Effect of cooling mode on the microstructure and mechanical properties of medium carbon steel after warm rolling

ABSTRACT

The effects of cooling modes (air, furnace and water) on the variation of microstructure and mechanical properties of medium carbon steel were investigated. SEM, TEM and EBSD techniques were used to observe the microstructure. The observed results show that the effect of cooling mode on the grain size is insignificant. The average sizes of ferrite grain obtained under different cooling modes were little different. Moreover, in all the cases, most of the cementite lamellas were transformed into cementite particles, except for some of the residual cementite lamellas which were present on the original pearlite colonies. It has also been found that the ferrite substructure and precipitation of cementite particles are significantly affected by the cooling modes. Compared to other cooling modes, the furnace cooling is beneficial to the homogeneity of microstructure. The particles are distributed on the ferrite matrix more homogeneously after furnace cooling which results in a better combination of strength and ductility.

KEYWORDS:

• Warm rolling
• microstructure
• mechanical properties
• strain hardening rate (SHR)
• cooling mode
• carbide particles
• dislocation variation
• fracture morpholog

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [Grant Number 51574104]; National Natural Science Foundation of China: [Grant Number 51574107]; National Natural Science Foundation of China: [Grant Number 51474091]; National Natural Science Foundation of China: [Grant Number 51975593]; Natural Science Foundation of Hebei Province: [Grant Number E2017209048]; Natural Science Foundation of Hebei Province: [Grant Number E2017209121]; Natural Science Foundation of Hebei Province: [Grant Number E2015209243]; and Research Funds from Department of Education Hebei Province (Grant No. QN2019051). Hebei Province Science and Technology Support Program: [Grant Number 16211036].