The application of metallographic techniques to the study of the tempering of HSLA-100 steel

A study of a quenched, and a quenched and tempered low-carbon, copper-containing steel (HSLA 100) was conducted. The primary investigative technique employed was transmission electron microscopy. Quenching the steel from the austenitizing temperature yielded a microstructure that was predominantly lath martensite. However, a significant amount of retained austenite was also present. Niobium carbide particles were also documented in the as-quenched structures. Tempering at 605°C for 1–3 h yielded a heterogeneous distribution of ---Cu, much of which was associated with the lath boundaries. The austenite was highly resistant to decomposition during tempering at 605°C and, as a consequence, little evidence of cementite precipitation was found.