Effect of Trace Elements on Creep Properties of 0.06C-2.25Cr-1.6W-0.1Mo-0.25V-0.05Nb Steel

摘要

The effect of trace elements such as Mn and B on creep properties of 0.06C-2.25Cr-1.6W-0.1Mo-0.25V-0.05Nb has been investigated from the standpoints of a long-term microstructrual stability. The chemical analysis of fextracted residues and TEM observation show that the M_(23)C_6 carbide and?or M_7C_3 carbides, precipitated by tempering are replaced by M_6C witha concentration of W; i.e., the amount of W in solution reduces during creep. On the other hand, MX type carbides such as VC and NbC are very stable during long-term aging and contribute to the creep strength by obstructing the dislocation annihilation.