What screws are used with Bimetallic Screw Barrel

2022.12.06
They specialize in manufacturing and exporting screws and barrels to customers worldwide. In addition to screws and barrels, they also offer various other services.The barrels are also available in various sizes. They are ideal for pelleting and extrusion. They can also be used in engineering plastics. The cost of manufacturing these barrels is higher than nitrided screws. However, they offer a long useful service life.Historically, nitriding has been used as a treatment for screws and barrels. This technique is used to improve corrosion resistance and increase peripheral toughness. It replaces the use of chemical coatings such as bluing and galvanizing.Nitriding is not a process that can be applied to all types of screws.

Twin extruder Bimetal screw and barrel
Twin extruder Bimetal screw and barrel
The bimetallic barrel for single screw extruder is a kind of barrel spray 2-5mm thick alloy coat on the barrel inner wall which has excellent corrosion resistance, abrasion resistance and high working temperature. And its useful service life is greatly improved contrast to common nitrided barrel. Bimetal has more obvious advantages when processing special plastics to enhance the abrasion life, such as engineering plastics, fluoride plastics, PPO etc. Our company use special alloy powders being sprayed and welded on the top of screw flights, and use different alloys and welding methods.


However, the hardness of a Bimetallic screw barrel is much higher than that of untreated steel. The nitrided layer is also abrasion resistant. However, its wear resistance is not as high as that of a bimetallic screw barrel. This treatment method is still in its early stages, so it is not recommended for use with corrosive resins or in applications that require high strength.The nitriding process involves the diffusion of nitrogen atoms into the surface of steel. This is achieved by heating the steel in a nitrogen atmosphere. The nitrogen atoms combine with nitride forming elements to form a very hard surface.Choosing the right lining for your bimetallic screw barrel can be a critical decision. A good lining can provide excellent wear protection and corrosion resistance.

Depending on your application, you may choose from a variety of cost/performance options.The first step in selecting a lining for your bimetallic screw barrel is to determine its application and operating conditions. These conditions will affect the length of time you will need to service the liner and how much you will need to pay for the liner.You can choose a lining that meets your needs by considering how much wear you expect to experience and what type of lining will best protect your equipment. Depending on your application, you may also choose a liner that is compatible with various screw finishes.Screw Company has developed a bimetallic screw barrel sleeve fitting technology. This technology helps in extending the life of bimetallic screw barrels. It is designed to improve the performance of PVC processing machinery. It provides abrasion resistance and also helps in increasing the production rate.A bimetallic sleeve is a layer of alloy powder that is molded and cladded to the screw. The layer can range from 0.025 mm to 25 mm in diameter.

It is usually made of HSS or tool steel. It can be coated by different techniques. It is also called an Internal Lining.The outer sleeve is mounted to the inner rifled liner tube 10. It provides compressive forces and improves the dynamic stability of the barrel. It can be mounted by mechanical mounts.Generally, there are three screw sections, namely, the metering section, the compression section and the mixing section. The metering section is located before the die restriction, whereas the compression and the mixing section are located at the discharge end.The metering section produces the highest temperature within the extruder. It also produces the highest shear rate. It is also the shortest section. The shortest section is the free flight. However, the free flight is not as powerful as the others.The compression section is longer than the others. It is typically made of an annealed alloy steel. It taper abruptly at the discharge end. It is a good choice for crystalline plastics, which have a low viscosity.