Oxidn.-resistant lead alloy for electrical accumulator - contains calcium aluminium, silicon, opt. tin, balance lead

摘要

The alloy contains 0.02-0.15(0.06-0.09)% Ca, 0-2(0.2-0.6)% Sn, 0.005-0.1-(0.007-0.015)% Al and also 5-20(10-15)%, w.r.t. Al, Si, balance Pb. The addn. of Al + Si prevents Ca loss by oxidn. at melting temp. Top temp. in Pb alloy prepn. is =600 degrees C. The Pb alloy is prepd. by (i) melting refined Pb in a fusion kettle; (ii) adding a ternary PbAlSi pre-alloy and then (iii) adding a binary PbCa pre-alloy and opt. Sn as Sn metal or PbSn pre-alloy. The PbAlSi pre-alloy is made by melting Pb with an AlSi alloy at 600 degrees C, e.g. by adding 0.05-1 kg. "AlSi-12" (RTM), contg. 11-13.5% Si, to 100 kg. Pb at 590 degrees C. The final alloy is made by adding 1 pt.wt. PbAlSi to 10 pts. wt. Pb at 400 degrees C; and while still molten, 1 pt.wt. PbCa pre-alloy contg. 1% Ca and opt. Sn.