Carburizing

Liquid Carburizing (salt bath)

The parts submitted to great stresses have been carburized for decades in salt baths. The carburizing, which consists of a surface enrichment with carbon, is until today the most used thermochemical treatment to obtain steel parts with surfaces that can stand high stresses and that are wear resistant, keeping at the same time its ductile core.

To reach carburizing depths in feasible times, the carburizing baths include, besides the carbon providing elements, the so called activators, which are products that accelerate the carburizing reaction. These activators increase not only the carburizing speed but also the carbon offer and the transportation speed of carbon from the liquid medium to the parts surface.

In the carburizing processes that use the “SINGLE-SALT System”, the composition of the replenishment salt is adjusted in a way to always keep the correct proportion of the activation in the carburizing bath, no matter the added quantity, and because of this to provide a carbon potential within narrow pre-determined limits, with great repeatabilty. This system reduces the risk of unbalance of the baths due to possible operational mistakes. We have developed single-salt systems for several carburizing needs.

In the carburizing processes that use the “2 SALT system”, it’s necessary to add, in correct rates, both the carbon providing salt and the activation salt. Since the carbon potential of these baths vary according to the proportion between the activation and the carbon providing salts, it’s possible to use them in baths with different carbon potentials.

Solid Carburizing (granulates for pack carburizing)

The necessary carbon to promote the carburizing can also be provided by a carburizing granulate. It is a product that, in a certain temperature, generates a gas responsible for the carburizing of steel parts located inside metal boxes made of heat resistant steel and covered by the granulate. These boxes must be covered by a lid (not tight) and then taken into a chamber furnace for heating at carburizing temperature.