On December 20th, the reporter learned from the China Iron and Steel Research Group Gaona Company that the company took the lead in jointly producing Fushun Special Steel and Erzhong Wanhang for the first time in recent days to successfully trial-produce the largest superalloy turbine disk integral die forging in my country at present—— The super-large GH4706 alloy turbine disk forgings, suitable for use under high temperature conditions of 650 degrees Celsius, with a strength level of 1200 MPa, a weight of 13.5 tons, and a diameter of 2380 mm, broke the foreign monopoly.
According to Zhao Guangpu, the leader of the research project and deputy director of the Steel Research Gona Science and Technology Committee, heavy-duty gas turbines for large power stations have outstanding advantages such as high power, high thermal efficiency, small volume and weight, and low pollution. Its manufacturing technology has become a national technology level. , One of the important symbols of comprehensive national strength. Its core hot-end components are one disc and two (turbine discs and guides, working blades), which act as the “heart” of human beings. They are the key technology for gas turbine manufacturing and the bottleneck restricting the localization of heavy gas turbines. Heavy-duty gas turbine turbine disks require more than 100,000 hours of long-term high-temperature and high-stress service, and require extremely high metallurgical quality of materials, such as homogeneous, pure, fine-grained, stable material structure and performance; larger size, and its diameter and projection area are respectively It reaches more than 2.2 meters and 4.2 square meters, which is 4 times the diameter of the aero engine turbine disk, 10 times the projected area, and 60 times the weight, and so on. The core manufacturing technology of super-sized superalloy turbine disks has been in absolute blockade abroad and has been monopolized by Western countries for a long time.
To this end, Zhao Guangpu led the project team to carry out a series of basic research and technological research, and finally adopted the most advanced international “triple smelting + repeated upsetting + twice upsetting + one-fire overall die forging” preparation technology to implement the international Standards, breaking through the technical bottleneck of large-scale superalloy turbine disk preparation encountered during the development process, such as triple low-segregation smelting technology for large steel ingots with ingots weighing more than 18 tons, and repeated upsetting and fine-grain blooming technology for large bars with a diameter of 1000 mm, with a diameter of 2200 Integral die forging and low-temperature forming and organization control technology for large plate parts larger than millimeters. The project team carried out independent research and development and original innovation for metallurgical defects such as the extremely high Nb content of the alloying element in the GH4706 superalloy, which is prone to black spots and white spot segregation. The key hot-end components of my country’s heavy gas turbines are “stuck neck”, which has opened up a process route for the preparation of large-scale deformed superalloy turbine disks with Chinese characteristics with independent intellectual property rights.
After anatomy, the performance of the turbine disc has reached the technical index requirements of similar foreign alloys, and a milestone result has been achieved. This is another important breakthrough that my country has made in the field of deformed superalloys, which has driven the preparation technology of domestic super-large turbine disks to reach the international leading level. On December 8th, the milestone node review meeting for GH4706 alloy full-size roulette forgings was held in Beijing. Experts gave a high evaluation, which means that a solid step has been taken towards the real use of the turbine disk.