The Role of Cold Rolling Reduction on the Microstructure and Mechanical Properties of Ultra-Low Carbon Bainitic Steel

Materials

Qingdong Liu¹  Feng Chai²  Zhanyong Wang³  Yu Dong³  Min Liu³  Lianbo Wang³  Zemin Wang³  Bin Fu³  Jiajun Li³ 

[1] Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai Jiaotong University, Shanghai 200240, China;Institute of Engineering Steel, Central Iron & Steel Research Institute, Beijing 100081, China;School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418, China;

关键词: ultra-low carbon bainitic steel;    cold rolling;    high strength;    dislocation density;    mechanical properties;   

DOI  :  10.3390/ma15093070

来源: DOAJ

【 摘 要 】

The present study investigates the microstructure and mechanical properties of ultra-low carbon bainitic steel (UCBS) under different cold rolling reductions. When the rolling reduction ratios were increased to 80%, the microstructure was refined, and the lath width of the bainite decreased from 601 nm to 252 nm. The ultimate tensile strength and yield strength increased from 812 MPa and 683 MPa to 1195 MPa and 1150 MPa, respectively, whereas the elongation decreased from 15.9% to 7.9%. In addition, the dislocation density increased from 8.3 × 10¹³ m⁻² to 4.87 × 10¹⁴ m⁻² and a stronger γ-fiber texture was obtained at the 80% cold rolling reduction ratio. The local stress distribution and kernel average misorientation were not uniform and became more severe with increased rolling reduction ratios. The strength increment of UCBS was primarily due to boundary strengthening and dislocation strengthening. The theoretical strength increment agreed well with the experimental measurements, which can be helpful for the design and production of UCBS for broad engineering applications.

【 授权许可】

Unknown