Metallurgical apparatus – With programmed – cyclic – or time responsive control means
Reexamination Certificate
1998-12-03
2001-04-03
Kastler, Scott (Department: 1742)
Metallurgical apparatus
With programmed, cyclic, or time responsive control means
C266S252000
Reexamination Certificate
active
06210630
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the manufacture of a hollow turbomachine blade, particularly a large chord fan rotor blade, and to a multiple-action furnace press for use in the process.
The advantages of using large chord blades in turbomachines are particularly apparent in the case of the fan rotor blades in bypass turbojet engines. However, such blades must cope with severe conditions of use and, in particular, must possess satisfactory mechanical characteristics combined with anti-vibration properties and resistance to impact by foreign bodies. The need to achieve sufficient speeds at the tips of the blades has also led to seeking a reduction in the mass of the blades, and this has been achieved, in particular, by using hollow blades.
2. Summary of the Prior Art
EP-A-0700738 describes a process for the manufacture of a hollow turbomachine blade, especially a fan rotor blade having a large chord. In a first stage (a) of this process a computer-aided design and manufacturing (CAD/CAM) system is used to create, starting from a geometric definition of the blade to be obtained, a digital simulation consisting of computing for the constituent parts of the blade, on both sides of the central fibre, the lengths of the fibres as a function of their position relative to the axis
20
of the respective part
19
as shown in
FIG. 1
, the parts being flattened. Also carried out at this stage is a digital simulation of an operation to shape the parts by twisting, for comparison with the final result.
After this first stage the manufacturing process known from EP-A-0700738 involves the following steps:
(b) die-forging the primary parts of the blade in a press.
(c) machining the primary parts;
(d) depositing diffusion barriers on at least one of the parts according to a predefined pattern;
(e) assembling the primary parts and diffusion welding them together under isostatic pressure;
(f) inflating the welded assembly using pressurized gas and superplastic shaping the assembly; and,
(g) final machining of the shaped assembly
One of the aims of the invention is to make it possible to perform, during the above sequence of operations, an additional shaping of the parts by twisting, without any risk of causing buckling type corrugations along the central fibre. These corrugations are generated by compression stresses induced at the time of the elongation of the lateral fibres resulting from the length differences between the initial flat part and the twisted part.
SUMMARY OF THE INVENTION
Accordingly, the invention provides a process for manufacturing a hollow turbomachine blade of the type which is known from EP-A-0700738, wherein said process includes a step of hot forming an element of the blade, which is made of a titanium alloy of TA6V type, in a press at a temperature between 700° C. and 940° C. using the action of at least two stamps and a holding clamp locking said element on a shaping die while ensuring a controlled deformation rate, so as to obtain a lengthening of the fibres of said element, that is to say the elongation of different fibres of said element, with a controlled distribution of said fibres on both sides of the central fibre.
It is known to carry out hot forming operations using special means including a heating enclosure associated with heating means, a press-bed structure associated with a power assembly comprising a plurality of actuators, and forming equipment. However, these known means are inadequate for carrying out the hot forming operation in the process in accordance with the invention.
Accordingly, the invention also provides a multiple-action furnace-press comprising: a heating enclosure; heating means associated with said heating enclosure; a press bed structure surrounding said heating enclosure and consisting of a lower metal plate, an upper metal plate, and columns inter-connecting said lower metal plate and said upper metal plate, said columns comprising prestressed tie rods; forming equipment comprising a lower soleplate incorporating a shaping die bounded at each end by a respective notch, an upper holding clamp for holding said element on said shaping die during deformation, and at least two upper stamps; multiple actuators connected to said holding clamp and said stamps; and a power unit for driving said multiple actuators.
The use of the multiple-effect furnace-press in accordance with the invention for the hot forming step in the blade manufacturing process enables the drawbacks of the earlier known processes to be avoided and blades to be obtained possessing improved geometric and mechanical characteristics optimized to the conditions of use, and also enables repeat quality to be ensured while facilitating relatively low cost manufacturing conditions.
REFERENCES:
patent: 3769696 (1973-11-01), Awano et al.
patent: 5323536 (1994-06-01), Fowler et al.
patent: 5636440 (1997-06-01), Bichon et al.
patent: 5933951 (1999-08-01), Bergue et al.
patent: 5946802 (1999-09-01), Calle et al.
patent: 0 700 738 A1 (1996-03-01), None
patent: 2 096 513 (1982-10-01), None
patent: WO 81/02128 (1981-08-01), None
Bergue Jean-Pierre Serges
Bichon Mathieu Philippe Albert
Lacuisse Jean-François Georges Julien
Lorieux Alain Georges Henri
Kastler Scott
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Societe Nationale d'Etude et de Construction de Monteurs d&
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