Abstract
The effect of molybdenum on creep-rupture properties and room-temperature toughness of 10Cr-Mo-0.1V-0.05Nb heat resisting steels was investigated. The amount of molybdenum content was varied from 0 wt% to 3 wt%. The influence of molybdenum content on creep-rupture strength and Charpy absorbed energy was investigated with respect to the ratio of delta ferrite to tempered martensite, the precipitates, the microstructure, and the lattice parameter.
The results indicated that the 10Cr-0.1V-0.05Nb steel with Mo-content less than 1.5 wt% had good toughness, and higher long term creep-rupture strength as compared to steels containing more than 1.5 wt%Mo. Charpy absorbed energy was analyzed in relation to the amount of the extracted residue, Vickers hardness, and delta ferrite content. It was concluded that the optimum amount of delta ferrite for creeprupture strength and Charpy absorbed energy was 10-20%, and the associated optimum molybdenum content was about 1.5 wt%.
