Barrel & Screw Manufacturing Material For Food and Pharmaceutical Extruder

In all of the Stainless Steel, for our experience, the hardness will be highest after quenching, it is the 440 series of Martensitic Stainless Steel, from the sheet below we can learn, such as the 440C (China corresponding grades is 9Cr18, 9Cr18Mo, 11Cr17), and the 440F (Chinese corresponding grade is Y11Cr17), after quenching, its hardness even will be up to 60~62HRC. If we want to obtain higher hardness and better wear resistance on stainless steel surface, more way is an ion or gas nitriding process after quenching, but a sorbite condition has to be got. 

From below sheet you can witness our experience above.

Since the food extruder and the pharmaceutical extruder are both powdery solid materials or granular solid materials to be fed, compared with the extrusion of ordinary polymer materials, they bear more severe shear wear and matching wear; and because these materials often still contain a certain amount of water or even a certain amount of salt, the barrel and screw are in alkaline corrosion conditions. Therefore, the barrel and screw of food extruder and pharmaceutical extruder need to be resistant to both wear and corrosion specially. Martensitic stainless steel with high corrosion resistance and high hardness has become our first choice for manufacturing the food barrel and screw. 

The hardness of the 440C series stainless steel after quenching can reach HRC58~62, and it has excellent wear and corrosion resistance. It can be suitable for manufacturing that needs to withstand high wear resistance, high load, high torque, and under the action of acid and salt corrosive media, can be made the barrel, screw and die for the food extruder.