Microstructural and Mechanical Properties of Nd:YAG Laser Welded Dissimilar DP600-DP1000 Steel Sheets

Yıl 2020, , 155 - 164, 17.03.2020

Oğuz Tunçel , Hakan Aydın , Şükriye Çetin

https://doi.org/10.35414/akufemubid.620768

Cited By: 1

Öz

In this study, the DP600
and DP1000 steel sheets were joined with the pulsed Nd: YAG (Neodymium-doped
Yttrium Aluminum Garnet (Y3Al5O12)) laser welding and, mechanical and
microstructure properties of the dissimilar welds were experimentally
investigated. As known, there is a demand in modern automotive industry for
performing dissimilar weld of DP steel sheets. In the laser welding operation,
the selection of welding parameters affects the final properties of welds
substantially. So, the main aim of this study was determining the influence of
pulse frequency on the mechanical properties of pulsed Nd:YAG laser welded
DP600-DP1000 steel sheet joints. For this purpose, dissimilar (DP600-DP1000)
steel sheets were double-sided welded with the butt joint. To analyze the
welding performance, microstructural studies, tensile tests and microhardness
measurements were carried out. The weld cross-sections of the joints revealed
three main distinct macrostructural zones: Base metal and heat affected zone of
both steels, and fusion zone. Moreover, a transition zone was observed between
the base metal and heat affected zone on the DP1000 sides. Higher pulse
frequency led to deeper penetration and larger fusion zone and heat affected
zone. The joints welded without any filler wires had macro porosities in the
fusion zones. The tensile properties of the joints significantly increased with
increasing pulse frequency. The tensile properties obtained in this study may
be quite satisfactory for automotive industrial applications. Fusion zone had
the highest microhardness values. However, the lowest microhardness values were
observed in the transition zone on DP1000 side. 

Anahtar Kelimeler

DP steels, Nd:YAG laser welding, Dissimilar welding, Pulse frequency, Microstructure

Destekleyen Kurum

Bursa Uludağ Üniversitesi Bilimsel Araştırma Projeleri Birimi

Proje Numarası

HDP (MH) 2017/47

Teşekkür

The authors thank the Bursa Uludag University Scientific Research Fund for supporting this research (Project No. HDP (MH) 2017/47).

Nd:YAG Lazer Kaynağı ile Birleştirilen Farklı Türdeki DP600-DP1000 Çeliklerinde Mekanik ve Mikroyapı Özellikleri

Öz

Bu çalışmada DP600 ve
DP1000 çelik sacları darbeli Nd:YAG (Neodymium-doped
Yttrium Aluminum Garnet (Y3Al5O12)) lazer kaynağı ile birleştirilmiş ve farklı
türdeki sacların kaynağında mekanik ve mikro yapı özellikleri deneysel olarak
incelenmiştir. Bilindiği gibi modern otomotiv endüstrisinde farklı türdeki DP
çeliklerimin birleştirilmesinde talep vardır. Lazer kaynak işleminde kaynak
parametrelerinin seçimi kaynak nihai özelliklerini büyük ölçüde etkiler. Bu
yüzden bu çalışmanın amacı  Nd:YAG lazer
kaynağı yapılan DP600-DP1000 çeliklerine kaynak parametrelerinden darbe
frekansının mekanik özelliklere etkilerinin belirlenmesidir. Bu amaçla farklı
türdeki DP600-DP1000 sacları çift taraflı olarak alın kaynağı ile
birleştirilmiştir. Kaynak performansını analiz etmek için mikro yapı
çalışmaları, çekme testleri ve mikro sertlik ölçümleri gerçekleştirilmiştir.
Kaynak kesiti temel malzeme, ısı tesiri altındaki bölge ve ergime bölgesinden
oluşan 3 farklı makro yapısal bölge göstermiştir. Ayrıca DP1000 tarafında ısı
tesiri altındaki bölge ile temel malzeme arasında bir geçiş bölgesi
gözlenmiştir. Yüksek darbe frekansı derin penetrasyon ve daha geniş ergime
bölgesi ve ısı tesiri altındaki bölgeye neden olmuştur. Dolgu teli olmadan
gerçekleştirilen kaynaklar ergime bölgesinde makro gözenekler içermektedir.
Kaynaklı birleştirmenin mukavemeti darbe frekansındaki artışla beraber önemli
ölçüde artmıştır. Bu çalışmada elde edilen çekme mukavemeti özellikleri
otomotiv endüstrisi için oldukça tatmin edicidir. Ergime bölgesi en yükske
mikro sertlik özelliklerine sahiptir. Bunun yanında en düşük mikro sertlik
değerleri DP1000 tarafından temel malzeme ile ısı tesiri altındaki bölge
arasındaki geçiş bölgesinde gözlenmiştir. 

Anahtar Kelimeler

DPçelikleri, Nd:YAG lazer kaynağı, Farklı malzemelerin kaynağı, Darbe frekansı, Mikro yapı, Mekanik özellikler

Proje Numarası

HDP (MH) 2017/47

Kaynakça

• Alves, P. H. O. M., Lima, M. S. F., Raabe, D., Sandim, H. R. Z. 2018. Laser beam welding of dual-phase DP1000 steel. Journal of Materials Processing Technology, 252, 498–510.
• ASTM E8/E8M.2009. standard test methods for tension testing of metallic materials.
• Aydin, H. 2015. The mechanical properties of dissimilar resistance spot-welded DP600-DP1000 steel joints for automotive applications. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 229, 599–610.
• Bandyopadhyay, K., Lee, M. G., Panda, S. K., Saha, P., Lee, J. 2017. Formability assessment and failure prediction of laser welded dual phase steel blanks using anisotropic plastic properties. International Journal of Mechanical Sciences, 126, 203–221.
• Dal, M., Fabbro, R. 2016. [INVITED] An overview of the state of art in laser welding simulation. Optics and Laser Technology, 78, 2–14.
• Farabi, N., Chen, D. L., Zhou, Y. 2011. Microstructure and mechanical properties of laser welded dissimilar DP600/DP980 dual-phase steel joints. Journal of Alloys and Compounds, 509(3), 982–989.
• Fernandes, F. A. O., Oliveira, D. F., Pereira, A. B. 2017. Optimal parameters for laser welding of advanced high-strength steels used in the automotive industry. Procedia Manufacturing, 13, 219–226.
• Fillafer, A., Werner, E., Krempaszky, C. 2017. On phase transformation induced effects controlling the initial flow behavior of ferritic-martensitic dual-phase steels. Materials Science and Engineering A, 708, 556–562.
• Hekmatjou, H., Naffakh-Moosavy, H. 2018. Hot cracking in pulsed Nd:YAG laser welding of AA5456. Optics and Laser Technology, 103, 22–32.
• Iordachescu, D., Blasco, M., Lopez, R., Cuesta, A., Iordachescu, M., Ocaña, J. L. 2011. Development of Robotized Laser Welding Applications for Joining Thin Sheets. , (Optirob), 26–28.
• Jia, Q., Guo, W., Li, W., Peng, P., Zhu, Y., Zou, G., Peng, Y., Tian, Z. 2017. Experimental and numerical study on local mechanical properties and failure analysis of laser welded DP980 steels. Materials Science and Engineering A, 680(37), 378–387.
• Mohammadpour, M., Yazdian, N., Yang, G., Wang, H. P., Carlson, B., Kovacevic, R. 2018. Effect of dual laser beam on dissimilar welding-brazing of aluminum to galvanized steel. Optics and Laser Technology, 98, 214–228.
• Pereira, A., Cabrinha, A., Rocha, F., Marques, P., Fernandes, F., Alves de Sousa, R. 2019. Dissimilar Metals Laser Welding between DP1000 Steel and Aluminum Alloy 1050. Metals, 9(1), 102.
• Prabakaran, M. P., Kannan, G. R. 2017. Optimization and metallurgical studies of CO 2 laser welding on austenitic stainless steel to carbon steel joint. Ferroelectrics, 519(1), 223–235.
• Sreenivasan, N., Xia, M., Lawson, S., Zhou, Y. 2008. Effect of Laser Welding on Formability of DP980 steel. Journal of Engineering Materials and Technology, 130(4), 41004.
• Sun, Q., Di, H. S., Li, J. C., Wang, X. N. 2016. Effect of pulse frequency on microstructure and properties of welded joints for dual phase steel by pulsed laser welding. Materials and Design, 105, 201–211.
• Tadamalle, A. P., Reddy, Y. P., Ramjee, E., Reddy, V. 2014. Evaluation of Nd : YAG Laser Welding Efficiencies for 304L Stainless Steel. Procedia Materials Science, 6, 1731–1739.
• Wang, J., Yang, L., Sun, M., Liu, T., Li, H. 2016. Effect of energy input on the microstructure and properties of butt joints in DP1000 steel laser welding. Materials and Design, 90, 642–649.
• Xia, M. ., Biro, E., Tian, Z. L., Zhou, Y. N. 2008. Efectos de la entrada de calor y martensita en ZAC reblandecimiento de soldadura láser de aceros Dual Phase. ISIJ International, 48(6), 809–814.
• Xue, X., Pereira, A., Amorim, J., Liao, J. 2017. Effects of Pulsed Nd:YAG Laser Welding Parameters on Penetration and Microstructure Characterization of a DP1000 Steel Butt Joint. Metals, 7(8), 292.
• Yuce, C., Tutar, M., Karpat, F., Yavuz, N., Tekin, G. 2017. The effect of process parameters on the microstructure and mechanical performance of fiber laser-welded AA5182 aluminium alloys. Strojniski Vestnik/Journal of Mechanical Engineering, 63(9), 510–518.
• Zhao, Y. Y., Zhang, Y. S., Hu, W. 2013. Effect of welding speed on microstructure, hardness and tensile properties in laser welding of advanced high strength steel. Science and Technology of Welding and Joining, 18(7), 581–590.