Evolution of the tempered lath structure of the 12%Cr steels with low N and high B contents during creep

Abstract 9-12%Cr martensitic steels are promising materials for elements of boilers, tubes, pipes, heaters and steam blades fossil power plants, which able to operate at ultra-supercritical parameters steam. Creep tests were carried out two 12%Cr 9%Cr 650°C. After tempering 750-770°C, a tempered lath structure was revealed in all the studied. The 12%Cr-Ta steel had smallest width among studied that provided longest creep rupture time after test 650°C/120 MPa. During creep, applied stress causes growth formation subgrains instead laths. experimental sizes equilibrium subgrains, calculated on balance driving retarding forces using dependence size during compared estimate contributions secondary particles different steels.