Research on relaxing the residual stress of 700 MPa high strength strip steel based on intensive cooling technology

Intensive cooling technology is widely used to produce high strength strip steel,but high cooling rate leads to some defects,such as shape waves caused by high residual stress. A numerical model was established to achieve a coupling calculation of temperature,phase transformation and stress for high strength steel(700 MPa) during intensive cooling. Commercial FEM software ABAQUS was used to build coupled models that verified by a series of experiments. The effects of edge masking and initial temperature difference on the residual stress were studied by modifying initial and boundary conditions. It is concluded that reducing the initial temperature difference is more effective to release the residual stress of strip steel during cooling. Proven by industrial experiments,these research results would be used to lower the residual stress and improve the quality of hot-rolled strips.