Short-term creep of advanced re-containing 10% Cr – 3% Co – 3% W martensitic steel at elevated temperature

Nine–12%Cr heat-resistant martensitic steels are the perspective materials for the elements of boilers, tubes and pipes for the fossil fuel power plants which are able to work at ultra-supercritical parameters of steam (T = 620– 650°C, P = 25–30 MPa). The advanced martensitic 10Сr–3Co–3W–0.2Re steel was crept at temperature of 650°C under the applied stresses from 200 to 140 MPa with a step of 20 MPa. Previously, the steel studied was normalized at 1050°C and tempered at 770°C. The addition of Re in the advanced martensitic 10Сr–3Co–3W–0.2Re steel positively affected the short-term creep at 650°C and stabilized the tempered martensite lath structure formed during tempering at 770°C. Moreover, no evidence for the significant changes in the tempered martensite lath structure of the 10Сr–3Co–3W–0.2Re steel excepting the precipitation of the Laves phase particles were revealed during 440 h of creep. The improvement of short-term creep strength can be related to the particle hardening from the Laves phase particles with the high volume fraction and the fine sizes.