Improvement in HSS grade for early stands of hot strip mills - Metallurgical features and mechanical properties assessment

Aurora and Kosmos grades are HSS alloys belonging to the complex Fe-Cr-C-X
system, where X is a strong carbide former element of the V, Mo or W type.
Both alloys were metallurgically characterised prior to their comparison.
Metallurgical analyses involved phases identification and carbides quantification by
using Scanning Electron Microscopy and Energy Dispersive X rays. Differential
Thermal Analysis was performed to allow a better understanding of the solidification
sequence of studied alloys while mechanical tests performed were compressive at
room temperature and bulk hardness at usual service temperatures. An attempt was
made in order to connect experimental results to the good behaviour in operation of
Aurora grade.
In fact Aurora grade appeared to exhibit strong metallurgical differences when
compared to Kosmos grade, especially as concern in nature and amount of carbides.