$(4$ marks$)$ We would like to produce a $2-$in$.-$thick steel wear plate for a rock$-$crushing unit. To

avoid frequent replacement of the wear plate, the hardness should exceed HRC $38$ within $0\mathrm{.}25$

in$.$ of the steel surface. The center of the plate should have a hardness of no more than HRC

$32$ to ensure some toughness. We have only a water quench available to us $(H=1\mathrm{.}0).$ Select

the appropriate material for the plate, assuming that we only have the steels given in the

figure below available to us$.$ Justify vour selection