1. Nitriding treatment
Nitriding treatment is a method of improving the wear resistance, corrosion resistance and fatigue resistance of the rubber screw of the extruder by forming a nitrided layer with extremely high hardness on the surface of the rubber screw of the extruder. This treatment method is widely used in the surface strengthening of the rubber screw of the extruder.
Function: The nitrided layer can significantly improve the hardness of the surface of the screw, making it more wear-resistant and corrosion-resistant. At the same time, the nitrided layer can also reduce the friction between the screw and the material and reduce energy consumption.
Process: Nitriding treatment usually adopts ion nitriding or gas nitriding technology. The screw is placed in a nitriding furnace, and nitrogen or ammonia and other nitrogen-containing gases are introduced at high temperature to allow nitrogen atoms to penetrate into the surface of the screw to form a nitrided layer.

2. Laser cladding technology
Laser cladding technology is a method of using a high-energy laser beam to melt the coating material on the surface of the screw. This method can form a coating on the surface of the screw that is tightly bonded to the substrate and has excellent performance.
Function: The laser cladding layer can significantly improve the wear resistance, corrosion resistance and fatigue resistance of the screw. At the same time, laser cladding technology can also repair and remanufacture the surface of the screw to extend its service life.
Process: Laser cladding technology usually includes pretreatment, coating material selection, laser cladding and post-processing. In the pretreatment stage, the screw surface needs to be cleaned, rusted and roughened; in terms of coating material selection, it is necessary to select a suitable coating material according to the working environment and performance requirements of the screw; in the laser cladding stage, it is necessary to accurately control the power, scanning speed and thickness of the laser beam; in the post-processing stage, the cladding layer needs to be polished, polished and inspected.

3. Spraying ceramic alloy coating
Spraying ceramic alloy coating is a method of forming a wear-resistant and corrosion-resistant coating by spraying a layer of ceramic alloy powder on the surface of the screw.

Function: Ceramic alloy coating has excellent wear resistance, corrosion resistance and high temperature oxidation resistance. It can significantly improve the hardness and wear resistance of the screw surface and reduce the friction and wear between the screw and the material.
Process: Spraying ceramic alloy coating usually adopts supersonic plasma spraying or flame spraying technology. Before spraying, the screw surface needs to be cleaned and rust-free; during the spraying process, the spraying parameters and coating thickness need to be accurately controlled; after spraying, the coating needs to be ground and polished.

4. Other surface treatment methods
In addition to the above three common surface treatment methods, chemical heat treatment methods such as carburizing, nitriding, and boronizing and surface plating methods such as electroplating and chemical plating can also be used to improve the service life of the extruder rubber screw. These methods can improve the hardness, wear resistance and corrosion resistance of the screw surface to a certain extent.