Metal working – Method of mechanical manufacture – Rocket or jet device making
Reexamination Certificate
1999-09-01
2002-02-26
Cuda Rosenbaum, I (Department: 3726)
Metal working
Method of mechanical manufacture
Rocket or jet device making
C029S889721
Reexamination Certificate
active
06349467
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a deflector plate in a gas turbine engine combustor and, in particular, to a process for manufacturing such deflector plates which does not include heat treatment of the workpiece between forming steps.
It is well known in the art for deflectors of gas turbine engine combustors to be manufactured by forming and trimming sheet metal material to a desired final part. During these forming processes, however, the workpiece deflector can exhibit excessive thinning or tearing. In order to avoid this defect, heat treatments or annealing steps have been performed between and after such forming steps. This is particularly applicable for parts manufactured out of Haynes® 188, a commonly used sheet metal material for gas turbine engine combustors due to its exposure to high temperatures.
Heat treatment of the deflector workpiece is not without its own disadvantages. Besides the time and expense of performing the heat treatment, typically by means of vacuum furnace equipment, it has been found to cause critical grain growth in the workpiece. Additionally, such heat treatment can cause the creation of a surface oxide layer which is detrimental to the subsequent brazing of such deflector to other combustor components. Thus, chemical treatment for removal of the oxide layer is oftentimes required prior to the brazing process.
In light of the foregoing, it would be desirable for an improved process of manufacturing combustor deflector plates to be developed which eliminates the need for heat treatment between forming steps without the workpiece incurring excessive thinning or cracking. It would also be desirable for such process to produce combustor deflector plates which have a finer grain size and more uniform structure, while still reducing the time and cost required as compared to current methods.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, a process for manufacturing components of gas turbine engine combustors is disclosed as performing a plurality of forming steps on a workpiece of a designated material to produce a combustor component of desired size and shape without exceeding a forming limit of the designated material, the forming steps being performed without any intermediate heat treatment on the workpiece.
In a second embodiment of the present invention, a deflector plate for a gas turbine engine combustor is disclosed as including a substantially ring-shaped central portion providing an opening through the deflector plate, a flange portion encircling the central portion, and a shoulder portion serving as a junction of the central and flange portions, wherein heat treatment of the deflector plate has been eliminated during forming so as to obtain a grain size along said central portion within a range of approximately ASTM 7.5-9.5 after a braze material is sintered thereto.
In a third embodiment of the present invention, a method of developing a sequence of steps for a process of manufacturing a gas turbine engine combustor component is disclosed, wherein heat treatment between forming steps of a workpiece is eliminated. This method includes the following steps: developing a finite element analysis model of the manufacturing process, wherein deformation and thinning of the workpiece are represented during the forming steps; creating a user interface for entering a plurality of parameters associated with the manufacturing process; automatically creating a finite element analysis input file from the user interface parameters; determining the likelihood of a tearing defect occurring for the workpiece during the manufacturing process from each input file; and, establishing a sequence of forming steps for the manufacturing process which produce a combustor component conforming to a predetermined shape and size within a predetermined risk of tearing defects.
REFERENCES:
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patent: 4688310 (1987-08-01), Kelm et al.
patent: 5363643 (1994-11-01), Halila
patent: 5784876 (1998-07-01), Alkabie
patent: 5924288 (1999-07-01), Fortuna et al.
patent: 5974805 (1999-11-01), Allen
patent: 6021570 (2000-02-01), Lockyer et al.
Karafillis Apostolos P.
Regan Ronald D.
Yokoyama Kena K.
Cuda Rosenbaum I
General Electric Company
Hess Andrew C.
Ramaswamy V.
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