Hardness of steel greatly improves with Cyaniding

Cyaniding is a heat treatment process used to improve the hardness of steel. It involves the introduction of carbon and nitrogen into the surface layer of the steel, resulting in a hard and wear-resistant surface.

1. Introduction to Cyaniding

Cyaniding is a case-hardening process that is commonly used for low carbon steels. It is a surface hardening technique that improves the hardness, wear resistance, and fatigue strength of the steel. The process involves the diffusion of carbon and nitrogen into the surface layer of the steel, creating a hard and wear-resistant outer layer.

2. Process of Cyaniding

The cyaniding process typically involves the following steps:

1. Preparing the steel: The steel is first cleaned to remove any impurities or contaminants from the surface. This is usually done through processes such as degreasing, pickling, or shot blasting.

2. Cyanide salt bath: The steel is then immersed in a bath of molten cyanide salt, which contains a source of carbon and nitrogen. The cyanide salt bath is typically maintained at a temperature of around 850-950°C.

3. Diffusion of carbon and nitrogen: As the steel is immersed in the cyanide salt bath, carbon and nitrogen atoms from the salt diffuse into the surface layer of the steel. This diffusion process occurs due to the concentration gradient between the high concentration of carbon and nitrogen in the salt bath and the low concentration in the steel.

4. Quenching: After the desired diffusion time, the steel is quickly removed from the cyanide salt bath and quenched in a suitable medium, such as oil or water. Quenching rapidly cools the steel, causing the carbon and nitrogen atoms to be trapped in the surface layer, resulting in the formation of a hardened case.

3. Benefits of Cyaniding

Cyaniding offers several advantages for improving the hardness of steel:

1. Improved hardness: The diffusion of carbon and nitrogen atoms into the surface layer of the steel significantly increases its hardness, resulting in improved wear resistance and durability.

2. Case depth control: The depth of the hardened case can be controlled by adjusting the time the steel spends in the cyanide salt bath. This allows for precise control over the hardness and wear resistance of the steel.

3. Cost-effective: Cyaniding is a relatively low-cost process compared to other surface hardening techniques, making it an attractive option for improving the hardness of steel.

4. Versatility: Cyaniding can be applied to a wide range of steel grades, making it suitable for various applications where hardness and wear resistance are essential.

In conclusion, cyaniding is a heat treatment process that greatly improves the hardness of steel. It involves the introduction of carbon and nitrogen into the surface layer of the steel, resulting in a hard and wear-resistant outer layer. Cyaniding offers several benefits, including improved hardness, case depth control, cost-effectiveness, and versatility.