Per: alisson paulo de oliveira (NSIGMA CONSULTING LTD), GILBERSON MENDONÇA STORCK DE MELO (GERDAU S/A), NICOLAS TENAGLIA (ADVANCED STEEL PROCESSING AND PRODUCTS RESEARCH CENTER, COLORADO SCHOOL OF MINES), EMMANUEL DE MOOR (ADVANCED STEEL PROCESSING AND PRODUCTS RESEARCH CENTER, COLORADO SCHOOL OF MINES), PELLO URANGA (CEIT-BRTA AND UNIVERSITY OF NAVARRA-TECNUN)
Abstract:
This work aims to determine the influence of solidification/cooling parameters on the microsegregation of HSLA+Nb steel slabs at different positions. Microsegregation is seen as one of the most important sources for variability in metallurgical properties, especially toughness, and measures that seek to reduce the microstructural banding and preferential precipitation will result in greater microstructural homogeneity and lower properties variability. The samples were taken at positions along the width (Center and -294mm in relation to the center) and thickness of the slab (12.50, 37.50, 102.50 and 125.00mm). Electron Probe Microanalysis (EPMA) by Wavelength-Dispersive X-Ray Spectroscopy (WDS) was performed to quantitatively characterize the microsegregation of several elements (C, Mn, Si, P, S, Nb and Ti) in the dendritic and in interdendritic areas. SDAS (Secondary Dendrite Arm Spacing) measurements were carried out, which allowed to calculate the cooling rate, using published equations, in each position. This work allowed to understand in detail the behavior of the different chemical elements in different positions in a cast slab, as well as to determine the influence of the cooling rate on this behavior. This knowledge can be the basis for process optimizations aimed at reducing microsegregation in products where microstructural homogeneity is a critical product quality factor.