Common materials for barrel and screw: Today, the most […]
Common materials for barrel and screw:
Today, the most commonly used and common barrel and screw materials in my country are No. 45 steel, 40Cr, nitrided steel and 38CrMOAl. The performance requirements of these materials are introduced one by one as follows:
1. No. 45 steel is relatively cheap, cost-effective, and has good processing functions. The only disadvantage is that it has poor wear resistance and corrosion resistance. Heat treatment: quenched and tempered HB220-270, high frequency quenched HRC45--48.
2. The function of 40Cr is stronger than that of No. 45 steel, but we should often coat it with a layer of chromium to improve its corrosion resistance and wear resistance. 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 will accelerate its corrosion, so it is currently used less. The heat treatment method is: quenching and tempering HB220-270, hard chrome 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 reaches 0.4-0.6 mm. However, the resistance of this material to hydrogen chloride corrosion is relatively low, and the price is relatively expensive. Its heat treatment method: quenching and tempering HB220-270, nitriding HRC>65.
Conical Twin Barrel screw material requirements:
We know from the extrusion process that the screw operates 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 under high temperature;
2) Wear resistance and long life;
3) Corrosion resistance, the material is corrosive;
4) High strength, can accept large torque, high speed;
5) It has good cutting function; 6) The residual stress after heat treatment is small, and the thermal deformation is small.
