ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
With the regard to the development of modern car bodies the focus lies on low productioncosts, environmental sustainability and high security standards. In order to meet these requirementsthe weight of modern car bodies has to be reduced consistently. Amongst other things, this becomespossible by the use of new high and ultra high strength steels. These materials are characterised bytheir high strength, good ductility and a high absorption capacity. In addition they have a lowerdensity in comparison to other steels. TRIP and TWIP steel belong to these high and ultra highstrength steels as well as iron-manganese steel.The development of new materials also puts new demands on the joining technologies used forproducing semi finished products and parts of car bodies. Due to its high flexibility, its goodautomation and the minor influence on the work piece, laser beam welding is an establishedprocedure in the automotive series production. The high cooling rates in combination with a carbonequivalent of the new materials which is usually higher then 0.4% lead to a martensiticsolidification of the weld seam. Martensite is characterized by its low ductility and thus affects theforming capability as well as the absorption capacity of the welded parts.In order to avoid this effect a new process has been developed within the scope of thecollaborative research program 362 (SFB 362, 1993-2005) at the Laser Zentrum Hannover. Usingthat process the weld seam structure is inductively annealed directly after the welding process.Experiments with high strength steel like TRIP700 and H320LA have shown that the temperingleads to an increase of ductility.The process is suitable for butt joints and overlap joints and is to be transferred into industrial usagewithin the scope of the project “Laser Beam Welding of Car Body Parts Made of High and UltraHigh Strength Steel”. Based on the results obtained in the SFB 362 continuous investigations willbe made in order to qualify the process for boron alloyed steel and iron-manganese steel
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.344.723.pdf
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