| Abstract |
| In this investigation, effects of nitrogen on the precipitation behavior of Fe-Cr-Mo ferritic steels were studied. Three alloys having different nitrogen content were manufactured by vacuum induction melting in N₂ gas atmosphere. Major precipitates in these steels containing 88 ppm.~682 ppm. nitrogen were M_(23)C_(6) and fine MX. Also, FeW₂B₂ and Cr₂C phases were precipitated in as-tempered condition. The precipitation rate of M_(23)C_(6) and MX were accelerated by addition of nitrogen. However, formation of the FeW₂B₂ phase was suppressed with increase in nitrogen contents. This is due to the increase of W solubility in the matrix by higher stabilization of austenite with increase in nitrogen contents. Small amounts of Laves and CrN phases were additionally precipitated in specimens tempered at 650℃ for 3 hours and aged at 700℃ for 1000 hours. (Received November 22, 2004) |
|
|
| Key Words |
| Fe-Cr-Mo ferritic steels, Precipitation behavior, FeW2B2 phase, Nitrogen effect |
|
|
 |
|
