A pipe carrying steam at 3.5 MPa has outside diameter 450 mm and wall 10 mm. How many 40 mm bolts are needed to hold the end cap if the allowable bolt stress is 80 MPa, of which 55 MPa is initial stress? What circumferential stress is developed? (answer: number of bolts; stress in MPa) Assume the pressure load is shared equally by the bolts and added to the initial stress.