![]() As much hardness data exist, and as hardness is easily measured, this would perhaps be more useful for calculation of thermal conductivity. Sufficient hardness data exist such that some further work would yield the desired thermal conductivity-hardness correlation. With further input of the volume % of each microstructure for each datum, the thermal conductivity could be predicted as a function of composition, heat treatment and temperature. However, the existing data could be studied by matrix statistics with modern computers. The lack of studies suggests that funding authorities did not expect worthwhile correlations to be obtainable. The lack of systematic data suggests that few studies have been conducted of thermal conductivity per se. Thermal conductivity can be greatly decreased by alloying (especially, with a change in structure to austenite) and slightly by hardening. Oil quenched from 850 oC + Tempered 1 hr at 600 oC + oil quenched, sometimes simply Q + T, annealed, normalized, normalized + tempered, normalized + stress-relieved at 600 oC, solution treated, solution treated + aged, etc. For each datum for other steels, in addition to composition, the heat treat state is specified: The carbon steel data listed above (%C as stated, Mn contents range from 0.31 to 0.64%) are for the annealed state. Thermal conductivity units are W/m/ oK ( = 418.4 x cal/cm/sec/deg oC). 14-27 to 14-41 in Smithells Metals Reference Book, 7th Edn. The data given by EnglishMuffin are included in ‘Table 14.11 PHYSICAL PROPERTIES OF STEELS,’ PP. RE: correlation of steel hardness and thermal conductivity Goahead (Aerospace) 14 Dec 03 08:56 Further testing could reveal the ferrite and cementite components of the pearlite conductivity, with corrections for interfaces. The data are for an 18-8 austenite, a ‘low-metalloid’ α-Fe ferrite, annealed 0.83%C steel for pearlite, and quenched 0.83% C steel for martensite. 13.7 in Physical Metallurgy Handbook (2003), reproduced from Quenching Flow of Heat in Metals, J. temperature for each of these structures is given on p. A composite model would be needed, as conductivity differs for the austenite, ferrite, martensite and pearlite microstructures. However, it would need to be done on a case-by-case basis per specific steel alloy, since conductivity varies with alloying, heat treatment and cold working. In principle, a correlation could be developed for steels. For these metals, the electrical conductivity (directly related to thermal conductivity by the Wiedemann-Franz law) can be used to follow annealing and age-hardening processes. However, the only practical ones with which I am familiar are for copper, brass and aluminum alloys. Correlations do indeed exist between hardness and thermal conductivity.
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