Heat Treatment of Heavy Section Low Alloy Steel Plates

Abstract

H eavy section low alloy steel plates are used Jar nuclear reactor and direct oil desulj"u ri z ing reactor p ressure vessels, etc. H igh integrity is, therifore, required oJ these steel plates. The J actors which aifect the internal soundness and notch toughness oJ heavy section low alloy steel plates are discussed in relation to heat treatment after rolling. Precipitation behavior oJ aluminum nitride in A 533B steel pla tes during hea t treatment cifter rolling is described w ith respect to the austenite grain size and notch toughness if the plate aJter .final rolling. Cooling down to 400°C beJore normali z ing is recommended to obtain good notch toughness. Selection oJ tem/)erature and time Jor dehy drogenation at the J errite region is discussed and it is shown that the op timum temperature Ja r dehy drogenation must be determined by takillg microsegregation in the plate into consideration.