Alloy carburizing

Low alloy carburizing steels wrought, quenched tempered 178 (1227) 62 (427)... 

With these initial assumptions, it was concluded that the corrosion model fails in predicting the right corrosion behavior for some helium compositions. Indeed, a slight alloy carburization was observed even when the steady-state carbon activity in the gas phase was lower than that needed for the formation of chromium carbides Cr23C6. To include this behavior in the model, the author [10] proposed to consider the Pq and a involved at the metal—oxide interface and not in the gas volume. These potentials depend strongly on the morphology of the oxide layer on the alloy surface. 

In ancient India, a steel called wootz was made by placing very pure kon ore and wood or other carbonaceous material in a tightly sealed pot or cmcible heated to high temperature for a considerable time. Some of the carbon in the cmcible reduced the kon ore to metallic kon, which absorbed any excess carbon. The resulting kon—carbon alloy was an excellent grade of steel. In a similar way, pieces of low carbon wrought kon were placed in a pot along with a form of carbon and melted to make a fine steel. A variation of this method, in which bars that had been carburized by the cementation process were melted in a sealed pot to make steel of the best quaUty, became known as the cmcible process. 

Environments. Among the environmental factors that can shorten life under thermal fatigue conditions are surface decarburization, oxidation, and carburization. The last can be detrimental because it is likely to reduce both hot strength and ductility at the same time. The usual failure mechanism of heat-resistant alloy fixtures in carburizing furnaces is by thermal fatigue damage, evidenced by a prominent network of deep cracks. 

Green Rot-a corrosion product particular to nickel alloys and greenish in color that normally results from carburization and oxidation of certain nickel alloys at temperatures around 1000 C (1832°F). 

DICTRA (Diffusion simulation software) (Borgenstam et al. 2000). DICTRA (coupled with Thermo-Calc) is a software for the simulation of diffusion in multi-component alloy systems (processes which can be simulated are for example the homogenization of alloys, micro-segregation during solidification, carburizing, and decarburizing, of steels, etc.). 

Carburizing One of several thermochemical treatments involving, by heating, carbon absorption from suitable material in contact with the surface layer, and diffusion into solid (ferrous) alloys. Surface hardening processes may then be... 

The two basic types are (1) through hardenable, and (2) surface harden-able. Subcategones of surface hardenable alloys include carburizing alloys, flame and induction-hardening alloys, and nitriding alloys. 

Pack and go carburizing creaie a diffused caiboii case. Base metals arc low -carbon steels and low -carbon alloy steels. Process temperature range is XIS-9.KO C H500 2000 F>. 

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