• Journal of the Korean Society for Heat Treatment
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• v.18 no.4
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• pp.223-228
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• 2005

Tube hydroforming provides a number of advantages over conventional stamping process, including fewer secondary operation, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. It can produce wide range of products such as subframe, engine cradle, and exhaust manifold. In this study, the effect of the heat treatment conditions such as post seam annealing (PSA) and bright annealing (BA) on the ovality and hydro-formability of steel tubes has been investigated. Hydroformabilities have been estimated by the bulging heights obtained at various processing parameters such as internal pressure, axial feeding and heat treatment conditions. The ovality and forming height are strongly influenced by material properties after heat treatments.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.348-348
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• 2005

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.339-339
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• 2005

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.905-910
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• 2010

Exhaust manifolds are the first structures to be developed by hydroforming; mass production of exhaust manifolds by this method will be possible soon. This is obviously related with tight emission regulation induced by environmental problems commonly for both domestic and worldwide and standards, thus evoking its solution for domestic automakers. Compared to conventional cast products, thin-gauge tubular hydroformed exhaust manifold have superior features; for example, in the hydroformed exhaust manifold, gas decomposition during the cold-start period of the engine is reduced by lowering the heat sink, and manufacturing process is simplified since less welding is involved. The aim of this study is to develop a hydroformed exhaust manifold; the study deals with the components, the hydroforming process, and tool design of the manifolds. The performance of the exhaust system is evaluated by performing flow analysis, heat-transfer analysis, heat-stress analysis, and fatigue analysis by using a computer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1105-1106
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• 2010

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.11-21
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• 1992

Modern manufacturing process requires machine intelligence to meet the demands for high technology products as well as intelligence-based operating skills to lessen human worker's intervene. To meet this trend there has been wide spread interest in applying artificial neural network(ANN) to the areas of manufacturing process monitoring and control. This paper addresses application problems in such processes as welding, assembly, hydroforming process and inspection of solder joints.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.29-29
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• 2005

• Proceedings of the Korean Society of Laser Processing Conference
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• 2002.11a
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• pp.41-44
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• 2002

• Journal of the Korean Society for Heat Treatment
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• v.20 no.4
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• pp.181-186
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• 2007

Effect of heat treatment conditions on formability and property of warm hydroformed parts for Al 6061 extruded tubes was investigated in this study. For the investigation, as-extruded, fully annealed and T6-treated Al 6061 seamless tubes were prepared. To evaluate the warm hydroformability, uni-axial tensile test and free bulge test were performed at various pre- and post-heat treatment conditions. And the tensile test specimens were obtained from hexagonal prototype hydroformed parts at $250^{\circ}C$. As a result, hydroformability of fully annealed tube is 25% higher than that of extruded tube. The tensile strength and strain of hydroformed part reach to 330 MPa and 12%, respectively, when the part was T6 treated after warm hydroforming. However, the hydroformability of T6 pre-treated tube is relatively low due to the decreased elongation, 8%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.1010-1015
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• 2008

In this study, the characteristics of aluminum tube hydroformed products at different extrusion type and heat treatment conditions were investigated. For the investigation, as-extruded, full annealed and T6-treated Al 6061 tubes at different extrusion type were prepared. To evaluate the hydroformability, free bulge test was performed at room temperature to $300^{\circ}C$. Also mechanical properties of hydroformed products at various pre- and post-heat treatments were estimated by hexagonal prototype hydroforming test at $250^{\circ}C$. And the tensile test specimens were obtained from hexagonal prototype hydroformed tube. As a results, hydroformability of full annealed tube is $5{\sim}8%$ higher than that of extruded and T6-treated tube. The tensile strength and elongation of T6-post heat treated indirect extrusion tube were more than 330MPa and 12%, respectively. However, T6 pre treated hydroformed product represents high strength, 330MPa and low elongation, 8%. Therefore, Hydroformability of Al6061 tube showed similar value for both extrusion types. However flow stress of direct tube showed $20{\sim}50MPa$ lower value than indirect tube.