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

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

• A. Remove the bottom of the ingot.
• B. Leave as is.
• C. Add deoxidizers.
• D. Remove the top of the ingot.

Answer: (D)

In killed steels, the lack of gas formation means shrinkage cavities form where solidification finishes—the top of the ingot. That top region tends to be porous and defect-prone, so it’s trimmed off before rolling to ensure the material you roll is sound and free of voids that could cause cracks or weakness in the final product. If you leave it, those defects can propagate into the rolled sections. Removing the top addresses the problem directly, while removing the bottom or adding deoxidizers wouldn’t fix the top shrinkage problem.

In killed steels, the lack of gas formation means shrinkage cavities form where solidification finishes—the top of the ingot. That top region tends to be porous and defect-prone, so it’s trimmed off before rolling to ensure the material you roll is sound and free of voids that could cause cracks or weakness in the final product. If you leave it, those defects can propagate into the rolled sections. Removing the top addresses the problem directly, while removing the bottom or adding deoxidizers wouldn’t fix the top shrinkage problem.