One of the oldest known heat-treating processes is carburizing. History tells us that sword blades and primitive tools were made by the carburization of low-carbon wrought iron.
The following carburizing processes are commonly used in industrial applications:
(1) pack carburizing
(2) gas carburizing
(3) liquid carburizing
Most mild steels do not come with enough carbon to enable them to be hardened by heating
and quenching, as are the higher-carbon-content tool steels. However, if carbon is added to
the steel, it can be made to harden upon quenching. There are many methods of adding carbon.
In the processes, the heated steel absorbs the carbon from the outside.
The interior of the metal does not absorb the added carbon and so remains soft after quenching.
A hard carbonous surface, or case, is formed on the metal.
Case-hardening is accomplished by impregnating the surface of steel with carbon, by heating it
at high temperatures while packed in an iron or steel box with proper carburizing materials, or
by heating the steel in potassium-cyanide in an iron pot, an iron pot.
Features
- This book covers several methods of Case hardening
- Most of the processes listed can be done in a small shop.
