International Journal of Engineering Advanced Research (IJEAR) eISSN: 2710-7167 [Vol. 1 No. 1 March 2020]
Journal website: http://myjms.mohe.gov.my/index.php/ijear
FRACTURE MODE EFFECT USING FINITE ELEMENT ANALYSIS ON RECYCLING ALUMINIUM CHIPS
Syaiful Nizam Ab Rahim1*, Mohd Zaniel Mahadzir2 and Mohd Amri Lajis3
1 2 Department of Mechanical Engineering, Politeknik Sultan Abdul Halim Mu’adzam Shah (POLIMAS), Jitra, Kedah, MALAYSIA
3 Sustainable Manufacturing and Recycling Technology, Advanced Manufacturing and Materials Center (SMART-AMMC), Universiti Tun Hussein Onn Malaysia, Batu Pahat, Johor, MALAYSIA
*Corresponding author: [email protected]
Article Information:
Article history:
Received date : 23 November 2019 Revised date : 28 November 2019 Accepted date : 8 December 2019 Published date : 19 January 2020
To cite this document:
Ab Rahim, S., Mahadzir, M., & Lajis, M. (2020). FRACTURE MODE EFFECT USING FINITE ELEMENT ANALYSIS ON RECYCLING ALUMINIUM CHIPS. International Journal Of Engineering Advanced Research, 1(1), 14-21.
Abstract: In order to develop an energy-efficient process chain for aluminum recycling, the purpose research enhances a method to recycle aluminum scrap of AA6061 alloys directly by a hot extrusion process without an energy intensive re-melting process. The importance of this study is to evaluate the hot extrusion parameters in the solid state and simulate in the DEFORM 3D simulation software. The final quality of the extruded product is influenced by the extrusion temperature, ram pressure and extrusion speed. 3D Deform simulation extrusion process on AA6061 alloy chips has been performed in order to study how process parameters influence the responses. The main focus of this study is to compare the results between simulation and experiment extrusion predict the best process parameters of hot extrusion of aluminum alloy 6061 chips using 3D simulation deform without lubricant. The amount of heat loss to the extrusion tooling and occurred a sufficient on quality bonding cause by affecting combination of parameter ram speed 1 mm/s at 500°C.
The surface integrity at 500°C reveals better sufficient fine grain at 400°C. A Normal Cockcroft and Latham (C
& L) ductile fracture criteria used in analysis simulation has resulted a higher accuracy rather than another model fracture criteria. Based on the numerical modeling prediction by variable conditions of temperature, strain rate, and pressure has been
1. Introduction
At present of the manufacturing sector, which is at the economic level, must be made to sustain societies in the high living by industrial societies and able to increase productivities so that they able to achieve the same standard of living equally. It will be a big issue because recycled materials have become very important to environmental (Marcel, W. et.al., 2015). This paper presents an overview of the trends and the concept of emerging to identify the recyclability contents of the product for recycling aluminum chips by the hot extrusion process. It shows that even though to achieve the sustainability, it needs the holistic optimization of the entire operations. Some of the trends in developing method determined by the research contributions reported in literature which is to improve the scoring methods for product and process design, it’s determined the optimum of the process by focusing hot extrusion parameter.
2. Literature Review
Metals have always been the most recycled material in the world. The recycling of waste metallic material and use of scrap is important for economic production of steelworks (Gattmah, J. et. al., 2017). In fact, the making of steel requires recycled steel in the production of the raw material. Recycling metals saves energy and helps prevent the depletion of natural resources (Yusuf N.K. et.al., 2017). An entire industry has grown up around recycling metal.
This is because everything that contains metal is intrinsically valuable. In subsequent decades, the transportation and construction sectors have always been the principal benefactors of aluminum extrusion products. Even in present times, the bulk of extrusion usage is in manufacturing doors and windows, followed by passenger vehicles.
Extrusion is defined as the process of shaping material, such as aluminum, by forcing it to flow through a shaped opening in a die. Aluminum extrusion is a technique used to transform aluminum alloy into objects with a definitive cross-sectional profile for a wide range of uses.
The extrusion process makes the most of aluminum’s unique combination of physical characteristics. Its malleability allows it to be easily machined and cast, and yet aluminum is one third the density and stiffness of steel so the resulting products offer strength and stability, particularly when alloyed with other metals. Extrusion is done by squeezing the metal in a closed cavity through a tool, known as an die using either a mechanical or hydraulic press.
Extrusion performance can be affected by three major factors, mainly, the number of billets used scrap, the die life and the extrusion speed (Rahim S.N. et. al., 2016). Extrusion produces compressive and shear forces in the stock. No tensile is produced, which makes high deformation possible without tearing the metal. The cavity in which the raw material is contained is lined with a wear resistant material. This can withstand the high radial loads that are created when the material is pushed into the die. According to Chiba R. et.al. (2015), that due to the occurring strains, pressure and temperature at high quality longitudinal seam weld within the profile was assumed during conventional extrusion.
Keywords: sustainable direct recycling, metal recycling, hot extrusion, aluminium recycling.
3. Problem Statement
Modelling and simulation are useful tools to deformation processes as they allow influential state variables effecting the extruded profiles to be investigated. DEFORM 3D Finite Element Analysis (FEA) was a most powerful on metal forming simulation. The advancement in the numerical simulation has eased the understanding of physical phenomena of bulk deformation and the metal behaviour during the process can be predicted accurately. Knowing these advantages, it is expected to be utilized to reduce the cost of experimental trials and die development during the solid-state recycling. Metal forming, numerical analyses mainly based on finite element method represent a beneficial way for die and process optimization.
4. Method
Finite-element (FE) simulations have been extensively used in scientific research and industrial practice to analyze the process and to aid in optimization. DEFORM is an engineering software that enables designers to analyze metal forming, heat treatment, machining and mechanical joining processes on the computer rather than the shop floor using trial and error. Process simulation using DEFORM has been instrumental in cost, quality and delivery improvements at leading performance and efficiency. DEFORM 3D is a powerful process simulation system designed to analyze the three-dimensional (3D) flow of complex metal forming processes (Kočiško et al., 2014). DEFORM 3D is a practical and efficient tool to predict the material flow in industrial forming operations without the cost and delay of shop trials. Typical applications include forging and extrusion. The efforts were made to demonstrate how the extrusion ratio and ram speed affect the temperature evolution aluminium bar during the extrusion process by using the DEFORM 3D programme, including the effect of plastic deformation of the workpiece, strain, and temperature distribution, and heat transfer characteristics. DEFORM is an FEM based process simulation system designed to analyze various forming and heat treatment processes used by metal forming and related industries. By simulating manufacturing processes on a computer, this advanced tool allows designers and engineers to reduce the need for costly shop floor trials and redesign of tooling and processes as well as; improving the tool and die design to reduce production and material costs and shortening the lead time in bringing a new product to market. Unlike general purpose FEM codes, DEFORM is tailored for deformation modelling. DEFORM 3D adds the capability of modelling heat treatment processes, including normalizing, annealing, quenching, tempering, aging, and carburizing. DEFORM 3D can predict hardness, residual stresses, quench deformation, and other mechanical and material characteristics important to those that heat treat. Simulation can be effectively performed at various stages of design to support decision making, as referred at Figure 1.
Figure 1: Tensile test for simulation of (a) strain, (b) stress
4.1 Data Collection
Numerical analyses by means of finite element method represent a beneficial way for process optimization. Numerical simulations allow local state variables concerning material temperature, strain, strain rate, pressure, and stress to be manipulated in several damage models for optimizing the extrudate quality in metal forming. As regards this, the effect of temperature in hot extrusion can be studied from a numerical point of view, through the damage prediction.
This study was deployed using DEFORM™ 3D, one of the most utilized commercial finite element method (FEM) codes for bulk metal-forming analysis. Several parameters such as the amount of pressure, strain, strain rate, normal contact stress, and shear stress are the critical factors for bonding quality among the chips. These parameters are also responsible for breaking the oxides enveloping the individual chips to enable bonding of the pure metal (Den Bakker A.J. et. al. 2014; Rahim S.N. et. al., 2017).
4.1.1 Validity and Reliability
One of the dies was a flat-face die conventionally used in the industry to produce aluminium solids section. The geometry of the machining chips is an important factor in the chip compaction strategy (Haase, M. et al., 2015). The process parameters and frictional conditions presented by billet temperature is 500°C, Extrusion ratio is 12, fraction factor at die-billet interface is 0.3 and friction factor at the billet container interface is 0.9. The chips were compacted into a thick-walled steel tube forming billets of 30 mm in diameter and 80 mm in length. With a compaction force of 50KN, a green density of approximately 2.24g/cm3 was achieved, which corresponds to 82% of the theoretical density of aluminium. The billets were heated in a furnace to the extrusion temperature of 500°C which was held at this temperature for 1 hour and then extruded into solid profiles with a cross-section of 10 x 6 mm and a ram speed of 1 mm/s using 250T direct extrusion press. The die and container temperatures were both set at 400°C. The geometries of the die, container, stem and billet were generated in AutoCAD and the meshes within their space domains in DEFORM 3D version 11.0 which is an FEM based process simulation system designed to analyze various forming and heat treatment processes.
5. Results and Discussion
Temperature contour profiles of billet went through the rectangular shape die at an extrusion ratio of 12:1, respectively (Rahim et al., 2016). The developments of the maximum temperatures of the container die and workpiece are given in Figure 2(a).
It also shows the temperature distribution along the extrusion process at a ram speed of 1 mm/s.
For that step the temperature achieved was 412°C. The results are revealed on Figure 2(b), which also shows the temperature distribution along the extrusion process at a ram speed of 1 mm/s which achieved 490°C. These figures show that the velocity distribution at the die exit is constant and the temperature variation along the die length is very small. Deformed grains in the peripheral zone and coarse grains on the edges of the bar can also be observed. Figure 3(a) shows the surface cracks and peel-off appear after extruded at 400°C. Results also showed warping occurred to extruded cause of poor bonding at low temperature.
Conversely, Figure 3(b) shows the smooth surface appeared after extrusion at 450°C ER12 when good consolidation occurred, which prolonged the conditions. At high extrusion temperature, good diffusion bonds and very low porosity of extruded composites could be obtained. These results show that the extrudate quality is superior to the billet extruded at a lower temperature. Hence, Figure 3 shows that the moderate surface appeared after extruded at 450°C ER6. The homogeneous distribution of oxide particles facilitates metal-to-metal contact and it is a precondition for better welding and also for higher ductility (Shokuhfar A.
et al., 2014). Furthermore, by decreasing billet length it will lead to less frictional heat.
(Kamaruzaman, A. F. et al., 2016) found that after leaving the die bearing the extrudate carries away with part of the heat generated. The plunger and the other assembly features have been removed for better clarification. It is apparent that the maximum stress occurs in corners because these regions are in contact with the die interior surfaces. Since the heat transfer was
According to (Ahmad A. et al., 2018), when the heated billet is inserted into the die, the temperature of the billet will be transferred to the die interior surfaces. It is concluded from the simulation results that the mode of deformation is also an important factor in reducing the grain size. This way, better welding performance and reduced tooling stress can be reached, looking contemporary at the process performance and at the environmental impact. On the other hand, the results of the work can be used for optimizing the parameters of hot extrusion process of the AA6061 aluminium alloy. Summarizes made by Paraskevas, D. et al., (2014) showed that brittle fractures of metallic materials appeared in the grain boundary surface between split atoms that combined with each other. Fracture is a separation of a body into pieces due to stress, at temperatures below the melting point. It will occur by steps as crack formation and crack propagation. It depends on the ability of a material to undergo plastic deformation before the two fracture modes can be defined as ductile or brittle (Sanabria, V. et.al., 2014; Yu, J. Et.
al., 2016). Ductile materials are extensive plastic deformation and energy absorption (“toughness”) before fracture. With precipitates and fine particles as a starting point, they form
(a) (b)
Figure 2 : Temperature contour profile; (a) temperature of 450°C ER12 and (b) temperature of 450°C ER6 on a ram speed of 1 mm/s
(a) (b) (c)
Figure 3 : Extruded experiment profile; (a) temperature of 400°C; (b) temperature of 450°C ER12; (c) temperature of 450°C ER6 on a ram speed of 1 mm/s
6. Conclusion
The welding quality of extruded profiles was characterized by means of microstructure elementary observation, tensile test and fracture analysis by FEA DEFORM 3D simulation.
The true stress-strain curves of homogenized AA6061 aluminium alloy with various strain rates and deformation temperatures were obtained by means of isothermal hot extrusion simulation.
The external appearance of the extruded profiles can be used to attribute the bonding strength of the individual chips. Thus, for the low extrusion ratio of 12 through the flat-face die, the recommended temperature for hot extrusion in the direct recycling of AA6061 chips is above 450°C with a minimum of 3 hours preheating time to achieve minimum homogenization.
7. Acknowledgement
The authors would like to express the deepest appreciation to the Ministry of Education (MOE), Malaysia, and Politeknik Sultan Abdul Halim Mu’adzam Shah (POLIMAS) Jitra Kedah and also for funding this project through the Fundamental Research Grant Schemes (FRGS - vot numbers 1426, 1463, and 1496). Additional support in terms of facilities was also provided by Sustainable Manufacturing and Recycling Technology, Advanced Manufacturing and Materials Center (SMART-AMMC), Universiti Tun Hussein Onn Malaysia (UTHM).
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