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What is the bimetal screw barrel

Update:Dec 10,2021

In bimetal products, two metals are Nitriding screw barrel fixed together, rather than mixed together. The mixture of two (or more) metals is called an alloy.Screw barrel with bimetallic characteristics. The bimetallic screw barrel is made of two metals or two metal alloys, most of which are coated with additional carbide layers and other commercial coating materials.The Bimetallic Screw Barrel is not a different type of screw barrel, such as advanced design. Screws of the same design can be manufactured by nitriding and bimetallic methods.Many customers ask us to give them a bimetal screw when they have questions about their screw design (not made by us) because "someone" told them to use a bimetal screw. Bimetal screw is used to increase the life of screw and barrel, because bimetal has better effect than single metal.If you are looking for a screw barrel with advanced design, such as super torque, super speed and high output, please contact our RD team or read more pages on this website. We make screw barrels according to your needs.

The advanced design screw barrel can be made of nitrided steel single or bimetal  according to the customer's budget.Thermal spray coating method and difference of bimetal screw barrel.The bimetallic screw barrel is made of two alloys  first as the base material, and second as the coating material, so they have a longer life than single metal steel.But this is not the case in all cases. For example, Raj Engineering Works uses D2 grade tool steel single metal to manufacture screws up to 1250 mm so the life of these screws is the same as that of bimetal screws (2 of nitrided steel). To 5 times), depending on compounding and processing technology.Moreover, these High-Life D2 grade screws of our company can be coated with any cermet to improve wear resistance, but they are still not bimetal screws. Because carbide is neither a metal nor a metal alloy. For example, tungsten carbide is a composite material called cermet. Tungsten is metal the hardest, and cemented carbide is ceramic.

When the two are mixed in different proportions  tungsten and 88% tungsten)the mixture is called tungsten carbide chemical formula. This composite mixture It is called cerm.The bimetal screw barrel is used to increase the service life of the screw barrel, not to increase the output and quality of the final product.The plastic/rubber/food/chemical processing feed screw barrel is basically a circular threaded metal shaft with strict tolerances. Due to the harsh and high-pressure environment, they are always at risk of wear or corrosion. This is why the screw and barrel are made of selected grades of steel and undergo surface hardening and nitriding treatment to solve these problems. But usually this is not suitable for abrasive material processing and high pressure environments, such as glass fiber fillers, calcium carbonate fillers, harsh additives, fluoropolymers, plastic recycling, elastomer compounds, high-speed and large-size drums.

Once the screw is worn out, it will cause many problems in the processing process, such as lower quality of the final product, low output, and high energy consumption. At this time, we replaced the old screw barrel with a new barrel. But this will cause downtime. Now where the downtime is most important, we must arrange some other innovative solutions to stop the frequent replacement of the screw and barrel. Sometimes, cheap nitrided screws (not properly nitrided) will wear out even 6 months ago.Therefore, single steel (nitriding) is easy to wear. The industry has developed many grades of performance steel alloys for specific functions and requirements, but they are very expensive. Using a specific performance grade or high-temperature alloy to manufacture a complete screw barrel may result in a cost that is 6 to 8 times that of a nitrided screw. Why? Because high-temperature alloys and other performance alloys require special processing, they require more time for milling than 4140 or En41b or 38CrmoAlA nitriding steel.