Abstract
The development and application of separately controlled atmospheres for use in conjunction with heat-treating processes has been rapid during recent years. By means of controlled atmospheres, finished machine parts which require heat-treatment can be processed without loss of surface hardness during heating, and without further grinding or cleaning. Many other applications in the treatment of metals, such as welding, forging, melting, sintering, and the like, are possible although at present somewhat limited. This paper outlines the principal types of atmospheres and describes briefly the equipment available for producing these atmospheres. A summary is given of the application of these atmospheres to a wide variety of heat-treating processes now in active commercial use.
