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Vol. 8. Num. 1.
Pages 1-1592 (January - March 2019)
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Vol. 8. Num. 1.
Pages 1-1592 (January - March 2019)
Original Article
DOI: 10.1016/j.jmrt.2018.08.006
Open Access
The effects of lubricants on temperature distribution of 6063 aluminium alloy during backward cup extrusion process
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Omolayo M. Ikumapayia,
Corresponding author
, Sunday T. Oyinboa, Ojo P. Bodundeb,c, Sunday A. Afolalud, Imhade P. Okokpujied, Esther T. Akinlabia
a Department of Mechanical Engineering Science, University of Johannesburg, South Africa
b Department of Mechanical and Mechatronics Engineering, Afe Babalola University, Ado Ekiti, Nigeria
c Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China
d Department of Mechanical Engineering, Covenant University, Ota, Nigeria
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Tables (5)
Table 1. Parameters used in simulation.
Table 2. AA6063 composition and properties.
Table 3. AA6063 composition and properties.
Table 4. Lubricants with varying strain rates.
Table 5. Simulation parameter.
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Abstract

Backward extrusion has received several applications in the production and manufacturing sectors, most importantly in the bulk forming processes and various researchers have carried out several studies about backward extrusion processes in the time past varying from experimental, theoretical, empirical, analytical to numerical methods in order to analyze and optimize it. In this present investigation, backward cup extrusion of AA6063 was successfully carried out experimentally and theoretically using tropical coconut oil and castor oil as lubricants. The experiment was also carried out without lubrication. With the different lubricating conditions, the strain rate was varied at 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1 respectively. A numerical analysis using DEFORM 3D software for backward cup extrusion at strain rates of 2.0×10−3s−1 and 2.5×10−3s−1 were then performed to determine optimum lubricated condition and temperature distribution during the deformation. It was found that the temperature increased with increasing strain rates. At a higher strain rate, the temperature of both punch and lower die also increased. The highest temperature was observed when lubricated with tropical coconut oil at a strain rate of 3.0×10−3s−1 which was observed to be above 33°C when compared to other lubricants. The punch temperature showed a higher temperature compared to the lower die temperature in all cases. The extrusion load–stroke curve of the simulation result was consistent with the experimental results.

Keywords:
Backward cup extrusion
Lubricants
Strain rate
DEFORM 3D
Temperature distribution
Full Text
1Introduction

Histories have it that about 200 years ago, Extrusion got debut entrance into the Industrial sector. But it has been observed that the benefits of extrusion process have increased tremendously in the past 60 years due to advancement in technology gotten from the practical knowledge and various fundamental search into the process of extrusion, tooling, metal forming, and metal flow [1].

The extrusion process can be hot or cold working process in which the intended work metal is forced through a female die opening to produce the desired shape. Generally, extrusion is used to produce long parts of uniform cross-section. The advantages of extrusion process over other metalworking processes are that varieties of sections can be achieved (i.e. through hot extrusion), the grain structure and desired strength are enhanced (i.e. via cold extrusion), and close tolerance can be obtained (i.e. via cold extrusion) and there is usually little or no material wastage.

Materials that are commonly extruded include polymers, metals, concretes, ceramics, and foodstuffs. Metals that could be extruded are alloys of aluminium, tin, lead, copper, etc. This research aims at the extrusion of aluminium alloy AA6063.

The most commonly extruded metallic material is the aluminium and even the most commonly extruded material. It could be hot or cold extruded. If hot extruded, it is heated from 300 to 600°C. Extruded aluminium shapes can be affected by various properties as a result of the way extrusion metal flows. The factors influencing extrusion metal flow are: type of extrusion (direct or indirect); press capacity and size and shape of container; frictional effects at the die or both container and die; type, layout, and design of die; the length of billet and type of alloy; the temperature of the billet and container; the extrusion ratio; die and tooling temperature and speed of extrusion [2].

A study to search for more accurate approaches in describing thermal and frictional boundary condition by Celalettin [3] using finite element model found out that extrusion process exhibits complex, closely coupled thermo-mechanical processes, the accurate computation of the material flow rates. For a deep knowledge of the extrusion process, Abrinia and Orangi [4] analyzed extrusion process by means of finite element analysis (FEA) to analyze stress, strain and velocity field of the shaped section in a backward extrusion process.

A similar study was carried out by Abrinia and Gharibi [5] by the use of thin-walled cans and it was observed that using appropriate punch head profile, more uniform and smaller can wall thickness would be achieved. Numerical simulations were used by van de Langkruis and his colleagues to study several isothermal laboratory scales of AA6063 extrusion billets with the aid of FEM (code DiekA). They used magnesium (Mg) and silicon (Si) to analyze the effect of solution hardening on the extrusion process by adopting a hyperbolic sine law. It was also observed that complete extrusion pressure levels will reduce with ram position. Similarly, the differences between experiments and simulations were studied on the effects of dynamic precipitation and recrystallization, adiabatic heating and strain localization [6]. Another research carried out by Ajiboye and Adeyemi [7] in which extrusion variables such as die preheat temperature, extrusion ratio, percentage reduction area and extrusion velocity were studied using a numerical method to analyze the transient temperature distributions of the forward extrusion process. In the study, it was concluded that an increase in temperature increased the percentage reduction area, also increase in dead zone temperature will increase deformation velocity.

Li et al. [8] used 3D FEA to study optimum extrusion velocity and the prediction of temperature distribution from the transient state to a steady state. They found out that ram velocity plays a crucial role on the distribution of temperature. It was observed that increase in ram velocity will lead to a fast reduction in extrusion pressure during steady state extrusion as a result of higher heat generated which will lead to decrease in heat loss subsequently there will be a reduction in flow stress as the process proceeds.

Uyyuru and Valberg [9] also studied backward cup extrusion process of aluminium alloy slug by the use of physical modelling and finite element method (FEM). They worked on tube-like/circular shape intrinsic contrast material specifically made to study material flow. Their results show that surface extension over the punch head varying along the length of the cup. Extension of the top of the cup is higher to that close to the base of the cup.

Al-Smadi et al. [1] developed a diagnostic power consumption model during extrusion in real time process, their study was based on extracting data from a sensor at the plan with a study centred on the regional signature. Numerical method algorithm was developed to extract certain features from the power consumption cycle in which the press needs to extrude one billet. Finally, they analyzed and developed a model that diagnoses the extrusion process online. Within the forming temperature range of hot extrusion of magnesium alloy fin structural parts, lower billet heating temperature can be selected to acquire higher compressive strength for the fin plates, also under the same process conditions, higher billet heating temperature or faster extrusion speed would reduce the hardness of billet. Hsiang et al. [10] used DEFORM to carry out simulation analysis of extrusion of magnesium alloy fin structural part. The combined effects of thermal behaviour and elastic–plastic deformation on the dimensional errors of a cold backward extruded cup were analyzed quantitatively by Long [11].

In extrusion, the temperature distribution, strain rate, and the velocity are important in selecting process variables such as initial temperature, ram speed of the billet and tooling in order to obtain the required properties of the extruded product [12].

For hot extrusion of a material with high flow stress, an enormous amount of heat generated which tends to locally alter the mechanical and microstructure properties of the material that are extruded and therefore makes it important to have knowledge the strain, strain rate, temperature and distribution of the material during extrusion [13]. Researches in forward extrusion focused on temperature and how its affect the component form-errors [14]. Extrusion force data obtained using developed procedures should show reasonable agreement with data obtained from calculations and FEA.

A research on the temperature distribution in hot aluminium extrusion billets was carried out by Johannes [15] using finite element analysis, concluded that temperature distribution was dependent on the length, diameter, and the external boundary conditions made intuitive estimates difficult. Saha [16] presented the relationship between tribology and thermodynamics in aluminium extrusion and proposed a thermodynamic model that could predict the effect of main extrusion variables on the maximum temperature rise at die entry. Also in the research series of temperature measurement were conducted to investigate the value of exit temperature of a thin-walled hollow extrusion shape under three experimental procedures.

Oyinbo et al. [2] studied the numerical simulation of axisymmetric and Asymmetric extrusion process using finite element method (FEM), Similarly, Moshksar et al. [17], Farhoumand et al. [18], and Shatermashhadi et al. [19] used different analytical approaches for backward extrusion. But Kimura et al. [13] in their work on the analysis of temperature of titanium alloys during hot extrusion at heating temperatures of 950 and 1100°C and extrusion ratios of 6 and 12. The strain was smaller in the centre than the surface, while the temperature was higher in the centre than in the surface because of the heated billet cooled down to a considerable extent before it was hot extruded. Hsiang et al. [10] worked on magnesium alloy at different temperatures between 300 and 360°C and extrusion ratio of 8.03. In their work, they investigated experimentally and compared with finite element analysis to prove the accuracy of the result from simulation analysis. While these works reviewed in this paragraph uses different temperatures while Carlos Fernado [20] did a model and controlled extrusion at a constant temperature throughout the cycle.

There is little information on the effects of die temperatures on extrusion process, although some investigations have been carried out on cold extrusion on the effect of some parameters such as loading rate, extruded shapes and die angles as reported by Ikumapayi et al. [21]. The purpose of this project is to carry out an experimental investigation of backward cup extrusion of aluminium alloy AA6063 at different extrusion speed compare with different lubricants and also compare results with FEM simulation DEFORM 3D.

2Material

Many extrusion parameters have been looked into by many researchers in the past as explained in the literature survey of the present study. In the present work, the authors determined experimentally the effect of temperature in backward cup extrusion process using aluminium alloy AA6063, by carrying out the following:

  • (a)

    Determining the distribution of temperature during backward cup extrusion of AA6063.

  • (b)

    Determining the temperature distribution using different lubricants in the extrusion process.

  • (c)

    Comparing the experimental result with FEM simulation DEFORM 3D.

The present research focused on the temperature of the billet and dies.

2.1Rig design and construction

For the experimental investigation of the billet temperature during the process of extrusion, an extrusion rig was modified and reconstructed for the purpose of the backward cup extrusion of aluminium. Fig. 1 shows a 2D schematic illustrating the flow of extrudate from the test rig.

Fig. 1.

2D schematic of the extrudate flow.

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The extrusion apparatus required for the experiment were:

  • (a)

    The extrusion rig (container)

  • (b)

    The punch

  • (c)

    The lower die

  • (d)

    Thermocouple

  • (e)

    Temperature metres

2.1.1The extrusion rig

This is the rig required for all extrusion tests. This extrudes the aluminium alloy AA6063 billets of diameter 34.8mm and height of 25mm to a reduction in the area of 0.6. Figs. 2 and 3 show the diagrams of the rig in 3D and Orthographic views (2D schematic) of the extrusion rig respectively.

Fig. 2.

Extrusion rig or container.

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Fig. 3.

Orthographic projection of the extrusion rig.

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2.1.2Determination of extrusion force

To determine the extrusion pressure required to extrude aluminium AA6063 for this research, FEA software DEFORM 3D was used. The simulation parameters are stated in Table 1 and the results are shown in Fig. 4.

Table 1.

Parameters used in simulation.

Parameter  Temperature  Strain rate  Ram speed  Max. displacement 
Input  30°  0.003s−1  0.075mm/s  20mm 
Fig. 4.

Simulation results (DEFORM 3D postprocessor).

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2.1.3Determination of shell diameter

The diameter of the shell of the extrusion rig (container) was determined based on criteria of failures [22]. The three guide pins holes are located on the container at a distance of the shell diameter. This is done to reduce the possibility of failure due to the drilled holes in the container wall.

The criteria for shell failure are based on the theory of elasticity.

2.1.3.1The maximum principal stress theory

This theory of failure given in Eq. (1) informs that failure occurs when the maximum principal stress is greater than the stress at the tensile yield point.

2.1.3.2The maximum shear stress theory

This theory has expressed in Eq. (2) says failure occurs when maximum shear stresses greater than the maximum shear stress at the tensile yield point.

2.1.3.3The maximum principal strain theory

Failure occurs when the maximum principal strain is greater than the strain at the tensile yield point as expressed in Eq. (3).

2.1.3.4Maximum distortion energy theory

Failure occurs when the maximum distortion energy is higher than the distortion energy at the tensile yield point as given in Eq. (4).

where pi is the internal pressure; σyp is the yield stress; v is the Poisson ratio; and k is the ratio of the outer diameter (do) to internal diameter (di).

Substituting the values of the parameters stated below into the failure theories (Eqs. (1)–(4)), the maximum diameter obtained was 109mm, and the guide pin holes are located at a displacement of 62mm from the centre.

pi=390MPa (from simulation); σyp=48MPa (for aluminium alloy); v=0.33 (aluminium alloy); and di=35mm.

2.2The punch

The punch is shown in Fig. 5. The punch has a diameter of 27mm and a hole is drilled from the back so that the thermocouple can go through it for the temperature reading during the experiment. For the punch to be centrally placed on top of the workpiece three guide pins were incorporated as shown in Fig. 6.

Fig. 5.

The punch.

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Fig. 6.

The punch assembly.

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2.2.1The lower die

The diagram of the lower die is shown in Fig. 7. In order to take the temperature reading at the base of the billet, a hole was drilled at the middle of the lower die with an allowance of 5mm to the surface so as to prevent any flow through the hole during the extrusion. A thermocouple (Type K) was inserted into the hole for temperature monitoring purpose.

Fig. 7.

The lower die.

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2.3Temperature measurement

The measurement during the experiment was done using a thermocouple (Type K) and temperature digital multi-metre (MASTECH MY64).

2.4Heat treatment of extrusion toolings

Heat treatment was carried out on extrusion tools in order to increase the tool life and for the extrusion toolings to withstand high pressure during the extrusion process. More so, to achieve optimum desirable properties and metallurgical characteristics by a systemic change in the microstructure, the punch, and lower die were heat treated. The punch and lower die were case-hardened at 910°C using a carburising box, containing a mixture of graphite and charcoal. It was then soaked at this temperature for half an hour. They were both quenched in engine oil (SAE 40) and at 200°C they were tempered for 1h to reduce the induced residual stresses. Case hardening was done so as to increase the content of surface carbon of the tools and consequently increase wear resistance, this was also in accordance with the findings of Onuh and colleagues [23].

The cylinder was then heated to a temperature of 910°C, soaked for 1h so as to have uniform temperature distribution thereby having uniform grain refinement. It was then quenched in water.

3Material composition3.1Properties and composition of workpiece/billets

Aluminium alloy AA6063 properties and composition are shown in Tables 2 and 3[24].

Table 2.

AA6063 composition and properties.

Element  Weight % 
Al  98.9 
Si  0.40 
Mg  0.70 
Thermal properties
Thermal expansion (10−6/°C)  23.4 
Thermal conductivity (W/mK)  218 
Table 3.

AA6063 composition and properties.

Mechanical properties   
Density (×1000kg/m32.7 
Poisson's ratio  0.33 
Elastic modulus (GPa)  70–80 
Tensile strength (MPa)  90 
Yield strength (MPa)  48 
Hardness (HB500)  25 
Shear strength (MPa)  69 
Fatigue strength (MPa)  55 
3.2Preparation of the specimens

After annealing was done, the workpiece was machined into billets of dimension 34.8mm in diameter and 25mm in height.

3.2.1The experimental setup

A 3D model of the experimental set up is shown in Fig. 8. The experiment was carried out at room temperature. The thermocouple was inserted into the holes in the lower die and punch to take the temperature reading as the extrusion tests were carried out.

Fig. 8.

3D model of experimental set-up.

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During the experiment, the container walls, a lower die, punch and the billet were lubricated with different lubricants for each test and at different strain rate. The tests were conducted on a 600kN Avery Denison Universal Testing Machine. After each test, the assembly was cleaned removing thin layers of metal left. The die was carefully placed in the extrusion rig.

4Results and discussions

Backward extrusion of AA6063 was conducted using Universal Hydraulic Pressing Machine at different die velocities and using variously selected lubricants. The experiments were performed at room temperature by inserting a thermocouple in the holes drilled on both dies. Table 4 shows the parameter of the experiment carried out.

Table 4.

Lubricants with varying strain rates.

S/N  Stain rate (10−3) (s−1Lubricant 
1.5  Nil (dry)
2.0 
2.5 
3.0 
1.5  Tropical coconut (TC) oil
2.0 
2.5 
3.0 
1.5  Castor oil
10  2.0 
11  2.5 
12  3.0 

The extruded specimen has minimum surface cracking. Fig. 9(a–c) shows the specimens and extruded specimen for both cases of lubrication and without lubrication. The extruded product with lubrication has a dark colouration on the body due to the lubricants has a finer surface finish compared to the extruded products done without lubrication. The strain rates varying from 1.5s−1 through 3.0s−1 are shown in Table 4.

  • A.

    Specimen (billet)

  • B.

    Extruded product with lubricant

  • C.

    Extruded product without lubricant

Fig. 9.

Specimen (billet) and extruded product.

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4.1Temperature–stroke curve

Fig. 10(a–d) shows the temperature of the punch and lower die during the experiment with lubrication (tropical coconut oil) at different strain rates of 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1. The tropical coconut oil was chosen as the experimental lubricant for comparison because it has a lower density of about 924kg/m3 so that the temperature distribution will reasonably be unaltered during the experiment. Castor oil has a greater density.

Fig. 10.

Temperature vs stroke at various strain rates (tropical coconut oil).

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The curves indicate that the punch temperature is higher than the lower die temperature for all strain rate used in the experiment. The curves also show a rise in the temperature and a decrease as the stroke increases. The rise in temperature is as a result of punching action and friction as discussed by Yang and others [25]. The seeming drop in the temperature as the stroke length increases is as a result of the escape of the extrudate from the die opening, just because the stroke length is still increasing as the extrudate is tending to escape. This result buttresses the points raised by Yeom et al. [26], Li and Ghosh [27], Kloppenburg et al. [28] and Muller et al. [29]. This reason justifies why the temperature distribution behaviour of the extrusion processes with and without lubrication are similar to each other.

There exists a variation in the temperature distribution of the extrusion process using the two lubricants selected for the study. This is obviously attributed to different properties such as density and viscosity. The densities of castor oil and tropical coconut oil are about 956 and 924kg/m3 respectively.

Similarly Fig. 11(a–d) also shows the temperature of the punch and lower die during the experiment without lubrication at different strain rates of 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1. The curves indicate that the punch temperature is higher than the lower die temperature for all strain rate used in the experiment. The graphs show a rise in the temperature and a later decrease as the stroke increases.

Fig. 11.

Temperature vs stroke at various strain rates (without lubricant).

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The punch temperature is higher at high strain rate. As the rate of deformation of the material increases the maximum temperatures attained by the punch and lower die increases. The strain rate has an effect on the temperature of the dies, at low strain rate the temperature of the punch and lower die is significantly lower compared with higher strain rate. Figs. 12 and 13 show the die temperature–stroke curves as the punch moves down into the billet at a strain rate of 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1 using castor oil as the lubricant. The maximum temperature is attained at strain rates of 2.5×10−3s−1 and 3.0×10−3s−1. A similar result is observed using tropical coconut oil as the lubricant, Figs. 14 and 15 show the die temperature–stroke curves as the punch moves down into the billet at a strain rate of 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1. The maximum temperature is attained at strain rates of 2.5×10−3s−1 and 3.0×10−3s−1. Without lubrication, the punch temperature is also higher at high strain rate. The rise in temperature affects the lubricating properties of the lubricants used in the experiment and also generated friction which deposited impurities on the surface of the final extrudate as seen in Fig. 9. Figs. 16 and 17 show the die temperature–stroke curves as the punch moves down into the billet at a strain rate of 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1.

Fig. 12.

Punch temperature vs stroke with castor oil at different strain rate.

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Fig. 13.

Lower die temperature vs stroke with castor oil at different strain rate.

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Fig. 14.

Punch temperature vs stroke with tropical coconut oil at different strain rate.

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Fig. 15.

Lower die temperature vs stroke with tropical coconut oil at different strain rate.

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Fig. 16.

Punch temperature vs stroke without lubricant at different strain rate.

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Fig. 17.

Lower die temperature vs stroke without lubricant at different strain rate.

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4.2Comparison of experimental result with FEM analysis simulation result

The experimental results without lubrication at a strain rate of 2.0×10−3s−1 and 2.5×10−3s−1 shown above was compared with FEM simulation result from DEFORM 3D. The experimental result and simulation result shown close relationship for both strain rate. Fig. 18(a and b) shows the temperature of the punch and lower die at a strain rate of 2.0×10−3s−1 while Fig. 19(a and b) shows for strain rate 2.5×10−3s−1 for both experimental and simulation result for backward cup extrusion of AA6063. The drop in temperature from the experimental result was due to the heat lost to the surrounding after it has gotten to the maximum temperature. The simulation results show an increasing temperature as the punch displacement increase due to a minimum or no heat loss during the deformation process.

Fig. 18.

Temperature vs stroke at strain rate of 2.0×10−3s−1 (without lubricant).

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Fig. 19.

Temperature vs stroke at strain rate of 2.5×10−3s−1 (without lubricant).

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Comparison of the temperature distribution via experiment and simulation vary as a result of real-life ejection of the extrudate in which the temperature decreases with stroke length after the extrudate has been ejected. However, there were no temperature drops from the simulated temperature-stroke relationship as shown in Figs. 18 and 19 (Table 5).

Table 5.

Simulation parameter.

Parameters  Temperature  Strain rate  Ram speed  Max. displacement  Friction 
Inputs 1  30°  0.0020s−1  0.0625mm/s  10mm  0.47 
Inputs 2  30°  0.0025s−1  0.0500mm/s  10mm  0.47 

DEFORM 3D software was used to simulate for FEA in order to obtain die geometry and actual extrusion parameters. The extrudate profile obtained with the simulation was similar to the shape obtained during actual extrusion (experiment) as predicted by Li et al. [8]. Using point tracking the punch (2) temperature and lower die (1) temperature was extracted and compared with the actual extrusion or experimental result at strain rates of 2.0×10−3s−1 and 2.5×10−3s−1.

4.3Modelling the stress–strain behaviour during deformation

The stress–strain relationship of the extrudate gotten through the backward cup extrusion of AA6063 aluminium alloy was a nonlinear type. The behaviour of which appeared to be that of a hyperelastic material. The stress–strain relationship depends solely on the state of the strain rate (point strain) at a particular point during deformation.

A linear model of stress–strain behaviour will normally follow from Hooke's law of elasticity as illustrated in Eq. (5) while a nonlinear model takes the form of Eqs. (6) and (7) in terms of strain energy density.

The quantity in the square bracket represents the strain energy density, ψ(∈)

where l is the differential of strain, with respect time, t.

Using the power–work relationship, the strain power is the differential of strain energy (rate of internal workdone) as illustrated in Eq. (8).

Stress, σ can then be re-written as Eq. (9).

If the stress–strain relationship is nonlinear and can be illustrated in a fourth order tensor equation as seen in Eq. (10) and which can be represented in matrix form as illustrated in Eq. (11). Eqs. (10) and (11) depict the stress–strain behaviour of aluminium extrudate during backward cup extrusion process.

where σ and F is the applied stress and force over a cross-sectional area, A respectively; E is the young's modulus; is the strain experienced by the AA6063 aluminium alloy; Wtotal is the total energy absorbed during extrusion; and l0 and dl are cross-sectional length and extension respectively.

The numerical analysis carried out in this study using DEFORM 3D FEA revealed that the plastic strains do not contribute to the volumetric change in the AA6063 aluminium alloy during backward cup extrusion. This finding is consistent with the inferences from the review made by Srinivasa and Raja [30] and this is also in agreement with the report of Ikumapayi et al. [21].

5Conclusions

Backward cup extrusion of AA6063 was successfully carried out using tropical coconut oil and castor oil as the lubricants. The experiment was also carried out without lubrication. With the different lubricating conditions the strain rate was varied at 1.5×10−3s−1, 2.0×10−3s−1, 2.5×10−3s−1 and 3.0×10−3s−1 respectively. All experiments were conducted at room temperature and the temperature was successfully measured at both the punch and lower die location.

The punch temperature during backward cup extrusion of aluminium Alloy AA6063 showed a higher temperature compared to the lower die temperature. The temperature distribution on the workpiece material was measured to be about 317°C. At higher strain rate the temperature of both punch and lower die also increases. It was established that the highest temperature was obtained using tropical coconut at a strain rate of 3.0×10−3s−1 which was observed to be above 33°C.

FEA using DEFORM 3D software to simulate the die geometry and actual extrusion parameters as shown in Fig. 20. The simulated extrudate is similar to the shape of the actual extrusion and was used successfully to predict the load and temperature distribution of the dies. The punch temperature was observed to be higher than the lower die temperature.

Fig. 20.

DEFORM 3D simulation.

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The extrusion load–stroke curve of the simulation result was consistent with the experimental results. However, there were discrepancies with the temperature–stroke curve between the simulation and the actual extrusion due to heat lost to the environment.

Conflict of interest

The authors declare that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work.

References
[1]
A. Al-Smadi, S. As’ad, S.W. Massarweh.
Identification and analysis of the power consumption for the aluminium extrusion process.
Proceeding of Mediterranean conference on control & automation,
[2]
S.T. Oyinbo, O.M. Ikumapayi, J.S. Ajiboye, S.A. Afolalu.
Numerical simulation of axisymmetric and asymmetric extrusion process using finite element method.
Int J Sci Eng Res, 6 (2015), pp. 1246-1259
[3]
C. Karadogan.
Advanced methods in numerical modeling of extrusion processes. Unpublished thesis.
Swiss Federal Institute of Technology Zurich, (2005), pp. 45-67
[4]
K. Abrinia, S. Orangi.
Numerical study of backward extrusion process using finite element method.
Finite element analysis, (2010), pp. 381-406
[Chapter 17]
[5]
K. Abrinia, K. Gharibi.
An investigation into the backward extrusion of thin-walled cans.
Int J Mater Form, 1 (2008), pp. 411-414
[6]
J. van deLangkruis, J. Lof, W.H. Kool, S.V. van der Zwaag, J. Huetink.
Comparison of experimental AA6063 extrusion trials to 3D numerical simulations, using a general solute-dependent constitutive model.
Comput Mater Sci, 18 (2000), pp. 381-392
[7]
J.S. Ajiboye, M.B. Adeyemi.
The effect of selected parameters on temperature distribution in the axisymmetric extrusion process.
J Mech Sci Technol, 21 (2007), pp. 1553-1559
[8]
L. Li, J. Zhou, J. Duszczyk.
Prediction of temperature evolution during the extrusion of 7075 aluminium alloy at various ram speeds by means of 3D FEM simulation.
J Mater Process Technol, 145 (2004), pp. 360-370
[9]
R. Uyyuru, H. Valberg.
Physical and numerical analysis of the metal flow over the punch head in backward cup extrusion of aluminium.
J Mater Process Technol, 172 (2006), pp. 312-318
[10]
S. Hsiang, Y. Lin, W. Chien.
Investigation of experimental and numerical analysis on extrusion process of magnesium alloy fin structural parts.
Recent researches in geography, geology, energy, environment and biomedicine, (2004), pp. 300-305
[11]
H. Long.
Quantitative evaluation of dimensional errors of formed components in cold backward cup extrusion.
J Mater Process Technol, 177 (2006), pp. 591-595
[12]
B. Altan, M. Gevrek, S.A. Onurlu.
Numerical method for predicting the temperature distribution in axisymmetric extrusion through flat dies.
J Mech Work Technol, 13 (1986), pp. 151-162
[13]
K. Kimura, M. Ishii, H. Yoshimura.
Analysis of deformation, temperature, and microstructure of titanium alloys during hot extrusion.
Nippon steel technical report, No. 62, pp. 69-73
[14]
Y. Qin, R. Balendra, K. Chodnikiewicz.
Analysis of temperature and component form-error variation with the manufacturing cycle during the forward extrusion of components.
J Mater Process Technol, 145 (2004), pp. 171-179
[15]
V.I. Johannes.
Temperature distribution in aluminum extrusion billets. Unpublished thesis.
(2006), pp. 1-12
[16]
P.K. Saha.
Thermodynamics and tribology in aluminium extrusion.
Wear, 218 (1998), pp. 179-190
[17]
M.M. Moshksar, R. Ebrahimi.
An analytical approach for backward-extrusion forging for regular polygonal hollow components.
Int J Mech Sci, 40 (1997), pp. 1247-1263
[18]
B.A. Bonab, M. Aghabalazadeh, A. Ebrahimiaraghizad, H. Arabi-blaghi.
Analysis of the forward–backward radial extrusion process.
MAGNT research report, 2, pp. 712-721
[19]
V. Shatermashhadi, B. Manafi, K. Abrinia, G. Faraji, M. Sanei.
Development of a novel method for the backward extrusion.
Mater Des, 62 (2014), pp. 361-366
[20]
C. Fernando.
Modeling and control for the isothermal extrusion of aluminium.
Swiss Federal Institute of Technology Zurich, (1999),
[21]
O.M. Ikumapayi, P.B. Mogaji, T.I. Mohammed, S.A. Afolalu, O.L. Rominiyi, B.A. Adaramola.
Effects of lubricants on extrusion load of 6063 aluminium alloy during backward cup extrusion process.
Proceedings of the 2017 annual conference of the School of Engineering & Engineering Technology (SEET), pp. 11-13
[22]
H.L. Cox.
Design of built-up cylinders.
Engineer, 162 (1936),
[23]
S.O. Onuh, M. Ekoja, M.B. Adeyemi.
Effects of die geometry and extrusion speed on the cold extrusion of aluminium and lead alloys.
J Mater Process Technol, 132 (2003), pp. 274-285
[24]
M.P. Groover.
Fundamentals of modern manufacturing: materials, processes, and systems.
4th ed., John Wiley & Sons, Inc., (2010), pp. 120-125
[25]
H. Yang, J. Zhang, Y. He, B. Han.
Effect of temperature and ram speed on isothermal extrusion for a large-size tube with piece-wing.
J Mater Sci Technol, 21 (2005), pp. 499-507
[26]
J.T. Yeom, N.K. Park, Y.H. Lee, T.J. Shin, S. Hwang, S.S. Hong, et al.
An improved process design for the hot backward extrusion of Ti–6Al–4V tubes using a finite element method and continuum instability criterion.
J Eng Manuf, 221 (2006), pp. 255-265
[27]
D. Li, Ghosh A.K..
Effects of temperature and blank-holding force on the biaxial forming behavior of aluminum sheet alloys.
J Mater Eng Perform, 13 (2004), pp. 348-360
[28]
T. Kloppenborg, M. Schwane, N. Ben Khalifa, A.E. Tekkaya, A. Brosius.
Experimental and numerical analysis of material flow in porthole die extrusion.
Key Eng Mater, 491 (2012), pp. 97-104
[29]
S. Müller, J. Mühlhause, J. Maier, P. Hora.
Experimental and numerical analysis of the friction condition in the die bearing during aluminum extrusion.
Key Eng Mater, 491 (2012), pp. 113-119
[30]
G.S. Srinivasa, N.R. Raja.
Finite element modeling of stress–strain curve and micro stress and micro strain distributions of titanium alloys – a review.
J Miner Mater Charact Eng, 11 (2012), pp. 953-960
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Journal of Materials Research and Technology

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