scholarly journals Influence of Mg Content on Deformability of AlMg Alloys during Extrusion

2016 ◽  
Vol 61 (1) ◽  
pp. 85-92
Author(s):  
D. Leśniak ◽  
M. Dziki ◽  
J. Zasadziński ◽  
W. Libura
Keyword(s):  
Surface Quality ◽  
Wall Thickness ◽  
Extrusion Process ◽  
Different Shapes ◽  
Exit Speed ◽  
Mg Content ◽  
Liquidus Temperatures

In this study the research on deformability of AlMg alloys with high Mg contents in extrusion was carried out. The different shapes from AlMg alloys containing 3.5%, 4.5% and 5.5% of Mg were extruded on 500 T semi-industrial press by using one-hole and multi-hole flat dies. The extrudates surface quality was under investigations in relation with the temperature-speed parameters of the extrusion process. The metal exit speed was estimated depending on the extrudates shape, wall thickness and Mg content. The alloy’s border solidus and liquidus temperatures were also determined.

Investigation of the Effects of Technological Parameters on Surface Roughness in Extrusion Bars of Aluminum Alloy

2019 ◽  
Vol 889 ◽  
pp. 155-160
Author(s):  
Trong Mai Nguyen ◽  
Đuc Quy Tran ◽  
Van Nghe Pham ◽  
Van Canh Nguyen
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Surface Quality ◽  
Research Work ◽  
Extrusion Process ◽  
Optimal Parameters ◽  
Technological Parameters

In this research work, the result of the effects of technological parameters on surface roughness in extrusion bars of aluminum alloy were pesented. The results of this study may be used for choosing optimal parameters of extrusion process so that surface quality of extruded bar was improved.

Optimization of Process Parameters on the Mechanical Properties of Semi-Solid Extruded AA2017 Alloy Rods

2019 ◽  
Vol 6 (2) ◽  
pp. 1-14
Author(s):  
Shashikanth Ch ◽  
G Venkateswarlu ◽  
Davidson M J
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Process Parameters ◽  
Extrusion Process ◽  
Percentage Reduction ◽  
Optimization Of Process Parameters ◽  
Different Temperatures ◽  
Semi Solid ◽  
Reduction In Area ◽  
Liquidus Temperatures

The extrusion of copper-based aluminium alloys is difficult in the cold state. Extruding these alloys between the solidus and liquidus temperatures offer preferred properties on these alloys. In the present work, AA2017, a copper-based aluminium alloy has been extruded in the semi-solid state. The mechanical and metallurgical properties of the alloy vary at different temperatures between the solidus and liquidus temperatures. The aim of the present work is to optimize the process parameters, namely, temperature of billet, strain rate, approach angle and percentage reduction in area on the semi-solid extrusion of AA2017 alloy. Experiments were designed according to Taguchi experimental design and L9 orthogonal array was used to conduct the experiments. Analysis of variance (ANOVA) method was used to find the significance of every process parameter on the thixo-extrusion process responses. The results indicate that percentage reduction area is the most important factor influencing the mechanical properties of thixo-extrusion specimen followed by temperature and strain rate.

Controllability Over Wall Thickness of Tubular Structures and Encapsulation During Co-Axial Extrusion of a Thermal-Crosslinking Hydrogel

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Ilhan Yu ◽  
Samantha Grindrod ◽  
Roland Chen
Keyword(s):  
Flow Velocity ◽  
Wall Thickness ◽  
Dynamic Viscosity ◽  
Element Model ◽  
Extrusion Process ◽  
Tubular Structures ◽  
Needle Size ◽  
Thermal Crosslinking ◽  
Outer Needle ◽  
Phosphate Buffered Saline

Abstract Tubular structures of the hydrogel are used in a variety of applications such as delivering nutrient supplies for 3D cell culturing. The wall thickness of the tube determines the delivery rate. In this study, we used the coaxial extrusion process to fabricate tubular structures with varying wall thicknesses using a thermal-crosslinking hydrogel, gellan gum (GG). The objectives of this study are to investigate the thermal extrusion process of GG to form tubular structures, the range of achievable wall thickness, and a possibility to form tubular structures with closed ends to encapsulate fluid or drug inside the tube. The wall thickness is controlled by changing the relative flow velocity of the inner needle (phosphate-buffered saline, PBS) to the outer needle, while keeping the velocity of outer needles (GG) constant. Two pairs of coaxial needles were used which are 18-12 gauge (G) and 20-12G. The controllable wall thickness ranges from 0.618 mm (100% relative velocity) to 0.499 mm (250%) for 18-12G and from 0.77 mm (80%) to 0.69 (200%) for 20-12G. Encapsulation is possible in a smaller range of flow velocities in both needle combinations. A finite element model was developed to estimate the temperature distribution and the wall thickness. The model is found to be accurate. The dynamic viscosity of GG determines the pressure equilibrium and the range of achievable wall thickness. Changing the inner needle size or the flow velocity both affect the heat exchange and thus the temperature-dependent dynamic viscosity.

Aluminium Extrusion Weld Formation and Metal Flow Analysis in Hollow Profile Extrusions of Different Section Thickness

2011 ◽  
Vol 491 ◽  
pp. 105-112 ◽  
Author(s):  
Yawar Abbas Khan ◽  
Henry Sigvart Valberg
Keyword(s):  
Wall Thickness ◽  
Perfect Match ◽  
Metal Flow ◽  
Extrusion Process ◽  
Experimental Results ◽  
Fe Model ◽  
Grid Pattern ◽  
Element Analysis ◽  
Weld Formation ◽  
Flow Through

Hollow and semi-hollow profiles are commonly produced by extrusion using porthole dies. The main characteristics of such dies are the presence of a mandrel (core) to shape the inner contour of hollow profile and bridges or legs to carry the mandrel. The bridges split the billet material into multiple metal streams that flow through the porthole channels and meet in the welding chamber behind the bridge where they are joined by pressure welding. When hollow profiles with different wall thickness are made the size of two adjacent portholes may be different. The material then flows through the two portholes with different flow velocity so that there is more feed through the bigger porthole into the weld chamber behind the bridge. Experiments have been performed and are reported here in which a grid pattern technique was used to characterize the metal flow through a 2D-die with porthole channels of unequal size. The design of the laboratory die has been modified in relation to the symmetric case to get different sizes of the two portholes. Since the metal flow through such a die is asymmetric the grid pattern technique was also modified to characterize the experimental flow. The results of an experimental metal flow study performed for a short billet was presented in a previous article [1]. Corresponding experiments performed with longer billets are now reported; so that two stages of the extrusion process is analysed here. The grid pattern technique has successfully mapped the non-symmetric material flow as in industrial extrusion when using different wall thickness over the section. The lateral movement of metal during extrusion is obtained from one set of experiments; the vertical movement from the other set. Finite element analysis of the extrusion process has been performed using Deform 3D. The encountering of the two metal streams behind the die bridge and the deformation characteristics within the welding chamber has been studied this way. Extrusion weld formation and deformations around the die bridge are considered here with the help of experimental results and simulation models. The nature of the metal flow achieved from the FE-model is compared with the experimental results. As regards the short billet some results are presented in [1], however improvement to the previous model gives a more perfect match. The model also provides information about the boundary conditions in real extrusion.

An Experimental Investigation on Surface Quality Extruded Wood-Polypropylene Composite

2012 ◽  
Vol 428 ◽  
pp. 89-93 ◽  
Author(s):  
Ehsan Soury ◽  
Amir Hossein Behravesh ◽  
Nathan Jafarian Jam ◽  
Ali Haghtalab
Keyword(s):  
Surface Quality ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Extrusion Process ◽  
Diameter Ratio ◽  
Flow Index ◽  
Screw Speed ◽  
Melt Temperature ◽  
Wood Content ◽  
Length To Diameter Ratio

This paper presents an experimental study on surface quality (roughness) for extruded wood plastic composites (WPC) in an extrusion process. A problem that usually occurs in production of extruded parts of polymeric materials, and in special case of WPC, is flow instabilities at the extrusion die exit. The instabilities lead to production of profiles with unacceptable surface quality. In this paper, the influences of the important material and process parameters on the surface quality are investigated. The variable parameters were selected as wood content, polymer melt flow index (MFI), screw speed, melt temperature, die diameter and finally length-to-diameter ratio of the die land. The experiments specified that increasing die land length-to-diameter ratio (L/D), die temperature and wood content and decreasing screw speed and polymer MFI lead to improve the surface quality.

Experimental Study on Csf/AZ91D Composite Using Extrusion Following Vacuum Infiltration Method

2010 ◽  
Vol 97-101 ◽  
pp. 382-385 ◽  
Author(s):  
Jun Tao Guan ◽  
Le Hua Qi ◽  
Li Zheng Su ◽  
Jian Liu
Keyword(s):  
Surface Quality ◽  
Great Influence ◽  
Extrusion Process ◽  
Vacuum Infiltration ◽  
Extrusion Temperature ◽  
Measuring System ◽  
Infiltration Process ◽  
Good Surface ◽  
Deformation Stages

10vol. % Csf/AZ91D composites were fabricated by extrusion following vacuum infiltration process with self-developed experimental device and measuring system. The relationships of load vs displacement during process and surface quality of composites at various extrusion temperatures were investigated. SEM microscope was used to observe the microstructure of fabricated composites. The experimental results showed that the extrusion process can be divided into three deformation stages. The extrusion temperature had a great influence on the maximum extrusion load. Based on proper infiltration parameters, a extruded bar with good surface quality was obtained at extrusion temperature of 420°C.

Robocasting of carbon-alumina core-shell composites using co-extrusion

2017 ◽  
Vol 23 (2) ◽  
pp. 423-433 ◽  
Author(s):  
Zongwen Fu ◽  
Matthias Freihart ◽  
Tobias Schlordt ◽  
Tobias Fey ◽  
Torsten Kraft ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Wall Thickness ◽  
Extrusion Process ◽  
Truss Structures ◽  
Core Shell ◽  
Lattice Structures ◽  
Content Type ◽  
The Core ◽  
Alumina Gels ◽  
Carbon Core

Purpose This study aims to achieve the fabrication of three-dimensional core-shell filament-based lattice structures by means of robocasting combined with co-extrusion. For core and shell materials, colloidal gels composed of submicron carbon and alumina powders were developed, respectively. Simultaneously, the co-extrusion process was also studied by numerical simulation to investigate the feed pressure-dependent wall thickness. Design/methodology/approach Significant differences in the rheological behavior of the carbon and alumina gels were observed because of differences of the particle morphology and surface chemistry of the carbon and alumina powders. Precise control over the cross-sectional diameter of the core and shell green state elements was achieved by alteration of the feed pressures used during co-extrusion. Findings After subsequent thermal treatment in an oxidizing atmosphere (e.g. air), in which the carbon core was oxidized and burned out, lattice structures formed of hollow filaments of predetermined wall thickness were manufactured; additionally, C-Al2O3 core-shell filament lattice structures could be derived after firing in an argon atmosphere. Originality/value Green lattice truss structures with carbon core and alumina shell filaments were successfully manufactured by robotically controlled co-extrusion. As feedstocks carbon and alumina gels with significantly different rheological properties were prepared. During co-extrusion, the core paste exhibited a much higher viscosity than the shell paste, which benefited the co-extrusion process. Simultaneously, the core and shell diameters were exactly controlled by core and shell feed pressures and studied by numerical simulation. The experimentally and numerically derived filament wall thickness showed qualitative agreement with each other; with decreasing core pressure during co-extrusion, the wall thickness increased.

The Full-Scale Viscous Drag of Actual Ship Surfaces and the Effect of Quality of Roughness on Predicted Power

1987 ◽  
Vol 31 (03) ◽  
pp. 189-206
Author(s):  
Christopher Grigson
Keyword(s):  
Surface Quality ◽  
Data Bank ◽  
Full Scale ◽  
Viscous Drag ◽  
Drag Coefficients ◽  
Predicting Performance ◽  
Different Shapes ◽  
Coated Surfaces

The hydrodynamic roughness functions of hull surfaces are surveyed. Δu+ is given for many different coated surfaces; all the surfaces have different topographies and all have roughness functions of different shapes which reveal that the quality of the roughness is as important as height in the generation of drag. The variety of these functions demonstrates that the viscous drag cannot be predicted without the use of the actual Au+ of the surface of interest. The planar drag coefficients of some of the hull surfaces are given as curves of CFR(Rn) and of ΔO(Rn). The behavior of ΔC with speed is compared with that deduced from careful trials, and is fully compatible with it. It is not compatible, however, with that of the ITTC formulae for AC, and the scientific foundations of the formulae are studied and found unsatisfactory. The influence of surface quality, hitherto not taken into account in predicting performance, could easily explain the relatively large errors in the statistics of predicted trial power. Shipbuilders need to measure the functions ΔU+ of their new hull surfaces and to acquire a data bank connecting their methods of finishing their hulls with Δu+.

Surface Quality Prediction in Aluminum Extrusion

2011 ◽  
Vol 491 ◽  
pp. 27-34 ◽  
Author(s):  
Matthijn de Rooij ◽  
X. Ma ◽  
A.J. den Bakker ◽  
Robert J. Werkhoven
Keyword(s):  
Surface Quality ◽  
Process Window ◽  
Process Conditions ◽  
Bearing Surface ◽  
Contour Lines ◽  
Exit Speed ◽  
Aluminium Extrusion ◽  
Calculated Number ◽  
Good Agreement

The surface quality of aluminium extrusion products can be hampered by undesired surface features like die lines and pickups. In particular the presence of pickups is considered as undesirable. Surface pickups appear as intermittent torn marks on the aluminium extrusion products, often terminated with a protruding lump rising above the surface up to hundreds of microns in height. Using a model calculating initiation, growth as well as detachment of the lumps on the die bearing surface, the surface quality of aluminium extrusion products can be predicted. The results of the model can be presented in terms of surface quality diagrams, where contour lines of the (normalized) calculated number of lumps are presented in terms of exit speed and extrudate surface temperature. These diagrams are unique for a certain combination of geometry of the extrudate and the aluminium alloy and can be used to optimise process conditions with respect to surface quality within a certain process window. In order to validate the model, the size and number of pickups on the surface of a labscale extruded strip of AA6063 have been measured. The results of the model are being compared to the experiments and show good agreement.

scholarly journals Numerical Simulation and Experimental Study on Rotary Cold Extrusion Forming of Screw Rod

2021 ◽  
Vol 2101 (1) ◽  
pp. 012017
Author(s):  
Peiai Li ◽  
Baoyu Wang ◽  
Jiapeng Wang
Keyword(s):  
Wall Thickness ◽  
Extrusion Process ◽  
Simulation Software ◽  
Cold Extrusion ◽  
Extrusion Force ◽  
Forming Process ◽  
Material Loss ◽  
Screw Pump ◽  
Plastic Forming ◽  
Extrusion Forming

Abstract The rotary cold extrusion forming process is a plastic forming process with very low material loss, especially in the production of hollow screw rods with equal wall thickness. In this work, the rotary cold extrusion forming process of a hollow T2 copper screw rod with a wall thickness of 4 mm and solid T2 copper screw rod was verified by experimental method. The finite element simulation software Deform-3D was also used to simulate the rotary cold extrusion forming process of the screw rod. The effects of the die with different heights of the working belt and the different wall thickness of the billet on the eccentricity, extrusion force, and forming torque in the forming process of the screw rod were studied. The results show that it is feasible to process hollow and solid T2 copper screw rods with equal wall thickness by rotary cold extrusion. With the increase of die working belt height, the eccentricity of the screw rod becomes smaller and closer to the ideal eccentricity. With the increase of the wall thickness of the billet, the amplitude fluctuation range of the eccentricity of the screw rod gradually decreases. The higher the height of the die working belt, the greater the extrusion force and torque required in the extrusion process, and the more intense the change of torque. These results also provide theoretical guidance for the production practice and lightweight transformation of the screw pump rotor.

Sign in / Sign up

Export Citation Format

Share Document