Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Malleable Bronze
Hard bronze may be made malleable by the addition of from 1/2 to 2 per cent mercury, which may be combined with either of the metals composing the mixture before the bronze is finally made. It can be put into the melted copper at the same time the tin is added, or can be used as an amalgam with the tin. See BRONZE; ALLOYS; BRASS.
Malleable Cast Iron is made by a process of de-carburizing the articles made from cast or pig iron in the annealing furnace, where they are subjected to an oxidizing atmosphere somewhat below the fusing-point. The furnaces employed for this purpose consist of iron plates to enclose the necessary space, which serve also as guides for the doors, which are raised perpendicularly, being balanced by a weight at the back of the furnace. The inside of the furnace consists of fire-space and the oven proper, an arch extending over both, the fire-space being separated from the oven by a bridge wall extending nearly to the arch, leaving only a narrow space through which the flame is forced by the blast, completely filling the oven. The gases escape through small outlets in the corners to the flues below, which are fitted with a damper operating from the front. The castings to be rendered malleable are placed in cast iron covered boxes or saggers, along with oxide of iron, and subjected to a red heat in these furnaces for from two to six days, according to the magnitude of the castings. They are then allowed to cool slowly. See DECARBONIZE.