An electron metallographic examination has been performed on samples of a 1Cr–1Mo–0·75V (Ti,B) bolting steel (Durehete 1055) as part of a long term creep programme. The apparently anomalous carbide composition results have been rationalised by the use of pseudoternary phase diagrams. This novel method of presenting the alloy carbide composition data enables the changes accompanying service exposure to be described. It is obvious that the conventional thermodynamic order of stabilities does not obtain over the entire range of temperatures experienced by this alloy.
MST/914
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