The surface decarbonization of special steel is a key process in metallurgical production. It is an important measure to improve the cleanliness, corrosion resistance and fatigue strength of the steel. On the other hand, the decarbonization process is of great importance for the subsequent processing of the steel, such as cold-forming, heat treatment, welding, etc.
In general, the surface decarbonization of special steel includes three steps: mechanical decarbonization, chemical decarbonization and heat decarbonization. During the mechanical decarbonization process, the steel is ground, sanded, pickled or blasted by a medium such as corundum powder, ferro-silicon powder, etc. These methods can effectively remove the oxide layer on the surface of steel and reduce the decarburization depth to certain extent.
Chemical decarbonization uses chemical means to remove carburization. Commonly used chemical solution is obtained by mixing sulfuric acid, hydrochloric acid and nitric acid in a certain proportion. Generally, this solution can effectively decompose the surface of steel and avoid excessive decarbonization caused by coarse mechanical equipment. In addition, the chemical solution has a certain inhibition effect on the oxidation layer.
Heat decarbonization is the most widely used process for surface decarbonization of special steel. In this process, the steel is heated up to a specific temperature. The decarbonizing agent reacts chemically with the steel surface, which leads to an exothermic reaction that accelerates the surface decarbonization process. Generally, the corrosion resistance and fatigue strength of special steel can be improved significantly by heat decarbonization.
In order to ensure the quality of the decarbonization process, it is necessary to strictly control the carbon content and the surface thickness of the steel. Generally, the carbon content of the steel surface should be less than 0.03%, and the surface should be less than 0.2mm. In addition, different steel grades have different decarbonization temperatures, and the temperature should be strictlycontrolled during the decarbonization process.
In conclusion, surface decarbonization of special steel is an important process to ensure the cleanliness, corrosion resistance and fatigue strength of the steel. With the development of metallurgical technology, various efficient and environmentally friendly decarbonization methods are emerging. In the production process, special steel manufacturers should fully understand these methods and strictly control the quality of decarbonization process, in order to obtain higher quality special steel products.
