Introduction of the screw in the screw pump

According to the solid transport theory, tapering and longitudinal grooves are machined on the barrel wall of the charging section and intensive cooling is performed, which greatly improves the solid transport power. If the structure of the cylinder used in this way, when planning the screw must be in the melting section and the homogenization section to adopt the appropriate method so that the melting rate, homogenization and feeding section can be consistent with the delivery.

Screw pump contains three screw pump and single screw pump and twin screw pump, the internal structure is inseparable from the screw on the screw we know not many, what is the most durable screw? At present, China's commonly used screw material 45 steel, 40Cr, ammoniated steel, 38CrMOAl and so on.

1) 45 steel cheap, good processing, but poor wear-resistant corrosion-resistant. Heat treatment: tempered HB220-270, high frequency quenching HRC45--48

2) 40Cr better than 45 steel, but usually to be coated with a layer of chromium, in order to improve its corrosion-resistant wear-resistant ability. However, the demand for chrome layer is higher, the coating is too thin and easy to wear, it is easy to fall off when it is too thick, but corrosion is accelerated after it falls off, which is less used at present. Heat treatment: tempered HB220-270, hard chrome plated HRC> 55

3) Nitrided steel, 38CrMoAl excellent comprehensive function, the use of a wide range of contrast. Nitride layer is usually 0.4-0.6 mm. However, this information against the corrosion of hydrogen chloride is low, and offers higher.