Common materials and requirements for barrel screwCommon materials and requirements for barrel screw
Common materials and requirements for barrel screw
Common materials for barrel screw:
Nowadays, the most common and common barrel screw materials in my country 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, high cost performance, and good processing function, the only shortcoming is: poor wear and corrosion resistance. Heat treatment: quenching and tempering HB220-270, high frequency quenching HRC45-48.
2. The function of 40Cr is stronger than that of No. 45 steel, but we often need to coat it with a layer of chromium 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 worn, and if it is too thick, it is easy to peel off. After peeling off, it accelerates its corrosion, so it is currently used less. The heat treatment method is: quenching and tempering HB220-270, hard chromium plating HRC>55.
3. The comprehensive functions of nitride steel and 38CrMoAl are relatively excellent, and their application functions are also extensive. The general nitride layer reaches 0.4-0.6 mm. However, the ability of this material to resist hydrogen chloride corrosion is relatively low, and the price is relatively expensive. Its heat treatment method: quenching and tempering HB220-270, nitriding HRC>65.
Barrel screw requirements for materials:
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:
1) High temperature resistance, no deformation at high temperature; 2) Wear resistance, long life; 3) Corrosion resistance, the material is corrosive; 4) High strength, acceptable high torque, high speed; 5) Has a good cutting function 6) The residual stress after heat treatment is small, and the thermal deformation is small.