Scale Effect in FEM Simulation of Axisymmetric Hot Micro-Extrusion of Aluminum Alloys

2016 ◽  
Author(s):  
André L. M. Costa ◽  
Henry S. Valberg ◽  
Wojciech Z. Misiolek
Keyword(s):  
Scale Effect ◽  
Material Flow ◽  
Metal Flow ◽  
Fem Simulation ◽  
Numerical Code ◽  
Flow Curves ◽  
Axisymmetric Mode ◽  
Complex Shapes ◽  
Ram Speed ◽  
Deform 2D

Hot micro-extrusion is a good candidate for manufacturing metallic micro-components with complex shapes and good mechanical properties. This work investigates the metal flow in direct hot mini- and micro-extrusion of aluminum rods by means of FEM simulations. The presented study was performed with the numerical code DEFORM 2D in axisymmetric mode using experimental material flow curves for AA 7108 alloy. The mini-to-micro dimensional scale factor was 10:1, the extrusion ratios were 16 and 100, and the ram speed ranged from 0.5 to 20 mm/s. The initial temperature of the billet and tooling was 400°C. It was found that the temperature distribution within the profile changed from mini-to micro-extrusion and the effect was more significant for higher reductions and higher extrusion velocities. The micro-scale effect increased the stress field just behind the die orifice and the material deformed more intensely to achieve the equilibrium velocity. It was shown that the scale effect can be evaluated by the relative strain rates associated with the corresponding deformation. Numerical results indicate that the scale effect does increase exponentially with the velocity and it becomes significant for final exit velocities of the extrudate above the level of 100 mm/s.

FEM Simulation on Extrusion of Magnesium Alloys

2012 ◽  
Vol 268-270 ◽  
pp. 492-495
Author(s):  
Guo Ping Chen ◽  
Jun Deng ◽  
Shui Wen Zhu
Keyword(s):  
Large Deformations ◽  
High Strain ◽  
Metal Flow ◽  
Fem Simulation ◽  
Transient State ◽  
Process Conditions ◽  
Strain Rates ◽  
Billet Temperature ◽  
Finite Element Software ◽  
Ram Speed

Extrusion of magnesium billets is associated with large deformations, high strain rates and high temperatures, which results in computationally challenging problems in process simulation. A simulation was carried out using the finite element software ABAQUS. The computed model was rotational symmetric and built up by meshing. Computed parameters including material characteristics and process conditions (billet temperature. reduction ratio, and ram speed) were taken into consideration. The distributions of temperature were different comparing the transient-state extrusion with the steady-state extrusion. The extrusion simulation was the reliable predictions of strain rate, effective strains, effective stresses and metal flow velocity in an AZ31 billet during direct extrusion.

Estimation of Strain-Hardness Correlation in Cold-Forged Austenitic Stainless Steel

2014 ◽  
Vol 622-623 ◽  
pp. 179-185 ◽  
Author(s):  
Piotr Skubisz ◽  
Maciej Rumiński ◽  
Łukasz Lisiecki
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Hardening ◽  
Effective Strain ◽  
Cold Deformation ◽  
Metal Flow ◽  
Fem Simulation ◽  
Large Head ◽  
The Relationship

The paper presents selected aspects of analysis cold micro-forging process of a screw made of austenitic stainless steel, concerning relation between strain and hardness. Strain hardening character of a material in consecutive forming operations was analyzed experimentally by the measurement of hardness distribution made on longitudinal axial sections of screws. The relationship between hardness and effective strain (hardness curve) was determined, which made it possible to obtain strain distributions in different regions of a material subjected to cold deformation on the basis of strain distribution numerically estimated with FEM simulation performed using QForm2D/3D commercial software. Conclusions were formulated concerning strain inhomogeneity and strain-hardening intensity with respect to the correlation between strain and hardness. It was also concluded, that nonuniformity of hardening rate in a bulk can lead to local variations in flow stress and eventually, to occurrence of the metal flow related defects, which was illustrated with a case study of cold heading of self-tapping screw of AISI 304Cu stainless steel, with large head diameter to shank diameter ratio. In order to validate the obtained results, the same method was used for analysis of hardness development in steel 19MnB4.

FEM Simulation of Copper Busbar Pressing on the Continuous Extrusion Line "CONFORM"

2018 ◽  
Vol 284 ◽  
pp. 547-551
Author(s):  
Georgy V. Shimov ◽  
Aleksandr Bogatov ◽  
D. Kovin
Keyword(s):  
Steady State ◽  
Deformation Zone ◽  
Metal Flow ◽  
Fem Simulation ◽  
Continuous Extrusion ◽  
3D Package ◽  
Deform 3D

Simulation using the DEFORM-3D package of the steady-state pressing mode of a copper busbar on the continuous extrusion line "Conform" was carried out. The nature of the metal flow in the deformation zone was studied. An analysis of the velocities of the metal flow in the prechamber was performed. It was shown that in the channel of the wheel there is pressing out, which negatively affects the quality of the finished busbars and can lead to such defects as "lamination".

scholarly journals Plastometric tests for plasticine as physical modelling material

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Łukasz Wójcik ◽  
Konrad Lis ◽  
Zbigniew Pater
Keyword(s):  
Strain Rate ◽  
Temperature Change ◽  
Compression Test ◽  
Constitutive Equations ◽  
Metal Forming ◽  
Material Flow ◽  
Physical Modelling ◽  
Flow Curves ◽  
Black And White ◽  
White Colour

Abstract This paper presents results of plastometric tests for plasticine, used as material for physical modelling of metal forming processes. The test was conducted by means of compressing by flat dies of cylindrical billets at various temperatures. The aim of the conducted research was comparison of yield stresses and course of material flow curves. Tests were made for plasticine in black and white colour. On the basis of the obtained experimental results, the influence of forming parameters change on flow curves course was determined. Sensitivity of yield stresses change in function of material deformation, caused by forging temperature change within the scope of 0&C ÷ 20&C and differentiation of strain rate for ˙ɛ = 0.563; ˙ɛ = 0.0563; ˙ɛ = 0.0056s−1,was evaluated. Experimental curves obtained in compression test were described by constitutive equations. On the basis of the obtained results the function which most favourably describes flow curves was chosen.

Lateral Extrusion of Gear-Like Components with Radial Tooth Profile: Metal Flow Simulation and Analysis

2011 ◽  
Vol 264-265 ◽  
pp. 72-77
Author(s):  
H. Haghighat ◽  
D. Almasi
Keyword(s):  
Material Flow ◽  
Metal Flow ◽  
Flow Simulation ◽  
Tooth Profile ◽  
Lateral Extrusion ◽  
Extrusion Die ◽  
Parallel Movement ◽  
Proposed Model ◽  
Two Stages ◽  
Theoretical Results

The process of lateral extrusion of gear-like components with radial tooth profile has been studied in this paper. The material flow in extrusion die cavity has been simulated using the SuperForge of FVM simulation package. The results of simulation have shown that the material fills the die cavity in two stages: Parallel movement to the end of toothed die cavity and fills the rest of shaped die cavity. Each stage of deformation has been analyzed by using slab method of analysis and the extrusion load values for each punch stroke have been estimated. Finally, comparisons between present theoretical results and experiments of other researchers’ work have been carried out to illustrate the validity of this proposed model.

Numerical Analysis of Multi-Field Coupled Phenomena in Friction Stir Welding and Applications

2014 ◽  
Vol 783-786 ◽  
pp. 1794-1807
Author(s):  
Qing Yu Shi ◽  
Gao Qiang Chen ◽  
Xi Bo Wang ◽  
Xu Kang
Keyword(s):  
Numerical Simulation ◽  
Friction Stir Welding ◽  
Heat Generation ◽  
Material Flow ◽  
Metal Flow ◽  
Friction Stir ◽  
Rate Dependent ◽  
Potential Applications ◽  
Complex Phenomena ◽  
Fsw Parameters

Friction stir welding (FSW) is an advanced solid state joining technology, which was invented by TWI in 1991. During the process, large amount of heat is generated due to the friction between the tool and the material. As a result, the metal around the tool is softened as the temperature rises, and significant plastic flow occurs. So FSW is a complex process with multi-field coupled phenomena. Material flow plays a central role in FSW. But it is still difficult to reveal the material flow regime and joining mechanism during FSW process. Numerical simulation is a powerful tool for investigating the metal-flow-related complex phenomena during FSW. Meanwhile, numerical simulation could also help to optimize FSW tool design and FSW parameters. In this paper, we review the recent development in simulation of material flow during FSW. Then, the important issues in modeling multi field coupled phenomena during FSW are summarized, which include the heat generation mechanism, the temperature and strain rate dependent material’s behavior, and the interaction between tool and material. Finally, a comprehensive simulation model is presented, which enables advanced study on the coupled phenomena of heat generation, temperature distribution, material flow, and defects formation. This model has shown potential applications in simulating the relation between the transport of material and the macrostructure formation or defects formation. In spite of these progresses, simulation of material flow during FSW still need quite a lot of researches to fulfill industry requirement.

An Investigation on Effect of Residual Stress on Springback Behavior of High Strength Steel in U-Bending Process

2011 ◽  
Vol 189-193 ◽  
pp. 2864-2868
Author(s):  
Komgrit Lawanwong
Keyword(s):  
Residual Stress ◽  
Fem Simulation ◽  
Sheet Thickness ◽  
High Strength ◽  
Spring Back ◽  
Workpiece Material ◽  
Bending Process ◽  
Commercial Program ◽  
Deform 2D ◽  
Springback Behavior

Bending process is an important process in the metal sheet forming in many industries. The main problem of the bending process is the spring-back phenomenon after removing the punch. This research aims the investigation on effect of residual stress on springback behavior of sheet metal in U bending process. The corner setting technique and bottoming process were designed for experiments. The corner setting technique and bottoming has reduced the thickness in bending area to 5, 10, 15 and 20 percent of the original sheet thickness. Clearance between punch and die of both processes was equal to same the thickness. The residual stress value and springback phenomenal were investigated by commercial program code DEFORM 2D which was able to analyze the effect stress and force in bending area. Electrolytic zinc coated carbon steel grade JIS; SECC, JIS; 440 and JIS; 590 which having the thickness of 1 mm were employed as the workpiece material for all experiments. The result of three materials in conventional U bending die shows larger spring back than the corner setting technique and bottoming process. Moreover, the corner setting technique reduces spring back value in bending process but requires high bending force. Corner setting technique and bottoming process at 15% and 20% shows that the spring go of all parts. The FEM simulation results explained the effect of residual stress to springback phenomenal. Comparisons between experimental and finite element method results were also performed.

Analysis of the Hydraulic Bulge Test with FEA Concerning the Accuracy of the Determined Flow Curves

2009 ◽  
Vol 410-411 ◽  
pp. 439-447 ◽  
Author(s):  
Alper Güner ◽  
Alexander Brosius ◽  
A. Erman Tekkaya
Keyword(s):  
Flow Curve ◽  
Material Flow ◽  
High Strength ◽  
Bulge Test ◽  
Flow Curves ◽  
Element Analysis ◽  
Hydraulic Bulge ◽  
The Finite Element Analysis ◽  
Curve Determination ◽  
Set Up

This work covers the finite element analysis of geometric and process parameters in hydraulic bulge tests in terms of the accuracy of the evaluated flow curve. The important parameters are identified and varied to cover the whole range of possible uses. The effects of these parameters are analyzed for three representative materials: aluminium, mid-strength steel, and high-strength steel. The flow curves of the materials for each set of parameters are calculated by using the results of the simulations and the membrane theory. It is seen that even with simulation results, it is not always possible to obtain the input flow curve, especially towards the end of the test. The dimensions of the sheet and the tooling affect the plastic strain development and geometry of the bulge, leading to errors in computed flow curves. In order to observe the effect of the material flow from the flange on the determined yield stresses, the function and position of the drawbeads are also examined. These parameters, together with the method used to calculate the radius of the bulge, determine the accuracy of the calculated flow curve. Guidelines for an accurate flow curve determination regarding the test set-up and calculation methods are given.

An Analytical Finite Element Technique for Predicting Temperature Distribution in Turning Titanium Alloy

2012 ◽  
Vol 184-185 ◽  
pp. 886-889
Author(s):  
Bin Li ◽  
Hong Wang
Keyword(s):  
Material Flow ◽  
Flow Behavior ◽  
Metal Flow ◽  
Cutting Temperature ◽  
Machining Process ◽  
Engineering Technology ◽  
Metal Machining ◽  
Tc4 Alloy ◽  
Simulation Results ◽  
Element Technique

With the development of engineering technology, FEM can be used to simulate metal machining process and gain better understanding of material flow within dies, so as to optimize tooling to eliminate tears, laps and other forging defects. In this paper, numerical simulation was conducted by using FEM software on the whole cutting process for TC4 alloy mounting parts in an effort to investigate the metal flow behavior. The thermal simulation results obtained were compared with the cutting temperature and discussed in terms of literature data.

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