Structure and mechanical properties of two copper bearing high-strength low
-alloy steels (HSLA)-one similar to HSLA 80 and the other to HSLA 100-are s
tudied in different aging conditions. Elemental copper precipitates of nano
meter size have been found to play an important role in the formation of di
fferent types of microstructures and in enhancing the strength and toughnes
s of the alloys. Other alloying elements such as Ti, Nb, and V result in fi
ne precipitates of carbides and nitrides, which improve the mechanical stre
ngth.