A cylindrical steam boiler shell is of riveted construction. It is made from plates 18mm thick, and has a diameter of 1.8m. Calculate the circumferential and longitudal stresses in the plate when the internal pressure is 800kN/m^2. If the ultimate tensile stress of the material used is 600MN/m^2, and the efficiency of the longitudinal joint is 70%?. D etermine the factor of safety? Solution .