| Title |
Joint - Syposium on Fine - Grained Materials by the Phase Transformation Committee ( Eighth ) and the Ferrous Metallurgy Committee ( Second ) : Fine - Grained steels ; Characteristics of a Fine Grained High Strength Structural Steel Weldment |
| Authors |
윤종근(Joong Geun Youn) ; 김광수(Kwang Soo Kim) ; 박태동(Tae Dong Park) ; 박영수(Young Soo Park) ; 박동환(Dong Hwan Park) |
| Abstract |
Properties of fine grained steel weldments have been investigated with reference to welding process in order to establish the basis of high efficient welding technologies for the high strength structural steel for next generation, the so-called HIPERS-21. The steel used mainly consisted of very fine grained ferrite of about 5-7㎛ in size, which was made experimentally using the controlled rolling and accelerated cooling technology. However conventional GTA and GMA welding practices caused remarkable microstructural changes including grain coarsening up to a few hundreds ㎛ in size at HAZ particularly near the fusion line of the steel, depending on the heat input applied. Laser welding process characterized with low heat input resulted in much finer HAZ microstructural characteristics and higher hardness distribution at HAZ than the GTAW process studied. This indicates laser welding process to be an effective method for controlling HAZ microstructure of the fine grained steel. |