A rub test program was conducted using Brunswick’s high speed rub rig to determine the independent effect of density and tensile strength on the abradability of FELTMETAL® seal material and to determine the optimum parameters for specific seal products. A series of 29 tests, 0.020 in. deep (0.5 mm) 360-deg rubs, were conducted on the inner air seal (knife edge) configuration with Hastelloy × and Haynes 188 seal material. Fifteen tests were conducted on the outer air seal (blade tip) configuration with seal materials of the same alloys. The program demonstrated that ultimate tensile strength rather than density is the predominant factor in determining abradability for the fiber metal system. Maximum tensile strengths were reduced and tighter density and tensile ranges were specified for four FELTMETAL® seal products to provide acceptable abradability for 360-deg rubs while maintaining erosion resistance.

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