Causes and characteristics of longitudinal cracks in continuous casting billetThe longitudinal cracks on the surface of continuous casting billet are those occu
Causes and characteristics of longitudinal cracks in continuous casting billet
The longitudinal cracks on the surface of continuous casting billet are those occurring along the casting direction, including the longitudinal cracks on the face and the longitudinal cracks on the corner. The longitudinal cracks usually occur in the center of the broad surface of the slab and in the corners of the square slab. The surface longitudinal crack directly affects the billet quality. After observation, the characteristics of the longitudinal crack structure are as follows :(1) compared with the part without crack, the quench layer composed of fine equiaxed grains in the crack area is thinner. (2) The thinner the quench layer, the greater the crack depth.
The main reason for the longitudinal crack is that the thickness of the initial billet shell is not uniform due to the uneven cooling strength in the mold, and the stress is concentrated in the place where the billet shell is thin. When the stress exceeds the tensile strength of the billet shell, the crack occurs.
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