DP800 çeliğinin ılık sıcaklık U eğme prosesinde geri esneme ve şekillendirme sonrası mekanik özelliklerinin incelenmesi

Year 2026, Volume: 14 Issue: 1, 38 - 48, 21.01.2026

Nurkan Karabulut , Nuri Şen , Tolgahan Civek

Abstract

Geri esneme, şekillendirilmiş ürünlerin montajı sırasında sorunlara yol açması ve zaman ve enerji kaybına yol açması nedeniyle bükme işleminin en istenmeyen sonuçlarından biridir. Bükme işleminden önce sac metali ısıtmak, geri yaylanmanın istenmeyen etkilerini hafifletmek için endüstride yaygın olarak kullanılan bir uygulamadır. Ancak, birçok durumda, sıcak veya ılık bükme işleminin bükülmüş ürünlerin mekanik özellikleri üzerindeki sonuçları tam olarak dikkate alınmamaktadır. Bu çalışmada, sıcak bükme işleminde, baskı plaka kuvveti ve yağlama gibi proses parametrelerinin DP800 çeliğinin geri yaylanma davranışı üzerindeki etkileri incelenmiştir. Ayrıca, bükülmüş numunelerin şekillendirme sonrası mekanik özellikleri araştırılmıştır. Bunun için, DP800 çelik saclar dört farklı sıcaklıkta (25 "℃", 200 "℃", 300 "℃", 400 "℃"), üç farklı baskı plaka kuvveti (25bar, 75bar, 125 bar) ve iki farklı yağlayıcı (grafit ve teflon) kullanılarak şapka biçiminde bükülmüştür. Elde edilen sonuçlara göre, baskı plaka kuvvetinin azaltılması ve daha iyi bir yağlayıcı (teflon) uygulanmasının daha düşük bir geri esneme elde etmede önemli bir etkiye sahip olduğu anlaşılmıştır. Ek olarak, sıcaklığın artırılması geri esnemeyi olumlu etkilerken, ılık sıcaklıklarda bükülmüş sacların şekillendirme sonrası mukavemetlerinin önemli bir azalma göstermediği görülmüştür.

Keywords

Geri esneme, DP800, , Ilık şekillendirme , Geliştirilmiş Yüksek Mukavemetli Çelik , U-bükme

Project Number

2021.06.05.1178

Evaluation of Springback and Post-Formed Mechanical Properties of DP800 Steel in Warm-Hat-Shaped Bending Process

Abstract

Springback is one of the most undesired outcomes of a bending process since it creates problems during the assembly of formed products and leads to waste time and energy. Heating the sheet metal before the bending process is an application that is widely used in the industry to alleviate the undesired effects of springback. However, in many cases, the consequences of a warm or hot bending process on the mechanical properties of bent products are not thoroughly considered. In this study, the effects of the warm bending process combined with the process parameters such as blank-holder force and lubrication on the springback behaviour of DP800 steel have been examined. Additionally, the post-mechanical properties of the bent specimens have been investigated. For this, sheets of DP800 steels have been bent to a hat-shaped product at four different temperatures (25 ℃, 200 ℃, 300 ℃, 400 ℃), by using three different blank-holder force (25bar, 75bar, 125 bar), and two different lubricants (graphite and teflon). According to the results, it has been shown that reducing the blank-holder force and applying a better lubricant (teflon) has had a considerable effect in attaining a lower springback. Additionally, while increasing the temperature has positively impacted the springback, it has been found that the post-mechanical strength of bent sheets at warm temperatures has not shown a significant reduction.

Keywords

Springback , DP800 , Warm forming , Advanced high strength steels , Hat-shaped bending

Ethical Statement

This study does not involve human or animal participants. All procedures followed scientific and ethical principles, and all referenced studies are appropriately cited.

Supporting Institution

Any external funding or organizational support received for the study should be detailed here. If the study received no external funding, it can be stated as: “This research received no external funding.”

Project Number

2021.06.05.1178

Thanks

For this work, the authors gratefully acknowledge the financial support provided by the Duzce University Research Fund [Project No: 2021.06.05.1178].

References

• Chalal, H., Racz, S. G., & Balan, T. (2012). Springback of thick sheet AHSS subject to bending under tension. International Journal of Mechanical Sciences, 59(1), 104–114. https://doi.org/10.1016/j.ijmecsci.2012.03.011
• Chen, P., & Koç, M. (2007). Simulation of springback variation in forming of advanced high strength steels. Journal of Materials Processing Technology, 190(1–3), 189–198. https://doi.org/10.1016/j.jmatprotec.2007.02.046
• Colla, V., De Sanctis, M., Dimatteo, A., Lovicu, G., Solina, A., & Valentini, R. (2009). Strain hardening behavior of dual-phase steels. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 40(11), 2557–2567. https://doi.org/10.1007/s11661-009-9975-1
• Çavuşoğlu, O., Yuce, C., & Aydın, H. (2023). Mechanical characterization and microstructure of fiber laser welded TWIP980 steel depending on welding speed and focal distance. Optik, 274, Article 170541. https://doi.org/10.1016/j.ijleo.2023.170541
• Eyercioglu, O., Alacaci, S., & Aladag, M. (2021). Experimental investigation of springback of locally heated advanced-high strength steels. International Journal of Research -GRANTHAALAYAH, 9(3), 269–277. https://doi.org/10.29121/granthaalayah.v9.i3.2021.3811
• Gnanasekaran, R. K., Shanmugam, B., Raja, V., & Kathiresan, S. (2022). Multi-disciplinary optimizations on flexural behavioural effects on various advanced aerospace materials: A validated investigation. Materiale Plastice, 59(1), 223–242. https://doi.org/10.37358/MP.22.1.5575
• Ingarao, G., Di Lorenzo, R., & Micari, F. (2009). Analysis of stamping performances of dual phase steels: A multi-objective approach to reduce springback and thinning failure. Materials and Design, 30(10), 4421–4433. https://doi.org/10.1016/j.matdes.2009.04.001
• Ivanišević, A., Milutinović, M., Štrbac, B., & Skakun, P. (2013). Stress state and springback in V-bending operations. Journal for Technology of Plasticity, 39(2), 157–168.
• Karabulut, S., Esen, İ., & Şahin, E. (2024). Springback Prediction performance and experimental analysis in the V-bending process of SCGADUB1180 advanced high-strength steel. Jordan Journal of Mechanical and Industrial Engineering, 18(2), 441–453. https://doi.org/10.59038/jjmie/180216
• Küçüktürk, G., Tahta, M., Gürün H., & Karaağaç, İ. (2022). Evaluation of the effects of local heating on springback behaviour for AHSS Docol 1400 sheet metal. Transactions of FAMENA, 46(3), 51–62. https://doi.org/10.21278/TOF.463037821
• Lawanwomg, K., Hamasaki, H., Hino, R., & Yoshida, F. (2014). A novel technology to eliminate U-bending springback of high strength steel sheet by using additional bending with counter punch. Procedia Engineering, 81, 957–962. https://doi.org/10.1016/j.proeng.2014.10.124
• Lawanwong, K., Hamasaki, H., Hino, R., & Yoshida, F. (2020). Double-action bending for eliminating springback in hat-shaped bending of advanced high-strength steel sheet. International Journal of Advanced Manufacturing Technology, 106, 1855–1867. https://doi.org/10.1007/s00170-019-04678-y
• Lim, H., Lee, M. G., Sung, J. H., Kim, J. H., & Wagoner, R. H. (2012). Time-dependent springback of advanced high strength steels. International Journal of Plasticity, 29(1), 42–59. https://doi.org/10.1016/j.ijplas.2011.07.008
• Liu, G., Lin, Z., Bao, Y., & Cao, J. (2002). Eliminating springback error in U-shaped part forming by variable blankholder force. Journal of Materials Engineering and Performance, 11(1), 64–70. https://doi.org/10.1007/s11665-002-0009-z
• Nikhare, C. P. (2017). Springback analysis in bilayer material bending. In ASME International Mechanical Engineering Congress and Exposition Proceedings Series (Vol. 2, V002T02A062). https://doi.org/10.1115/IMECE2017-70549
• Özek, C., & Taşdemir, V. (2017). AA 5754-O alaşımının ılık derin çekilmesi üzerine kalıp yüzey açısı ve baskı plakası kuvvetinin etkisinin deneysel araştırılması. Journal of the Faculty of Engineering and Architecture of Gazi University, 32(1), 171-179. https://doi.org/10.17341/gazimmfd.300608
• Padmanabhan, R., Sung, J., Lim, H., Oliveira, M. C., Menezes, L. F., & Wagoner, R. H. (2008). Influence of draw restraining force on the springback in advanced high strength steels. International Journal of Material Forming, 1(Suppl. 1), 177–180. https://doi.org/10.1007/s12289-008-0020-5
• Prasad, K., Venkatesh, B., Krishnaswamy, H., Banerjee, D. K., & Chakkingal, U. (2021). On the interplay of friction and stress relaxation to improve stretch-flangeability of dual phase (DP600) steel. CIRP Journal of Manufacturing Science and Technology, 32, 154–169. https://doi.org/10.1016/j.cirpj.2020.11.014
• Saito, N., Fukahori, M., Hisano, D., Hamasaki, H., & Yoshida, F. (2017). Effects of temperature, forming speed and stress relaxation on springback in warm forming of high strength steel sheet. Procedia Engineering, 207, 2394–2398. https://doi.org/10.1016/j.proeng.2017.10.1014
• Saito, N., Fukahori, M., Minote, T., Funakawa, Y., Hisano, D., Hamasaki, H., & Yoshida, F. (2018). Elasto-viscoplastic behavior of 980 MPa nano-precipitation strengthened steel sheet at elevated temperatures and springback in warm bending. International Journal of Mechanical Sciences, 146–147, 571–582. https://doi.org/10.1016/j.ijmecsci.2017.11.044
• Sun, Y., Wang, K., Politis, D. J., Chen, G., & Wang, L. (2020). An experimental investigation on the ductility and post-form strength of a martensitic steel in a novel warm stamping process. Journal of Materials Processing Technology, 275, Article 116387. https://doi.org/10.1016/j.jmatprotec.2019.116387
• Şen, N., & Civek, T. (2022). Detailed deformation behaviour analysis of DP steels at warm forming temperatures via warm tensile tests. Ironmaking and Steelmaking, 49(6), 1–11. https://doi.org/10.1080/03019233.2022.2036083
• Şen, N., Civek, T., & Seçgin, Ö. (2022). Experimental, analytical and parametric evaluation of the springback behavior of MART1400 sheets. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 44, Article 451. https://doi.org/10.1007/s40430-022-03749-8
• Şen, N., Taşdemir, V., & Seçgin, Ö. (2020). Investigation of formability of HC380LA material via the TPIF-RL incremental forming method. Ironmaking & Steelmaking, 47(10), 1199–1205. https://doi.org/10.1080/03019233.2019.1711351
• Wei, B., Wei, Y., Zhang, F., He, K., Dang, X., & Du, R. (2020). Influence of different heating methods on springback of mild steel plate during dieless bending process. Procedia Manufacturing, 50, 318–323. https://doi.org/10.1016/j.promfg.2020.08.059
• Xie, H., Dong, X., Wang, Q., Peng, F., Liu, K., Wang, X., Chen, F., & Wang, J. (2016). Investigation on transient electrically-assisted stress relaxation of QP980 advanced high strength steel. Mechanics of Materials, 93, 238–245. https://doi.org/10.1016/j.mechmat.2015.11.007
• Yang, H., Li, H., Zhang, Z., Zhan, M., Liu, J., & Li, G. (2012). Advances and trends on tube bending forming technologies. Chinese Journal of Aeronautics, 25(1), 1–12. https://doi.org/10.1016/S1000-9361(11)60356-7
• Yu, J. H., & Lee, C. W. (2021). Study on the time-dependent mechanical behavior and springback of magnesium alloy sheet (AZ31B) in warm conditions. Materials, 14(14), Article 3856. https://doi.org/10.3390/ma14143856
• Zhao, J., & Jiang, Z. (2018). Thermomechanical processing of advanced high strength steels. Progress in Materials Science, 94, 174–242. https://doi.org/10.1016/j.pmatsci.2018.01.006