@article{AhmedReisgenSchleseretal.2010,
  author    = {Ahmed, Essam and Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg},
  title     = {On formability of tailor laser welded blanks of DP/TRIP steel sheets},
  series = {Science and technology of welding and joining},
  volume    = {15},
  journal   = {Science and technology of welding and joining},
  number    = {5},
  publisher = {Maney},
  address   = {Leeds},
  issn      = {1743-2936},
  doi       = {10.1179/136217110X12731414739754},
  pages     = {337 -- 342},
  year      = {2010},
  abstract  = {This paper aims to evaluate the formability of tailor welded blanks of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets. In this work, bead on plate butt joints of 2·5 mm DP600 and 1·2 mm TRIP700 steel sheets were performed using CO2 laser beam welding. Microhardness measurements and transverse tensile testing were carried out to characterise the welds. The formability of base metals and welds were investigated by standard Erichsen test. In a perpendicular tensile test to the weld line, all specimens were fractured at the TRIP base metal, and the strengths were somewhat higher than those of base metal. There was a significant reduction in formability caused by welding of the DP600/TRIP700 steel sheets, and the formability increased with increasing welding speed.},
  language  = {en}
}
@article{ReisgenSchleserMokrovetal.2012,
  author    = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam},
  title     = {Statistical modeling of laser welding of DP/TRIP steel sheets},
  series = {Optics and laser technology},
  volume    = {44},
  journal   = {Optics and laser technology},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1879-2545 (E-Journal); 0030-3992 (Print); 0308-4280 (Print)},
  doi       = {10.1016/j.optlastec.2011.05.025},
  pages     = {92 -- 101},
  year      = {2012},
  abstract  = {In this research work, a statistical analysis of the CO2 laser beam welding of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets was done using response surface methodology. The analysis considered the effect of laser power (2-2.2 kW), welding speed (40-50 mm/s) and focus position (-1 to 0 mm) on the heat input, the weld bead geometry, uniaxial tensile strength, formability limited dome height and welding operation cost. The experimental design was based on Box-Behnken design using linear and quadratic polynomial equations for predicting the mathematical models. The results indicate that the proposed models predict the responses adequately within the limits of welding parameters being used and the welding speed is the most significant parameter during the welding process.},
  language  = {en}
}
@article{ReisgenSchleserMokrovetal.2012,
  author    = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam},
  title     = {Optimization of laser welding of DP/TRIP steel sheets using statistical approach},
  series = {Optics and laser technology},
  volume    = {44},
  journal   = {Optics and laser technology},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1879-2545 (E-Journal); 0030-3992 (Print); 0308-4280 (Print)},
  doi       = {10.1016/j.optlastec.2011.06.028},
  pages     = {255 -- 262},
  year      = {2012},
  abstract  = {Generally, the quality of a weld joint is directly influenced by the welding input parameter settings. Selection of proper process parameters is important to obtain the desired weld bead profile and quality. In this research work, numerical and graphical optimization techniques of the CO2 laser beam welding of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets were carried out using response surface methodology (RSM) based on Box-Behnken design. The procedure was established to improve the weld quality, increase the productivity and minimize the total operation cost by considering the welding parameters range of laser power (2-2.2 kW), welding speed (40-50 mm/s) and focus position (-1 to 0 mm). It was found that, RSM can be considered as a powerful tool in experimental welding optimization, even when the experimenter does not have a model for the process. Strong, efficient and low cost weld joints could be achieved using the optimum welding conditions.},
  language  = {en}
}
@article{ReisgenSchleserMokrovetal.2011,
  author    = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam},
  title     = {Numerical and experimental investigation of tensile behavior of laser beam welded TRIP700 steel},
  series = {ISIJ international},
  volume    = {Vol. 51},
  journal   = {ISIJ international},
  number    = {No. 3},
  publisher = {ISIJ},
  address   = {Tōkyō},
  organization    = {Iron and Steel Institute of Japan (ISIJ)},
  issn      = {1347-5460 (E-Journal); 0915-1559 (Print)},
  pages     = {429 -- 434},
  year      = {2011},
  language  = {en}
}
@article{ReisgenSchleserMokrovetal.2010,
  author    = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam},
  title     = {Uni- and bi-axial deformation behavior of laser welded advanced high strength steel sheets},
  series = {Journal of materials processing technology},
  volume    = {210},
  journal   = {Journal of materials processing technology},
  number    = {15},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0924-0136},
  doi       = {http10.1016/j.jmatprotec.2010.08.003},
  pages     = {2188 -- 2196},
  year      = {2010},
  abstract  = {Bead-on-plate butt joints of 2.5 mm hot rolled DP600/DP600 and 1.2 mm cold rolled TRIP700/TRIP700 steel sheets were performed using 6 kW CO2 laser beam welding. The welding speed ranged from 1.5 to 3.0 and from 2.1 to 3.9 m/min in DP/DP and TRIP/TRIP steel weldments respectively. A top surface helium gas was used as a shielding gas at a flow rate of 20 l/min. Metallographic examinations and transverse tensile testing (DIN EN 895: 1995) were carried out to characterize the weldments. The formability of base metals and weldments were investigated by standard Erichsen test (DIN EN ISO 20482). It was found that the uniaxial plastic behavior of both DP600 and TRIP700 base metals was in agreement with Swift and modified Mecking-Kocks models respectively. In a perpendicular tensile test to the weld line, all specimens were fractured at the base metal however the strengths were somewhat higher than those of base metal. There was a significant reduction in formability caused by welding of both DP/DP and TRIP/TRIP steel weldments and the formability has been improved with the increase of the welding speed.},
  language  = {en}
}
@article{ReisgenSchleserMokrovetal.2010,
  author    = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam},
  title     = {Shielding gas influences on laser weldability of tailored blanks of advanced automotive steels},
  series = {Applied surface science},
  volume    = {257},
  journal   = {Applied surface science},
  number    = {5},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-4332 (E-Journal); 0169-4332 (Print)},
  doi       = {10.1016/j.apsusc.2010.08.042},
  pages     = {1401 -- 1406},
  year      = {2010},
  abstract  = {The effects of shielding gas types and flow rates on CO2 laser weldability of DP600/TRIP700 steel sheets were studied in this work. The evaluated shielding gases were helium (He), argon (Ar) and different mixtures of He and Ar. Weld penetration, tensile strength and formability (Erichsen test) of laser welds were found to be strongly dependent upon the shielding gas types. The ability of shielding gas in removing plasma plume and thus increasing weld penetration is believed to be closely related to ionization potential and atomic weight which determine the period of plasma formation and disappearance. It was found that the higher helium shielding gas flow rate, the deeper weld penetration and the lower weld width.},
  language  = {en}
}
@inproceedings{ReisgenSchleserMokrovetal.2009,
  author    = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam and Schmidt, Andre and Rossiter, Eduardo},
  title     = {Integrative Berechnung von Verzug und Eigenspannungen auf Basis realer Schweißparameter},
  series = {Tagungsband / SYSWELD-Forum 2009 : 22. - 23. Oktober 2009, Weimar},
  booktitle = {Tagungsband / SYSWELD-Forum 2009 : 22. - 23. Oktober 2009, Weimar},
  editor    = {Hildebrand, J{\"o}rg},
  publisher = {Univ.-Verl.},
  address   = {Weimar},
  isbn      = {978-3-86068-401-6},
  pages     = {32 -- 41},
  year      = {2009},
  language  = {de}
}