What is the Difference Between Cyaniding and Carbonitriding?

Cyaniding and carbonitriding are two forms of case hardening processes used to achieve a hard surface on metals. The main differences between these two processes are:

1. Medium: Cyaniding uses sodium cyanide liquid, while carbonitriding uses a gaseous atmosphere consisting of ammonia and hydrocarbons.
2. Temperature: Cyaniding involves temperatures around 871 to 954 °C (1,600 to 1,750 °F), whereas carbonitriding has different temperature ranges depending on whether the part is to be quenched or not. If the part is to be quenched, it is heated to 775 to 885 °C (1,427 to 1,625 °F), and if not, the part is heated to 649 to 788 °C (1,200 to 1,450 °F).

Both processes result in a hardened surface layer on the metal, with cyaniding producing a thinner, harder shell compared to carbonitriding. Cyaniding is particularly used for parts requiring a very thin hard case, such as screws, small gears, bolts, and nuts. Carbonitriding, on the other hand, is a modification of the carburizing process and is also known as dry cyaniding, gas cyaniding, and nicarbing.

Comparative Table: Cyaniding vs Carbonitriding

Cyaniding and carbonitriding are two forms of case hardening processes that are used to harden the surface of a metal while allowing the deeper layers to remain soft. Here is a table summarizing the differences between cyaniding and carbonitriding:

Cyaniding uses sodium cyanide liquid as the medium for the case hardening process, while carbonitriding uses a gaseous atmosphere consisting of ammonia and hydrocarbons. In cyaniding, temperatures range from 871 to 954 °C, and quenching is typically required. Carbonitriding, on the other hand, involves temperature ranges of 445 to 885 °C if the object is to be quenched, and 649 to 788 °C if it is not to be quenched. Quenching is optional in carbonitriding.