Structure and Tensile Properties of Pb–0.3%Sn–0.1%Ca Negative Grid Alloy for Lead-Acid Batteries

Abstract

The structure and tensile properties of Pb–0.3%Sn–0.1%Ca alloy for negative grids of lead-acid batteries have been characterised as functions of mould preheating temperature during casting and ageing time during storage under atmospheric conditions. Several techniques have been used to study microstructure, including quantitative metallography, scanning electron microscopy, and energy dispersive analysis. Tensile properties such as ultimate tensile strength, yield strength, Young’s modulus, and elongation have been determined at room temperature. The increase of mould preheating temperature in the range between 60 °C and 170 °C causes the decrease in ultimate tensile strength (by ~25 %) and increase in elongation (by ~50 %) due to twofold increase in the grain size of the alloy. Whereas natural ageing for 35 days influences neither grain size nor tensile properties markedly.

Keywords

• lead-acid batteries
• negative grids
• lead-tin-calcium alloy
• casting conditions
• mould temperature
• natural ageing
• grain size
• tensile properties