Creep behavior of a 10% Cr heat-resistant martensitic steel with low nitrogen and high boron contents at 650 °C

The purpose of this study is to identify the relationships between the creep behavior of the 10% Cr martensitic steel with 0.008% B and 0.003% N and changes in microstructure and precipitations of secondary phases. Creep tests were carried out at 650 °C under an applied stress ranging from 180 to 120 MPa. The 10% Cr steel exhibits a linear stress vs. time to rupture dependence without creep strength breakdown up to approximately 40 000 h. The 100 000 h creep rupture strength at 650 °C is predicted to be 110 MPa. The high creep strength of the 10% Cr steel is attributed to high threshold stress of 111.5 MP