Technical Challenges in Narrow-Gap Root Pass Welding during Tandem and Hybrid Laser-Arc Welding of a Thick Martensitic Stainless Steel

Abstract:

As part of a collaborative program to develop advanced manufacturing processes for next-generation hydraulic turbines, this study investigated the technological challenges for joining 25-mm thick martensitic stainless steel (MSS) plates using tandem and hybrid laser-arc welding. Although candidate materials for the intended application typically include wrought AISI 415 and cast CA6NM, a martensitic 410 stainless steel (SS) was especially selected in this study due to its greater crack sensitivity. A narrow-gap groove was designed to minimize the amount of 410NiMo filler metal required to fill the groove using a multi-pass single-sided welding technique. All the welding trials were performed using a 5.2 kW fiber laser. The root-pass quality was characterized in terms of weld bead geometry, defects and microstructure. The main technical challenges observed for the root pass were lack of penetration, lack of fusion and cracking, as detailed in this work.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1305-1310
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1305
• Online since: November 2016
• Authors: F. Mirakhorli*, X. Cao, X.T. Pham, Priti Wanjara, J.L. Fihey
• Keywords: Hybrid Laser-Arc Welding, Martensitic Stainless Steel, Narrow-Gap Groove, Tandem Laser-Arc Welding, Thick Plate

References

[1] M. Zhang, G. Chen, Y. Zhou, S. Liao, Optimization of deep penetration laser welding of thick stainless steel with a 10kW fiber laser, Mater. Des. 53 (2014) 568-576.

DOI: 10.1016/j.matdes.2013.06.066

[2] C. Bagger, F.O. Olsen, Review of laser hybrid welding. J. Laser. Appl. 17 (2005).

[3] F. Mirakhorli, X. Cao, X.T. Pham, P. Wanjara, J-L. Fihey, Hybrid Fiber Laser–arc Welding of 10-mm Thick CA6NM Stainless Steel, Materials Science & Technology. (2014) Pittsburgh, PA, USA.

DOI: 10.1007/s11661-016-3523-6

[4] J.C. Lippold, D.J. Kotecki, Welding metallurgy and weldability of stainless steels, Wiley-VCH, (2005).

[5] N. Abe, M. Hayashi, Trends in laser arc combination welding methods, Weld. Int. 16 (2002) 94-98.

DOI: 10.1080/09507110209549498

[6] J. Chen, C. Schwenk, C. S. Wu, M. Rethmeier, Predicting the influence of groove angle on heat transfer and fluid flow for new gas metal arc welding processes, Int. Journal. Heat Mass Transfer, 55 (2012) 102-111.

DOI: 10.1016/j.ijheatmasstransfer.2011.08.046

[7] Y. Wang, H. -L. Tsai, Effects of surface active elements on weld pool fluid flow and weld penetration in gas metal arc welding, Metall. Mater. Trans B. 32 (2001) 501-515.

DOI: 10.1007/s11663-001-0035-5

[8] LU. Shanping, F. Hidetoshi, T. Manabu, N. Kiyoshi, Weld shape variation in Ar-O2 and Ar-CO2 shielded GTA welding, Transactions of JWRI 33, 1 (2004) 5-9.

DOI: 10.1016/j.msea.2004.05.057

[9] H. Castner, Cause and prevention of 12% chromium steel fillet weld cracks, Weld. J. Research Supplement, 56, (1977).

[10] A. Matsunawa, Problems and solutions in deep penetration laser welding, Sci. Technol. Weld. Joining, 6 (2001) 351-354.

DOI: 10.1179/stw.2001.6.6.351

[11] Blakeley, P., Magnetic arc blow-causes and remedies. Weld Met Fabr, 59 (1991).