PRESSURE-VESSEL STEELS - PROMISE AND PROBLEM

With respect to fabrication, lamellar tearing is being minimized by special melting and solidification practices. With respect to bursting, recent studies indicate that high-yield-strength steels have higher burst-strength indices than lower-strength steels even for vessels with unground weld reinforcements, with nozzles, and with notches up to 25 pct of the wall thickness. Strength, and therefore resistance to bursting, can be increased without loss in toughness through new control-rolling practices, except that these practices are limited to plates up to about 3/4 in. (19 mm) thick. New high-toughness line-pipe steels are now available that should be very attractive for pressure vessels that require very high resistance to shear tearing.