Creep Properties of 16Cr-14Ni Stainless Steel Bearing Carbon and Vanadium

Abstract

The creep rates were measured by the short period testing, during which the microstructural changes Were expected to be small, on 16 Cr-14 Ni stainless steels bearing carbon and vanadium with various heat treatments, and the correlation between creep rate and microstructure was discussed. For the solutiontreated condition, the creep rate of steels increases with increasing contents of both carbon and vanadium.
The values of coefficient of stress dependence of minimum creep rate and the activation energies of the creep are 5 to 9 and 1OO to 200 kcal/mol, respectively. The increasing tendency of these values with alloying was observed. The effect of precipitated M₂₃C₆ on the creep rate was observed, that is the precipitation of a great deal of fine M₂₃C₆ carbides leads to the lower creep rate and the coalescence of the threadlike VC carbides leads to the higher creep rate.
The creep strength of the steels with the precipitation of both threadlike VC and granular V₂C carbides is smaller than that of the solution treated steels. In the comparison of steels with the similar matrix composition, however, the strengthening effect of vanadium carbide is obviously observed.