Effects of tooling temperatures on formability of titanium TWBs at elevated temperatures

Lai, Chi Ping; Chan, Luen Chow; Chow, C. L.

doi:10.1016/j.jmatprotec.2007.03.094

Cited by 22 publications

(10 citation statements)

References 3 publications

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“…Numerous studies have been performed to get a better solution for formability and springback reduction of the sheet metals at elevated temperatures. Results reveal the temperature contributes to an improved formability and springback [7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Effect of Warm Temperature on Springback Compensation of Titanium Sheet

Öztürk

Ece

Polat

et al. 2010

Materials and Manufacturing Processes

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In the present study, the effect of warm temperature on springback compensation of commercially pure grade 2 (CP2) titanium sheet is investigated. The results reveal that the springback is substantially reduced with increasing temperature. The elastic energy and the ratio of tensile strength/yield strength (TS/YS) of the material are measured at various temperatures under tensile loading condition. A gradual decrease of elastic energy is observed with increasing temperature. The change in the ratio of TS/YS is left diminutive with increasing temperature. IntroductionTitanium (Ti) and its alloys are widely used in aerospace applications due to their high strength-to-weight ratio, excellent mechanical properties,corrosion, and thermal resistance. They are 45% lighter than steel and 60% heavier than aluminum. They have very attractive features such as higher melting points, and corrosion and thermal resistance, which are the best of all known metallic materials. That is why titanium and its alloys are widely used in various applications [1,2]. Titanium is known as a rare element in the earth's crust, despite the fact it is the ninth most abundant element and is the seventh metal used [3]. Titanium and its alloys have been widely used in various applications such as aircraft components, biomedical implant applications, hand tools, and sport equipments. Titanium can be found in various forms such as sheets, strips, plates, foil, rounds, tubes, pipes, and wire. Because of sheet and plate forms are strain hardened by cold forming of the material, the tensile strength (TS) and yield strength (YS) increase, while ductility decreases. Formability of titanium is very important in its various application areas. Although pure titanium has a good formability, its springback after the forming is severe due to its high yield strength and low modulus of elasticity. There is a serious problem with springback; therefore, the great majority of formed titanium components are made by hot forming or cold forming followed by hot sizing to overcome this problem. Springback is defined as an elastic behavior of material which tries to return its original shape after removing the forming forces on the formed parts. It creates serious problems during the assembling of the parts. The amount of the springback can be associated with material properties, forming conditions, and tool

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Section: Introductionmentioning

confidence: 99%

Effect of Warm Temperature on Springback Compensation of Titanium Sheet

Öztürk

Ece

Polat

et al. 2010

Materials and Manufacturing Processes

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“…In order to verify the accuracy of the simulation results, these results were compared with the experimental data in terms of LDH value and failure location. Similar to the previous section, the formability and failure behaviours of the Ti-at 550ºC were characterized by using a self-developed sheet metal forming machine with temperature control [14]. Ti-TWBs were prepared by Titanium alloy sheets (Ti-6Al-4V) in widths of 25mm, 90mm and 110mm and laser-welded by using a specific fixture [14] for experimental verification.…”

Section: Results Of Modeling With Experimental Verificationmentioning

confidence: 99%

Finite-Element Modeling of Thermal Forming of Ti-TWBs with Experimental Verification

Lai

Chan

2014

KEM

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The titanium tailor-welded blanks (Ti-TWBs) are being developed in different industries such as automobile and aerospace, combining the advantages of both tailor-welded blanks technology and titanium alloys. In recent decades, computer simulation of sheet metal forming processes has been employed increasingly over conventional production test and adjustment methodology to achieve the optimum and cost-effective operation procedures. Recently, certain amounts of theoretical analysis for the sheet metal forming process have been developed. However, these analyses could not be applied directly to the material under multi-stage forming process. Thus, some researchers have developed a damage-based model to predict the instability and failure of sheet metals, particularly for the above Ti-TWBs, with consideration of material damage under discontinuous or proportional loading strain paths. So far this model has been used and proved to be successful to predict formability of selected sheets of steel and aluminium alloy. However, the application of the damage-coupled model has yet to be extended to the Ti-TWBs under thermal multi-stage forming operation.The main objective of this paper is to investigate numerically the formability of Ti-TWBs under multi-stage forming process with experimental verification. Titanium alloy sheets (Ti-6Al-4V) in thickness of 0.7mm and 1.0mm were selected and laser-welded the specimen of Ti-TWBs. The model based on the damage mechanics is introduced to predict the thermal formability of Ti-TWBs with change of strain paths. In this study, the anisotropic damage model incorporate with the finite element codes and user-define material subroutine were developed to predict the formability of Ti-TWBs with change of strain paths. The mechanical properties and damage parameters of Ti-TWBs for the simulation were measured experimentally. The simulation of Ti-TWB under multi-stage forming process were then conducted and validated experimentally at similar forming conditions. The predicted results have been found to agree well with those obtained from the experiments. This analysis can be applied readily to design and manufacture TWB components or structures so as to satisfy the need of such market demands.

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“…Kotkunde et al [11] proposed a set of isothermal uniaxial tests of Ti-6Al-4V flat-sheet samples at temperature range from room temperature up to 650°C, and noticed the complicated interaction between strain hardening and thermal effects. Compared with room temperature condition, approximately half the ultimate tensile stress and twice the maximum strain of Ti-6Al-4V are achieved at 650°C, as proved by Lai et al [12]. Chen et al [13] studied the temperature dependent work hardening in Ti-6Al-4V alloy over large temperature range (20-900°C).…”

Section: Introductionmentioning

confidence: 95%

FE modeling of a complete warm-bending process for optimal design of heating stages for the forming of large-diameter thin-walled Ti–6Al–4V tubes

Tao

et al. 2017

Manufacturing Rev.

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Abstract. Warm rotary draw bending (WRDB) of large-diameter thin-walled (LDTW) Ti-6Al-4V tube is a multi-nonlinear thermo-mechanical coupled process. Due to the high-cost, energy-wasting and long-term, the traditional physical experiments based on "trial and error" are no longer suitable for the WRBD process. Considering the non-uniform local heating and multi-tool constraints, a thermal-mechanical coupled 3D FE model of complete WRDB process for LDTW Ti-6Al-4V tube is established on ABAQUS as heating-bendingunloading three-stage. The FE models could predict the overall temperature distribution, describe thermomechanical bending deformation considering a modified Johnson-Cook model, and simulate the heatingbending-springback-cooling process. On that basis, the temperature distributions on both tube and dies under various heating schemes are compared, and the optimal heating scheme is determined on the basis of forming quality and efficiency. Combined with the experiments of WRDB, the optimal heating scheme and the established FE models are verified. In conclusion, the FE simulation provides a replacement of physical experiment and a convenient method of deformation prediction for WRDB of LDTW Ti-6Al-4V tube.

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Effects of tooling temperatures on formability of titanium TWBs at elevated temperatures

Cited by 22 publications

References 3 publications

Effect of Warm Temperature on Springback Compensation of Titanium Sheet

Effect of Warm Temperature on Springback Compensation of Titanium Sheet

Finite-Element Modeling of Thermal Forming of Ti-TWBs with Experimental Verification

FE modeling of a complete warm-bending process for optimal design of heating stages for the forming of large-diameter thin-walled Ti–6Al–4V tubes

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