Study on corrosion damage characterization and tensile strength evaluation for locally corroded bridge steel via metal magnetic memory method

•Mutational features of SMFL signal can reflect the region and degree of corrosion.•One SMFL characteristic parameter can locate the corrosion defect accurately.•Two SMFL characteristic parameters can characterize the degree of corrosion damage.•The theoretical correlation between SMFL and corrosion degree was established.•Tensile strength of corroded steel was evaluated quantitatively via SMFL.