The effects of welding heat input on the usability of high strength steels in welded structures

Abstract

High strength steel (HSS) has been in use in workshops since the 1980s. At
\nthat time, the significance of the term HSS differed from the modern conception
\nas the maximum yield strength of HSSs has increased nearly every year. There
\nare three different ways to make HSS. The first and oldest method is QT
\n(quenched and tempered) followed by the TMCP (thermomechanical controlled
\nprocess) and DQ (direct quenching) methods.
\nThis thesis consists of two parts, the first of which part introduces the research
\ntopic and discusses welded HSS structures by characterizing the most
\nimportant variables. In the second part of the thesis, the usability of welded HSS
\nstructures is examined through a set of laboratory tests.
\nThe results of this study explain the differences in the usability of the welded
\nHSSs made by the three different methods. The results additionally indicate that
\nusage of different HSSs in the welded structures presumes that manufacturers
\nknow what kind of HSS they are welding. As manufacturers use greater
\nstrength HSSs in welded structures, the demands for welding rise as well. Therefore, during the manufacturing process, factors such as heat input, cooling
\ntime, weld quality, and more must be under careful observation.