Springback-free Isothermal Forming of High-strength Steel Sheets and Aluminum Alloy Sheets under Warm and Hot Forming Conditions

Ye, Jun; Oyamada, K.

doi:10.2355/isijinternational.46.1324

Cited by 25 publications

(16 citation statements)

References 13 publications

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“…This is the main reason for the springback reduction at high temperature. The same results can be found in the literature (Keum and Han, 2002;Yanagimoto and Oyamada, 2006). r e f e r e n c e s…”

Section: Discussionsupporting

confidence: 85%

“…Keum and Han (2002) measured the springback in various forming temperatures by performing draw bending tests for Al 1050 and 5052 alloys. They showed that the springback reduces in warm forming, especially in the forming temperatures of above 150 • C. Yanagimoto and Oyamada (2006) conducted quasi-isothermal forming experiments for high-strength steel and aluminum alloy sheets. The characteristic of springback reduction due to the elevation in forming temperature was clarified and springback-free forming could be realized by controlling the forming temperature.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigations on springback characteristics of aluminum sheet metal alloys in warm forming conditions

Kim

Koç

2008

Journal of Materials Processing Technology

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Numerical investigations on springback characteristics of aluminum sheet metal alloys in warm forming conditions

Kim

Koç

2008

Journal of Materials Processing Technology

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“…Recrystallization was reported to affect shape fixability in the hot stamping process. 8) However, the study examined forming in the ferrite single phase region, which is not the target of our study. The current study focuses on the conventional hot stamping technique, which is accompanied by martensitic transformation from austenite.…”

Section: Introductionmentioning

confidence: 99%

Mechanism for Excellent Shape Fixability in Hot Stamping Process

2020

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Automobile body parts produced by the hot stamping process exhibit excellent shape fixability with an ultra-high tensile strength of 1.5 GPa. We investigated the effect of flow stress during forming and phase transformation in the hot stamping process. Referring to both experimental and FEM coupled simulation results, we discussed the mechanism behind the excellent shape fixability in the hot stamping process. Steel of 0.2% C was used for hot stamping in this study. IF steel and SUS 304, which have different transformation behaviors, were used for comparison. The forming start temperature varied from 400°C to 800°C. After hot stamping, the springback of the parts was evaluated. The results showed that shape fixability in hot stamping is caused by low flow stress during stamping and martensitic transformation. When martensitic transformation occurs after stamping, excellent shape fixability is obtained regardless of the flow stress during forming. Accordingly, it was concluded that the stress introduced by hot stamping is relaxed and becomes uniform during martensitic transformation. The application of tensile stress due to thermal contraction also contributes to the decrease in springback.

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“…The results showed that the bauschinger effect has a significant effect on the springback of the alloy sheet, while the bauschinger effect can be neglected for the steel sheet. Keum Y T and Han B Y [23] measured the springback amount of 1050 and 5052 aluminum alloys when bent at various forming temperatures. The results showed that the springback amount of the deformed sheet during warm forming is reduced, especially above 150°C.…”

Section: Introductionmentioning

confidence: 99%

Effect of heat treatment conditions on stamping deformation and springback of 6061 aluminum alloy sheets

Wang

Zhu

Kou

et al. 2019

Mater. Res. Express

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The stamping deformation and springback of the 6061 aluminum alloy sheets under different heat treatment conditions were investigated by three-point bending tests. A validated reliable finite element (FE) model was used to further reveal the springback mechanism. It was found that the heat treatment conditions have great influence on the stamping deformation and springback of 6061 aluminum alloy sheets. The most severe local deformation occurred at the punch position of the T6-8 h alloy sheet, showing minimum bending radius and thickness. However, the bending radius and thickness of the homogenization treated (HT) alloy sheet were maximum, resulting from more materials participate in bending deformation. The HT and solution treated (ST) alloys exhibited higher stamping performance than that of the natural aged (NA) and T6 alloys. The material strength of the T6 alloys can be improved by aging time, motivating greater springback and neutral layer offset. The springback and neutral layer offset of the T6-8 h alloy sheet were the highest, while the HT alloy sheet was the lowest. Furthermore, the effect of material parameters on stamping deformation and springback of sheet was studied by combining with theoretical analysis and experimental results. The research showed that the bending radius and thickness of the sheet in the fillet region increase with the increase of strain-hardening exponent and elongation and with the decrease of yield ratio. After unloading, springback angle and radius increase with the increase of yield strength and strength factor and with the decrease of strain-hardening exponent. These achievements may serve as a guideline for enhancing stamping performance and reducing springback of the aluminum alloy sheet in bending process.

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Springback-free Isothermal Forming of High-strength Steel Sheets and Aluminum Alloy Sheets under Warm and Hot Forming Conditions

Cited by 25 publications

References 13 publications

Numerical investigations on springback characteristics of aluminum sheet metal alloys in warm forming conditions

Numerical investigations on springback characteristics of aluminum sheet metal alloys in warm forming conditions

Mechanism for Excellent Shape Fixability in Hot Stamping Process

Effect of heat treatment conditions on stamping deformation and springback of 6061 aluminum alloy sheets

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