Common materials for barrel screw: The most common and […]
Common materials for barrel screw:
The most common and common barrel screw materials in China today are 45 # steel, 40Cr, ammoniated steel and 38CrMOAl. The performance requirements of these materials are introduced one by one, as follows:
1. 45 steel is relatively cheap, cost-effective, and processing function is also good, the only disadvantage is: poor wear resistance and corrosion resistance. Heat treatment: quenched and tempered HB220-270, high-frequency quenching HRC45-48.
2. 40Cr has better function than 45 # steel, but we need to plate a layer of chromium frequently to improve its ability to resist corrosion and wear. However, it has higher requirements for the chrome plating layer. If the plating layer is too thin, it is easy to be abraded, and if it is too thick, it is easy to peel off. After peeling, it will accelerate its corrosion, so it is currently used less. The heat treatment method is: quenched and tempered HB220-270, hard chromium plating HRC> 55.
3. The comprehensive functions of nitrided steel and 38CrMoAl are relatively excellent, and their application functions are also relatively extensive. Generally, the nitride layer is 0.4-0.6 mm. However, this material has a relatively low resistance to hydrogen chloride corrosion and is relatively expensive. Its heat treatment method: quenched and tempered HB220-270, nitriding HRC> 65.
Material requirements of barrel screw:
We know from the extrusion process that the screw is operated under high temperature, certain corrosion, strong wear and high torque. Therefore, the barrel screw must meet the following requirements:
high temperature resistance, no deformation under high temperature; wear resistance, long life; corrosion resistance, material is corrosive; high strength, can accept large torque, high speed; has good cutting function .After the heat treatment, the residual stress is small and the thermal deformation is small.