Thermal and electrical conductivities of an improved 9 Cr-1 Mo steel from 360 to 1000 K

The electrical and thermal conductivities and Seebeck coefficients of three 9 Cr-1 Mo samples were measured over the temperature range 360-1000 K. All of the samples were in the normalized and tempered condition and two of the samples were from different heats of a new, modified alloy. The thermal conductivity of the third sample, which was from a commercial heat, was found to agree well with the ASME code values for this steel. The two heats of modified 9 Cr-1 Mo were found to have significantly higher thermal conductivities and this difference appears to be due to the lower Si content of the modified alloy. The results were compared with the predictions of standard transport theory and data on bcc Fe. These comparisons show that phonon energy transport is important and quite dependent upon the Si content. 24 references, 6 figures, 2 tables