| 摘要 |
1289621 Aluminium alloys ELECTRONIC SPECIALTY CO 14 Jan 1970 [15 Jan 1969] 1768/70 Addition to 1090960 Heading C7A An aluminium base alloy has a composition, in percent by weight, in the following range Cu 3À5-6À0 Ag 0À05-3À0 Mg 0À15-0À4 Al and impurities the remainder subject to the presence of the following optional constituents Mn 0-1À0 Ti 0À15-0À7 Zn 0-4À0 Cr 0-0À5 Si less than 0À15 Fe less than 0À15 B 0À001-0À05 Mo less than 0À3 Ce less than 0À3 Other elements such as Cd, Na, Ca, Li, Co, Sn, Sb, Ni, Zr may be present up to 0À15 in total and up to 0À05 each. The alloy may be prepared by melting down high purity Al with returns from previous castings, adding an Al-Ti master alloy, electrolytic copper, silver and zinc (if required). Nitrogen is bubbled through via a graphite pipe. An Al-Ti-B alloy is then added followed by pure Mg. A grain refiner such as a 2:1 mixture of K 2 TiF 6 and KBF 4 may be added before pouring. In order to remove Na, herachlorethane or chlorine gas may be added at 1300‹ F. After casting heat treatment may consist of 3 to 8 hours at 980-1000‹ F., quenching in water at 130‹ F. and age hardening for 8 to 24 hours at 280-340‹ F. |
