| 摘要 |
1381170 Austenitic steels; heat treatment KOBE SEIKOSHO KK [trading as KOBE STEEL Ltd] 7 March 1972 [9 March 1971] 10579/72 Heading C7A An austenitic heat-resisting steel, in which carbides precipitate on the grain boundaries in continuous or partially-continuous form to occupy at least 30% of the boundaries comprises, in weight per cent:- the balance being iron and impurities. After casting or working, the steel is solution heated to a temperature in the range of from 1150‹C to the solidus temperature, slow cooled down to a temperature not lower than 950‹C the duration of the cooling being 5 seconds to 1 hour, and then rapidly cooled, e.g. by water-or airquench. The heat-treated steels exhibit a high creep-rupture strength even at temperatures over 750 C, and are particularly suited for forging, or extruding to form heat-exchanger, reformer or cracking tubes, or rolling to sheet form. |
