Micro‐to‐Nanostructural Evolution and Precipitation Mechanisms of Lean‐Alloyed Steel Strips During Batch Annealing

This study investigates the micro‐to‐nanostructural evolution during batch annealing treatments of thermomechanically controlled processed (TMCP) cold‐rolled steel strips featuring a lean alloy design (including Mo alloy reduction). By configuring coiling temperatures and annealing parameters, the interactions among recrystallization, precipitation, growth, and coarsening mechanisms are clarified. Advanced characterization via SEM, TEM, and EDS illustrates critical nanoscale features, specifically the enrichment of nitrogen within ultrafine precipitates and the formation of interphase hexagonal‐type precipitates exhibiting an uncommon orientation relationship (OR) with the ferritic matrix. These nanostructural phenomena are directly correlated with the mechanical response, evaluated via Vickers hardness testing. The findings provide a substantial understanding of the relationship between processing routes and complex precipitate sequences in lean‐alloyed nanoprecipitated steel strips, validating their potential for demanding automotive applications.