Screw barrel material selection


Just like a screw, in order to meet the working require […]

Just like a screw, in order to meet the working requirements of the barrel, it must be made of high-quality materials with high temperature resistance, wear resistance, corrosion resistance and high strength. These materials should also have good machinability and heat treatment properties. In addition to 45 gauge steel, 40Cr, 38CrMoAL, the cylinder can also be made of cast steel and ductile iron. The bushing feed section can be made of high quality cast iron.

With the development of high-speed extrusion and engineering plastics, especially when extruding glass fiber reinforced plastics and plastics containing inorganic fillers, higher requirements are placed on the wear resistance and corrosion resistance of the cylinders. Xaloy alloy developed by the United States, the United States and other countries is a novel wear-resistant, corrosion-resistant material, which is widely used abroad. This material has a low melting point, is hard, has good weldability with steel, has good machinability, good casting performance, and no casting stress. Even if it is bent after casting, it will not fall into scales.

Applying it to the barrel is a method in which the powdered Xaloy alloy and the barrel are heated together at a high temperature, and because of its low melting point, it can be melted into a flowing state at about 1200 ° C. The barrel rotates at a high speed, and the huge centrifugal force generated by the molten Xaloy is cast on the inner wall of the red hot cylinder, and its thickness is about 2 mm. After cooling, it is ground by grinding to about 0.20 mm. General barrel requirements. The hardness value can reach Rc58-64. At 482 °C, the hardness does not decrease significantly, and the corrosion resistance is 12 times larger than that of nitriding steel.