This article introduces a practical technique pioneered by a metallurgist at the Indian Institute of Technology. The technique enables any kind of steel to be heated without the problems associated with oxidation and decarburization.
Heat treatment is an important operation in the manufacture of engineered metallic components, machine parts and tools. The oxidation and decarburization of steel take place when steel components are heated in the presence of air or products of combustion. Undesired and excessive oxidation can lead to problems such as scale pit marks, dimensional changes, poor surface finish, rejections and quench cracking. Additionally, these problems may lead to the need for expensive operations like shot blasting, machining and acid pickling. Protection against scaling and decarburization is achieved by heating in molten salts, fluidized-bed furnaces, protective gaseous media or vacuum. These measures demand heavy capital investment, highly skilled personnel and special safety precautions. Many companies cannot afford them, yet they are under mounting pressure to prevent oxidation and decarburization.