Abstract
Systematical investigation has been conducted on the influence of impurities, alloying elements, and grain refining elements on the strength at elevated temperature and the temper embrittlement of 21/4Cr-1Mo steel.
Impurities such as P, Sb and Sn markedly increases the degree of the embrittlement. C content, cooling rate at quenching, and strength level also have a great effect on it.
The addition of grain refining elements and rare earth metals decreases the susceptibility to the temper embrittlement, while elements effective for strength at elevated temperature generally increases the susceptibility.
A combined addition of Ti, B and rare earth metals to 21/4Cr-1Mo steel induces both the high strength at elevated temperature and lesser degree of susceptibility to the temper embrittlement.
