| 摘要 |
1,174,342. Casting processes. GENERAL ELECTRIC CO. 7 Feb., 1967 [6 June, 1966], No. 5804/67. Heading B3F. [Also in Division H5] In producing alloy ingots by a consumable electrode vacuum arc-melting and casting process solidification cracks are prevented in the finished ingot by using an electrode formed of a central body 10, a bottom portion 14 and a top portion 12, said top portion being melted last to cover the top of the molten alloy of the ingot in a mould 18 and being made of a material that does not have a harmful effect on the alloy body of the ingot and that is ductile to prevent crack initiation and propagation into the ingot. The thickness of the top portion 12 when melted and solidified on the ingot has a nominal value of at least one inch. The central body 10 of the electrode may have a longitudinal hole 16 for holding alloying elements. In examples described the central body is made of sintered molybdenum and carbon rod with a hole 16 for holding titanium and zirconium alloying elements. The top and bottom portions 12, 14 were made of sintered unalloyed molybdenum. Other high temperature super alloys may be used such as tungsten base alloys and those based on iron, nickel and cobalt. In one example, cracking was prevented by providing a stress relief heat treatment process. The mould 18 is a water-cooled copper mould provided with a base padding 20 and chips 22 to facilitate arc starting. |
