Autogenous laser welding of 0.8 mm thick butt joints of car body electro-galvanized steel sheet DC04 was investigated. The Yb:YAG disk laser TruDisk 3302 with the beam spot diameter of 200 μm was used. The effect of laser welding parameters and technological conditions on weld shape, penetration depth, process stability, microstructure and mechanical performance was determined. It was found that the laser beam spot focused on the top surface of a butt joint tends to pass through the gap, especially in the low range of heat input and high welding speed. All test welds were welded at a keyhole mode, and the weld metal was free of porosity. Thus, the keyhole laser welding of zinc coated steel sheets in butt configuration provides excellent conditions to escape for zinc vapours, with no risk of porosity. Microstructure, microhardness and mechanical performance of the butt joints depend on laser welding conditions thus cooling rate and cooling times. The shortest cooling time t8/5 was calculated for 0.29 s.
 A. Ribolla, et al. The use of Nd:YAG laser weld for large scale volume assembly of automotive body in white, Journal of Materials Processing Technology 164-165, 1120-1127 (2005).
 J. Ma,etal., Two-pass laser welding of galvanized high-strength dual-phase steel for a zero-gap lap joint configuration, Journal of Materials Processing Technology 213, 495- 507 (2013).
 U.Reisgen, et al., Shielding gas influences on laser weldability of tailored blanks of advanced automotive steels, Applied Surface Science 257, 1401-1406 (2010).
 Yi Zhang, et al., Characteristics of zinc behavior during laser welding of zinc ‘‘sandwich’’ sample, Optics & Laser Technology 44, 2340-2346 (2012).
 Tzeng Yih-fong, Gap-free lap welding of zinc-coated steel using pulsed CO2 laser, Int. J. Adv. Manuf. Technol. 29, 287-295 (2006).
 W. Chen, et al., CO2 laser welding of galvanized steel sheets using vent holes, Mat. and Des. 30, 245-251 (2009).
 M. Lifang, et al., Comparative study on CO2 laser overlap welding and resistance spot welding for galvanized steel, Mat. and Des. 40, 433-442 (2012).
 J. Milberg, A. Trautmann, Defect-free joining of zinc-coated steels by bifocal hybrid laser welding, Prod. Eng. Res. Devel. 3, 9-15 (2009).
 S. Iqbal, et al., Dual beam method for laser welding of galvanized steel: Experimentation and prospects, Optics & Laser Technology 42, 93-98 (2010).
 L. Mei, et al., Research on laser welding of high-strength galvanized automobile steel sheets, Optics and Lasers in Engineering 47, 1117-1124 (2009).
 A.K. Dasgupta, J. Mazumder, Laser welding of zinc coated steel: an alternative to resistance spot welding. Science and Technology of Welding and Joining 13, 289-293 (2008).
 S. Yang, et al., Vacuum-Assisted Laser Welding of Zinc- Coated Steels in a Gap-Free Lap Joint Configuration, Welding Journal 92, 197-204 (2013).
 Z. Chen, et al., A study of fiber laser welding of galvanized steel using a suction method, Journal of Materials Processing Technology 214, 1456-1465 (2014).
 A. Lisiecki, Welding of thermomechanically rolled fine-grain steel by different types of lasers, Arch. Metall. Mater. 59(4), 1625-1631 (2014).
 A. Lisiecki, Diode laser welding of high yield steel, Proceedings of SPIE, Laser Technology 2012: Application of Lasers, 8703 (2013).
 A. Lisiecki: Welding of titanium alloy by Disk laser. Proceedings of SPIE, Laser Technology, Applications of Lasers, 87030 (2013).
 A. Lisiecki, Titanium Matrix Composite Ti/TiN Produced by Diode Laser Gas Nitriding, Metals 5(1), 54-69 (2015), doi:10.3390/met5010054.
 D. Janicki, Disk laser welding of armor steel, Arch. Metall. Mater. 59(4), 1641-1646 (2014).
 A. Kurc-Lisiecka, W. Ozgowicz, W. Ratuszek, J. Kowalska: ‘Analysis of Deformation Texture in AISI 304 Steel Sheets’, Sol. St. Phenomena 203-204, 105-110 (2013).
 M. Bonek, The investigation of microstructures and properties of high speed steel hs6-5-2-5 after laser alloying, Arch. Metall. Mater. 59(4), 1647-1651 (2014).
 R. Burdzik, Ł. Konieczny, Z. Stanik, P. Folega, A. Smalcerz, A. Lisiecki, Analysis of impact of chosen parameters on the wear of camshaft, Arch. Metall. Mater. 59(3), 957-963 (2014).
 J. Jezierski, K. Janerka, Parameters of a Gas-Solids Jet in Pneumatic Powder Injection into Liquid Alloys with a Non- Submerged Lance, Metalurgija 54(2), 365-367 (2015).
 M. Bonek, L.A. Dobrzański,Characterization performance of laser melted commercial tool steels, Mat. Sci. Forum 654-656, 1848-1851 (2010).
 W. Sitek, L.A. Dobrzański, Comparison of hardenability calculation methods of the heat-treatable constructional steels, J. Mat. Proc. Tech. 64(1-3), 117-126 (1995).
 J. Górka, Analysis of simulated welding thermal cycles S700MC using a thermal imaging camera, Adv. Mat. Res. ISI Proceedings 837, 375-380 (2014).
 J. Bodzenta, A. Kaźmierczak, T. Kruczek, Analysis of thermograms based on FFT algorithm, Journal de Physique IV 129, 201-206 (2005).
 A. Grajcar, M. Różański, S. Stano, A. Kowalski, B. Grzegorczyk: ‘Effect of Heat Input on Microstructure and Hardness Distribution of Laser Welded Si-Al TRIP-Type Steel’ Adv. in Mat. Sci. and Eng. 2014 (2014),  M. Musztyfaga, L.A. Dobrzański, S. Rusz, M. Staszuk, Application examples for the different measurement modes of electrical properties of the solar cells, Arch. Metall. Mater. 59(1) 247-252 (2014).
 G. Moskal, A. Grabowski, A. Lisiecki, Laser remelting of silicide coatings on Mo and TZM alloy, Sol. St. Phenomena 226, 121-126 (2015). doi:10.4028/www.scientific.net/ SSP.226.121
 B. Oleksiak, G. Siwiec, A. Blacha-Grzechnik, J. Wieczorek, The obtained of concentrates containing precious metals for pyrometallurgical processing, Metalurgija 53(4), 605-608 (2014).
 L. Blacha, R. Burdzik, A. Smalcerz, T. Matuła, Effects of pressure on the kinetics of manganese evaporation from the OT4 alloy, Archives Of Metallurgy And Materials 58 (1), 197-201 (2013).
 B. Oleksiak, J. Labaj, J. Wieczorek, A.Blacha-Grzechnik, R. Burdzik, Surface tension of cu-bi alloys and wettability in a liquid alloy - refractory material - gaseous phase system, Arch. Metall. Mater. 59(1), 281-285 (2014).
 G. Golański, A. Zieliński, J. Słania, J. Jasak, Mechanical Properties of VM12 steel after 30 000hrs of ageing at 600°C temperature, Arch. Metall. Mater. 59(4), 1357-1360 (2014).
 G. Golański, P. Gawień, J. Słania, Examination of Coil Pipe Butt Joint Made of 7CrMoVTib10 - 10(T24) Steel After Service, Arch. Metall. Mater. 57(2), 1067-1070 (2012).
 G. Golanski, J. Slania, Effect of different heat treatments on microstructure and mechanical properties of the martensitic GX12CrMoVNbN9-1 cast steel, Archives of Materials and Metallurgy 58(1), 25-30 (2013).
 A.N. Wieczorek, The role of operational factors in shaping of wear properties of alloyed Austempered Ductile Iron. Part I. Experimental studies abrasive wear of Austempered Ductile Iron (ADI) in the presence of loose quartz abrasive. Archives of Metallurgy and Materials 59(4), 1665-1674 (2014).
 A.N. Wieczorek, The role of operational factors in shaping of wear properties of alloyed Austempered Ductile Iron. Part II. An assessment of the cumulative effect of abrasives processes and the dynamic activity on the wear property of Ausferritic Ductile Iron. Archives of Metallurgy and Materials 59 (4), 1675-1683 (2014).
 J. Górka, Weldability of thermomechanically treated steels having a high yield point, Arch. Metall. Mater. 60(1) 471-477 (2015).
 T. Węgrzyn, J. Piwnik, B. Łazarz, D. Hadryś, Main micro-jet cooling gases for steel welding, Arch. Metall. Mater. 58(2), 555-557 (2013).
 T. Węgrzyn, J. Mirosławski, A. Silva, D. Pinto, M. Miros, Oxide inclusions in steel welds of car body, Mat. Sci. Forum 6, 585-591 (2010).
 T. Węgrzyn, J. Piwnik, D. Hadryś. Oxygen in steel WMD after welding with micro-jet cooling, Arch. Metall. Mater. 58(4), 1067-1070 (2013).
 G. Golański, J. Jasak, J. Słania, Microstructure, properties and welding of T24 steel - critical review, Kovove Materialy 52, 99-106 (2014).
 R. Burdzik,Ł. Konieczny, Research on structure, propagation and exposure to general vibration in passenger car for different damping parameters, Journal of Vibroengineering 15(4), 1680-1688 (2013).
 R. Burdzik, Research on the influence of engine rotational speed to the vibration penetration into the driver via feet - multidimensional analysis, Journal of Vibroengineering 15(4), 2114-2123 (2013).
 R. Burdzik, Identification of structure and directional distribution of vibration transferred to car-body from road roughness, submitted to Journal of Vibroengineering 16(1), 324-333(2014).
 Z. Dąbrowski, M. Zawisza, The choice of vibroacoustic signal measures, in mechanical fault diagnosis of diesel engines, Solid State Phenomena 236, 220-227 (2015).
 M. Zawisza, Energy loss and the choice of damper of torsional vibration combustion engines, Solid State Phenomena 236, 188-195 (2015).
 J. Pankiewicz, P. Deuszkiewicz, J. Dziurdź, M. Zawisza. Modeling of powertrain system dynamic behavior with torsional vibration damper, Advanced Materials Research 1036, 586-591 (2014).