related art.

[0006] The technical solutions of the present invention are as follows: The present invention provides a method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler, comprising the following steps: S1, weighing raw materials, smelting, casting, and forming to obtain steel billets; S2, heating and extruding the steel billet to obtain a forged tee blank; S3, subjecting the forged tee blank to a first heat treatment, punching, and a second heat treatment to obtain the ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler; In step S2, the heating is divided into a first heating stage, a second heating stage and a third heating stage; During the first heating stage, the temperature is 640-660°C and the holding time is 3-6 hours; During the second heating stage, the temperature is 840-860°C and the holding time is 3-6 hours; During the third heating stage, the temperature is 1200-1240° C. and the holding time is 38-45 hours.

[0007] As a further technical solution, during the first heating stage, the temperature is raised to 640-660°C at a heating rate of 50-60°C / h; During the second heating stage, the temperature is raised to 840-860°C at a heating rate of 10-30°C / h; During the third heating stage, the temperature is raised to 1200-1240° C. at a heating rate of 10-30° C. / h.

[0008] As a further technical solution, the heating rate of the second heating stage is lower than the heating rate of the third heating stage.

[0009] In the present invention, the heating rates of the first, second and third heating stages are precisely controlled, and when the heating rate of the second heating stage is 10-30°C / h, the heating rate of the third heating stage is 10-30°C / h, which can further improve the mechanical properties of the forged tee and increase its tensile strength to above 699 MPa. When the heating rate of the second heating stage is less than that of the third heating stage, the effect of improving the mechanical properties is better.

[0010] As a further technical solution, in step S2, before the extrusion molding, the steel billet after the heating treatment is descaled; During the extrusion molding, upsetting is first performed, and then extrusion is performed until the final forging temperature is 950-1000° C., and then cooling is performed to room temperature.

[0011] As a further technical solution, during the extrusion molding, when cooling to room temperature, the cooling method is furnace cooling.

[0012] As a further technical solution, during the upsetting, the extrusion speed is 4-6 mm / s and the extrusion pressure is 230-260 MPa; During the extrusion, the extrusion speed is 7-10 mm / s and the extrusion pressure is 320-350 MPa.

[0013] As a further technical solution, in step S3, during the first heat treatment, the temperature is first raised to 900~930℃ at a heating rate of ≤60℃ / h, kept warm for 3~6h, cooled to 700~730℃, kept warm for 60~70h, and then cooled to room temperature.

[0014] As a further technical solution, during the first heat treatment, the temperature is cooled to 700-730° C. by furnace cooling, and then cooled to room temperature by furnace cooling.

[0015] In the present invention, the temperature is raised to 900-930° C. at a heating rate of ≤60° C. / h and heat preservation treatment is performed, which can further refine the grains and lay the foundation for obtaining a forged tee with a stable structure.

[0016] As a further technical solution, in step S3, during the second heat treatment, the temperature is first raised to 1030~1080℃ at a heating rate of ≤60℃ / h, kept warm for 3~6h, cooled to room temperature for the first time, and then raised to 770~790℃ at a heating rate of ≤60℃ / h, kept warm for 5~8h, and cooled to room temperature for the second time.

[0017] As a further technical solution, when cooling to room temperature for the first time, the cooling method is oil cooling; When cooling to room temperature for the second time, the cooling method is air cooling.

[0018] As a further technical solution, the steel billet is composed of the following components in weight percentage: C 0.055%~0.085%, Si 0.3%~0.45%, Mn 0.4%~0.5%, Co 0.1%~0.3%, W 0.18%~0.58%, Nb 0.01%~0.04%, Y 0.05%~0.25%, Cu 0.2%~0.3%, V 0.11%~0.15%, B 0.008%~0.015%, N 0.005%~0.01%, P≤0.008%, S≤0.005%, the balance is iron and its inevitable impurities.

[0019] As a further technical solution, the weight ratio of the sum of the weights of Y and Co to the weight of W is 1-2:1.

[0020] As a further technical solution, the weight ratio of Y to Co is 1:1.

[0021] In the present invention, by adjusting and optimizing the composition of the steel billet and through the coordinated effect of the various components, the internal structure of the forged tee can be stabilized and the forged tee has good impact resistance. Specifically, by regulating the content ratio of Y, Co and W, when the weight ratio of the sum of Y and Co to W is 1-2:1, the impact resistance of the forged tee can be further improved.

[0022] The working principle and beneficial effects of the present invention are: 1. In the present invention, the billet is heated in three stages. The first stage is heated at a temperature of 640-660°C. The billet is first heated at a relatively low temperature of 640-660°C to avoid cracking of the billet due to thermal stress concentration when the subsequent heating temperature is higher. The second stage is heated at a temperature of 840-860°C. This temperature stage can make the interior of the billet present a relatively dense structure. The third stage is heated at a temperature of 1200-1240°C. This temperature stage can make the billet material homogenized and diffused, with high diffusion efficiency, and is conducive to subsequent extrusion molding. When the temperature is lower than 1200°C, the temperature is relatively low, and the degree of diffusion inside the billet material is low. When the temperature is higher than 1240°C, liquid boron-containing compounds will appear and be adsorbed on the grain boundaries, which will have an adverse effect on the billet. Therefore, the steel billet is heated in sections during the heating process, and the heating temperature of each section is precisely controlled, which can effectively prevent the precipitation of harmful inclusions and grain coarsening, thereby ensuring the stability of the organizational structure and performance of the ferritic heat-resistant steel forged tee, and effectively improving the mechanical properties of the forged tee.

[0023] 2. In the present invention, in the process of preparing the forged tee, extrusion molding is carried out by extruding the steel billet at a high temperature. The flow of the material is more uniform, and it can be well filled in the extrusion die cavity, reducing the processing allowance, thereby increasing the material utilization rate to 45% to 60%, reducing the waste of raw materials. In addition, in the high-temperature extrusion molding process of the present invention, multiple heating and forging operations of the traditional forging method can be avoided, thereby effectively improving the processing efficiency, reducing costs, and meeting the needs of power station boiler construction more quickly. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples, the Si content in the ferrosilicon alloy is 75 wt %; the Mn content in the ferromanganese alloy is 75 wt %; the Co content in the iron-cobalt alloy is 50 wt %; the W content in the ferrotungsten alloy is 75 wt %; the Nb content in the ferroniobium alloy is 70 wt %; the Y content in the ferroydtrium alloy is 60 wt %; the Cu content in the copper-iron alloy is 90 wt %; the V content in the ferrovanadium alloy is 50 wt %; the B content in the ferroboron alloy is 18 wt %; and the Fe content in the scrap steel is 97 wt %.

[0026] Example 1 A method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler comprises the following steps: S1. Weighing iron-silicon alloy, ferromanganese alloy, iron-cobalt alloy, ferrotungsten alloy, ferroniobium alloy, ferroyttrium alloy, copper-ferroalloy, ferrovanadium alloy, ferroboron alloy and scrap steel, and then smelting, casting and forming to obtain steel billets; S2. The steel billet is heated to 640°C at a heating rate of 50°C / h, kept warm for 3h, then heated to 840°C at a heating rate of 50°C / h, kept warm for 3h, then heated to 1200°C at a heating rate of 50°C / h, kept warm for 38h, descaled, upset at 4mm / s and 230MPa, and extruded at 7mm / s and 320MPa. The final forging temperature after extrusion is 950°C, and then the steel billet is furnace cooled to room temperature to obtain a forged tee blank. S3, the forging tee blank is heated to 900 ℃ at a heating rate of 50 ℃ / h, kept warm for 3h, furnace cooled to 700 ℃, kept warm for 60h, after furnace cooled to room temperature, the main pipe and branch pipe inner holes are opened up, heated to 1030 ℃ at a heating rate of 50 ℃ / h, kept warm for 3h, oil cooled to room temperature, then heated to 770 ℃ at a heating rate of 50 ℃ / h, kept warm for 5h, air cooled to room temperature, and obtained ferrite heat-resistant steel forged tee for ultra-supercritical power station boiler; The steel billet is composed of the following components in weight percentage: C 0.055%, Si 0.3%, Mn 0.4%, Co 0.1%, W 0.18%, Nb 0.01%, Y 0.05%, Cu 0.2%, V 0.11%, B 0.008%, N 0.005%, P 0.003%, S 0.002%, and the balance is iron and inevitable impurities.

[0027] Example 2 A method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler comprises the following steps: S1. Weighing iron-silicon alloy, ferromanganese alloy, iron-cobalt alloy, ferrotungsten alloy, ferroniobium alloy, ferroyttrium alloy, copper-ferroalloy, ferrovanadium alloy, ferroboron alloy and scrap steel, and then smelting, casting and forming to obtain steel billets; S2. The steel billet is heated to 650°C at a heating rate of 55°C / h, kept warm for 4h, then heated to 850°C at a heating rate of 50°C / h, kept warm for 4h, then heated to 1220°C at a heating rate of 50°C / h, kept warm for 40h, descaled, upset at 5mm / s and 250MPa, and extruded at 8mm / s and 350MPa. The final forging temperature after extrusion is 980°C, and then the steel billet is furnace cooled to room temperature to obtain a forged tee blank. S3, the forging tee blank is heated to 920 ℃ at a heating rate of 60 ℃ / h, kept warm for 4h, furnace cooled to 720 ℃, kept warm for 65h, after furnace cooled to room temperature, after the main pipe and branch pipe inner hole are opened up, heated to 1050 ℃ at a heating rate of 60 ℃ / h, kept warm for 4h, oil cooled to room temperature, then heated to 780 ℃ at a heating rate of 60 ℃ / h, kept warm for 6h, air cooled to room temperature, and obtained ferrite heat-resistant steel forging tee for ultra-supercritical power station boiler; The steel billet is composed of the following components in weight percentage: C 0.075%, Si 0.38%, Mn 0.45%, Co 0.13%, W 0.34%, Nb 0.025%, Y 0.13%, Cu 0.25%, V 0.13%, B 0.012%, N 0.008%, P 0.005%, S 0.004%, and the balance is iron and inevitable impurities.

[0028] Example 3 A method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler comprises the following steps: S1. Weighing iron-silicon alloy, ferromanganese alloy, iron-cobalt alloy, ferrotungsten alloy, ferroniobium alloy, ferroyttrium alloy, copper-ferroalloy, ferrovanadium alloy, ferroboron alloy and scrap steel, and then smelting, casting and forming to obtain steel billets; S2. The steel billet is heated to 660°C at a heating rate of 60°C / h, kept warm for 6 hours, then heated to 860°C at a heating rate of 50°C / h, kept warm for 6 hours, then heated to 1240°C at a heating rate of 50°C / h, kept warm for 45 hours, descaled, upset at 6 mm / s and 260 MPa, and extruded at 10 mm / s and 350 MPa. The final forging temperature after extrusion is 1000°C, and then the steel billet is furnace cooled to room temperature to obtain a forged tee blank. S3, the forging tee blank is heated to 930 ℃ with a heating rate of 60 ℃ / h, kept warm for 6h, furnace cooled to 730 ℃, kept warm for 70h, after furnace cooled to room temperature, after the main pipe and branch pipe inner hole are opened up, heated to 1080 ℃ with a heating rate of 60 ℃ / h, kept warm for 6h, oil cooled to room temperature, then heated to 790 ℃ with a heating rate of 60 ℃ / h, kept warm for 8h, air cooled to room temperature, and obtained ferrite heat-resistant steel forging tee for ultra-supercritical power station boiler; The steel billet is composed of the following components in weight percentage: C 0.085%, Si 0.45%, Mn 0.5%, Co 0.3%, W 0.58%, Nb 0.04%, Y 0.25%, Cu 0.3%, V 0.15%, B 0.015%, N 0.01%, P 0.008%, S 0.005%, and the balance is iron and inevitable impurities.

[0029] Example 4 The difference between this embodiment and embodiment 2 is that, in the method for manufacturing a ferrite heat-resistant steel forged tee for a supercritical power station boiler in this embodiment, step S2 is different, specifically, as follows: S2. The steel billet is heated to 650°C at a heating rate of 55°C / h, kept warm for 4h, then heated to 850°C at a heating rate of 5°C / h, kept warm for 4h, then heated to 1220°C at a heating rate of 5°C / h, kept warm for 40h, descaled, upset at 5mm / s and 250MPa, and extruded at 8mm / s and 350MPa. The final forging temperature after extrusion is 980°C, and then the furnace is cooled to room temperature to obtain a forged tee blank.

[0030] Example 5 The difference between this embodiment and embodiment 2 is that, in the method for manufacturing a ferrite heat-resistant steel forged tee for a supercritical power station boiler in this embodiment, step S2 is different, specifically, as follows: S2. The steel billet is heated to 650°C at a heating rate of 55°C / h, kept warm for 4h, then heated to 850°C at a heating rate of 30°C / h, kept warm for 4h, then heated to 1220°C at a heating rate of 10°C / h, kept warm for 40h, descaled, upset at 5mm / s and 250MPa, and extruded at 8mm / s and 350MPa. The final forging temperature after extrusion is 980°C, and then the furnace is cooled to room temperature to obtain a forged tee blank.

[0031] Example 6 The difference between this embodiment and embodiment 2 is that, in the method for manufacturing a ferrite heat-resistant steel forged tee for a supercritical power station boiler in this embodiment, step S2 is different, specifically, as follows: S2. The steel billet is heated to 650°C at a heating rate of 55°C / h, kept warm for 4h, then heated to 850°C at a heating rate of 10°C / h, kept warm for 4h, then heated to 1220°C at a heating rate of 30°C / h, kept warm for 40h, descaled, upset at 5mm / s and 250MPa, and extruded at 8mm / s and 350MPa. The final forging temperature after extrusion is 980°C, and then cooled to room temperature in the furnace to obtain a forged tee blank.

[0032] Example 7 The only difference between this embodiment and embodiment 6 is that, in the steel billet of this embodiment, the weight percentage of Y is 0.21%, the weight percentage of Co is 0.21%, and the weight percentage of W is 0.18%.

[0033] Example 8 The only difference between this embodiment and embodiment 6 is that, in the steel billet of this embodiment, the weight percentage of Y is 0.15%, the weight percentage of Co is 0.15%, and the weight percentage of W is 0.3%.

[0034] Example 9 The only difference between this embodiment and embodiment 6 is that, in the steel billet of this embodiment, the weight percentage of Y is 0.2%, the weight percentage of Co is 0.2%, and the weight percentage of W is 0.2%.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that, in the method for manufacturing the ferrite heat-resistant steel forged tee for supercritical power station boiler in this comparative example, step S2 is different, specifically, as follows: S2. The steel billet is heated to 640°C at a heating rate of 50°C / h, kept warm for 3h, then heated to 840°C at a heating rate of 50°C / h, kept warm for 3h, then heated to 1150°C at a heating rate of 50°C / h, kept warm for 38h, descaled, upset at 4mm / s and 230MPa, and extruded at 7mm / s and 320MPa. The final forging temperature after extrusion is 950°C, and then furnace cooled to room temperature to obtain a forged tee blank.

[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that, in the method for manufacturing the ferrite heat-resistant steel forged tee for supercritical power station boiler in this comparative example, step S2 is different, specifically, as follows: S2. The steel billet is heated to 640°C at a heating rate of 50°C / h, kept warm for 3h, then heated to 840°C at a heating rate of 50°C / h, kept warm for 3h, then heated to 1300°C at a heating rate of 50°C / h, kept warm for 38h, descaled, upset at 4mm / s and 230MPa, and extruded at 7mm / s and 320MPa. The final forging temperature after extrusion is 950°C, and then furnace cooled to room temperature to obtain a forged tee blank.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that, in the method for manufacturing the ferrite heat-resistant steel forged tee for supercritical power station boiler in this comparative example, step S2 is different, specifically, as follows: S2. The steel billet is heated to 840°C at a heating rate of 50°C / h, kept warm for 6 hours, and then heated to 1200°C at a heating rate of 50°C / h. After keeping warm for 38 hours, the steel billet is descaled, upset at 4 mm / s and 230 MPa, and extruded at 7 mm / s and 320 MPa. The final forging temperature after extrusion is 950°C. The steel billet is then furnace cooled to room temperature to obtain a forged tee blank.

[0038] Comparative Example 4 The difference between this comparative example and Example 1 is that, in the method for manufacturing the ferrite heat-resistant steel forged tee for supercritical power station boiler in this comparative example, step S2 is different, specifically, as follows: S2. The steel billet is heated to 640°C at a heating rate of 50°C / h, kept warm for 6 hours, then heated to 1200°C at a heating rate of 50°C / h, kept warm for 38 hours, descaled, upset at 4 mm / s and 230 MPa, and extruded at 7 mm / s and 320 MPa. The final forging temperature after extrusion is 950°C, and then the steel billet is furnace cooled to room temperature to obtain a forged tee blank.

[0039] Comparative Example 5 The difference between this comparative example and Example 1 is that, in the method for manufacturing the ferrite heat-resistant steel forged tee for supercritical power station boiler in this comparative example, step S2 is different, specifically, as follows: S2. The steel billet is heated to 1200°C at a heating rate of 50°C / h, kept at this temperature for 44 hours, descaled, upset at 4 mm / s and 230 MPa, and extruded at 7 mm / s and 320 MPa. The final forging temperature after extrusion is 950°C, and then cooled to room temperature in the furnace to obtain a forged tee blank.

[0040] Experimental Example 1 The tensile strength of the forged tees prepared in Examples 1 to 9 and Comparative Examples 1 to 5 was tested according to the test method in GB / T 5310-2023 “Seamless Steel Tubes for High-Pressure Boilers”. The test results are shown in Table 1.

[0041] Table 1 Tensile strength test results of Examples 1 to 9 and Comparative Examples 1 to 5

[0042] Compared with Comparative Examples 1 to 5, the tensile strength of the ferritic heat-resistant steel forged tees for ultra-supercritical power station boilers prepared in Examples 1 to 9 is improved, indicating that during the preparation of the forged tees, the steel billets are heated by a first-stage heating, a second-stage heating, and a third-stage heating method, and the temperature of the first-stage heating is reasonably controlled to be 640-660° C., the temperature of the second-stage heating is 840-860° C., and the temperature of the third-stage heating is 1200-1240° C., which can effectively improve the mechanical properties of the forged tees and increase their tensile strength to above 672 MPa.

[0043] Experimental Example 2 The forged tees prepared in Examples 6 to 9 were tested for impact absorption energy KV2 according to the test method in GB / T 5310-2023 “Seamless Steel Tubes for High-Pressure Boilers”. The test results are shown in Table 2.

[0044] Table 2 Impact absorption energy KV2 test results of Examples 6 to 9

[0045] Compared with Examples 6 and 7, the impact absorption energy KV2 of the ferritic heat-resistant steel forged tees for ultra-supercritical power station boilers prepared in Examples 8 and 9 is improved, indicating that by optimizing the component content in the steel billet, when the weight ratio of the sum of Y and Co to W is 1 to 2:1, the impact resistance of the forged tee can be improved, and its impact absorption energy KV2 can be increased to above 31.1 J.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler, characterized in that: The following steps are involved: S1, weighing raw materials, smelting, casting, and forming to obtain steel billets; S2, heating and extruding the steel billet to obtain a forged tee blank; S3, subjecting the forged tee blank to a first heat treatment, punching, and a second heat treatment to obtain the ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler; In step S2, the heating is divided into a first heating stage, a second heating stage and a third heating stage; During the first heating stage, the temperature is 640-660°C and the holding time is 3-6 hours; During the second heating stage, the temperature is 840-860°C and the holding time is 3-6 hours; During the third heating stage, the temperature is 1200-1240° C. and the holding time is 38-45 hours.

2. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 1, characterized in that: During the first heating stage, the temperature is raised to 640-660°C at a heating rate of 50-60°C / h; During the second heating stage, the temperature is raised to 840-860°C at a heating rate of 10-30°C / h; During the third heating stage, the temperature is raised to 1200-1240° C. at a heating rate of 10-30° C. / h.

3. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 2, characterized in that: The heating rate of the second heating stage is lower than the heating rate of the third heating stage.

4. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 1, characterized in that: In step S2, before the extrusion molding, the steel billet after the heating treatment is descaled; During the extrusion molding, upsetting is first performed, and then extrusion is performed until the final forging temperature is 950-1000° C., and then cooling is performed to room temperature.

5. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 4, characterized in that: During the upsetting, the extrusion speed is 4-6 mm / s and the extrusion pressure is 230-260 MPa; During the extrusion, the extrusion speed is 7-10 mm / s and the extrusion pressure is 320-350 MPa.

6. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 1, characterized in that: In step S3, during the first heat treatment, the temperature is first raised to 900-930°C at a heating rate of ≤60°C / h, kept at this temperature for 3-6 hours, cooled to 700-730°C, kept at this temperature for 60-70 hours, and then cooled to room temperature.

7. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 1, characterized in that: In step S3, during the second heat treatment, the temperature is first increased to 1030-1080°C at a heating rate of ≤60°C / h, kept at this temperature for 3-6 hours, cooled to room temperature for the first time, and then increased to 770-790°C at a heating rate of ≤60°C / h, kept at this temperature for 5-8 hours, and then cooled to room temperature for the second time.

8. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 7, characterized in that: When cooling to room temperature for the first time, the cooling method is oil cooling; When cooling to room temperature for the second time, the cooling method is air cooling.

9. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 1, characterized in that: The steel billet is composed of the following components in weight percentage: C 0.055%~0.085%, Si 0.3%~0.45%, Mn 0.4%~0.5%, Co 0.1%~0.3%, W 0.18%~0.58%, Nb0.01%~0.04%, Y 0.05%~0.25%, Cu 0.2%~0.3%, V 0.11%~0.15%, B 0.008%~0.015%, N 0.005%~0.01%, P≤0.008%, S≤0.005%, the balance is iron and its inevitable impurities.

10. The method for manufacturing a ferrite heat-resistant steel forged tee for an ultra-supercritical power station boiler according to claim 1, characterized in that: The weight ratio of the sum of the weights of the Y and Co to the weight of the W is 1-2:1.

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