| 摘要 |
1276080 Progressive crystallization UNITED AIRCRAFT CORP 19 April 1971 [28 April 1970] 26151/71 Heading BIS [Also in Divisions B3 and H5] An assembly for making directionally solidified castings comprises a shell mould 10 placed within a bore 8 of a susceptor 6 surrounded by induction coils 2. The susceptor 6 has a varying wall thickness to control heat-loss from the metal cast in the mould and to control heating of the mould. At the base of the mould is a cavity 14 in which is placed a slug of alloy to be cast. The cavity 14 is sealed with a cap 17 and the mould 10 is held in the susceptor 6 by a screw-cap 28. The coils 2 are energised to melt the alloy in the cavity 14. The assembly is inverted and placed upon a chill plate (not shown), thereby pouring the alloy into the article-forming cavity 20, 22, 24 of the mould to form a turbine blade. The induction heating is switched off or reduced and solidification proceeds upwardly from a single crystal-selecting helix 26 (now at the base of the assembly and adjacent the chill plate) into the article-forming cavity 20, 22, 24. Columner grained castings can also be made if the helix 26 is omitted from the mould and a crystal growth zone substituted. |
