Question: A seamless pipe 600 mm in diameter is to be used to manufacture a pressure vessel designed to carry steam under a pressure of 2 MN. The vessel is made up of a continuous length of pipe with end covers that are butt-welded to the pipe on transverse sections. The pipe material has an ultimate tensile strength of 900 MPa, and a safety factor (based on ultimate) of 5 is specified. The allowable stress for the butt weld is 110 MPa. What should the wall thickness of the pipe be?