Influence of coiling temperature on mechanical properties in hot rolling C-Mn-Si-Al steel

摘要

A low carbon C-Mn-Si-Al steel was hot rolled with coiling temperatures ranged from 510 oC to 710 oC. The microstructure of specimens consisted of deformed ferrite, lath martensite, twin martensite and bainite. Cementite was only observed in sample coiled at 570 oC. With increasing coiling temperature, deformed ferrite fraction decreased and recrystallized ferrite fraction increased. The ultimate tensile strength increased gradually from 1084 MPa to 1183 MPa due to the increasing fraction of martensite and bainite. The optimal mechanical properties were obtained when coiled at 570 oC with an ultimate tensile strength of 1085 MPa and ultimate elongation of 19.1 %.