Cellular automaton modelling for the deflection of columnar grains of high-carbon steel with melt flow

ABSTRACT

The deflection of columnar grains grown under melt flow is characteristic of the alloy solidification structure and strongly influences the performance of products. Here, a model of grain growth in melt flow was established with the cellular automaton (CA) method. After validation by comparison to an analytical model, the model was used to investigate the deflection of columnar grains in high-carbon steel. The deflection angle of columnar grains increases with the flow velocity and decreases with the melt undercooling. At the flow velocity of 0.10 m s^–1 and the melt undercooling of 2°C, a maximum deflection angle of 18.2° is achieved. The deflection angles predicted by the model agree well with the empirical values. The melt flow was found to promote the grains with a preferred growth orientation towards the upstream direction over others. This flow-influenced selection mechanism is a key reason for the deflection of columnar grains.

KEYWORDS:

• Deflection
• high-carbon steel
• melt flow
• columnar grains
• cellular automaton method
• deflection mechanism
• grain growth
• mathematical model

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge the financial support of the National Key Research and Development Plan [grant numbers 2017YFB03044100, 2016YFB03001051], National Natural Science Foundation of China [grant numbers 51674072, 51704151], China Postdoctoral Science Foundation [grant number 2018M631805], and Fundamental Research Funds for the Central Universities [grant numbers 170708020, 172503013].