Showing papers on "Hydroforming published in 2000"

Theoretical and experimental analysis of stroke-controlled tube hydroforming

Abstract: To select tube hydroforming instead of conventional fabrication, one has to know the tube material behaviour and tribological effects during hydroforming and how the hydroforming operation itself should be controlled. The hydroforming operation is either force- or stroke-controlled. This paper deals with stroke-controlled hydroforming. Hydroforming consists of free forming and calibration. In this paper, only the so-called free forming is treated. Stroke-controlled free forming is studied theoretically and experimentally. The theoretical part consists of analytical modeling and finite-element simulations. The conducted experiments are used to show the types of errors that might occur, when the theoretically obtained loading paths are transferred to the hydroforming equipment. The forming limit curve (FLC) is normally used as an aid/instrument in component and process design (which include finite-element simulations). The present study shows that the FLC of the tube material must be determined by hydroforming, if component and process design are to rely on this instrument.

The use of FEA and design of experiments to establish design guidelines for simple hydroformed parts

Abstract: We present models to predict the protrusion height of “Tee-shaped” hydroformed parts, both because this information is of direct relevance to engineers attempting to build such parts and also to illustrate an advantageous process for developing design guidelines for tube hydroforming (THF) in general. A newly proposed design of experiments technique, Low Cost Response Surface Method (LCRSM), was utilized to facilitate the economical prediction and optimization of this height as a function of geometrical parameters subject to thinning of the wall thickness at the protrusion region. The same methodology is also proposed for the economical investigation of other geometries and conditions. As a result of this investigation, not only were known and expected trends of effect of parameters verified, but also numerical values within a practical range of parameters at certain conditions were obtained. In addition, interactions between factors were also revealed as predicted. Moreover, this information was gained from a substantially reduced number of finite element analysis (FEA) simulations via LCRSM compared to standard response surface method (RSM) or factorial techniques, avoiding costly physical experimentation.

Analysis and design of hydroforming process for automobile rear axle housing by FEM

Abstract: An FEM program, HydroFORM-3D, for the analysis and design of tube hydroforming processes, has been developed by modifying and adding some subroutines to the previous rigid-plastic finite element program, and then applied to the hydroforming process for an automobile rear axle housing. This paper includes the theoretical background of the program development. Through a numerical simulation, an optimum process is proposed to meet the practical requirements, which shows the efficiency of the numerical simulation. Two types of hydroforming dies are analyzed by numerical simulation. The sliding-type die has the drawback of a possibility of buckling, whereas the fixed-type die causes bursting failure. The thickness distribution of the final product is affected not only by the types of die, but also by the loading paths. The potential failure site for rear axle housing predicted by the numerical simulation is consistent with the experimental results. The values of maximum axial compression force for the first and second hydroforming processes are also in good agreement with experimental data. To manufacture a sound automobile rear axle housing without failure, it is better to use the sliding-type die and it is also critical to maintain a suitable hydraulic pressure level.

Reinforced hydroformed members and methods of making the same

Abstract: A method of hydroforming a reinforced tube comprising providing a metal tubular blank (10) having an interior defined by an inner surface (12) and an exterior defined by an outer surface (14). A metal reinforcing member (20) is provided and inserted into the interior of the tubular blank (10). The reinforcing member (20) is engaged with the inner surface (12) of the tubular blank (20) and is attached to the inner surface of the tubular blank. The tubular blank (10) and reinforcing member (20) welded thereto are placed into a hydroforming die (34) having die surfaces (40, 42) defining a die cavity (44), and pressurized fluid is provided within the tubular blank (10) so as to conform the tubular blank (10) with the die surfaces (40, 42) of the die cavity (44).

Hydroforming method and hydroforming device

Abstract: 17 A plurality of closing cylinder devices are provided between a bolster of a press machine and a bed containing a lower mold of a hydroforming device An upper mold is attached to a slide of the press machine The upper mold and lower mold come together to form a cavity having the shape of the exterior of the desired molded product A closing block, being movable between a first position which is between the slide and a crown of the press machine, and a second position, which avoids the slide, permitting free movement of the slide from the crown to the lower mold When a material to be hydroformed is place in the lower mold, the upper mold is lowered The closing block is fit into its first position, thereby restricting movement of the slide in the vertical direction A inner work pressure is provided by a fluid inside the material to be molded The closing cylinder devices provide a pressure, based upon the inner work pressure, to maintain the cavity at the desired shape, preventing the upper mold and the lower mold from being separated by the inner work pressure

Hydroformed collapsible drive shaft and steering shaft and methods of making the same

Abstract: A collapsible drive shaft (20) and method of making the same The collapsible drive shaft (20) includes a tubular member having first (24) and second (22) portions that are integrally formed as a one-piece member The first portion has splines (26) formed on an exterior surface thereof The second (22), opposite portion has both outer (Do2) and inner diameters (Di2) that are greater than the outer diameter (Do1) of the first portion The method includes placing a tubular metal blank into a hydroforming die (70) having a die cavity and expanding the blank by pressurizing the interior of the blank with hydroforming fluid During the hydroforming process, the first portion of the blank is expanded to form splines while the second portion is expanded to form inner and outer diameters that are greater than the outer diameter of the first portion

Method and device for forming tubular work into shaped hollow product by using tubular hydroforming

Abstract: For forming a tubular work into a shaped hollow product by using hydroforming process, a method and a device are described. In the method, female and male dies are prepared. The female die has a longitudinally extending cavity which has a polygonal cross section when receiving the male die. The tubular work is placed into the cavity of the female die. The interior of the tubular work is then fed with a hydraulic fluid, and the pressure of the fluid is increased to a given level. The given level is smaller than a critical level that causes a bulging of the tubular work. The male die is then pressed against the tubular work to deform the same while keeping the hydraulic fluid at the given level, thereby forming a shaped hollow product that has a polygonal cross section that conforms to that of the cavity. The pressing work is continued until a circumferential length of the shaped hollow product becomes shorter than that of the tubular work.

Method of manufacturing a lead screw and sleeve mechanism using a hydroforming process

Abstract: A method of manufacturing a sleeve mechanism without the use of machines by using a hydroforming process. The method includes the steps of providing an inner sleeve, an intermediate sleeve, and an outer sleeve concentrically within one another. The concentric sleeves are then expanded by using a hydroforming process such that an external thread is formed on the inner sleeve and an internal thread is formed on the outer sleeve. After the hydroforming process, the intermediate sleeve is removed by using any desired manner, such as melting or chemical dissolution. The relatively small space remaining between the inner and outer sleeves allow them to freely rotate about each other to ensure smooth operation of the screw and sleeve mechanism. Alternatively, the inner and outer sleeves may be hydroformed in separate operations.

Highly corrosion resistant steel tube having excellent formability and its manufacturing method

Abstract: PROBLEM TO BE SOLVED: To provide a highly corrosion resistant steel tube which has excellent formability in hydroforming or the like by limiting the characteristic value of the material, and to provide its production method. SOLUTION: This highly corrosion resistant steel tube which has excellent formability has a composition containing, by mass, 0.001 to 0.3% C, 0.001 to 0.2% N, 0.01 to 2% Si, 0.01 to 5% Mn and 5 to 30% Cr, and the balance iron with inevitable impurities. Either or both of that the average of the X-ray random intensity ratios in the 110} to 111} orientation groups in the sheet face at a sheet thickness of 1/2 in the steel sheet is >=2.0 and that the X-ray random intensity ratio in 110} in the sheet face at a sheet thickness of 1/2 in the steel sheet is >=3.0 are satisfied.

Method and apparatus for hydroforming multiple components with reduced press loading

Abstract: Apparatus and method for hydroforming multiple components simultaneously with a smaller capacity press than would be possible using conventional hydroforming methods and apparatus. Die pairs are positioned with multiple die cavities in series so that the separating force transmitted to a press holding the dies equals the force developed in a single die cavity, even though multiple components are being formed in the die cavities.

Method to produce a turbomachine blade

Abstract: The invention relates to a method of manufacturing a blade of a turbomachine, in particular of a gas turbine engine, which consists of a metallic enveloping structure and a suitable within this provided and the containment structure connected to the supporting structure made of a composite material. In this case, is welded onto a sheet, the wrap structure forming a metal felt fabric, or soldered, after which this sheet-fabric unit is formed by hydroforming or an internal high-pressure forming process to the blade-shell structure. Finally, the support structure forming the composite material is introduced into the cavity of the casing structure. When using a reinforced by long fibers composite material thereby a fiber structure can first be inserted into the blade-shell structure, and thereafter the composite material are introduced by the high-pressure infiltration, wherein the wrap structure preferably said deforming is carried out in a mold, in which by an internal high-pressure forming process, is located.

Method for hydroforming pipe-like components, e.g. for motor vehicles, where component has different cross-section sections; involves selecting suitable sized pipe blank and hydroforming in form die

Abstract: The method involves selecting a pipe blank with constant cross-section shape and diameter, which is larger than or equal to a minimum outer diameter of one section of the component to be formed, and has a cross-section that can be fitted inside that of the first section. The wall thickness of the pipe blank is selected to be between or equal to the average wall thickness of one section of the component to be formed The precursor is arranged in the form die and hydroformed to manufacture the component. An Independent claim is included for a pipe-like component manufactured using the method.

Method and apparatus for sequential axial feed hydroforming

Abstract: A tube member is placed in a die having a plurality of nodules formed in the cavity thereof. A chamber is formed between a mandrel and end piece within the tube. The mandrel is positioned adjacent a first of the nodules and the chamber is pressurized during a hydroforming cycle to form a node on the tube by simultaneously expanding a portion of the tube outward and feeding the tube linearly into the die cavity. A mechanism for feeding the tube linearly is external to the die cavity and has a member in abutment with one end of the tube. During a positioning cycle, the pressure in the chamber is reduced and the mandrel is moved longitudinally within the tube to a position adjacent the next sequential nodule to permit a repeat of the hydroforming cycle. In one embodiment of the hydroforming process, a mandrel is positioned into the tube from each tube end and a feed mechanism is disposed adjacent each tube end. This permits the sequential simultaneous hydroforming of pairs of nodes on the tube.

External casing anchor

Abstract: A plurality of steel rings are affixed, as by crimping using hydroforming means, to the outside of a joint of steel well casing. The rings are distributed in spaced relation along the joint. The resulting anchor joint is run into a well as part of the casing string and cemented in place.

Method for hydroforming metal tube and die

Abstract: PROBLEM TO BE SOLVED: To provide a method to obtain a special shaped tubular product having a bulged part having partially different plate thickness/strength and a die used therefor. SOLUTION: In the hydroforming method in which a liquid 105 is introduced into a metal tube stock 300 and pressurized, thus the metal tube is partially bulged to form the special shaped tubular product, bulging is conducted by pressing at least an outer peripheral face of the section easily bulged out of a bulging planned part constituting of a section 300a easily bulged and a section 300b hardly bulged, and by controlling restricting force so that the section easily bulged and the section hardly bulged are bulged synchronously with each other. COPYRIGHT: (C)2001,JPO

Reinforced hydroform tube

Abstract: Selectively reinforced blanks are used in a hydroforming process to produce completed components having a predetermined shape and sufficient structural integrity to perform their desired function. To reinforce those components, reinforcing patches are added to the blank prior to hydroforming. Planar patches can be bonded to planar blanks or arcuate patches can be bonded to tubular blanks. In so doing, the hydroforming process produces a complete component, which does not require additional manufacturing steps to reinforce it. Additionally, by selectively using the reinforcing patches, the overall weight of the component is not unduly increased.

Steel tube excellent in formability and its production method

Abstract: PROBLEM TO BE SOLVED: To produce a steel tube having excellent formability in hydroforming, or the like, and to provide its production method. SOLUTION: In this steel tube excellent in formability, the (r) value in the axial direction of the steel tube is >=17, the average of the X-ray random intensity ratios in the orientation groups of 110} to 221} of the sheet face in the sheet thickness of 1/2 of the steel sheet is >=3.0, the X-ray random intensity ratio in 110} of the sheet face in the sheet thickness of 1/2 of the steel sheet is >=6.0, and X-ray random intensity ratios in 001} and 112} of the sheet face in the sheet thickness of 1/2 of the steel sheet is all =10% in the temperature range of the Ar3 point or above and >=20% in the temperature range of Ar3 to (Ar3-60) deg.C, and the reduction working is completed at =600 deg.C to control the total reduction ratio in diameter to >=30%.

High strength steel sheet excellent in formability after preworking, and its producing method

Abstract: PROBLEM TO BE SOLVED: To provide a high strength steel sheet used for automotive under-carriage members or the like particularly excellent in formability, e.g. in hydroforming accompanied with tube making and preworking before forming, and to provide its producing method. SOLUTION: This high strength steel sheet excellent in formability after preworking has a composition containing, by mass, 0.05 to 0.3% C, 0.3 to 2.5% Si, 0.5 to 3.0% Mn and 0.001 to 2.0% Al, and the balance iron with inevitable impurities and has a structure containing retained austenite including carbon of >=1.0% by the average mass concentration and equi-axial ferrite having an aspect ratio of 0.5 to 3.0 in >=50% by volume ratio.

Hydroforming of sheet metal pairs for the production of hollow bodies

Abstract: The hydroforming technology is well-known since several years and undergoes an extremely dynamic development in automotive applications, especially in Germany and the United States. The hydrofoming of sheet metal pairs is still at a pre-industrial stage. This publication presents the process and draws attention to some particular results of research work. Principal working directions for investigations, regarding the transfer of the hydroforming process for sheet metal pairs to industry are mentioned.

Hydroforming, hydroforming method of the forming and vehicle member using hydroforming

Abstract: PROBLEM TO BE SOLVED: To provide a hydroformed product for improving the quality of a forming having an external section gradually and variously changing its outer diameter. SOLUTION: The hydroformed part is obtained by a method that a tube stock 18, which is roughly conical shape obtained by rolling a steel plate member 18a of roughly trapezoidal shape to trace an external shape change of a product, is subjected to hydroforming. Thus, in the case of the product 14 to have the external section changing gradually and variously its external diameter, the high quality product 14 with a tube expanding rate falling in a restricted range is obtained. COPYRIGHT: (C)2001,JPO

Improved method for hydroforming an aluminum tubular blank

Abstract: A method of hydroforming a tubular aluminum alloy blank (T) into a desired configuration, including providing a tubular blank having opposing longitudinal end portions; rapidly heating the blank to an elevated temperature for a brief period of time, the values of the elevated temperature and the brief period of time being selected such that, after the rapid heating, the blank has a reduced hardness below an initial hardness without otherwise significantly changing the microstructure of the blank; quencing the blank while the blank is at or near the elevated temperature; disposing the quenched blank in a die cavity of a hydroforming die (102, 104), the hydroforming die having interior surfaces (106, 108) that provide the die cavity with a shape corresponding to the desired configuration of the tubular blank; sealing the opposing longitudinal end portions of the tubular blank; supplying pressurized fluid to the hollow interior of the tubular blank and relatively forcing the opposing end portions of the tubular blank inwardly toward one another such that the pressurized fluid diametrically expands the temporarily softened portions of the tubular blank such that the temporarily softened aluminum alloy of the blank is caused to flow longitudinally along the blank.