The goal of this project is the realization of a new material, a new concept will be developed for the calculus and design of high speed centrifugals rotors to improve their performance and characteristics correlated with their original control solutions and processing.
The execution of these rotors ( a complete set of five centrifugal rotors, speeding from 18974 rpm ( first stage) till 33823 rpm (fifth stage) will be done using a high precision special casting technology that attend to reach a very high quality level necessary for these parts. The rotors gas- dynamic surfaces (the airfoils and the hub contact limit) will suffer a plasmatic pulverization coating process, in low pressure argon, the coating containing special materials for improvements against wear and corrosion.
Lots of years researching experience, the Research Institute COMOTI’s participation in three great international partnerships (METHOD SILENCE® and ABRANEW) in the same field exactly, give us the trust to solve the project’s multitude of problems.
The material for centrifugal rotors must accomplish next characteristics: high strength (sr) and a yield point as close as much to the strength (the rotor has not to deform because the clearance becomes little and seizing appears leading to the destruction al entire turbo machinery), high strain (A%) and tenacity (KCU) . In the same time, the material must have good characteristics for corrosion and wear.
At this time, in the international market of rotors is used a material known as 17-4PH, which has copper in its composition. This alloy is hard to fabricate, technologically it is very hard to use it, it is tiny cracks susceptible and it has a difficult thermal treatment.
Numerous possibilities were studied together with consortium partners, finding this type of alloy that can be successfully promoted in the rotors materials market.
It is an medium mixed steel, including Cr, Mo, Mn, Si, V, with no equivalent in Romanian and EU's standard. Its mechanical qualities are perfectly comparable to 17-4 PH alloy, the tests made until now about corrosion and weariness set it closed to 17-4 PH.
Within the project it is followed in the same measure a new design and calculus concept for centrifugal rotors, domain well known in CMT. In the last period, within international contracts( METHOD and SILENCER) CNMT has elaborated and tested ( only in experimental pattern and only special type of rotors) a new concept of calculus and design that is proposed for the realization of centrifugal rotors (5 stages) that equip CCAE 21-300 compressor.
The third goal of the project is the elaboration of an original precision casting technology that leads to fabrication of a high quality blanks using the presented material and the new calculus and design concept applied both rotors and stamps. The rotors quality level is very high (the highest for cast parts).
Before, the final preparation, the active rotors surfaces will be covered by a special material capable of realizing o great adherence to the new designed material and conferring more strength to corrosion and weariness.