Continuous Casting Shape&Dimension Problems

Various shape defects occur in the slabs produced in the continuous casting facility, depending on the problems experienced during casting. These defects can cause quality defects and equipment damage in the rolling processes later in the operation.

In this article, we will examine the problems that occur during slab casting. You will find information about the solutions we have realized as SpechtLab.

Off Flat / Bow Shape

This defect is identified when a wide slab/slab bends in its length axis. The temperature difference between the bottom and top surface of the slab can cause the defect to occur.

Tapered Slab

With the exception of the die width change during casting, lowering the casting speed basically results in a narrower plate end. This situation can often occur due to an unstable casting. The result of this is "extra" shrinkage of the billet due to a higher heat transfer (as the time inside the mold increases).

Bulge / Crown

This defect occurs when a tensile stress on the wide faces of the slab due to ferrostatic pressure is higher than the solidified shell can support. This type of issue can be caused by a combination of the following two reasons or one of them:

1) Low water flow to the secondary cooling zones, which introduces a thin solidified crust;

2) Bad compression

Convexity

This defect is the same as bulge/crown, but occurs on the narrow faces of the slabs: the tensile stress on these faces is higher than the solidified crust can support, due to ferrostatic pressure. The main reason for this is low heat transfer to the narrow faces of the mold and a thin solidified crust as a result.

Concavity

This defect is defined as a narrow facial depression. The main reasons for this are high heat transfer to the narrow faces of the die and a poor die taper.

Height Difference Between Edges(Wedge)

This defect is defined as a trapezoidal shape in cross section. The root cause is poor segment alignment (upper and lower rolls)

SpechtLab Profile Measurement System

The profile measurement system we developed as SpechtLab creates a profile along the slab surface. The quality defects appearing in the slab profile are detected and followed on the operator's screen.