Flatness evolution of cold-rolled high-strength steel strips during quenching process

Abstract

Drastic flatness changes in high-strength steel strips during water quenching cause problems for both their subsequent manufacture and final products. In this work, a temperature-microstructure-stress coupled finite element model is established to simulate the quenching process of cold-rolled high-strength steel strips using a UMAT subroutine in ABAQUS. The evolution mechanisms of two main forms of flatness defects, including C warping defect and edge wave defect, are investigated. Our simulations reveal that the temperature gradients of the strips induce their extension differences along transversal/thickness direction and the sequential phase transformation, both of which finally cause the flatness changes. Furthermore, flatness control strategies are proposed according to the integrated effects of the tension and initial temperature differences during quenching. In addition, quenching experiments are implemented to validate the numerical results.

Development of a virtual shapemeter based on a shape control model for continuous annealing

“…In fact, the plastic deformation of thin strip with high temperature and tension is also serious in heat treatment process and shape control in heat treatment process has recently become a research hotspot. Zhang et al (2017) established a temperature-microstructure-stress coupled finite element model to simulate the quenching process of cold-rolled high-strength steel strips using a UMAT subroutine in ABAQUS and investigated the evolution mechanisms of two main forms of flatness defects, including C warping defect and edge wave defect. Similarly, Wrozyna et al (2016) and Hou et al (2018) studied phase transformations of DP steel and enhanced grain growth behaviour of ferritic steel during continuous annealing.…”