About 55 million pounds of clean and contaminated superalloy scrap were processed in 1986; about 92 pct (50 million pounds) went to domestic buyers, and 8 pct (4.3 million pounds) was exported. About 93 pct (4.0 million pounds) of the exported material was refinery-destined grindings and 7 pct (0.3 million pounds) was vacuum-melting-grade superalloy scrap. Of the 55 million pounds of superalloy scrap processed in 1986, about 70 pct (38.5 million pounds) was recycled into the same superalloy, 20 pct (11 million pounds) was downgraded, and 10 pct (5.5 million pounds) was sold to refineries. The average element content of superalloy scrap processed in 1986 was about 44 pct Ni, 16 pct Cr, 5 pct Co, 2 pct Cb, less than 1 pct each of Mn and Ta, and nil for Re. The remaining 30 pet was primarily Al, Fe, Mo, Ti, W, and other minor constituents. The major changes in the superalloy recycling industry since 1976 were the introduction of premelted superalloy scrap as a material supply source and increased use of closed loop recycling agreements among forger-scrap processor-alloy producer-engine manufacturer groups. Since 1976 Inconel 718 has become the predominantly produced superalloy.

Source: J. F. Papp. "Superalloy Recycling 1976-1986". Superalloys 1988. TMS. 1988.
Read Article