On Fracture Toughness at Heat Affected Zones (HAZs) and Microstructures of Electric Arc Furnace Steels including Much Tramp Elements and Nitrogen

Abstract

Scrap is raw materials of the recycled steels refined in electric arc furnaces, and this recycle process is good for keeping our living environment. The reports on microstructures and mechanical properties of heat affected zones (HAZs) of these recycled steels are not so many. This report contains mechanical properties and microstructures of HAZs in thermal cycled mother steels, and these HAZs were estimated a heat input of 42-62 kJ/cm. The following experimental results are obtained. TiN particles act as the nucleation sites of acicular ferrite, and also fasten on γ grain boundaries, and improve the toughness of HAZs.