Achieving Excellent Strength–Ductility Combination by Cyclic Quenching Treatment in 22MnB5 Steel

This work elucidated microstructure and mechanical properties of 22MnB5 steel fabricated by cyclic quenching treatment through OM/SEM and tensile tests. The influences of cyclic quenching treatment (CQT) on 22MnB5 steel based on the experimental results can be described as follows: (1) CQT can refine initial austenite grain sizes up to 4.2 μm; (2) CQT can refine lath martensite size, which may be related to the decreased initial austenite grain sizes; (3) 22MnB5 steel after 2 passes cyclic quenching exhibited tensile strength of 1703 MPa and elongation of 20.3% for the ultra-fine microstructure; (4) the vickers hardness of martensite of 22MnB5 increase from 0 pass cyclic quenching to 2 passes cyclic quenching. Therefore, excellent strength-ductility combination of 22MnB5 steel can be achieved by CQT.