PROTEC-12068;No.of Pages 12 ARTICLE IN PRESS JOURNAL OF MATERIALS PROCESSING TECHNOLOGY XXX (2008)XXX-XXX ity of aluminum alloys increases with increasing the forming enhanced using the appropriate temperature distribution for temperature.It is also determined that Al 5754 forming tem- the local heating and cooling technique and with variable perature sensitivity is greater than other type aluminums blank holder pressure control.Kim et al.(2006)investigated Takuda et al.(2002)studied the deformation behavior and thermomechanically coupled FEA which was performed for the temperature change in cylindrical deep drawing of an forming of aluminum rectangular cups at elevated tempera- aluminum alloy sheet at elevated temperatures by the com- tures.They examined applicability,accuracy and repeatability bination of the rigid-plastic and the heat conduction finite of three different failure criteria (maximum load,minimum element methods.It was clarified that the appropriate distri- load,and thickness ratio)to identify the onset of failure dur- bution of flow stress depending on temperature must exist ing FEA.They selected the thickness ratio criterion since it in the sheet for the higher LDR.In their study,the numeri- resulted in accurate prediction of necking-type failure when cal results as well as the experimental show that the LDR in compared with experimental measurements obtained under the warm deep drawing increases with the die profile radius. a variety of warm forming conditions.They also compared Jain et al.(1998)investigated experimentally and numerically predicted part depth values from FEA at various die-punch the limiting draw ratios (LDRs)and other axisymmetric deep temperature combinations and blank holder pressures con- drawing characteristics of AA5754-O and AA6111-T4 automo- ditions with experiments.Results indicate that they were in tive aluminum sheet materials as a function of die profile radii. good agreement.They established forming limit diagrams at Other deep drawing characteristics such as punch load versus three different warm forming temperature levels(250,300 displacement traces,flange draw-in,strain distribution along and 350C).It is concluded that limit strain increases with the cup profile,flange wrinkling,wall ironing and fracture increasing forming temperatures.In addition,strain distribu- characteristics are experimentally assessed for the two sheet tions on the formed part obtained under different die-punch materials as a function of the die profile radius.They observed temperature combinations were also compared to further that the deep drawability of AA5754-0 as measured by cup validate the accuracy of FEA.A high temperature gradient depth at fracture and LDR is superior to that of AA6111-T4. between die and punch (Tdie>Tpunch)was found critical to They explained the differences in the deep drawing behav- increase formability.Naka and Yoshida (1999)investigated ior of the two materials in terms of the competition in work the effects of forming speed and temperature on the deep hardening between the material in the flange at the die profile drawability for a fine grain Al-Mg alloy(5083-O)sheet by per- region versus the material at the punch profile region,bend- forming cylindrical deep drawing tests at various forming ability of the two materials,and fracture characteristics.They speeds(0.2-500 mm/min)at die temperatures of 20-180C(the also observed that a decrease in LDR and flange draw-in as a die was heated,while the punch was water cooled during function of the die profile radius.Namoco et al.(2007)stud- the tests).They observed that the LDR mostly increases with ied embossing and restoration process of A5052 and A6061 to increasing die temperature,because the deformation resis- reduce the deformation force,the drawing resistance and to tance in flange shrinkage decreases with temperature rise and increase the drawability of the sheet and LDR.Palumbo and the LDR also becomes lower with increasing forming speed at Tricarico(2007)investigated warm deep drawing process of all temperatures because of the flow stress of the heated blank AA5754-0 aluminum alloy.In this experimental work,they at the flange increases with increasing strain rate.Moreover, took into account the parameters which were temperature the cooled blank at the punch comner becomes less ductile. level of the blank in the centre of the specimen and the Naka et al.(2001)investigated the effects of forming speed forming speed;in addition they used grease lubricant.They and temperature on the FLD experimentally for a fine grain observed that the temperature in the blank centre had a strong Al-Mg alloy(5083-O)sheet by performing stretch-forming test influence on the process feasibility and thus on the material at various forming speeds(0.2-200mm/min)at several tem- formability.Spigarelli et al.(2004)investigated the deforma- peratures from 20 to 300C.It is found that the forming tion behavior of an Al alloy between 120 and 180C by means limit strain increased drastically with decreasing speed for of uniaxial compression tests to identify possible differences any strain paths at a high temperature ranging from 150 to in the deformation response compared with uniaxial tensile 300C.It is known that the FLD was not sensitive to speed at data.They found that the strength of the alloy was slightly room temperature.The improvement in formability at 300C greater in compression than in tension and this difference at low forming speed is specifically due to the high strain gradually disappearing as strain rate decreased.Yoshihara et rate hardening characteristic of the material,but below 200C al.(2004)demonstrated spin formability of Al-Mg alloy using the formability is also affected strongly by strain harden- an NC control machine at 300C with a main shaft rotational ing.The number of available 5XXX series Al-based alloys for frequency of 300rpm and feed per revolution of 180 mm/min. passenger vehicles is very limited.At the present time,5052 By spin forming,it is possible to form a domed shape similar and 5456 are the most commonly used alloys.Although 5052 to a pressure vessel at the end of a pressurized gas cylinder offers a good combination of mechanical properties,corro- for passenger and aeronautical vehicles.Their study presents sion resistance,and formability,it is unsuitable for use at the finite element simulation of the spin forming of Al-Mg temperatures above 120C due to its poor creep resistance alloys.This model was constructed based on the material and its low strength at elevated temperatures.In order to properties at 300C as recorded in the real forming process. get a better overall understanding of alloys and to identify They also developed a new deep drawing process (Yoshihara the most promising compositions,most researchers examine et al.,2003a,b)and localized heating and cooling technique and evaluate the micro structural features,tensile properties (Yoshihara et al.,2003a,b)to improve formability.The con- and creep resistance.Zhang et al.(1998)presented some new clusion is deep drawing performance of the alloy would be Al-Mg alloys with good creep resistance,acceptable formabil- Please cite this article in press as:Toros,S.,et al.,Review of warm forming of aluminum-magnesium alloys,J.Mater.Process.Tech.(2008) doi:10.1016/j.jmatprotec.2008.03.057Please cite this article in press as: Toros, S., et al., Review of warm forming of aluminum–magnesium alloys, J. Mater. Process. Tech. (2008), doi:10.1016/j.jmatprotec.2008.03.057 PROTEC-12068; No. of Pages 12 ARTICLE IN PRESS journal of materials processing technology xxx (2008) xxx–xxx 9 ity of aluminum alloys increases with increasing the forming temperature. It is also determined that Al 5754 forming tem￾perature sensitivity is greater than other type aluminums. Takuda et al. (2002) studied the deformation behavior and the temperature change in cylindrical deep drawing of an aluminum alloy sheet at elevated temperatures by the com￾bination of the rigid-plastic and the heat conduction finite element methods. It was clarified that the appropriate distri￾bution of flow stress depending on temperature must exist in the sheet for the higher LDR. In their study, the numeri￾cal results as well as the experimental show that the LDR in the warm deep drawing increases with the die profile radius. Jain et al. (1998) investigated experimentally and numerically the limiting draw ratios (LDRs) and other axisymmetric deep drawing characteristics of AA5754-O and AA6111-T4 automo￾tive aluminum sheet materials as a function of die profile radii. Other deep drawing characteristics such as punch load versus displacement traces, flange draw-in, strain distribution along the cup profile, flange wrinkling, wall ironing and fracture characteristics are experimentally assessed for the two sheet materials as a function of the die profile radius. They observed that the deep drawability of AA5754-O as measured by cup depth at fracture and LDR is superior to that of AA6111-T4. They explained the differences in the deep drawing behav￾ior of the two materials in terms of the competition in work hardening between the material in the flange at the die profile region versus the material at the punch profile region, bend￾ability of the two materials, and fracture characteristics. They also observed that a decrease in LDR and flange draw-in as a function of the die profile radius. Namoco et al. (2007) stud￾ied embossing and restoration process of A5052 and A6061 to reduce the deformation force, the drawing resistance and to increase the drawability of the sheet and LDR. Palumbo and Tricarico (2007) investigated warm deep drawing process of AA5754-O aluminum alloy. In this experimental work, they took into account the parameters which were temperature level of the blank in the centre of the specimen and the forming speed; in addition they used grease lubricant. They observed that the temperature in the blank centre had a strong influence on the process feasibility and thus on the material formability. Spigarelli et al. (2004) investigated the deforma￾tion behavior of an Al alloy between 120 and 180 ◦C by means of uniaxial compression tests to identify possible differences in the deformation response compared with uniaxial tensile data. They found that the strength of the alloy was slightly greater in compression than in tension and this difference gradually disappearing as strain rate decreased. Yoshihara et al. (2004) demonstrated spin formability of Al–Mg alloy using an NC control machine at 300 ◦C with a main shaft rotational frequency of 300 rpm and feed per revolution of 180mm/min. By spin forming, it is possible to form a domed shape similar to a pressure vessel at the end of a pressurized gas cylinder for passenger and aeronautical vehicles. Their study presents the finite element simulation of the spin forming of Al–Mg alloys. This model was constructed based on the material properties at 300 ◦C as recorded in the real forming process. They also developed a new deep drawing process (Yoshihara et al., 2003a,b) and localized heating and cooling technique (Yoshihara et al., 2003a,b) to improve formability. The con￾clusion is deep drawing performance of the alloy would be enhanced using the appropriate temperature distribution for the local heating and cooling technique and with variable blank holder pressure control. Kim et al. (2006) investigated thermomechanically coupled FEA which was performed for forming of aluminum rectangular cups at elevated tempera￾tures. They examined applicability, accuracy and repeatability of three different failure criteria (maximum load, minimum load, and thickness ratio) to identify the onset of failure dur￾ing FEA. They selected the thickness ratio criterion since it resulted in accurate prediction of necking-type failure when compared with experimental measurements obtained under a variety of warm forming conditions. They also compared predicted part depth values from FEA at various die-punch temperature combinations and blank holder pressures con￾ditions with experiments. Results indicate that they were in good agreement. They established forming limit diagrams at three different warm forming temperature levels (250, 300 and 350 ◦C). It is concluded that limit strain increases with increasing forming temperatures. In addition, strain distribu￾tions on the formed part obtained under different die-punch temperature combinations were also compared to further validate the accuracy of FEA. A high temperature gradient between die and punch (Tdie > Tpunch) was found critical to increase formability. Naka and Yoshida (1999) investigated the effects of forming speed and temperature on the deep drawability for a fine grain Al–Mg alloy (5083-O) sheet by per￾forming cylindrical deep drawing tests at various forming speeds (0.2–500mm/min) at die temperatures of 20–180 ◦C (the die was heated, while the punch was water cooled during the tests). They observed that the LDR mostly increases with increasing die temperature, because the deformation resis￾tance in flange shrinkage decreases with temperature rise and the LDR also becomes lower with increasing forming speed at all temperatures because of the flow stress of the heated blank at the flange increases with increasing strain rate. Moreover, the cooled blank at the punch corner becomes less ductile. Naka et al. (2001) investigated the effects of forming speed and temperature on the FLD experimentally for a fine grain Al–Mg alloy (5083-O) sheet by performing stretch-forming test at various forming speeds (0.2–200mm/min) at several tem￾peratures from 20 to 300 ◦C. It is found that the forming limit strain increased drastically with decreasing speed for any strain paths at a high temperature ranging from 150 to 300 ◦C. It is known that the FLD was not sensitive to speed at room temperature. The improvement in formability at 300 ◦C at low forming speed is specifically due to the high strain rate hardening characteristic of the material, but below 200 ◦C the formability is also affected strongly by strain harden￾ing. The number of available 5XXX series Al-based alloys for passenger vehicles is very limited. At the present time, 5052 and 5456 are the most commonly used alloys. Although 5052 offers a good combination of mechanical properties, corro￾sion resistance, and formability, it is unsuitable for use at temperatures above 120 ◦C due to its poor creep resistance and its low strength at elevated temperatures. In order to get a better overall understanding of alloys and to identify the most promising compositions, most researchers examine and evaluate the micro structural features, tensile properties and creep resistance. Zhang et al. (1998) presented some new Al–Mg alloys with good creep resistance, acceptable formabil-