Weirui Screw, Barrel and Front End Components Material Selection Table
Products Grade Material Applications
Barrel Nitrided SACM645, ACM2, 38CrMoAL
(Chromium/Molybdenum/Aluminium alloy steel, Nitided HRC >68, T0.5mm )
For most Rubber materials :
Natural Rubber, Synthetic Rubber,
Liquid Silicon Rubber
Screw Nitrided SCM440, ACM2, 42CrMo, 38CrMoAL, DH2F
(Chromium/Molybdenum/Aluminium alloy steel, Nitrided HRC >63,T0.08mm)
Plunger Nitrided SCM440, ACM2, 42CrMo, 38CrMoAL, DH2F
(Chromium/Molybdenum/Aluminium alloy steel, Nitrided HRC >63,T0.08mm)
End Cap SACM645, SCM440, SUS440C, H13 (SKD61) with optional Gas/Plasma Nitriding, Chroming 
Nozzle Tip SACM645, 1.2379, SCM440, SUS440C, H13 (SKD61) with optional Gas/Plasma Nitriding, Chroming