Effects of Alloying Additions and Material Microstructure on the Accuracy of the Predictive Law of Creep Crack Growth for W-Strengthened 9-12%Cr Ferritic Heat-Resistant Steel *

The life of creep crack growth for W-strengthened 9–12%Cr steel is sensitive to the alloying additions and to differences in material microstructure, such as lath martensitic structure and grain size caused by differences in cooling rates in the steel ingots during the manufacturing process, which results in the large scatter of experimental data from the law of creep crack growth life. In the present study, creep crack growth tests were conducted using W-strengthened 9–12%Cr steels with various contents of alloying additions and the dimensions of micro-nano structures. The effects of the composition of alloying additions and material microstructures on the life of creep crack growth for W-strengthened 9–12%Cr steel were clarified. [doi:10.2320/matertrans.MRA2007112]