Abstract
The quality of steels generally degrades when the steels are used at elevated temperature for long periods. The degradation consists of an increase in the 50% shear fracture appearance transition temperature (FATT), and a decrease in the rupture ductility in the creep rupture test (creep embrittlement).
The creep embrittlement is more marked in the HAZ than in the base metal.
This paper describes the factors influencing the creep embrittlement and measures against it. The factors contain peak temperature of heat affected zone, PWHT temperature, impurity elements in steels, and Cr content ect.. The measures are higher PWHT temperature, decrement of impurity content, and addition of REM and Ca which scavenge impurities on the grain boundaries.
