Continuous Casting of Low-Carbon Steel Slabs by the Hazelett Strip-Casting Process

Summary

The Hazelett Strip-Casting has the attractive advantage of rapid change of slab width and thickness. It was demonstrated during our program that width was easier to change than thickness.

From our experience, machine operation was good and attention was required only for routine mechanical maintenance and belt replacement. As a result of our own design innovations, satisfactory edge-dam operation was achieved and we believe that the stationary water-cooled edge-dams will have long, troublefree life.

Concurrent motion of the mold belts and the solidifying slab did not result in the anticipated improved surface quality. In particular, the top surface was extremely vulnerable to oxide pitting.

The advantage of low head room was not realized. Casting at a 20° angle caused an oxide segregation which resulted in a metallurgically unacceptable product for sheet application produced from either Alkilled or vacuum-treated steels. No way to remove these oxides was found. Operation of the mold in the vertical position is a possibility to overcome this problem.

In the case of casting slabs of less than 3 in., the system is judged not to be practical for high-tonnage production; however, the 6 × 14-in. tests reveal a potential of at least as high and perhaps higher tonnage rates than are currently reported for conventional casting machines. Thicker sections would further increase the tonnage throughput, and we see no reason why this is not possible.

As for casting speed, the Hazelett machine has demonstrated a capability of high casting speeds, and our thermal analysis coupled with anticipated new designs including longer molds indicate that still higher tonnage throughputs are feasible.