Constitutive Model and Flow Behavior of B1500HS High-Strength Steel During the Hot Deformation Process

Li Li,Yao Yao,Yang Yang,Guan Guan,Duan Duan

doi:10.3390/met10010064

Abstract

Hot compression tests were carried out on a Gleeble-3800 thermal mechanical simulator in the temperature range from 700 to 900 °C and strain rate range from 0.005 to 10 s−1 to investigate the hot deformation behavior of B1500HS high-strength steel. Softening mechanisms of B1500HS high-strength steel under different deformation conditions were analyzed according to the characteristics of flow stress–strain curves. By analyzing and processing the experimental data, the values of steady flow stress, saturated stress, dynamic recovery (DRV) softening coefficient, and other factors were solved and these parameters were expressed as functions of Zener–Hollomon factors. Based on the dislocation density theory and the kinetic model of dynamic recrystallization (DRX), constitutive models corresponding to different softening mechanisms were established. The flow stress–strain curves of B1500HS predicted by a constitutive model are in good agreement with the experimental results and the correlation coefficient is . The comparison results indicate that the constitutive models can accurately reflect the deformation behavior of B1500HS high-strength steel under different conditions.

Highlights

With the development of the automobile industry and the increase in environmental protection consciousness, high-strength steel is becoming widely used in the production of automobile parts, such as A-pillar, B-pillar, and roof frame structure [1,2]
The relationship between flow stress and strain under hot deformation conditions is the basic material property of metal, which plays an important role in the research of forming theory, the establishment of finite element simulation, and the formulation of the hot stamping process
The discussion of deformation behavior under different deformation conditions and the establishment of the corresponding constitutive model are of great significance to the application of hot stamping forming technology

Summary

Introduction

With the development of the automobile industry and the increase in environmental protection consciousness, high-strength steel is becoming widely used in the production of automobile parts, such as A-pillar, B-pillar, and roof frame structure [1,2]. B1500HS is a high-strength steel widely used in the hot stamping process. The microstructure of the test material without heat treatment is composed of ferrite and pearlite with low strength. After the hot stamping process, the microstructure of the material is transformed into martensite which can greatly improve the strength of the steel. The relationship between flow stress and strain under hot deformation conditions is the basic material property of metal, which plays an important role in the research of forming theory, the establishment of finite element simulation, and the formulation of the hot stamping process. The discussion of deformation behavior under different deformation conditions and the establishment of the corresponding constitutive model are of great significance to the application of hot stamping forming technology

Methods

Discussion

Conclusion