Characterization of HAZ microstructure for hypoeutectoid steel undergone laser rapid heating

Special microstructures of HAZ for hypoeutcctoid steel,which could not be found in conventional are welding,were observed in laser welding and clectron beam welding because of the high energy densily and the rapid heating and cooling rate.OLM and TEM analyses showed that martensite with high carbon content and ferrite with practically no carbon were obtained.