In killed steels, shrinkage occurs at the top of the ingot due to no gas formation. What action is required before rolling?

• A. Shrinkage occurs at the top of the ingot and must be removed prior to rolling.
• B. Shrinkage occurs at the bottom.
• C. No shrinkage occurs.
• D. Shrinkage occurs uniformly.

Answer: (A)

In killed steels, shrinkage porosity forms at the top of the ingot because there is little or no gas escaping during solidification, so a void develops as the metal contracts at the surface. The correct action is to crop or trim off that top portion before rolling to expose sound metal. This removes the defect before it can be reduced and spread into the finished product during rolling, ensuring better internal quality and surface finish. Shrinkage at the bottom or uniformly, or no shrinkage at all, doesn’t match the observed behavior, so removing the top defective layer is the appropriate step.