Abstract
(1) Alloying method. First by sintering process we prepared a mother alloy of 10 per cent of chromium and 90 per cent of copper. Then it was alloyed with copper melt and we obtained copper alloys containing about 0.5 per cent of chromium.
(2) Hot and cold working properties. We could deformed these alloys easily in both hot and cold states.
(3) Age-hardening properties. As in the preliminary experiments, by measuring hardness change we studied age-hardening properties of cast alloys which were quenched from 950° and aged from 300° to 700° for 1 hour. The maximum. hardness was obtained with the tempering temperature of 500°. For the temperature of solution treatment, 950° is insufficient and above 1000° is nesessary. Next, for the tempering time, treating at 500° for 1 hour or 450° for 3 hours we obtained the maximum hardness.
(4) Properties for electrical conductors. We made three kinds of wires (diameter 2 mm): first, after cold-drawn to 2 mm, solution treated and quenched, then tempered; second, after quenching, cold-drawn to 2 mm and tempered; third, after quenching, cold-drawn to intermediate diameter, tempered and then cold-drawn again. For example, properties obtained are as follows:
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(5) Conclusion. For electirical conductors, this, alloy has very good conductivity, but its strength is inferior to that of alloys, such as copper-cadmium or corson alloys. However, we think there is a hope of to improving its tensile properties a little more by the modification of production process.
