Continuous Casting of Carbon Steel

Presuming same flow rate on water, and mold oscillations, the lack of hardenability in the low mn material (six points of mn = 1 point of carbon for hardenability) is probably resulting in too thin an initial chill, wall thickness in your casting. Slow the withdrawal rate , increase sprays, increase flow of water through molds.

Hardenability carbon equivalent at .35 C + .90 Mn = .35+.90/6= .35+ .15= .50CE;

HCE at .28 C and .60 Mn= .28+ .60/10= .38CE

Chemistry differences do result in casting differences.

milo (wait till you try cold heading quality at .10 max carbon and .30 Mn!)