Study of Large-Expansion-Ratio Tube Hydroforming with Movable Dies

2016 ◽  
Vol 725 ◽  
pp. 616-622 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Shin Yan Hsieh ◽  
Nai Jung Kuo
Keyword(s):  
Finite Element ◽  
Tube Hydroforming ◽  
Geometric Analysis ◽  
Expansion Ratio ◽  
Carbon Steels ◽  
Low Carbon ◽  
Relative Speed ◽  
Second Stage ◽  
Large Expansion ◽  
Two Stages

In this paper, finite element codes LS-DYNA and DYNAFORM are used to analyze the plastic flow pattern of a tube hydroforming into a product with large expansion ratio and eccentric axes. Tube hydroforming with a movable die is proposed to enhance the forming capacity of tube hydroforming technology. The relative speed of the axial feedings to the movable die for obtaining a sound product is determined by a geometric analysis. The whole forming processes are divided into two stages. At the first stage, an internal pressure is applied on the inner surface of the tube and two axial feedings and a movable die move forward simultaneouly. At the second stage, one of the axial feedings keeps moving forward, whereas, the movable die moves backward. With this forming schedule for the axial feedings and movable die, products with more uniform thickness distributions are obtained. Finally, experiments of tube hydroforming with a movable die are conducted. Low-carbon steels are used as the tube specimen in the experiments. The simulation results of the product shape and thickness distributions are compared with experimental results to verify the validity of the finite element modeling and the proposed forming schedules.

Numerical and Experimental Study of the Effect Pressure Path in Tube Hydroforming Process

2011 ◽  
Vol 473 ◽  
pp. 579-586
Author(s):  
Majid Elyasi ◽  
Hassan Khanlari ◽  
Mohammad Bakhshi-Jooybari
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Stainless Steel ◽  
Experimental Approach ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Initial Pressure ◽  
Low Carbon ◽  
Element Simulation ◽  
Hydroforming Process

In this paper, the effect of pressure path on thickness distribution and product geometry in the tube hydroforming process is studied by finite element simulation and experimental approach. In simulations and experiments, low carbon stainless steel (SS316L) seamless tubes were used. The obtained results indicated that with increasing of the initial pressure, the bulge value of the part increases and the wrinkling value decreases. In addition, if the initial pressure is highly decreased, then bursting may occur.

Tube Hydroforming of Fuel Filler Pipes with Movable Dies

2014 ◽  
Vol 626 ◽  
pp. 524-528 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Shin Yan Hsieh ◽  
Ming Chung Chen
Keyword(s):  
Tube Hydroforming ◽  
Expansion Ratio ◽  
Die Design ◽  
Pipe Material ◽  
New Approach ◽  
Metal Structures ◽  
Loading Paths ◽  
Adaptive Simulation ◽  
Large Expansion ◽  
Deform 3D

Tube hydroforming is a relatively new approach to manufacture light weight metal structures. As the manufacturing technology became advanced, demands of lighter and stronger metal structures are also increasing. This research is to use tube hydroforming to expand the tube of a fuel filler for cars. The pipe material is JIS G3141. The product has a large expansion ratio at the edge of the pipe. Traditional tube hydroforming is difficult to achieve this large expansion ratio of a metal product. Tube hydroforming with movable dies is proposed to enhance the capacity of tube hydroforming technology. With movable die design, product with more uniform thickness can be obtained, and the forming pressure becomes lower than that needed in tube hydroforming without movable dies. A finite element code DEFORM-3D is used to analyze the plastic flow pattern of the tube. The loading paths of internal pressure, axial punches and movable dies for obtaining a sound product are determined by an adaptive simulation algorithm. The thickness distributions of the product for different loading paths are discussed.

Investigation of Load Path Effect on Thickness Distribution and Product Geometry in the Bulge Hydroforming Process

2011 ◽  
Vol 110-116 ◽  
pp. 1477-1482 ◽  
Author(s):  
Majid Elyasi ◽  
Hassan Khanlari ◽  
Mohammad Bakhshi-Jooybari
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Simulation ◽  
Experimental Approach ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Low Carbon ◽  
Load Path ◽  
Element Simulation ◽  
Hydroforming Process

In this paper, the effect of load path on thickness distribution and product geometry in the tube hydroforming process is studied by finite element simulation and experimental approach. The pressure path was obtained by using finite element simulation and its validation with experiments. In simulations and experiments, low carbon stainless steel (SS316L) seamless tubes were used. The obtained results indicated that if pressure reaches to maximum faster, bulge value and thinning of the part will be more and wrinkling value will be less.

scholarly journals One-Step Enameling and Sintering of Low-Carbon Steels

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1007
Author(s):  
Miguel Angel Martinez ◽  
Juana Abenojar ◽  
Mohsen Bahrami ◽  
Francisco Velasco
Keyword(s):  
Iron Powder ◽  
Sintering Temperature ◽  
Single Step ◽  
Carbon Steels ◽  
Basic Solution ◽  
Low Carbon ◽  
Bending Resistance ◽  
Mechanical Anchoring ◽  
One Step ◽  
Two Stages

Powder technology allows manufacturing complex components with small tolerances, saving material without subsequent machining. There is a growing trend in using sintered steel components in the automotive industry. Within 2020, about 2544 million US dollars was invested for manufacturing sintered components. Not only does this industry uses steel components, but the gas cooker industry also uses steel in its burners since they are robust and usually demanded by Americans, with forecasts of 1097 million gas cookers in 2020. Steel gas burners have a ceramic coating on their surface, which means that the burner is manufactured in two stages (casting and enameling). This work aims to manufacture the gas burners by powder metallurgy, enameling and sintering processes in a single step. To achieve this aim, the ASC100.29 iron powder has been characterized (flow rate, relative density and morphology); subsequently, the most suitable parameters for its compaction and an adequate sintering temperature were studied. Single-step sintering and enameling was achieved by compacting iron powder at 500 MPa and sintering at 850 °C for 5 min. The necessary porosity for mechanical anchoring of the coating to the substrate is achieved at this sintering temperature. Bending resistance tests, scratching, degradation under high temperature and basic solution and scanning electron microscopy were used to characterize and validate the obtained samples.

Cr Influence on Steel Microstructure and Kinetics of Austenite Decomposition at Near-Bay Temperatures

2005 ◽  
Vol 500-501 ◽  
pp. 311-320 ◽  
Author(s):  
Andrej Samoilov ◽  
Yuri Titovets ◽  
Nikolay Y. Zolotorevsky ◽  
Gottfried Hribernig ◽  
Andreas Pichler
Keyword(s):  
Isothermal Transformation ◽  
Carbon Steels ◽  
Austenite Decomposition ◽  
Low Carbon ◽  
Transformation Kinetics ◽  
Low Carbon Steels ◽  
Steel Microstructure ◽  
Second Stage ◽  
Cr Content ◽  
Kinetics Of

An experimental study of Fe-C-Mn-Cr low-carbon steels with varying Cr content is presented. Pronounced bay and a near-stasis behavior were shown in the alloy with 1.1% Cr. Isothermal transformation at temperatures roughly between 500 and 600°C reveals two pronounced stages. SEM examination of the microstructures showed that the rapid first stage is controlled by carbide-free bainite formation while the slow second stage is controlled by a eutectoid-type reaction. Some microstructure features of the transformation were noted and discussed. Based on experimental observations, a model of austenite decomposition was developed to account for the main features of transformation kinetics in the alloys with varying Cr content.

scholarly journals Numerical modeling of space umbrella-type mesh reflector

2019 ◽  
Vol 221 ◽  
pp. 01004
Author(s):  
Sergey Belov ◽  
Aleksey Belkov ◽  
Andrey Zhukov ◽  
Mikhail Pavlov ◽  
Stanislav Kuznetsov ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Finite Element Model ◽  
Displacement Field ◽  
Element Model ◽  
Force Density ◽  
Second Stage ◽  
Nonlinear Force ◽  
Two Stages ◽  
Node Displacement

This paper describes numerical modeling of space umbrella-type mesh reflector. The modeling includes two stages. The first stage embraces the calculation of the shape of cable elements for reflector frontal (rear) nets by the nonlinear force density method. The second stage involves the design of the reflector finite-element model based on the calculated nets. After this, the node displacement and prestress boundary conditions are imposed to determine a node displacement field.

Modelling of the post-localization behaviour in tube hydroforming of low carbon steels

2007 ◽  
Vol 182 (1-3) ◽  
pp. 248-256 ◽  
Author(s):  
D. Daly ◽  
P. Duroux ◽  
M. Rachik ◽  
J.M. Roelandt ◽  
J. Wilsius
Keyword(s):  
Tube Hydroforming ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels

Die Design and Axial Feeding in the Tube-Hydroforming Process

2010 ◽  
Author(s):  
Sin-Liang Lin ◽  
Fuh-Kuo Chen
Keyword(s):  
Finite Element ◽  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Expansion Ratio ◽  
Loading Path ◽  
Structural Part ◽  
Axial Feeding ◽  
Internal Fluid ◽  
Hydroforming Process ◽  
Production Part

In the present study, the loading path with constant internal fluid pressure during axial feeding to hydroform an automotive structural part with higher expansion ratio was investigated. The axial feedings employed at various internal fluid pressures were simulated by the finite element method. It is found that the axial feeding applied at a favorable internal fluid pressure, the production part with higher expansion ratio still could be made. Compared with other loading paths published in literature, which are mainly linear paths, the proposed loading path provides a simple approach to achieve better performance in the hydroforming process. The factors causing wrinkling fin the hydroforming process were also studied by analyzing the relationship between the die face shape and the material flow in the die cavity. An optimum die face design that avoided pinching at the die closing process was then proposed. The actual hydroforming process for manufacturing the automotive structural part was conducted as well in the present study to validate the proposed loading path and the optimum die face design. The consistent agreement between the production part and the finite element simulation results confirms not only the proposed loading path and die face design, but also the effectiveness of the finite element analysis employed in the tube-hydroforming process.

Lattice Imaging of Twin, Lath and α/Martensite Boundaries in Duplex Low Carbon Steels

1977 ◽  
Vol 35 ◽  
pp. 118-119
Author(s):  
J. Y. Koo ◽  
G. Thomas
Keyword(s):  
High Resolution Electron Microscopy ◽  
Ferrite Matrix ◽  
Carbon Steels ◽  
Bright Field Image ◽  
Low Carbon ◽  
Lattice Imaging ◽  
Bright Field ◽  
Lattice Image ◽  
New Information ◽  
Resolution Electron

High resolution electron microscopy has been shown to give new information on defects(1) and phase transformations in solids (2,3). In a continuing program of lattice fringe imaging of alloys, we have applied this technique to the martensitic transformation in steels in order to characterize the atomic environments near twin, lath and αmartensite boundaries. This paper describes current progress in this program.Figures A and B show lattice image and conventional bright field image of the same area of a duplex Fe/2Si/0.1C steel described elsewhere(4). The microstructure consists of internally twinned martensite (M) embedded in a ferrite matrix (F). Use of the 2-beam tilted illumination technique incorporating a twin reflection produced {110} fringes across the microtwins.

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