Consider the ring casting shown below. This casting is to be

made from gray cast iron with a composition of $3\mathrm{.}5\%C,2\mathrm{.}2\%Si,$

and $0\mathrm{.}07\%P$ and a density of $0\mathrm{.}26lb\frac{s}{i}{n}^3.$ The pouring

temperature is $2650$ F $.$ Using the relationships given in lecture

and the fluidity chart in the back of this handout, calculate the

optimum fill time for this casting. $(6$ pts$.)$