Papers by Keyword: Aluminum Sheet

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Authors: Geoff M. Scamans, Andreas Afseth, George E. Thompson, Y. Liu, Xiao Rong Zhou
Abstract: Over the past ten years a detailed understanding of the dominant factors controlling the corrosion susceptibility of painted aluminium alloy sheet used for architectural and automotive applications has been developed. Work carried out in this field will be reviewed and the different modes of cosmetic corrosion that can occur-, the mechanisms of surface activation, and the role of different thermo-mechanical processing steps on controlling corrosion susceptibility for different alloy systems, including Al-Mn, Al-Mg and Al-Mg- Si-(Cu) will be discussed. The critical role of chemical or electro-chemical cleaning prior to pre-treatment and coating will be highlighted and prospects for meaningful accelerated testing will be discussed.
Authors: Takumi Kobayashi, Kohshiroh Kitayama, Takeshi Uemori, Fusahito Yoshida
Abstract: In sheet metal forming, the anisotropy and the Bauschinger effect of sheets affect greatly their formability. This paper discusses how the planar anisotropy and cyclic plastic behavior (the Bauschnger effect and cyclic workhardening characteristics) correlate with the crystallographic texture based on the crystal plasticity analysis on A5052-O sheet. The analytical predictions of r-values and the cyclic stress-strain responses are compared with the experimental observations (S. Tamura et al., Materials Trans, 52-5 (2011), pp.868-875).
Authors: Khaled Habib, K. Al-Muhanna, F. Al-Sabti, A. Al-Arbeed
Abstract: The technique of electrochemical impedance spectroscopy (EIS) is widely used in laboratories and industries for materials evaluation. The aim of this investigation is to monitor the thickness of the anodized (oxide) aluminium sheets (samples) by using the EIS in a laboratory and a field study at a predetermined exposure duration in the field, i.e., 0, 1, 3, 6, 9, 12 months, in 0-10 % sulphuric acid. Four experimental stations were built out of KISR in order to monitor the thickness of the anodized (oxide) layer and the electrochemical parameters of anodized aluminium sheets by using the EIS. The zero state results at 0 exposure duration, indicating that as the concentration of the sulphuric acid increased from 0-10% H2SO4, the polarization resistance was observed to decrease from 3.15E+05 to 9.80E+03 Ohms, except at a concentration of 4% H2SO4, where the polarization resistance was observed to increase from 5.20E+03 to 2.90E+04 Ohms. On the contrary, the value of the solution resistance was observed to vary several times between 1.33E+04 to 1.53E+00 Ohms as a function of the increase of the sulphuric acid concentration from 0-10% H2SO4. In similar fashion to the polarization resistance, as the concentration of the sulphuric acid increased from 0-10% H2SO4, values of the alternating current impedance were found to vary several times between 1.94E+09 to 3.95E+05 Ohms, in a non-linear fashion. A similar behavior was observed on the values of the double layer capacitance as a function of the sulphuric acid increased, from 0-10% H2SO4, in which the values of the double layer capacitance was observed to change several times from 2.24E-09 to 2.53E-06 μF. The optimum thickness of the oxide film was detected (26.5 nm) at 8% H2SO4 of the sulphuric acid concentration. In order to determine the performance of the anodized aluminium-sheet in surrounding areas of Kuwait, a plan was arranged for such a field study. The field study consists of setting up four racks of sample panels in different locations in Kuwait. The racks were installed in the main field of Kuwait Institute for Scientific Research (KISR) in Shuwaikh area, in a residential area of South Sura area, in the main field of the Petroleum Research Department and Studies Center (PRSC) of Kuwait Institute for Scientific Research (KISR), in an industrial area of Ahmadi city, and in the main field of the fishery department of Kuwait Institute for Scientific Research (KISR) in a marine area of Salmia. The investigation planned to take a sheet each three months, for a 12 months duration, in order to determine the electrochemical parameters and the oxide film thickness of the sheets by the EIS technique in the field and to compare the data with those obtained in this report, at zero state.
Authors: Masaki Ishibashi, Keigo Okagawa, Tomokatsu Aizawa
Abstract: In this paper, we describe an electromagnetic bulging for a SUS304-O stainless steel sheet (0.15 mm thick) and its experimental results. In the die forming, the flat one-turn coil is adopted for the bulging of the SUS304-O sheet, when an aluminum sheet (0.3 mm thick) as a driving plate (driver) is used together. When an impulse current from an energy-storing capacitor bank passes through the flat one-turn coil, a high-density magnetic flux is suddenly generated around the coil. Eddy currents are induced in the driver placed on the coil. The SUS304-O sheet is pressed by an electromagnetic force generated in the driver, leading to bulge into a meandering groove with small concave shape. The bank energy required for the bulging of 12mm wide, 60mm long and 0.43mm high is about 4.5 kJ, and the obtained workpiece does not almost have wrinkles and curves.
Authors: Lăcrămioara Apetrei, Vasile Rață, Ruxandra Rață, Elena Raluca Bulai
Abstract: Research evolution timely tendencies, in the nonconventional technologies field, are: manufacture conditions optimization and complex equipments design. The increasing of ultrasonic machining use, in various technologies is due to the expanding need of a wide range materials and high quality manufacture standards in many activity fields. This paper present a experimental study made in order to analyze the welded zone material structure and welding quality. The effects of aluminium ultrasonic welding parameters such as relative energy, machining time, amplitude and working force were compared through traction tests values and microstructural analysis. Microhardness tests were, also, made in five different points, two in the base material and three in the welded zone, on each welded aluminium sample. The aluminum welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara. The ultrasonic welding temperature is lower than the aluminium melting temperature, that's so our experiments reveal that the aluminium ultrasonic welding process doesn't determine the appearance of moulding structure. In the joint we have only crystalline grains deformation, phase transformation and aluminium diffusion.
Authors: Shohei Kajikawa, Takashi Iizuka, Takashi Kuboki
Abstract: This paper presents a new stretch forming method that applies compressive force for forming a deep cup with a flange. In this method, a punch and a die having a hole are used, and the main parameters are the depth of the die hole, ddh, and the clearance between the punch and the die, c. The effect of ddh and c was investigated by using an aluminum blank of thickness 2 mm in an experiment and a finite element analysis (FEA). When ddh was too small, the material flow could not be controlled appropriately, and when ddh was too large, a local thinning occurred during initial stretching into the die hole. When c was set at large, the side wall thickness of the formed cup was uneven, but a deep cup could be obtained by setting c below a half of the blank thickness. As a result, a deep cup of height 8.3 mm and with a flange was formed successfully under the condition that ddh was 1.5 mm and c was 0.5 mm.
Authors: Irfan Manarvi, Amer Sattar, Jawad Ahmed Jadoon
Abstract: Aluminum is one of the most popular metal in a wide variety of applications in manufacturing of components for airplanes, automobiles, house hold etc. A wide variety of parts are manufactured using aluminum sheet of different alloy composition. Wrinkling of sheet metal is the most undesirable phenomenon in sheet metal forming, drawing, punching and other similar manufacturing processes. Current research is focused on Finite Element Analysis of Aluminum 6061-T6 sheet to simulate onset and growth of wrinkles of various thicknesses using ANSYS. Based on the results a comparison was drawn between the wrinkling behaviors at varying load values.
Authors: T. Kato, Y. Abe, Kenichiro Mori
Abstract: The joinability of three aluminium alloy sheets using a self-piercing rivet was evaluated from a finite element simulation and experiment. The self-piercing riveting is hopeful as replacement of spot resistance welding generally used for steel sheets, because it is not easy to apply the resistance welding to joining of three aluminium alloy sheets due to the high thermal conductivity. Defects in the riveting are categorized into the penetration through the lower sheet, the necking of the lower sheet and the short overlap of sheets to obtain optimum joining conditions. The penetration and the necking are caused by small total thickness. The short overlap tends to occur as the ratio of lower sheet and total thickness is small. In addition, the cross-tension test was simulated by the finite element method to evaluate the joint strength.
Authors: Chang Gil Lee, Sung Joon Kim, Heung Nam Han, Kwan Soo Chung
Abstract: Formability and mechanical property of Al sheets whose surface was locally modified by the concept of SFJ (Surface Friction Joining) were analyzed. It is noteworthy that the formability of the surface-modified sheets is greatly improved compared with as-received sheets. The formability is improved as the tool diameter is increased. It is found that more plastic deformation is accommodated at modified region during LDH test.
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