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The increasing use of aluminum alloys in automotive industry brings new challenges regarding formability and springback. Servo presses and servo hydraulic cushions can accurately control ram motion and blank holder force during the forming process, reducing the difficulties encountered in forming Al alloys. This study presents an experimental and numerical analysis of springback and residual stresses induced during the U-channel drawing of Al 5182-O. During the U-channel drawing, the draw-in of the sheet material into the die cavity is controlled by blank holder force. So, the material is under stretch bending condition when it slides around the die corner radius. When the material passes the die corner radius it unbends. The reverse loading resulted from the unbending process provides heterogeneous stress distribution through the sheet thickness in the wall section. The effect of post stretching, applied by the use of a servo hydraulic cushion, on reduction of residual stresses and springback at the wall is investigated. The benefit of using servo hydraulic cushion for reducing springback and residual stresses has been demonstrated experimentally. Results illustrate a significant reduction of residual stresses and springback when post stretching is applied. [ABSTRACT FROM AUTHOR]

This paper describes two computer-aided design (CAD) programs developed for modeling the shape rolling process for airfoil sections. The first program, SHPROL, uses a modular upper-bound method of analysis and predicts the lateral spread, elongation, and roll torque. The second program, ROLPAS, predicts the stresses, roll separating force, the roll torque and the details of metal flow by simulating the rolling process, using the slab method of analysis. ROLPAS is an interactive program; it offers graphic display capabilities and allows the user to interact with the computer via a keyboard, CRT, and a light pen. The accuracy of the computerized models was evaluated by (a) rolling a selected airfoil shape at room temperature from 1018 steel and isothermally at high temperature from Ti-6A1-4V, and (b) comparing the experimental results with computer predictions. The comparisons indicated that the CAD systems, described here, are useful for practical engineering purposes and can be utilized in roll pass design and analysis for airfoil and similar shapes. [ABSTRACT FROM AUTHOR]

The forging engineer must often estimate the load necessary in a press forging operation. Thus, the appropriate press capacity can be selected and, in some cases, it can be decided whether or not in-house capability exists for quoting on a given forging. This paper describes a simple load calculation method and its application to forging a steel connecting rod. The results, obtained with a hand calculator, are evaluated by comparing them with the results of computer-aided analysis and with experimental forging data. This comparison indicated that hand calculator results are sufficiently accurate for estimating forging loads and stresses. It is expected that the technique, described in this paper, will be a useful tool for the engineers in forge shop practice. [ABSTRACT FROM AUTHOR]

This paper reviews the application of systems approach to massive forming processes. A detailed classification of massive forming processes is given and using impression die forging as an example, the significant process variables and their interactions are systematically discussed. The paper also gives an example in forging, which illustrates the application of the systems approach to modeling of forging, a massive forming process. Finally, the future potential, capabilities and shortcomings of process modeling are discussed and recommendations for future work are made. It is expected that the paper can be useful to the metalforming engineer, active in research or production, who is interested in systematic analysis and design of massive forming processes. [ABSTRACT FROM AUTHOR]