Abstract:
The invention relates to plastic metal working, more specifically to methods for producing parts of the disk- or shell-type having conical, hemispherical, and also combined parts, such as disk-and-shaft ones. The invention is instrumental in producing large axially symmetric parts from hard-to-work multiphase alloys. The method consists in that the billet is heated in a temperature range above 0.4 m.p. but below the temperature at which a total content of precipitates or an allotropic modification of the matrix of a multiphase alloy is not below 7 %. Then the preheated billet is rolled, while controlling its temperature and the tool load, as well as the rolling speed. Once rolled the billet is heat-treated at a temperature depending on the microstructure of the billet material resulting from rolling. Prerolling preparing of a specified microstructure of the billet material is also described.
Abstract:
The invention relates to plastic working of metals and alloys, predominantly low-plastic and hard-to-work ones, e.g., nickel-, titanium-, and iron-base high-temperature alloys, and producing billets for parts made by plastic working of said billets. The method comprises thermomechanical processing which is performed beginning with the temperature at which a total content of precipitates or an allotropic modification of the matrix exceeds 7 %, followed by a stage-by-stage decrease of the working temperature down to the temperature at which a stable fine-grained microstructure of the material is obtained, with ratio between the grain size of various phases differing by not more than 10 times, the billet under processing undergoes deformation with a 1.2 to 3.9 times change in the billet cross-sectional area. When preparing billets from nickel-base alloys a stage-by-stage decrease of the working temperature is carried out so as to provide a maximum 14 % gain in the gamma -phase at each stage. At the end of each process stage a successive annealing of the billet is performed.
Abstract:
A metal forming method is used for manufacturing vehicle wheels. The invention comprises manufacturing of a wheel block comprising a central part and initially formed rim; drawing of the rim by hot rolling to obtain a wheel profile that approximates a finished wheel, and a final wheel treatment process. The rolling is conducted from either side of the wheel block, which may comprise any granular microstructure. Rolling temperature-strain rate conditions correspond to the microstructure. For a coarse-grain microstructure, the rim includes a shoulder with a thickness greater than that of the finished wheel, and thickness differences transform the microstructure into a recrystallized and/or polygonized microstructure. For a fine-grain microstructure, the rim includes a shoulder or flange with a thickness close to a thickness of a finished wheel. For mixed microstructures, the rim includes a shoulder and has a thickness greater or equal to a finished wheel.
Abstract:
The invention relates to metal forming using diffusion welding and superplastic forming. Stop-off material is preliminarily applied in a predetermined screen pattern to areas where surfaces of skin and core preforms come into contact. Skin preforms are provided with a groove, and core preform is provided with a slot for mounting at least one tube. A stack is sealed along edges with the exception of where at least one tube is to be mounted. A tube is mounted to be connected to a collector zone, and oxygen and binder of the stop-off material are removed from cavities in the stack. The stack is fully sealed, heated, and the preforms are diffusion-welded in predetermined areas, also along an entrance edge, an exit edge and a peripheral edge. An integral structural preform is given an airfoil shape and subjected to superplastic forming by supplying working fluid into cavities between the skin and core preforms through also at least one tube. The collector zone is disposed on the side of the stack, which corresponds to the peripheral edge of the blade. For mounting one or more tubes for supplying working fluid at superplastic forming, the groove in the skin preforms and the slot in the core preform are provided at a distance from the outer boundary of the entrance edge or exit edge less than L/3, where L is the length of the blade chord along the peripheral edge. It is thus possible to eliminate risk of defects during blade forming without compromising performance characteristics of the blade and increase in labor intensity of producing same.
Abstract:
A method for manufacturing a hollow fan blade of a titanium alloy, said blade consisting of skins and a filler forming stiffeners, comprises the step of working skin workpieces with a preformed blade root portion, during which working on surfaces of the skin workpieces, areas to be bonded to a filler workpiece are shaped in the form of projections with a surface flat in a cross-section, and areas to be not bonded to the filler workpiece are shaped in the form of recesses, respectively, wherein at least a part of a surface of recesses opposite to projections in a stack assembled for diffusion welding is made flat in a cross-section, and also comprises the steps of: applying a bond preventing coating onto surfaces of workpiece areas to be not bonded; assembling the skin and filler workpieces into a stack; diffusion welding the skin and filler workpieces; forming stiffeners by superplastic forming, the method further comprises the step of providing the skin and filler workpieces with an aerodynamic profile by applying a deforming load thereto, including forming a pressure face and a suction face of the blade and twisting its airfoil. The method is characterized in that said projections and recesses are made on the surfaces of the skin workpieces prior to providing them with the aerodynamic profile, while the step of providing the workpieces with the aerodynamic profile is performed after diffusion welding. The method is particularly applicable to aircraft engine building.
Abstract:
This method refers to a method by which the physical and mechanical properties intrinsic to a fine-grain structure may be formed in metal billets using pressure treatment. The method is designed to treat rods, bars and other particularly long billets. This method is designed to lower the cost of deformational treatment for long rods and large diameter billets and creates a pre-specified microstructure, including micro-crystal structure, and specific physical and mechanical properties. This may be achieved using various treatment techniques, one of which includes the deformation of at least a part of the billet through reduction of the billets cross-section. In this method, a long rod shaped billet is used. Reduction of the cross-section is achieved using tools that permit movement along and across the billet's axis as well as being rolled about its surface, for example, a roller. In this case at least one support stand is employed for correct placement of the billet. Additionally, a pre-specified strain level is achieved using at least one of the techniques of deformation: torsion, settling and extension using tools, for example the above-mentioned stand. The stand is designed to apply a specified scheme of deformation to the billet at the deformed (strained) section and at a specified temperature. This obtains specified structure with intrinsic physical and mechanical properties.
Abstract:
The invention relates to the electronic engineering and, more specifically, to the fields thereof where the physical phenomenon of electron, or ion-electron, or cold emission is used, and concerns a cold cathode and a method for fabricating the same. Provided is a method for fabricating a cold cathode, according to which a cathode workpiece of a metal or alloy is subjected to severe plastic deformation to transform an initial structure of the workpiece into a fragmented structure comprising fragments of nanometric size or into a mixed structure comprising grains and fragments of nanometric size, characterized in that , after the severe plastic deformation, the cathode workpiece is subjected to a low-temperature annealing for transforming at least part of said fragments into grains of nanometric size at a temperature not lower than the operating temperature T oper of the cathode. The invention is an improvement of the method for fabricating a cold cathode using severe plastic deformation and allows to further enhance efficiency of the cathode via a reduction in the electronic work function value.
Abstract:
A mill for producing axially symmetric parts which has a means (35, 36) for fixing the billet under process with a possibility of its rotating about its own axis, rolling rolls (1, 2, 3, 4), a working furnace (44) provided with openings for inserting the rolling rolls therein, and means for control and monitoring the billet processing conditions, comprising means for monitoring and changing the load applied to the rolling rolls and the billet under process, as well as means for establishing a specified temperature gradient in the individual portions of the billet. The mill is intended for producing wheels, disks, and other axially symmetric parts from superalloys.