The steel industrially employed for the transport of liquid hydrocarburics
in the presence of hydrogen at high temperatures is ASTM A335 P11, a steel
for seamless pipes for use at high temperature. Three different kinds of te
sts have been performed: tests of prenatured fracture, tests of thermal ana
lysis and infrared analysis. The present work has deeply studied the mechan
isms of interaction between hydrogen and steel, trying to integrate and mot
ivate the industrial data, commonly used for plant planning and sizing (A.P
.I. Diagrams), proving that the cause for the damaging of this material is
mainly due to the harmful interaction of carbides and inclusion with hydrog
en. (C) 1999 International Association for Hydrogen Energy. Published by El
sevier Science Ltd. All rights reserved.