Abstract
The melting of gunmetal under the oxidising atmosphere decreases the hydrogen content and improves the mechanical properties of gunmetal.
The auther recomends the following operations.
(1) Melt the cathode cupper in the crucible in oxidising atmosphere without flux up to 1,200°C or 1,250°C.
(2) Deoxidise the melt with 0.2% phosphor-cupper.
(3) Cover the surface of the melt with common salt of 0.2%.
(4) Add zinc.
(5) Tin followed.
(6) Draw out the crucible at about 1,300°C.
By this process, the mechanical properties are impnoved to the following degree, the tensile strength 8%, the elongation 20%, the specific gravity 1.7% etc.
