Microstructure and mechanical property of cold rolled low carbon steel after prolonged annealing treatment

The effects of ferrite–pearlite and ferrite–martensite starting microstructures on ferrite grain sizes and carbide particle sizes after cold rolling and prolonged annealing treatment have been investigated. Ferrite–martensite starting microstructures showed finer grain and particle sizes and improved tensile properties after cold rolling annealing cycle compared to ferrite–pearlite starting microstructures. A ‘fibrous’ martensite morphology developed by intermediate quenching treatment is more beneficial in that respect compared to the ‘blocky’ martensite morphology obtained from the step quenching treatment.