Castability, lead alloys

The use of lead alloy (traditionally lead-antimony, with 5 per cent or less antimony) for the inert grids is based on the metal s excellent corrosion resistance, alloying capability and castability, and the benefits it imparts in paste to grid adhesion. Due to these properties, and its relatively low cost, lead remains a highly suitable material for the manufacture of efficient and competitive battery systems, despite its weight. 

Lead alloys characterized by the addition of selenium exhibit a fine grain structure even at very low antimony contents (<2%). This structure yields acceptable quality of the castings as indicated by mechanical strength, natural hardness, age-hardening and total hardness, and also yields acceptable castability characteristics. The hardness necessary for handling the battery plates is achieved by age-hardening due to finely dispersed antimony. 

Arsenic added in amounts of 0.1—3% improves the properties of lead-base babbitt alloys used for bearings (see Bearing materials). Arsenic (up to 0.75%), has been added to type metal to increase hardness and castability (21). Addition of arsenic (0.1%) produces a desirable fine-grain effect in electrotype metal without appreciably affecting the hardness or ductility. Arsenic (0.5—2%) improves the sphericity of lead ammunition. Automotive body solder of the composition 92% Pb, 5.0% Sb, and 2.5% Sn, contains 0.50% arsenic (see Solders and brazing alloys). 

Pewter (metal alloy) An easily castable, tin-based, non-work-hardenable aUoy. A non-leaded composition is 91% tin, 7.5% antimony, and 1.5% copper. A leaded composition can be 70% tin and 30% lead. 

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