TUBITAK Marmara Research Center (MAM) has been working on superalloys since the 1980s. These materials are of strategic importance for our country and are used in priority industrial areas. However, almost all of them are still imported from abroad. One of the most important goals of our institute is to create the necessary knowledge, database and technological infrastructure for the production, repair and maintenance of "steam turbine" and "gas turbine" parts of power plants in our country. In this project, 1 set each of the 3rd stage rotor (moving) and stator (fixed) blades of a 130MW and above gas turbine within the Electricity Generation Corporation (EÜAŞ) were produced in accordance with their original forms and specifications by precision casting technique and will be tested for 8,000 hours on a 130MW turbine. The design life of the blades is determined to be 33000 hours. The selection of 3rd stage blades has two main purposes. These blades are of suitable size for casting and have aluminized coating on their surfaces. By selecting 3rd stage wings, it is aimed to gain coating technology together with casting technology.
Project partners TÜBİTAK MAM Materials Institute (ME), METU, Gür Metal, SDM and EÜAŞ worked together under the coordination of TÜBİTAK MAM. Within the scope of the project, TÜBİTAK MAM ME determined the metallurgical properties of the old used blades provided by EÜAŞ through destructive examinations. In-turbine conditions were determined and modeled by SDM Engineering with the help of sensors.
As a result of this study, regional stress maps of the wings were prepared and the mold design was made by Gür Metal by paying attention to the stress concentrations in the casting method. The designed molds were developed with the casting simulation program and the most suitable casting wax and ceramic mold was modeled. The entire casting process was carried out at Gür Metal under TÜBİTAK MAM control. System optimizations of production methods were carried out in TÜBİTAK MAM. By applying HIP to cast super alloy blades used in gas turbines, the metallurgical defects that may arise from the casting method were reduced.
HIP treatment of nickel-based superalloys was carried out in TÜBİTAK MAM ME. Heat treatment was applied to the cast wings. These wings were then machined at Kaan Makine under the control of TÜBİTAK MAM and their final shapes were given. R&D work on CVD coating was carried out at the Middle East Technical University. The coating of the wings with CVD was carried out at TÜBİTAK MAM ME. Shot peening process was carried out at HMS machine under the control of TÜBİTAK MAM. Frequency tests were carried out at Novosim under the control of SDM and TÜBİTAK MAM.
In all process stages, TÜBİTAK MAM was characterized by destructive and non-destructive methods using extensive laboratory facilities and the processes were optimized as required at each stage.
