Effect of Normalization Heat Treatment on Creep and Tensile Properties of Modified 9Cr-1Mo Steel

摘要

Creep and tensile properties have been investigated on modified 9Cr-1Mo steel subjected to single and double normalization heat treatments. Optical, scanning and transmission electron microscopic investigations revealed the presence of finer prior austenite grain size and coarsening of MX precipitates in the double normalized steel as compared to the steel subjected to single normalization heat treatment. Increased minimum creep rate and significant reduction in creep rupture life were observed in the double normalized steel. Increased tensile ductility coupled with marginal decrease in tensile strength was observed with double normalized steel compared to single normalized steel. The double normalized steel exhibited lower creep strength and higher tensile ductility than the single normalized steel.