Flash weldability studies of Incoloy Alloy{reg_sign} 908
- Edison Welding Inst., Columbus, OH (United States)
- Massachusetts Inst. of Technology, Cambridge, MA (United States). Plasma Fusion Center
Initial trials done to assess the potential for flash welding Incoloy Alloy{reg_sign} 908 showed good tensile strength, typically failing in the base material. However, compact tension tests showed reduced fracture toughness. It was inferred from the data that the reduced fracture toughness was related to an artifact of the flash welding process, a ``light etching band`` along the bondline. This light etching band is representative of a solute-depleted region down the bondline, typically on the order of 10--40 {micro}m wide. This band is relatively soft, providing an easy fracture path some added triaxial constraint (condition experienced by brazed joints). The measured fracture toughness is, to a degree, also an artifact of the testing procedure, as fatigue precracking virtually guaranteed that the starting crack was located in the soft region. It is also known that the extent and severity of the light etching band can be modified by changes in the process and the use of post-weld annealing. This program was to determine if modifications to the process (and post-process annealing) could effectively minimize the light etching band and improve weld fracture performance. A screening experiment allowed six separate process and annealing variables to be studied in a series of 16 trials. Three process variables (flashing acceleration, upset distance, and initial die opening) and three annealing variables (temper current, temper time, and furnace solution annealing) were studied Welds were evaluated using a fatigue-precracked three-point bend test. Samples were then analyzed in a number of ways, including estimations of energies to failure, normalized energies (energy/fracture area), a ranking of the degree of ductility in the fracture, reduction in the sample width, and estimations of the sample`s K{sub Q}.
- OSTI ID:
- 86007
- Report Number(s):
- CONF-941024-; ISBN 0-7918-1213-8; TRN: IM9534%%78
- Resource Relation:
- Conference: 8. COGEN-TURBO power congress and exposition: gas turbines in cogeneration and utility, industrial and independent power generation, Portland, OR (United States), 25-27 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of ASME cogen turbo power `94. IGTI-Volume 9; Kidd, H.A.; Cooke, D.H.; Fransson, T.H.; Greitzer, E.M. [eds.]; PB: 759 p.
- Country of Publication:
- United States
- Language:
- English
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