Effect of titanium on the discontinuous growth of as-cast coarse columnar γ grain of peritectic carbon steel

ABSTRACT

The effect of titanium on the discontinuous growth of coarse columnar γ grain (CCG) of peritectic steel during solidification was investigated by a fast-directional solidification device. Based on the experiments, the growth characteristic of CCG and Ti(C, N) precipitates were detected by optical microscope, transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. The results showed that the averages height of CCG region and the growth rate of CCG (V_CCG) decrease with the increase of titanium content. When the titanium content increases to 0.09 wt-%, the CCG completely disappears during the whole solidification process. The microscale Ti(C, N) particles formed in liquid would decrease the growth rate of CCG which provides the convenient condition for the growth of nanoscale Ti(C, N) in the γ phase. The pinning pressure provided by Ti(C, N) precipitates increases with the titanium content, which is the main reason of the decrease of V_CCG.

KEYWORDS:

• Peritectic steel
• coarse columnar grain
• Ti(C, N)
• pinning pressure
• discontinuous growth
• solidification
• casting
• austenite grain refinement

Acknowledgements

The present study was supported by the National Natural Science Foundation of China (51774075, 52174307), Liaoning Revitalization Talents Program (XLYC1802032). The authors greatly appreciate their support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [grant number 51774075] and National Natural Science Foundation of China: [grant number 52174307].