A 1000 MPa galvanised dual phase steel was fibre laser lap welded by different welding parameters. The surface appearance, cross-section macrostructure and tensile shear properties of laser lap welds were evaluated. The different methods for improving the laser lap weldability of galvanised steel were analysed. The results showed that the increasing laser power resulted in the formation of the keyhole, which could be used as the escape route for the vapourised zinc formed at the faying surface. Therefore, the weld defects, such as spatter, cavity and blow hole, were eliminated, and the full penetrated laser lap welds with smooth surface appearances were acquired. A proper joint gap also worked as the escape route for the zinc vapour and led to the formation of sound welds. Adding proper preheating procedures improved the mechanical properties of the welds to some degree, but weld defects still existed owing to the residual zinc.
MeiL. F., YiJ. M., YanD. B., LiuJ. W. and ChenG. Y.: ‘Comparative study on CO2 laser overlap welding and resistance spot welding for galvanized steel’, Mater. Des., 2012, 40, 433–442.
2.
AslanlarS., OgurA. and OzsaracU.: ‘Effect of welding current on mechanical properties of galvanized chromided steel sheets in electrical resistance spot welding’, Mater. Des., 2007, 28, 2–7.
3.
MaJ. J., KongF. R., CarlsonB. and KovacevicR.: ‘Two-pass laser welding of galvanized high-strength dual-phase steel for a zero-gap lap joint configuration’, J. Mater. Process. Technol., 2013, 213, 495–507.
4.
XieJ. and DenneyP.: ‘Galvanized steel joined with lasers’, Weld. J., 2001, 80, (6), 59–61.
5.
SchmidtM., OttoA. and KägelerC.: ‘Analysis of YAG laser lap-welding of zinc coated steel sheets’, CIRP Ann. Manuf. Technol., 2008, 57, 213–216.
6.
RibicB., PalmerT. A. and DebRoyT.: ‘Problems and issues in laser-arc hybrid welding’, Int. Mater. Rev., 2009, 54, 223–244.
7.
MaJ. J., KongF. R. and KovacevicR.: ‘Finite-element thermal analysis of laser welding of galvanized high-strength steel in a zero-gap lap joint configuration and its experimental verification’, Mater. Des., 2012, 36, 348–358.
8.
KimC. H., AhnY. N. and KimJ. H.: ‘CO2 laser-micro plasma arc hybrid welding for galvanized steel sheets’, Trans. Nonferrous Met. Soc. China, 2011, 21, s47–s53.
9.
LoredoA., MartinB., AndrzejewskiH. and GreveyD.: ‘Numerical support for laser welding of zinc-coated sheets process development’, Appl. Surf. Sci., 2002, 195, 297–303.
10.
KimC., ChoiW., KimJ. and RheeS.: ‘Relationship between the welding ability and the process parameters for laser-TIG hybrid welding of galvanized steel sheets’, Mater. Trans., 2008, 49, (1), 179–186.
11.
YangS. and KovacevicR.: ‘Welding of galvanized dual-phase 980 steel in a zero gap lap joint configuration’, Weld. J., 2009, 88, (8), 168–178.
12.
ZhaoY. Y., ZhangY. S., HuW. and LaiX. M.: ‘Optimization of laser welding thin-gage galvanized steel via response surface methodology’, Opt. Lasers Eng., 2012, 50, 1267–1273.
13.
ChenG. Y., MeiL. F., ZhangM. J., ZhangY. and WangZ. J.: ‘Research on key influence factors of laser overlap welding of automobile body galvanized steel’, Opt. Laser Technol., 2013, 45, 726–733.
14.
Yih-fongT.: ‘Gap-free lap welding of zinc-coated steel using pulsed CO2 laser’, Int. J. Adv. Manuf. Technol., 2006, 29, (3-4), 287–295.
15.
WeiS. T., LiuR. D., LvD., XuR. J., LinL., GuoJ. Y. and LuX. F.: ‘Study on fibre laser spot welding of TRIP980 steel’, Mater. Sci. Technol., 2015, DOI 101179/1743284714Y0000000681.
16.
WeiS. T., LvD., LiuR. D., LinL., XuR. J., GuoJ. Y. and WangK. Q.: ‘Similar and dissimilar resistance spot welding of advanced high strength steels: welding and heat treatment procedures, structure and mechanical properties’, Sci. Technol. Weld. Join., 2014, 19, (5), 427–435.
17.
TorkamanyM. J., SabbaghzadehJ. and HamediM. J.: ‘Effect of laser welding mode on the microstructure and mechanical performance of dissimilar laser spot welds between low carbon and austenitic stainless steels’, Mater. Des., 2012, 34, 666–672.
18.
KatayamaS., KawahitoY. and MizutaniM.: ‘Elucidation of laser welding phenomena and factors affecting weld penetration and welding defects’, Phys. Proced., 2010, 5, 9–17.
19.
OhnishiT., KawahitoY., MizutaniM. and KatayamaS.: ‘Butt welding of thick, high strength steel plate with a high power laser and hot wire to improve tolerance to gap variance and control weld metal oxygen content’, Sci. Technol. Weld. Join., 2013, 18, (4), 314–322.
20.
PouranvariM. and MarashiS. P. H.: ‘Critical review of automotive steels spot welding: process, structure and properties’, Sci. Technol. Weld. Join., 2013, 18, (5), 361–403.
21.
JaberH. L., PouranvariM., MarashiS. P. H., Alizadeh-ShM., SalimR. K. and HashimF. A.: ‘Dissimilar spot welding of dual phase steel/ferritic stainless steel: phase transformations’, Sci. Technol. Weld. Join., 2014, 19, (7), 565–571.
22.
BrauserS., PepkeL. A., WeberG. and RethmeierM.: ‘Deformation behaviour of spot-welded high strength steels for automotive applications’, Mater. Sci. Eng. A, 2010, A527, (26), 7099–7108.
23.
Baltazar HernandezV. H., KuntzM. L., KhanM. I. and ZhouY.: ‘Influence of microstructure and weld size on the mechanical behaviour of dissimilar AHSS resistance spot welds’, Sci. Technol. Weld. Join., 2008, 13, (8), 769–776.
24.
SharmaR. S. and MolianP.: ‘Yb:YAG laser welding of TRIP780 steel with dual phase and mild steels for use in tailor welded blanks’, Mater. Des., 2009, 30, 4146–4155.
25.
GoodarziM., MarashiS. P. H. and PouranvariM.: ‘Dependence of overload performance on weld attributes for resistance spot welded galvanized low carbon steel’, J. Mater. Process. Technol., 2009, 209, 4379–4384.
