ELECTRON MICROANALYSIS FOR LASER MELTED ZONE IN 45 STEEL WITH Fe-Ni-Cr COATING
激光合金化熔化区电子显微分析

In this paper the Fe-Ni-Cr coated layer has been alloyed with 45 steel base metal by transverse flow type CO_2 gas laser with maxmum output of 5 kW. The characteristics of the melted zone and the essence of the "bright band" has been investigated using the electron microscopy. The results show that the "bright band" belongs to the melted zone and is a vertical section of the plane crystal. The width of the "bright band" equals the height of the plane crystal, which decreases with the increase of laser beam scanning rate and the decrease of laser power. This has been explained in terms of constitutional supercooling G/R.