High temperature yield strength, good structural stability during high temperature application and delta ferrite are basic requirements for 321H austenitic steel for nuclear reactors.
A controlled TiC/TiCN particle count/area , along with other intermetallic phases and precipitates except grain boundary Cr23C6 carbides are helpful in achieving good high temperature tensile and creep properties along with good corrosion resistence in this steel.
Shivraj