$($A$)$ A thin porcelain coating becomes bonded to the underlying stainless steel when both are heated to about $600C.$ During subsequent cooling the enamel ceases to flow at about $425C$ and becomes stressed by the more rapidly contracting steel at $25C.$ If ${}_p=9{10}^{-6}(\frac{1}{C})$ and ${}_s=12{10}^{-6}(\frac{1}{C})$; calculate the blocked strain at the interface $(5$P$)$;

B$)$ if $ES=20{10}^{10}Pa$ and $Ep=10{10}^{10}Pa$ calculate approximately the compressive stress that occurs on porcelain coating and tensile stress that occurs on steel plate and draw schematically the deformation and stresses on the coated material $($SP$)$