Formulation of Water-Soluble Carburizing Liquids
Carburizing liquids are used to enable the surface of metals to meet design requirements. These liquids are designed to increase the surface carbon content of the metal, which provides strength and durability.
There are two major types of carburizing liquids: molten salts and water-soluble solutions. In this article, we will focus on the formulation of water-soluble carburizing liquids.
Water-soluble carburizing liquids are composed of aqueous solutions of carburizing agents such as salts, acids or bases. The most commonly used salts are potassium cyanide, chromium chloride, lead chlorocyanide, and lithium carbonate. The most common acids are hydrochloric, nitric and sulfuric. The most commonly used bases are sodium hydroxide and potassium hydroxide.
The carburizing agents in the solution are kept in balance by carefully controlling the pH. This is done by adding a buffer such as sodium carbonate, which helps maintain a constant pH. The amount of carburizing agent in the solution is also important for proper carburization of the metal. Typically, a solution should contain 2 to 3 percent carburizing agent.
A chemical stabilizer is also often added to the solution to ensure that the carburizing liquid does not deteriorate over time. This is especially important if the solution is stored for long periods of time. Common stabilizers include borax, citric acid or boric acid.
The carburizing solution is heated to the desired temperature before use. This can be done in two different ways. One way is to heat the solution in a tank or container using a recirculating hot water system. Another option is to heat the solution on a plate or rack using an electric heater.
Once the solution is heated, it is ready to use. The part to be carburized is submerged in the solution and allowed to react. Depending on the material and desired carburizing depth, the process can take several hours or even days. Once the process is complete, the part is removed and soaked in a water bath to remove any remaining carburizing agent.
In summary, a formulation for an effective water-soluble carburizing liquid consists of an aqueous solution of carburizing agents, a buffer to maintain a constant pH, a stabilizer to ensure the carburizing liquid does not deteriorate, and heating prior to use. With a well-formulated carburizing liquid, carburization processes can be successfully completed to meet design requirements.
