Today there are several technologies for improving the performance of steel, and boriding is one of them. When steel is borided in molten salts, the surface layer of the metal becomes saturated with boron. Boriding is commonly used for ploughs, ploughshares and other parts, as well as for stamping and cutting tools, because it produces stronger, harder metal with increased wear resistance.
Main boriding methods:
Surface boriding increases the wear resistance of steel in aggressive environments and at temperatures up to 800 °C. The main boriding methods include:
- salt bath boriding
- gas boriding
- electrolytic boriding
Liquid boriding
A barium chloride bath consists of a melt based on borax with the addition of manganese silicate, boron and sodium chloride. The temperature of the mixture is 900 °C. In liquid boriding, the treatment depth does not depend on the shape of the surface, and the method makes it possible to obtain a layer up to 0.2 mm thick.
Gas boriding
Gas boriding technology ensures stable and uniform penetration of boron into the surface layer of steel under the action of a boron-containing gas. This type of boriding is carried out at 850 °C in gases containing boron hydrides, halides and oxides. At high temperature, atomic boron diffuses into the metal surface and covers it with a thin film.
The drawbacks of gas boriding include a high risk of explosion and fire, so safety regulations must be strictly followed during the process.
Electrolytic boriding
Electrolysis can significantly reduce boriding time in a barium bath. Electrodes are installed in the bath, and an electric current is passed through them. The current flowing through the melt at 900 °C releases atomic boron, which penetrates the surface layers of the steel and forms a protective film that strengthens the metal.
Boriding slightly changes the dimensions of parts, so they need to be machined, ground and polished afterwards.
The wide range of boriding methods makes it possible to choose the best option for steel tools and parts and obtain strong, wear-resistant products as a result.
Need boriding for steel parts?
Karbaz provides boriding of parts to form a hard protective layer and improve the wear resistance, corrosion resistance and heat resistance of the surface.