The surface folding defect of continuous casting billet refers to the transverse folding marks that appear on the surface of continuous casting billet, which is usually accompanied by transverse cracks. This defect is mainly caused by the following reasons:
Tear of solidified shell in copper mould tube: In the crystallizer, the solidified shell formed by the solidification of molten steel is subjected to uneven cooling, which may cause the shell to tear. The molten steel leaking from the tear immediately solidifies on the surface to form folding marks.
Improper adjustment of copper mould tube vibration parameters: If the vibration parameters of the crystallizer are improperly set, the solidified shell may be unevenly generated, causing folding defects.
Poor alignment between the copper mould tube outlet and the secondary cooling section: Poor alignment between the crystallizer outlet and the secondary cooling section will cause the solidified shell to be unevenly cooled when it leaves the copper mould tube, which may cause folding defects.
Poor crystallizer lubrication: If the lubrication in the crystallizer is poor, the billet shell and the copper wall will adhere, which may cause the solidified shell to tear, thereby forming folds on the surface.
In order to prevent this surface folding defect, it is necessary to correctly adjust the vibration parameters of the crystallizer, ensure that the crystallizer outlet and the secondary cooling section are accurately aligned, and maintain good lubrication conditions.
