Carburization of steels-An overview

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">A high carbon upper layer is produced by diffusing carbon and the carburized steel is used in gears, crankshafts where high ware and tare occurs. The thermodynamic, kinetic and transport phenomenon occurring during carburization is studied. Importance of thermochemical phase diagrams to determine the stability region of the oxides and carbides is illustrated. The relationship between the composition of the carburizing atmosphere and the carbon content of the steel is brought out Development of a suitable heat treating environment for obtaining the correct penetration depth is attempted. Mechanism of carburization, kinetic and reaction mechanism of decomposition of gas mixture on the steel surface is described. Models for predicting carburization depth are reviewed. A diffusion model is proposed which is applicable to any diffusion-cum-reaction process. Application and hazards of carburization are explained.</span>