Cast iron is subsumable to thermo shock. That means heat-up and cool-down slowly, if not it may warp or crack..Cast iron can take extremely high heat. An example would be a heat deflector used in my
kamado. The charcoal fire is over 750º+... Any cast iron should be heated-up with the pit or flame from cold. Once it starts to heat, crank on the heat..Cool-down; just let it cool gradually..
High temperatures, say over 450º will burn the seasoning off requiring re seasoning...I find 425ºish to be a good temperature to cook a steak on C I. Let us know the outcome please.