When a global manufacturer of ga path components needed to increase production without compromising on product performance, little did it know it was about to form an industry partnership that would still be delivering benefits over 20 years later.
AETC Ltd, a part of PCC Airfoils LLC, is a major manufacturer of rotating blades and stationary nozzle guide vanes for the aerospace and gas turbine industries. These blades must operate at very high rotating speeds and temperatures, while the vanes have to direct the steam propelled by the rotating blades to the next turbine stage with optimum efficiency. As a result, both blades and vanes must be resistant to oxidation, corrosion and wear, providing longevity during operation. Key to effectiveness of these products is the stability of the inner cores, which determine the inner shape and geometry of the turbine components.
Challenges in casting process
In order to be effective, these cores must be developed using a material which can perform well in extremely challenging casting conditions, and rigorously tested to ensure they meet demanding tolerances. There can be very little room for error throughout the overall blade manufacturing process. Not only must very high tolerances be reached, but manufacturers also must overcome challenges surrounding the high price of nickel and titanium, which are commonly used to manufacture the components; a cost that is realised every time a component must be reworked or wasted, if tolerances are not met. First time success is critical to AETC’s\ manufacturing process, as engineering work would be undone if the inner core was not engineered to the highest levels of precision prior to production.
It is for this reason that AETC turned to Morgan Advanced Materials, a world leader in the development and application of advanced material technologies, for expert support in the design and testing of inner cores.
Morgan turned to its proprietary K120 material, a directionally solidified single crystal material, which shows high levels of stability at high temperatures. This makes it ideal for use with alloys requiring high-temperature pre-heats, allowing for minimal interaction between the core and the metal used in the casting process. The low coefficient of thermal expansion also ensures that the core remains dimensionally stable when the molten metal engulfs it during the casting process. This stability of the K120 at high temperatures is what allows Morgan to manufacture ceramic inner cores to the very high tolerances required by AETC, to suit its individual designs.
For each new blade design, Morgan’s dedicated team is required to design and test prototype cores to demonstrate that they are continuing to meet profile tolerances as tight as +/-0.008 mm, prior to manufacture. AETC is currently manufacturing in excess of 30-40 different blade designs, each with their own discrete core design. The Morgan team works closely with the company to ensure all the required new cores are designed and manufactured on time for AETC to begin the casting process. The responsiveness and agility of Morgan is instrumental in minimising disruption to the casting process.
Taking forward the partnership
The consistent high performance and dependability of Morgan’s inner cores have facilitated a relationship that has been going strong for the last two decades, enabling AETC to manufacture more reliable and high performing blades and vanes, with greater precision, and less waste caused by reworked or failed cores. As AETC continues to respond to demand for its products, its relationship with Morgan continues to flourish.
Robert Park, General Manager of Morgan Advanced Materials’ Certech business, added, “As a supplier to some of the biggest names in global industry, AETC cannot afford to miss a deadline when it comes to delivering blades. Our role is to ensure not only that they have the cores they need, when they need them, but that each core conforms to stringent design parameters. The extension of the relationship into additional projects which has followed over the years, is confirmation of our ability to deliver to the needs of our customers in terms of speed, quality, and consistency.” ☐ Courtesy: Morgan Advanced Materials