A study of tailored blank welding between mild steel sheet and zn-coated steel sheet by CO2 laser beam
Research was conducted on tailored blank welding between mild steel sheet and Zn-coated steel sheet using CO2 laser beam. The materials used in this study were low carbon steel sheets with a thickness of 1.2 mm and Zn-coated steel sheet with the same thickness and 6.3 μm Zn coating. Experiments were conducted by applying the Taguchi method to obtain optimum conditions for the application of this tailored blank laser welding method in practical manufacturing processes. Optical microscopy, XRD, SEM and TEM analysis were performed to observe the microstructures and to determine the structures of welded zone. In addition, mechanical properties were measured by the microhardness test, tensile test and Erichsen test to evaluate the formability of the welded specimen. There was no trapped Zn in the fusion zone, and the phases of this region consisted of polygonal ferrite, quasi-polygonal ferrite, banitic ferrite and martensite. The elongation value of welded specimen was more than 80% of the value in substrate metal, and the LDH value was more than 90% of the value in substrate metal.
Key wordtailored blank welding laser welding mild steel sheet Zn-coated steel sheet Taguchi method LDH value formability
Unable to display preview. Download preview PDF.
- 1.J.-C. Mombo-Caristan, V. Lobring, W. Prange and A. Frings, inThe Industrial Laser Handbook (eds., D. Belforte and M. Levitt), p. 89, Springer-Verlag, New York (1992).Google Scholar
- 2.R. H. Lochner and J. E. Matar,Designing for Quality, Quality Resources (1990).Google Scholar
- 3.G. S. Peace,Taguchi Method, Addison-Wesley (1993).Google Scholar
- 4.S. Katayama and A. Matsunawa,Proc. of Int. Con. on Appl of Lasers and Electro-Optics, p. 60, Laser Inst. of America, U.S.A. (1984).Google Scholar
- 7.New Aspects of Microstructure in Modern Low Carbon High Strength Steel, ISIJ, Tokyo (1994).Google Scholar