Effect of isothermal cooling on solidification behaviour of peritectic steel under in situ observation

In order to improve the volume shrinkage of peritectic steel during solidification, the solidification path of peritectic steel was changed by adjusting the cooling mode in this article. The solidification behaviour of peritectic steel under isothermal cooling conditions was studied by in situ observation experiment. The transformation shrinkage degree was reflected by sample surface roughness. The results show that the solidification path under the isothermal cooling is L→L+δ-Fe→δ-Fe→δ-Fe+γ-Fe without peritectic reaction. Moreover, the sample surface morphology was flat under isothermal cooling, and no granular morphology was observed. The surface roughness was 2.55 μm under isothermal cooling, which is much lower than that under different continuous cooling conditions. The surface roughness decrease indicates the solidification volume shrinkage is reduced. Therefore, the risk of cracking can be decreased by adjusting the cooling mode to control the solidification pattern of peritectic steel.