Effects of electroslag remelting process and Y on the inclusions and mechanical properties of the CLAM steel

Abstract

Y-containing CLAM steels were melted via vacuum induction melting and electroslag remelting. In this study, the evolution, microstructure, and mechanical properties of the alloy inclusions (ESR-1 (0 wt.% Y), ESR-2 (0.016 wt.% Y) and ESR-3 (0.042 wt.% Y)) were investigated. Further, the number of inclusions in ESRed steel was observed to obviously decrease, and the distributions were more uniform. The fine Y–Al–O inclusions (1–2 μm) were the main inclusions in ESR-2. The addition of Y affected the prior austenite grain size (PAGZ), increasing the tensile strength at test temperature. Low ductile–brittle transition temperature (DBTT) was obtained because of the fine PAGZ and dispersive inclusions. For the ESRed CLAM steel with 0.016 wt.% Y, the yield strengths were 621 MPa at 20 °C and 354 MPa at 600 °C in air. Further, the uniform elongation and elongation of the ESR-2 alloy were 5.5% and 20.1% at 20 °C, respectively. Meanwhile, the DBTT tested using full-size Charpy impact specimen (55 cm × 10 cm × 10 cm) was reduced to −83 °C. Keywords: CLAM, Yttrium, Inclusion, Electroslag remelting, Mechanical properties