March 2009
IGTI Manufacturing, Materials and Metallurgy Committee Tutorial Session
14-8
Material
Processing Technology, LLC
Investment Casting
Technology for Gas Turbine Airfoil Applications
June 10th
2:30-5:30 pm
Abstract
High
temperature superalloy blades and vanes have been
called the “Crown Jewels” of the gas turbine engine. Great strides have been
made in airfoil investment casting technology since cast airfoils were first
introduced in gas turbine engines in the 1940’s. The Neuchâtel
4000 kW power station, the first commercial power generation GT featured
a turbine inlet temperature (TIT) of 1015 F (545 C)
and achieved a thermal efficiency of 17.4% using uncooled,
heat resisting steel turbine blades. Today turbine inlet temperatures are in
the range of 2700 F (~1500 C) for the G & H class utility combustion
turbines with thermal efficiency on the order of 60% for combined cycle applications.
Perhaps even more dramatic is the 3600 F (~2000 C) TIT for the Joint Strike
fighter turbine engine. These remarkable increases in the gas turbine
firing temperature and thermal efficiency have been made possible in part by
dramatic advances in hot section airfoil materials and manufacturing technology
during the past seventy years.
This session will provide an overview of
the superalloy investment casting process and
challenges as it relates to manufacture of complex aero-engine & large IGT
hot section airfoils. The focus will be to walk through the many steps involved
in investment casting manufacture, covering unit operations from wax pattern
& ceramic core production, shell build, equiaxed,
DS or single crystal vacuum casting and post cast operations. This will include
discussion of advances in cooling configurations, casting imperfections,
inspection methods and general acceptance criteria as it relates to equiaxed, directionally solidified columnar grained and
single crystal castings. Throughout the session some of specific challenges
related to making large F G & H-class components and sophisticated air
cooled, multiwall single crystal aero-engine airfoils will be noted.
Material Processing Technology, LLC
Phone
231-780-1265; e-mail JeffSmith@mpt-llc.com
Copyright 2009