Radial hydro-forging bending: A novel method to reduce the springback of AHSS tubular component

Lin, Chuang; Chu, Guannan; Sun, Lei; Chen, Gang; Liu, Peixing; Sun, Wei

doi:10.1016/j.ijmachtools.2020.103650

Cited by 16 publications

(8 citation statements)

References 31 publications

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“…This is further validated based on the final model requiring lower pressure to form to the disk shape as the shaping step reaches the same location for each configuration. The results from reference 12 correlate with the strain hardening exponent results of Table 3. This is determined from the low strain hardening exponents for the material, low strain hardening exponent values (0.05-0.2) provide a greater stiffness, which is correlated to the springback effect.…”

Section: Discussionsupporting

confidence: 70%

“…10 Hydroforging is also used to deform the tube to non-circular shapes and how the axial displacement affects the shaping. 11 However, there are limited literature 12,13 showing the effect of the strain hardening exponent on the deformation behavior during hydroforging. Multiple configurations of setting the strain hardening exponent have shown that the critical compression displacement is dependent.…”

Section: Introductionmentioning

confidence: 99%

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Deformation behavior of advanced high strength steel with different strain hardening exponents during tube hydroforging

Fischer

Nikhare

2022

Proceedings of the Institution of Mechanical Engineers, Part E:

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Hydroforging is an innovative forming method used to form tubes with irregular cross-sections by using internal fluid pressure and axial force. Normally tube forming operations use solid mandrel to expand/bend the tube which does negative effect on tube or mandrel due to friction, buckling, and wrinkling. In this study, the tube material with various strain hardening exponents were hydroforged in a two-step numerical analysis with ramped fluid pressure and axial compression. The tube will be allowed to bulge with a ramped internal pressure and then shaped to a maximum expansion ratio by the axial compression in the shaping step. Some advanced materials exhibit the change in strain hardening exponent based on the plastic strain, the study focuses how the strain hardening exponent affects the deformation mechanics in tube hydroforging. It was found that the formability of tube during hydroforging is affected by the strain hardening exponent. The results show that tube can achieve a greater wall thickness reduction with increase in strain hardening exponent. Also, higher strain hardening exponent allowed tube to achieve a greater expansion ratio when axially compressed in the forging step. It was also observed that as the strain hardening exponent increases, the internal pressure requirements for the bulging and shaping steps decrease. The two model configurations of N01 and N02 failed from bursting and wrinkling, respectively, while every other model could form to the targeted disk-like shape. The forging step of the process showed that the die force for axial compression decreased as the strain hardening exponent increased for all successful models.

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Section: Discussionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Deformation behavior of advanced high strength steel with different strain hardening exponents during tube hydroforging

Fischer

Nikhare

2022

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…To deal with this problem two major research directions have emerged. One is based on refining the traditional bending process, including superposition of extra stresses [11] and torque [12], free bending with a spherical connection between the bending die and guider [13], flexible stretch bending having multiple rotational axes [14], radial hydro-forging bending where circumferential compression is applied during tube bending [15], and the recently developed differential heating-based rotary draw bending (DH-RDB) method which contributes to breaking the forming limit of difficult-to-form tubular materials utilising neutral layer shifting reconstruction (NLSR) [16]. Another is developing integrated extrusion-bending methods, in which the profiles are bent during forward extrusion using an external deflection device such as a guiding tool [17], or bending discs [18].…”

Section: Introductionmentioning

confidence: 99%

A comparative study on deformation mechanisms, microstructures and mechanical properties of wide thin-ribbed sections formed by sideways and forward extrusion

Zhou

et al. 2021

International Journal of Machine Tools and Manufacture

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“…According to the model of this paper, the critical internal pressure required for THFG when considering the pre-bending is 54MPa. Finally, not only the axis springback can be controlled (dropped almost to zero) [17], but also the variable cross-section along the axis can be obtained without wrinkling.…”

Section: Pre-bending Radiusmentioning

confidence: 99%

“…In other words, the internal pressure only plays the function of supporting, thereby diminishing the demand for high-pressure equipment [16]. Most importantly, when THFG combines with the pre-bending, Lin [17] relied on hoop compression to eliminate the springback and cross-sectional distortion caused by pre-bending, and this further broadens the practicability of THFG.…”

Section: Introductionmentioning

confidence: 99%

An Investigation Into the Effect of Pre-bending on the Tube Hydro-forging Technology

Lin

Chu

Sun

2021

Preprint

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Tube hydro-forging (THFG) combining with the pre-bending is an advanced method to manufacture the complex cross-sectional tubular component with curved axis. However, the effect of pre-bending on the subsequent THFG, especially on the critical internal pressure required to inhibit wrinkling, has not been clarified yet. Therefore, this paper makes a detailed study on it. At first, based on the energy method, the change rule between the critical internal pressure and the hoop strain was established when pre-bending was considered. Subsequently, the mechanics condition difference between single and double curvature differential segment during THFG was analyzed. Via the plastic theory, the distribution of hoop strain could be obtained. Mainly due to the uneven distribution of thickness and cold work-hardening caused by pre-bending, the maximum hoop strain at the outer straight-wall was greater than that at the inner straight-wall during THFG. Substituting the maximum hoop strain at the outer/inner straight-wall into the change rule, then their mathematical model of the critical internal pressure to restrain the wrinkling could be solved respectively. Finally, the critical internal pressure considering pre-bending was determined by that of outer straight-wall, and its value was always greater than the critical internal pressure without considering pre-bending under the same punch stroke. With the increase of bending radius, the critical internal pressure difference between considering and not considering pre-bending also increases. When the bending radius was 250 mm, the critical internal pressure difference was 33%, while it increased to 74% as the bending radius reduced to 100 mm, all of which were verified by experiment. The effect of friction coefficient on the critical internal pressure was also studied. In conclusion, this work provided a new and more accurate prediction model of critical internal pressure to guide practical production for when existing the pre-bending.

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Radial hydro-forging bending: A novel method to reduce the springback of AHSS tubular component

Cited by 16 publications

References 31 publications

Deformation behavior of advanced high strength steel with different strain hardening exponents during tube hydroforging

Deformation behavior of advanced high strength steel with different strain hardening exponents during tube hydroforging

A comparative study on deformation mechanisms, microstructures and mechanical properties of wide thin-ribbed sections formed by sideways and forward extrusion

An Investigation Into the Effect of Pre-bending on the Tube Hydro-forging Technology

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